How to Successfully Implement a Robotic Welding System
In today’s marketplace, companies continue to automate portions, if not all of their welding operation. The reasons are many: to address a shortage of skilled labour, to improve quality, to decrease waste and rework, and/or to increase productivity — in short, to seek benefits that provide a competitive edge.
Not all companies, however, are successful in the process. Those beginning without a well-thought-out roadmap risk losing valuable time during implementation and operation and may miss the full benefits provided by a robotic welding system.
Conversely, companies that begin with a careful examination of their welding needs and existing processes — and develop a detailed plan with clearly established goals — are more likely to achieve success. Planning should include an accurate assessment of parts, work flow and the current facility, as well as an evaluation of the potential return on investment (ROI).
Companies should not only look at current needs, but also consider future opportunities to determine the best robotic welding system to scale for potential growth or changes to products they may produce later.
Why robotic welding?
In an economy where orders are increasing and welding positions are hard to fill, robotic welding can help maintain or increase productivity. In a semi-automatic welding operation, labour accounts for approximately 70 to 85% of the total cost of welding a part. A robotic welding system can reduce that cost and increase throughput by completing the work of two to four people in the same amount of time — however, companies still require skilled welding operators to oversee the robotic cell.
In addition, the national and international marketplace has become increasingly competitive, with companies seeking contracts from any number and any size of business. Investing in welding automation can help set up a company on the path to compete at a global level.
Here are additional benefits:
1. With the right robotic welding system, companies can improve first-pass weld quality and reduce the amount of rework or scrap parts. Depending on the welding wire and mode used, the system may also minimize or eliminate spatter, which reduces the need to apply anti-spatter compound or perform post-weld clean up.
2. A robotic welding system can reduce over-welding, a common and costly occurrence associated with the semi-automatic process. For example, if a company has welding operators who weld a bead that is 1/8-inch too large on every pass, it can potentially double the cost of welding (both for labour and for filler metals). Over-welding may also adversely affect the integrity of the part.
3. Companies can reallocate skilled employees to other production areas to fill open positions and gain additional productivity and efficiencies.
4. Welding automation can also provide a competitive advantage as it may be considered attractive to customers. The improvement in quality may prompt new customers to place orders or lead existing customers to increase their orders with the objective of growing their own businesses.
5. Finally, robots are fast. They don’t have to weld all day to be profitable. That fact improves productivity and the bottom line by making the same number of parts as in a semi-automatic process in less time.
Repeatability is key
When considering an investment in a robotic welding cell, companies should have part blueprints, preferably in an electronic format. Without a blueprint, the part likely won’t meet the basic criterion necessary to ensure repeatability during the manufacturing process.
A robotic welding system welds in the same place every time. When a part’s tolerances are unable to hold its position — if there are gap and/or fit-up issues — the company will simply be automating a broken process. This can increase rework or scrap.
If a company currently relies on its welding operators to compensate for fit-up issues, it will need to look upstream in the manufacturing process to establish consistency. What processes need to change so these welding operators send uniform parts downstream? Or, if vendors supply the parts, can they guarantee consistency?
Assess the workflow
A streamlined workflow is one of robotic welding’s benefits. To achieve it, companies need to look beyond the weld cell, making certain the facility can accommodate a smooth flow of materials. It makes little sense, for example, to invest in a robotic welding system to increase productivity, but then place it in a corner where employees may have to handle each part multiple times.
There should be a consistent supply of parts to avoid moving a bottleneck from one area to another. It is also important to look at the expected cycle time of the robot. Can personnel supply parts to keep up with the demand of the robot’s cycle time? If not, the supply of parts, including where the company stores them and how it moves them, will need to be adjusted. Otherwise, a robot will sit idle waiting for components to come down the line.
Robotics or fixed automation?
There is no single welding automation solution that is best for every company. When a company is considering the investment, it should factor in the expected lifetime of the job, the cost of tooling and the flexibility the equipment offers.
Fixed automation is the most efficient and cost-effective way to weld parts with simple, repetitive, straight welds or round welds, where the part is rotated with a positioner. If a company wants to reuse the equipment when the current job ends, however, a robotic welding system offers more flexibility. A single robot can store programs for multiple jobs, so it may be able to handle the tasks of several fixed-automation systems.
There is a certain volume of parts that justify the investment of welding automation for each company. An accurate assessment of goals and workflow can help determine what that volume is. If a company makes only small runs of parts, robotic welding becomes more challenging. But, if a company can identify two or three components that can be automated, a robot can be programmed to manufacture those parts, offering greater versatility and boosting productivity. This may benefit even small companies that may not have significant volume of a single part.
Although a robot is more expensive than a fixed-automation system, it is important to consider the cost of the tooling before deciding between the two. Fixed automation systems can become quite expensive if they require extensive changes to retool a new part so it can be welded consistently.
Consider the available space
The physical footprint for a robotic welding system and the area needed for parts to flow into the welding cell is typically greater than that of a semi-automatic welding operation. The available space needs to be adequate for the robot, welding power source and other equipment. This helps minimize the need to customize products, such as cables, nozzle cleaning stations (or reamers) or the robotic MIG gun to fit the work envelope.
A company with less space can still make welding automation work. One option is to purchase fewer pieces of robotic welding equipment that are capable of performing multiple tasks, such as material handling or vision/scanning systems.
A third-party integrator can help determine whether a facility suits the installation of a robotic welding system. System integrators are knowledgeable about facility modifications, including important safety regulations that apply in a company’s region, country or state — in addition to those specified by OSHA and RIA (Robotic Industries Association).
Integrators and equipment selection
In addition to offering advice on facility modifications and helping a company select the right robot, a robotic systems integrator or welding automation specialist can:
1. Help determine if parts are suitable for automation, and, if not, what is required to make them suitable
2. Analyze the workflow and facility to identify potential roadblocks
3. Analyze the true costs involved with the investment, including facility updates and tooling
4. Determine the potential payback of the investment
5. Help identify goals and develop a precise plan and timetable to achieve those goals
6. Explain automation options and help select those that best fit the company’s needs
7. Help select a welding equipment that has the flexibility to maximize travel speed, minimize spatter, eliminate over-welding, provide great arc stability and increase first-pass weld quality
Integrators can also help select additional equipment for the robotic welding cell, including positioners, tooling, the robotic MIG gun, welding wire and peripherals. Each item serves a distinct function.
The positioner turns, rotates or otherwise moves the part into an optimal position for welding. In many cases, this involves moving the part so that the system can weld in a flat position for optimal deposition efficiency. A positioner can also allow for coordinated motion between the robot and weldment.
The tooling holds the part in place during welding and is a critical component of a robotic welding system. The robot arm and robotic MIG gun travel a programmed path each cycle. If the weld joint is out of place because the part is misaligned, it can result in inadequate fusion or penetration and rework or scrap. It is important to design the tooling correctly upfront when investing in a robotic welding cell and monitor it for mechanical wear or heat distortion once it has been put into operation. This helps ensure consistent part fit up so that weld quality doesn’t suffer.
The robotic MIG gun should never be an afterthought when considering an investment in welding automation, nor should the welding wire. Both can have a significant impact on productivity and profitability. An integrator can help with the selection based on how the gun and wire perform in conjunction with the rest of the system’s components. The gun will be subject to intense heat and spatter, so it must be durable. It also needs to be the appropriate size to maneuver around the tooling and gain proper joint access.
Finally, peripherals, such as reamers, an anti-spatter sprayer and wire cutter are good options to discuss with an integrator prior to making the investment in welding automation. These devices can improve uptime and welding performance by keeping the welding gun consumables free of spatter, operators out of the weld cell and providing consistent wire stickout during welding.
Employee training
Companies cannot simply purchase a robotic welding system and let it go. They need a welding operator or other employee skilled in robotic welding programming. This will likely involve additional training to upgrade his or her skill sets. The good news is, programming a robot today is much quicker than in the past. Simplified teach pendants, along with the availability of desktop programming, help expedite the process and reduce downtime. Despite the ease of programming, however, companies may need to alleviate some existing tasks to allow time for the employee to oversee the robotic welding cell without becoming overloaded with too many responsibilities.
Most robot OEMs offer a weeklong training course explaining how to operate the equipment. This course, followed by a week of advanced programming, is recommended when implementing welding automation.
Justifying the expense and calculating payback
If the personnel investigating the prospect of robotic welding determine it’s a good fit, they will likely need to justify the investment to upper management or an owner. Calculating the potential payback is essential. There are several steps to consider.
First, determine whether the volume of parts the company needs to produce requires the speed of welding automation. Remember, the key benefit of a robotic welding system is the ability to produce high volumes of quality welds or in smaller facilities to offer the flexibility to weld smaller volumes of multiple parts.
Calculate payback by assessing the current volume of semi-automatic parts and cycle times. Compare these to the potential cycle times of a robotic welding system. Again, an integrator or welding automation specialist can help. Establishing the comparison is critical to estimating the potential return on investment.
That said, even if a company will produce the same number of parts with a robot, it could justify the investment by the amount of labour it can reallocate elsewhere in the operation for jobs that boost production, eliminate bottlenecks or increase quality. For example, a company could utilize the skills of semi-automatic welding operators to complete challenging welds that are too complicated for a robot to manage.
It’s important to factor the bulk cost of shielding gas and welding wire when looking at the potential payback. While there is an initial cost for a shielding gas/manifold system, it can help optimize a company’s robotic welding capabilities in the long term by minimizing downtime for cylinder changeover. The same is true for welding wires. The larger drums — typically ranging from 500 to 1500 pounds — can further reduce costs in a robotic welding cell since they require fewer changeovers and often come with purchasing discounts.
Companies need to keep in mind that the benefits of robotic welding can be significant. However, those benefits come at an upfront price. Many companies, especially smaller ones or those that frequently change production lines, need a faster payback — no more than 12 to 15 months is common to justify the investment. If a company will have the same production needs for many years, it can typically justify a longer payback period. Management and owners should discuss their payback goals with a trusted robotic welding integrator as part of the assessment process.
Robotic welding systems continue to gain in popularity due to their ability to increase productivity, improve quality and decrease costs in the right application. But they also offer a way to address a shortage of skilled labor for manual operations. Welding automation provide companies with a means of staying competitive in a demanding marketplace, while using their existing and potential workforce to oversee the weld cell. With more and more robotic welding systems being implemented — the Robotics Industries Association (RIA) cited that 20% of all industrial applications had robotic welding cells as of 2017 — comes the need for increased attention to safety. From the robotic welding gun and peripherals to the robot itself, following safety best practices is essential. Statistically, welding automation is safer than manual or semi-automatic welding. However, operators overseeing the robotic welding cell must still remain vigilant. This is particularly true when performing nonstandard operations; these include programming, maintenance and any other tasks that involve direct human interaction with the robot. Conducting a thorough welding risk assessment helps identify potential safety hazards associated with a specific robotic welding system (whether it is a pre-engineered or custom cell) and is a critical first step in establishing a safer welding environment. This assessment provides a baseline for implementing solutions for identified risks and establishing appropriate welding safety training. In addition, it helps companies maintain compliance with safety standards, which most importantly protects employees but also protects the bottom line. Noncompliance and/or safety violations that can lead to injury become can be costly in terms of fines and workers’ compensation. Companies can obtain welding safety resources through the American Welding Society (AWS), including Safety in Welding, Cutting, and Allied Processes, ANSI Standard Z49.1, a free download at aws.org. The National Fire and Protection Association (NFPA) also offers resources. RIA follows American National Standards Institute (ANSI) standards and offers safety seminars and webinars. RIA also provides information on industrial machinery and guarding, as well as guidelines to help companies, including the American National Standard for Industrial Robots and Robot Systems – Safety Requirements, ANSI/RIA R15.06-2012. The Occupational Safety and Health Administration (OSHA) is another valuable safety resource. Many robotic welding integrators or robotic welding system manufacturers offer training for the safe use of their equipment, including how to test safety functions and at what frequency. They also provide manuals and safety standards for their systems. It is critical to read and follow these thoroughly. Manufacturers of robotic MIG welding guns often integrate design elements into these products to aid in their safe use. These elements are intended to protect operators during routine maintenance and minimize or eliminate the need to enter the weld cell to complete tasks. For example, guns that are compatible with front-loading liners help improve safety in a robotic welding cell. These liners can be installed from outside the weld cell — there is no need to climb over tooling or maneuver around the robot to complete replacement. Operators or maintenance personnel also don’t need to remove electrical connections to replace components during the process. An insulating disc is another important safety feature in select guns. It helps protect operators from the welding current during maintenance and protects the robot from the current, limiting potential damage. In addition to integrated safety features, there are some key best practices for working with robotic welding guns, consumables and reamers (or nozzle cleaning stations). First and foremost, always de-energize the robotic welding system when installing a robotic MIG gun or consumables, and follow all lockout/tagout procedures. When possible, it’s ideal to have a window or opening that allows consumables to be changed or inspected from outside the weld cell. When possible, it’s ideal to have a window or opening that allows consumables to be changed or inspected from outside the weld cell. If this isn’t feasible, programming the robot to stop near the weld cell door simplifies consumable changeover and eliminates the need for the operator to enter the cell, maneuver around tooling or climb on anything to complete the job. The appropriate personal protective equipment (PPE) is also important when changing over consumables or the welding wire. The nozzle and contact tip may be hot, and there is the risk of the welding wire puncturing the operator. Leather or other thick work gloves are a must, and safety glasses should be worn at all times. Always use the proper tool to change over the nozzle and contact tip. We recommend a pair of welpers. When performing maintenance on a reamer, begin by resetting the equipment to a home state, de-energizing it and following lockout/tagout procedures. Be certain there is no supply of air or electricity to the reamer. When changing over cutter blades, always wear gloves and use two wrenches to remove and install them. Reset the reamer to a home state when finished. This is an important last step, as the reamer will automatically complete a cycle as soon as it receives a start signal and is reenergized. Welding operators and maintenance personnel should familiarize themselves with the emergency stops on a robotic welding system as a first safety step. The number and location of these stops varies by system. For example, welding cells typically have an operator station emergency stop that ceases all robot functions and turns off the robot servo power, along with an emergency stop on the teach pendant. Operators should test these emergency stops periodically, although testing too frequently is stressful on the mechanics of the robotic welding system. Understanding brake release procedures is also critical. RIA sets standard requirements for these; however, every robotic welding system is different, and the location of the override buttons may vary. As when interacting with a robotic MIG welding gun, consumables or reamer, always follow proper lockout/tagout procedures before entering the robotic welding cell. Many systems have multiple lockout/tagout locations that are indicated by stickers. Some pre-engineered welding cells feature sliding programming access doors with magnetic keys that indicate that they are fully open and ready to be locked out prior to maintenance, helping to prevent pinch points or a trap hazard. A built-in awareness barrier in pre-engineered cells is another means of aiding operator safety. This hooped barrier inside the weld cell covers the sweep area of the indexing table. Its purpose is to protect the operator from pinch points during teaching operations by separating the him or her from the space between the robot and the wall of the weld cell. For robotic systems that are not enclosed, guards around the cell are necessary. These can take the form of physical barriers, like perimeter fencing or light curtains and/or electronic guarding such as area scanners that stop the robot when an operator is present in a specific area of the system. Lastly, robotic integrators and robotic welding system manufacturers provide risk assessment documentation, typically in the operator’s manual. It is important to review this assessment thoroughly and train employees on the proper techniques to mitigate any identified risks. For example, programming the robot introduces mechanical hazards such as the potential for pinching or impact, which can be addressed by standing a safe distance outside of the weld cell or by using a slower teach speed if offered on the teach pendant. In addition to the best practices outlined for robotic MIG welding guns, consumables and systems, there are steps to further protect employees. Safety in welding automation should be top of mind among operators, management and maintenance personnel. Ongoing training needs to be a priority, whether it is conducted through company programs or seminars offered by outside resources. The goal is to ensure that everyone involved with the robotic welding system is playing an active role in employing best practices. When following them properly, the result is a safer work environment and a stronger bottom line.
MIG welding gun configurators, like the Bernard® BTB semi-automatic air-cooled MIG gun configurator, allow you to choose specific styles or types of consumables to match the demands (amperages and waveforms) of your application. Know the wire size and type when choosing the size and style of contact tip. Joint access, operating temperatures and arc-on time are important considerations in choosing the right welding nozzle. Having the right MIG gun liner helps minimize downtime to address wire feeding issues. It is important that you always trim the liner to the proper length. Consider these tips: Note, selecting the same welding consumables across multiple weld cells, when possible, can help with inventory management and can be more cost-effective. Visit the Bernard® MIG gun configurators
In addition to the amperage of MIG welding gun you choose, the MIG gun parts — cable, neck and handle — affect how comfortably and efficiently you can weld. Configure your gun accordingly. Cable lengths can vary greatly — from 10 feet to 25 feet or longer. Use the shortest cable possible that can get the job done to prevent kinking or creating a tripping hazard. Consider your options: Remember, smaller welding wire sizes typically call for a shorter cable; it is more difficult to push a smaller wire over a greater length. It is also more difficult to push soft wires, like aluminum, through longer cables. Choosing a neck and handle for a MIG welding gun comes down to your preference, as well as the available weld cell space and the welding wire. The bottom line: Choose the options that make it easiest and most comfortable for you to reach the weld joint. Configure a Bernard® semi-automatic MIG gun This article is the second in a three-part series discussing how configuring a MIG gun can improve the welding operation, as well as what to consider in the process. Read article one, Configuring a MIG Welding Gun for Your Application and article three, Selecting the Right MIG Welding Consumables.
Have you struggled to gain proper joint access when welding? Or found yourself fatigued at the end of the day because of repeatedly welding in awkward positions? Configuring a MIG welding gun can help. A MIG welding gun configured for the exact application can maximize efficiency and productivity. When you are more comfortable, you are able to weld longer. A customized MIG welding gun also reduces downtime for assembly, since it’s ready right out of the box. You can configure each welding gun part with online configurators like those from Bernard. These parts include the: To configure the right MIG welding gun, look at the needs of your welding application. One answer influences the next choice. The physical space of the weld cell factors into MIG welding gun configuration. Consider these factors: Taking the time to consider the factors that impact how you configure your MIG welding gun can go far in ensuring you have the exact one for your application. See options for configuring a Bernard® MIG gun This article is the first in a three-part series discussing how configuring a MIG gun can improve the welding operation, as well as what to consider in the process. Read article two, How to Choose Welding Gun Parts, and article three, Selecting the Right MIG Welding Consumables.
MIG welding consumables are a critical but often overlooked part of the welding operation. Unfortunately, without a clear understanding of the problems that can arise with consumables — and the best way to fix them — companies stand to lose productivity, jeopardize quality and increase costs. In some cases, the biggest issue is choosing the wrong consumable for the job. Consider this real-life example: A company with 90 arcs is using five contact tips per day, per welder — that adds up to 450 contact tips a day. By simply changing to a more robust consumable system, the company could potentially use one contact tip per welder every three to four days. The savings in reduced downtime and purchasing costs in this situation is significant. So how can companies avoid common pitfalls? A willingness to look at the impact of welding consumables on the overall operation — not just the product purchase price — is key. Training is also a vital part of success. Welding operators and maintenance personnel should know how to properly select, install and maintain consumables and troubleshoot problems when they arise. Or better yet, understand how to prevent them in the first place. Welding nozzles play an important role in the welding operation, directing shielding gas to the weld pool to protect it from contaminants. Incorrect contact tip recess within the welding nozzle is among the biggest problems. The more the contact tip is recessed, the longer the wire stickout, which can lead to an erratic arc and increased spatter in the nozzle. It can also negatively impact shielding gas coverage. In approximately 90% of applications, a 1/8-inch contact tip recess provides the best shielding gas coverage with a welding wire stickout that helps support consistent arc stability. Using the wrong welding nozzle for the application can cause downtime for changeover due to premature failure. For a standard welding application (100 to 300 amps), a copper nozzle provides good heat resistance. Copper nozzles also resist spatter buildup. For higher-amperage applications (above 300 amps), a brass welding nozzle is the better choice. Brass does not anneal as fast as copper, so the welding nozzle will maintain its hardness longer under higher temperatures. Choosing the wrong shape and size of nozzle can be problematic. Too large of a nozzle can make it difficult to obtain the joint access needed to complete a sound weld. Long or short tapered nozzles work well for restricted joints. However, there is an increased risk of spatter buildup due to the narrower bore, which can shorten the consumable’s life. To gain good gas coverage, use a longer nozzle when possible. MIG welding contact tips provide the current transfer to the welding wire to create an arc. Using a contact tip with an inside diameter (ID) that’s too small can lead to poor wire feeding and, potentially, a burnback. Using a tip with too large of an ID can cause the welding wire and arc to wander. Every consumables manufacturer has proprietary formulas for gauging contact tip ID and implementing it into their design. Select a high-quality contact tip for consistent tolerances, and match the contact tip ID to the diameter of the welding wire to gain the best electrical conductivity. This happens because the contact tip ID is actually slightly larger than the specified measurement. For example, pairing a contact tip with an ID of 0.035 inch and a wire with the same diameter allows the wire to feed smoothly through the bore, connecting enough to generate a stable welding arc. The wrong contact tip outside diameter (OD) can also cause problems. For higher amperage applications, use a contact tip with a larger OD to better withstand heat. 1. Copper contact tips provide good thermal and electrical conductivity for light- to medium-duty applications. 2. Chrome zirconium contact tips are harder than copper ones and are good for higher-amperage applications. They are also a good option if a company experiences ongoing instances of keyholing — oblong wear on the bore that can lead to an unstable arc and premature contact tip failure. 3. Contact tips are available in the marketplace that feature proprietary materials and design. These tips cost more than copper or chrome zirconium contact tips but have been shown to last more than 10 times as long. They are designed for pulsed, spray transfer or CV MIG welding. Cross-threading the contact tip is another issue that can lead to downtime. When a contact tip isn’t threaded properly during installation, or if the welding operator introduces dirt or debris to the threads, the gas diffuser can be damaged during installation. This will require replacement and increase costs. To avoid cross-threading, look for contact tips with coarse threads that install with fewer turns. The welding liner has a single and relatively simple purpose: to guide the welding wire from the wire feeder through the power cable to the contact tip. However, it is capable of causing significant problems if it isn’t installed properly. Trimming a liner incorrectly is the most common installation error. A liner that is too short lessens the support of the welding wire as it passes through the length of the gun. This can lead to micro-arcing or the formation of small arcs within the contact tip. Micro-arcing causes welding wire deposits to build up in the tip, resulting in an erratic arc and burnbacks. In more extreme cases, micro-arcing can cause MIG gun failure due to increased electrical resistance throughout the front-end consumables and gun neck. It may also prompt the welding operator to increase voltage in an effort to rectify poor welding performance, which can cause the gun to overheat. On the other hand, a too-long welding liner can lead to kinking and poor wire feeding. When trimming a conventional welding liner, avoid twisting it and use a liner gauge to ensure the proper measurement. There are also consumable systems available that provide error-proof liner installation and require no liner measuring. The gas diffuser locks the liner in place while concentrically aligning it with the power pin and contact tip to eliminate any gaps. The welding operator or maintenance personnel feeds the liner through the neck of the gun, locks it in place and cuts the liner flush with the back of the power pin. As with contact tips, remember that quality matters when it comes to welding liners. Always select a stiffer liner, so it is capable of supporting the wire as it feeds from the spool through the power pin and the length of the gun. Paying close attention to MIG gun consumables is important to gaining good welding performance. That means looking at the overall quality of the products being purchased; the manner in which they are inventoried, stored and handled; and how they are being installed. Always follows the consumable manufacturer’s recommendations, and when in doubt, contact their customer service or a trusted welding distributor for help.
Using the wrong shielding gas for MIG welding applications — or having improper gas flow — can significantly impact weld quality, costs and productivity. Shielding gas protects the molten weld pool from outside contamination, so it’s critical to choose the right gas for the job. Learn more about which gases and gas mixes are best suited for certain materials, along with some tips for optimizing gas performance — and saving money — in your welding operation.
Robotic MIG welding guns and consumables are an important part of the welding operation yet are frequently overlooked when investing in robotic welding systems. Companies may often choose the least expensive option when, in reality, purchasing quality robotic MIG guns and consumables can lead to significant cost savings in the long run. There are many other common misconceptions about robotic MIG guns and consumables that, if corrected, can help increase productivity and decrease downtime for the entire welding operation. Here are five common misconceptions about MIG guns and consumables that may be affecting your robotic weld cell.
It’s important for new welding operators to establish proper MIG techniques in order to achieve good weld quality and maximize productivity. Safety best practices are key, too. It’s just as important, however, for experienced welding operators to remember the fundamentals in order to avoid picking up habits that could negatively impact welding performance. From employing safe ergonomics to using the proper MIG gun angle and welding travel speeds and more, good MIG welding techniques provide good results. Here are some tips. A comfortable welding operator is a safer one. Proper ergonomics should be among the first fundamentals to establish in the MIG welding process (along with proper personal protective equipment, of course). Ergonomics can be defined, simply, as the “study of how equipment can be arranged so that people can do work or other activities more efficiently and comfortably.”1 The importance of ergonomics for a welding operator can have far reaching effects. A workplace environment or task that causes a welding operator to repetitively reach, move, grip or twist in an unnatural way, and even staying in a static posture for an extended period of time without rest. All can lead to repetitive stress injuries with life-long impacts. Proper ergonomics can protect welding operators from injury while also improving productivity and profitability of a welding operation by reducing employee absences. 1. Using a MIG welding gun with a locking trigger to prevent “trigger finger”. This is caused by applying pressure to a trigger for an extended period of time. 2. Using a MIG gun with a rotatable neck to help the welding operator move more easily to reach a joint with less strain on the body. 3. Keeping hands at elbow height or slightly below while welding. 4. Positioning work between the welding operator’s waist and shoulders to ensure welding is being completed in as close of a neutral posture as possible. 5. Reducing the stress of repetitive motions by using MIG guns with rear swivels on the power cable. 6. Using different combinations of handle angles, neck angles and neck lengths to keep the welding operator’s wrist in a neutral position. The proper welding gun or work angle, travel angle and MIG welding technique depends on the thickness of the base metal and the welding position. Work angle is “the relationship between the axis of the electrode to the welders work piece”. Travel angle refers to employing either a push angle (pointing in the direction of travel) or a drag angle, when the electrode is pointed opposite of travel. (AWS Welding HandBook 9th Edition Vol 2 Page 184)2. When welding a butt joint (a 180-degree joint), the welding operator should hold the MIG welding gun at a 90-degree work angle (in relation to the work piece). Depending on the thickness of the base material, push the gun at a torch angle between 5 and 15 degrees. If the joint requires multiple passes, a slight side-to-side motion, holding at the toes of the weld, can help fill the joint and minimize the risk of undercutting. For T-joints, hold the gun at a work angle of 45 degrees and for lap joints a work angle around 60 degrees is appropriate (15 degrees up from 45 degrees). In the horizontal welding position, a work angle of 30 to 60 degrees works well, depending on the type and size of the joint. The goal is to prevent the filler metal from sagging or rolling over on the bottom side of the weld joint. For a T-joint, the welding operator should use a work angle of slightly greater than 90 degrees to the joint. Note, when welding in the vertical position, there are two methods: weld in an uphill or a downhill direction. The uphill direction is used for thicker material when greater penetration is needed. A good technique for a T-Joint is call the upside-down V. This technique assures the welding operator maintains consistency and penetration in the root of the weld, which is where the two pieces meet. This area is the most important part of the weld.The other technique is downhill welding. This is popular in the pipe industry for open root welding and when welding thin gauge materials. The goal when MIG welding overhead is to keep the molten weld metal in the joint. That requires faster travel speeds and work angles will be dictated by the location of the joint. Maintain a 5 to 15 degree travel angle. Any weaving technique should be kept to a minimum to keep the bead small. To gain the most success, the welding operator should be in comfortable position in relation to both the work angle and the direction of travel. Wire stickout will change depending on the welding process. For short-circuit welding, it is good to maintain a 1/4- to 3/8-inch wire stickout to reduce spatter. Any longer of a stickout will increase electrical resistance, lowering the current and leading to spatter. When using a spray arc transfer, the stickout should be around 3/4 inch. Proper contact-tip-to-work distance (CTWD) is also important to gaining good welding performance. The CTWD used depends on the welding process. For example, when using a spray transfer mode, if the CTWD is too short, it can cause burnbacks. If it’s too long, it could cause weld discontinuities due to lack of proper shielding gas coverage. For spray transfer welding, a 3/4-inch CTWD is appropriate, while 3/8 to 1/2 inch would work for short circuit welding. The travel speed influences the shape and quality of a weld bead to a significant degree. Welding operators will need to determine the correct welding travel speed by judging the weld pool size in relation to the joint thickness. With a welding travel speed that’s too fast, welding operators will end up with a narrow, convex bead with inadequate tie-in at the toes of the weld. Insufficient penetration, distortion and an inconsistent weld bead are caused by traveling too fast. Traveling too slow can introduce too much heat into the weld, resulting in an excessively wide weld bead. On thinner material, it may also cause burn through. When it comes to improving safety and productivity, it’s up to the experienced veteran welding operator as much as the new welding to establish and follow proper MIG technique right. Doing so helps avoid potential injury and unnecessary downtime for reworking poor quality welds. Keep in mind that it never hurts for welding operators to refresh their knowledge about MIG welding and it’s in their and the company’s best interest to continue following best practices. 1. Collins Dictionary, “ergonomics,” collinsdictionary.com/dictionary/english/ergonomics.
The potential advantages of robotic welding are well known — increased productivity, improved quality and greater cost savings compared to semi-automatic welding. But the question is: How do companies best implement this technology to gain these benefits? And how can they ensure a quick return on the investment (ROI)? Simply stated, planning. More preparation upfront helps minimize the cost and time for correcting errors in the robotic welding system once it has gone into production. From the welding power source to the robot or weld process to the gun and consumables, each component should be thoroughly researched to make sure it is feasible to operate in the weld cell — not just on paper, but in reality. Take advantage of turnkey integrators who run their own process and capability studies. They can provide useful double checks to a plan and often conduct reach studies that model the weld tooling and workpiece. These mock up how the robot would weld in the finished system to test the gun reach and the overall efficiency of the process. Also remember, success in robotic welding is as much a matter of doing the right thing as it is avoiding pitfalls that could hinder the efficiency of the operation. With planning comes budgeting. A robotic welding cell may be installed on time, produce good weld quality and meet cycle time, but if the implementation and use of the system is over budget it will be an uphill battle to gain a good ROI. Consider the associated goals to help establish a feasible ROI. For example, a company with the goal of producing 1000 parts a day needs to determine how much it can make from those parts. From there, it would subtract the cost of utilities and labor, along with the cost to make the product and the cost of raw materials, to determine a budget on equipment costs that would make the company profitable. If this equipment will only be used for 5 years, the company may need a quicker ROI than if it’s planning to use the robotic welding system for 10 years or more. Companies can make the most of their budget by considering equipment that could be reused. This can cut down on the investment in the long run. Robots can have an extensive life if maintained well, allowing them to be re-purposed from project to project. The same holds true with welding power sources and nozzle cleaning stations. Ultimately, ROI depends on the company and what practices it follows for making profit. Some may be able to allow the equipment to take 18 months or more to pay for itself if the company plans on re-using or re-purposing the welding robots on multiple platforms over the next 10 years. Others may stand by the goal of a one-year ROI, which is common. Proper training is important for keeping a robotic welding system running successfully and profitably in the long term. Robot integrators and other equipment manufacturers often offer training as part of the implementation process. This training provides welding operators with a knowledge of robotic welding in general, as well as providing the information they need to operate the robot effectively for the application at hand. A well-trained operator will also be able to determine ways to maximize the efficiency of the robotic weld cell. They do this by troubleshooting and resolving issues quickly, keeping the robot online and supporting greater productivity and cost savings. Likewise, train welding operators to implement PM for the robotic gas metal arc welding (GMAW) gun to gain longer life, reduce downtime and achieve more arc-on time. Regularly check that the gun connections, consumables and power pin are secure. Look for any signs of power cable wear and replace if necessary.Training geared toward the preventive maintenance (PM) of a robotic welding system and the weld cell is also key. For example, spatter build-up on the robotic welding gun can cause grounding issues and build-up on tooling may lead to dimensional movement of the steel from cycle to cycle. The latter can block the datum placements causing gun reach issues. In a worse-case scenario, spatter builds up on equipment over time, creating solid formations that are difficult to remove and prevent the re-use of the equipment. To avoid these problems, train operators to follow a regular cleaning schedule for the weld cell and the equipment. There are several common mistakes that can negatively affect productivity and quality in a robotic welding system. Knowing how to avoid these can help companies make the most out of the equipment and gain greater success. Consider the following: 1. Implementing the wrong equipment in a robotic welding cell can lead to spending more money than is required. Be sure to rate the power source, robotic GMAW gun and consumables for the application. Doing so helps minimize the risk of premature equipment failures that can lead to unplanned downtime and costly equipment replacement. For example, if a company selects an air-cooled system, but actually requires a water-cooled system for the application, it could incur unnecessary costs to repair or upgrade a failed robotic GMAW gun system that cannot handle the heat. 2. Underutilizing the robotic welding system can prevent companies from realizing their full productivity potential. Robotic welding systems should be programmed to maximize the arc-on time during the weld process cycle. In some cases, it may be possible to have fewer robots that weld for slightly longer cycles. This helps drop the initial implementation costs. Take this example. A company has four robots in cell welding at 30 inches per minute with a cycle time of 60 seconds. These robots are inefficient since they are only welding half of the cycle time. That could be due to the positioner rotating for weld access, too slow of robot air cut movements, poor welding angles or other limiting factors. In this scenario, the total length of completed welds for all four robots is 60 inches (30 in. / min. x 1 min. / 60 seconds x 30 seconds of welding per robot = 15 inches of weld per robot). An alternative here is to keep the cycle time at 60 seconds and drop down to three robots by improving items like the weld angles, creating quicker air cuts between welds, utilizing gun reaming during positioner movements and more. Now with improvements, the robots could weld at an average of 35 inches per minute for 35 seconds each cycle. That provides an average of 20 inches of weld per cycle per robot, allowing for the same total of 60 inches of weld with one less robot. 3. Underutilizing available labor can also hinder productivity. While companies should take care not to overload operators, it’s important to balance manpower in robotic welding process so that employees are efficient and busy at the same time. If an operator is idle waiting for the weld cycle to complete, there could be room for process improvements by allocating labor to other activities near the weld cell. 4. Poor tooling design can impede quality. Thoroughly plan the tooling design and understand how the parts being welded will impact it. Different parts and materials react differently to heat and may draw, flex or bend during the welding process. Factor in how much heat a given weld sequence generates. The tooling will have to be designed with these in mind. If possible, design tooling to permit welding in the flat or horizontal position with appropriate robotic GMAW gun access. This allows for faster and more consistent results. Finally, remember, less expensive tooling may be attractive when looking at upfront costs, but it can be a pitfall later if it doesn’t meet the demands of the job. 5. Overlooking activities outside the robotic weld cell can be detrimental. Plan for part inspection and cosmetic rework, as well as the final stages of palletizing the product if that is part of the operation. Some of these processes can be automated or manual labor driven. These are key stages in a robotic welding operation that can quickly become bottlenecks that cause the entire process to slow down. These bottlenecks can also add unplanned manpower or equipment costs, which can become expensive. Remember that no plan for welding automation can be successful without a good schedule for its implementation. Being thorough is more important than being fast. Set realistic goals for completing the installation of the robotic weld cells and don’t rush or over-complicate the process. For first-time investors in robotic welding starting small can also help ensure greater success. Once the robotic weld cell or cells begin operating, keep in mind that the startup may not be perfect. There may be adjustments required to optimize performance to gain the best productivity and quality.
From reamers or nozzle cleaning stations to wire cutters and anti-spatter sprayers, welding peripherals and accessories can contribute significantly to the success of a robotic welding operation. In addition to improving weld quality, they can also help companies maintain high levels of productivity. Reamers, in particular, are most prevalent in automotive manufacturing, where uptime and quality are critical. This peripheral cleans the welding consumables — for example, welding nozzles and gas diffusers — free of spatter, and most automotive welding operations rely on the process after virtually every weld cycle. Other industries, such as heavy equipment manufacturing, also employ reamers and other peripherals in their robotic welding operations, as do some general manufacturers. It’s not by chance that peripherals work the way they do. Like any equipment, caring for them with routine preventive maintenance (PM) is important to gaining optimal performance and longevity. A reamer requires regular attention since it operates frequently during the weld cycles. Its job is important though, as it performs essential welding nozzle cleaning that helps keep the robotic welding cell up and running and quality on par. With the PM for this equipment also comes PM for its associated accessories: the lubricator, cutter blades and anti-spatter sprayer. All require varying levels of PM activities — some daily, weekly, monthly or yearly. In addition to inspecting the consumables for wear and replacing as needed, follow this PM routine on a daily basis: On a weekly basis, continue to examine the integrity of the consumables and follow these guidelines: Monthly PM for reamers and accessories requires less steps but is more intensive. It may require scheduling a time off cycle to complete. Lastly, on an annual basis: While it may seem time-consuming to implement these PM measures, they can typically be completed during routine pauses in production. More intensive activities can be scheduled so as to prevent interruption to production. Ultimately, the PM is time well spent and can help protect the investment in the reamer and its accessories. Wire cutters are increasingly being used in automotive and other manufacturing operations. This equipment is integrated into a reamer configuration and used in conjunction with a wire brake on the robotic MIG gun. The wire brake prevents the welding wire from moving, while the wire cutter cuts it at a set distance. This allows for a consistent wire stickout so the robot can touch sense and track the joint before welding. The results are more accurate weld placement and smooth arc starting. PM for wire cutters is relatively simple. Peripherals like reamers with anti-spatter sprayers and wire cutters can help companies realize a greater return on their investment in a robotic welding system. They aid in high weld quality, minimize rework and help meet productivity goals. Train welding operators to follow recommended PM activities as a part of a routine care of the weld cell. The time and cost to care for them properly will be small in comparison to the improvements they can provide to the bottom line.
When MIG welding consumables aren’t properly installed or maintained, it can result in wire- feeding issues and weld quality problems. Troubleshooting and correcting these challenges can cost hundreds of dollars — and hours per day — in a manufacturing operation. As the industry faces a shortage of skilled welders and those entering the profession have less experience, it may be more common for welders to incorrectly install MIG gun consumables and liners. Consumables that simplify the installation process can help eliminate errors, reduce downtime for changeover and troubleshooting, and decrease costs. Learn how new consumables available in the marketplace can help address wire-feeding problems and the role they play in maximizing throughput and productivity. Not addressing poor consumable performance can result in, among other problems, lower-quality parts and expensive rework. Wire-feeding issues are some of the most common complaints in the welding industry. Often, improper trimming or installation of the MIG gun liner is the cause of these problems. As with other consumables, the MIG gun liner wears out over time and must be changed periodically. Typically, replacement liners are longer than necessary and must be trimmed appropriately for the style and length of the MIG gun. Trimming the liner to the proper length can be difficult. In some cases, the welder may change the liner without taking the time to complete the proper steps of installation or may not know the proper steps. This can result in a host of problems. A liner that is cut too short can lead to the issues a lot of welders experience: wire chatter, erratic arc and burnback. A too-long liner, which happens less frequently, results in a tight fit and can cause the wire to weave and curve as it feeds through the gun. If the operator continues to weld without diagnosing the cause of any of these problems, it may result in bad welds that require rework or result in scrap. It seems to be common in the industry that welders typically change the contact tip at the first sign of trouble with the welding gun, and this may help for a short-term fix. But if the liner is the root cause, the problem will repeat itself, leading the welder to use more tips than if a correctly trimmed liner was installed. This increases costs due to wasted consumables and downtime for changeover. In some operations, welders don’t install or trim liners. Instead, MIG guns are taken to a maintenance department whenever a liner must be changed. This adds downtime and costs and decreases throughput in the operation. Solutions that are designed to address liner trim length errors and poor wire feeding can reduce troubleshooting, downtime and rework — ultimately saving money. The AccuLock™ S consumables system from Bernard® take the guesswork out of liner trimming and installation in semi-automatic welding operations. The system offers an error-proof liner replacement process that eliminates measuring and incorrectly trimming liners. In contrast to most MIG gun liners that load from the back of the gun, AccuLock S liners load through the neck at the front of the gun. The liner is then locked and trimmed flush with the power pin at the back of the gun, which eliminates the need to measure. This design also eliminates doubt about proper liner length — and the time spent troubleshooting liner trimming issues — because operators can simply look at the back end of the gun to see that the liner is correctly trimmed and in place. With traditional MIG guns, welders can’t see if a liner is cut too short, since the end of the liner that’s been trimmed is hidden under the nozzle and gas diffuser. A welder would have to remove all the consumables to see the liner inside the gun. In addition, the system optimizes wire feeding because the liner is locked and concentrically aligned to both the contact tip and the power pin without the use of fasteners. Capturing the liner at both ends of the gun keeps the liner from extending and contracting based on gun position — and it allows for a flawless wire-feeding path. Typically, the longer the welding gun, the more the cable bends and twists. Even when a traditional liner is perfectly cut and installed, the liner gets pushed forward and back inside the gun as it’s used, since the liner is affixed at the back end of the gun but free floating at the front end of the gun. This liner movement can result in wire chatter and erratic arc. When the liner is affixed at both ends of the gun, as with the AccuLock S consumables system, welders are assured the liner won’t pull back, or push into the contact tip — allowing for smooth, uninterrupted delivery of the wire to the weld pool. And because the liner is concentrically aligned with the contact tip, it creates less mechanical wear on the tip’s interior diameter, possibly leading to longer life by reducing the risk of keyholing associated with misaligned liners and contact tips. Reducing keyholing also lessens the opportunity for an erratic arc, excessive spatter and burnback, all issues that shorten contact tip life. Additional features of the new consumables system also contribute to optimized MIG gun performance: Cool, connected contact tip: Sixty percent of the AccuLock contact tip is buried in the gas diffuser to protect it from heat damage. As the shielding gas flows through the gun, it cools the contact tip tail inside the gas diffuser, which helps reduce heat and wear. These features differ from traditional tips that screw onto the gas diffuser with little to no portion of the contact tip exposed directly to the shielding gas as it exits the diffuser to the arc. A tapered design of the consumables tightly locks the conductive parts together to minimize electrical resistance and further reduce heat buildup. Versatile nozzle: A patent-pending nozzle design allows operators to choose thread-on or slip-on — with the same nozzle part number. Typically, nozzles are either thread-on or slip-on style, a choice that often comes down to welder preference. A thread-on nozzle is locked in, while a slip-on nozzle can be adjusted to different heights and easily pulled off. With AccuLock S consumables, the same nozzle can be used as a slip-on or thread-on nozzle, and the change is determined by using a different diffuser. This allows operations to greatly simplify their consumables inventory and changeover, with fewer parts to manage. In addition, a steel retaining ring and friction lock on the diffuser help prevent the nozzle from unthreading or loosening when it’s threaded on. This also helps eliminate the potential for gas leaks at the back of the nozzle or insufficient gas coverage of the weld — a common occurrence when traditional thread-on nozzles loosen over time. Coarse threads: The AccuLock contact tip features coarse threads, making it less likely to become cross-threaded and also requires fewer turns to install or remove — speeding up tip replacement. One full turn disengages the contact tip from the diffuser. Significant time and money can be spent troubleshooting weld quality problems and wire- feeding issues, such as erratic arc, bird-nesting and burnback. In addition, many welding operations are dealing with increasing welder retirements and turnover, which can increase troubleshooting time associated with less experienced welders installing consumables. The AccuLock S consumables system is designed to eliminate liner trimming errors and optimize wire feeding to help operations reduce downtime, costs and rework — maximizing throughput and efficiency.
Every operation wants to avoid downtime, as well as the cost for troubleshooting problems in the robotic MIG welding cell. But sometimes issues happen, whether it’s due to equipment failure or human error. Since most companies invest in welding automation to boost throughput and profitability, getting a robotic welding cell back online as quickly as possible is critical to production and the bottom line. The first things to consider are whether anything has changed in the welding process or with the equipment, or if the operator has recently reprogrammed the robot. In many cases, evaluating the most recently changed variable can help you pinpoint an issue’s cause. After that, analyzing some of the most frequent sources of trouble in the robotic weld cell can help you get to the root of the problem sooner. Consider these five common issues and ways to fix them. A: The material being welded and the parameters being used affect welding consumables’ longevity. But if it seems that nozzles, contact tips, diffusers or liners aren’t lasting their typical life or are performing poorly, there could be several causes. Check all connections between welding consumables and tighten them as needed. A loose connection increases electrical resistance and generates additional heat, which can shorten consumable life and cause poor performance. It’s especially important to ensure consumables are properly tightened when the application involves long welds or welds on thick materials, since any rework due to quality issues will cost more time and money in these cases. Common contact tips issues, such as burnback, are often caused by a too-short liner. Always follow the manufacturer’s instructions for liner trimming and installation, and use a liner gauge to confirm length when possible. Over time, debris and spatter buildup inside the liner can contribute to shortened contact tip life. It’s important to create a schedule for changing liners, just as you would for other consumables. If you’re frequently experiencing weld defects like porosity or lack of penetration, this can also stem from a consumables issue. Make sure the contact tip and nozzle are free of debris and replace them as needed. A: Erratic or poor wire feeding in robotic welding is a common issue that can ultimately result in poor weld quality. Poor wire feeding can have many causes. Cutting a liner too short is particularly problematic when robotic welding with smaller diameter wires, which have less column strength. Extreme articulation of the robotic MIG gun can also lead to poor wire feeding. Program the robotic MIG gun cable to stay as straight as possible. The robot may not weld quite as fast, but proper gun orientation helps minimize downtime for feeding problems. Excessive conduit length and multiple bends or junctions can cause poor wire feeding as well. With the drive rolls open, you should be able to pull the wire through the contact tip by hand with minimal effort. If you need to pull with two hands or put your bodyweight into the process, that indicates interference with the wire path between the wire drum and the contact tip. Check for bends tighter than 90 degrees, multiple junctions between sections of conduit or worn conduit sections that can increase drag on the wire. Ideally, the conduit between the drum and the wire feeder should be less than 20 feet, with no junctions or tight bends. Improper drive roll selection and tension setting can also lead to poor wire feeding. Consider the size and type of wire being used and match that to the drive rolls. Inspect drive rolls for signs of wear and replace them as necessary. A: Whether you have a through-arm robotic welding system, where the cable is routed through the robotic arm, or a standard over-the-arm robotic welding system, premature power cable failure can happen. A power cable that becomes kinked or worn can fail and short-out against the robot casting, leading to costly repairs. To help prevent premature cable wear, consider the programmed path of the robot as well as the power cable’s length. If the robot’s movements cause the cable to bunch up or kink, it can cause the power cable to fail. If the power cable rubs against tooling or catches on components during the programmed cycle, this can also cause premature failure. A: In robotic welding, TCP refers to the location of the end of the welding wire with respect to the end of the robot arm. If you are experiencing inconsistent welds or welds that are off-location, this may stem from a problem with TCP. If the robotic MIG gun neck is bent or damaged during a collision in the weld cell, this can result in TCP issues. Use a neck-checking fixture or neck alignment tool to help ensure proper angle of the neck bend. Also, be sure the neck and consumables are installed and torqued properly. Failure to do so may affect TCP. However, a problem with off-location welds isn’t always caused by TCP issues. Improper fixturing or part variations may also be the root cause. If a TCP check using the robotic program turns up with no issues, a part or position variation is the likely culprit. A: Companies often implement peripherals, such as reamers or nozzle cleaning stations, to optimize robotic welding performance and get more life out of consumables. But a problem with the reamer can cause spatter buildup on the consumables. Reamers can perform poorly for three common reasons: Problems in the robotic welding cell can be as simple as a loose contact tip or more complex like incorrect TCP. Understanding the steps for proper troubleshooting helps narrow down potential causes and can prevent replacement of components that don’t need replacing — so the operation can save money and quickly get back to producing quality parts. Learn more from the Tregaskiss Troubleshooting Guide.
Taylor Machine Works Inc. has spent over 90 years building a reputation by engineering and producing exactly what its customers need. The company manufactures more than 85 models of powered industrial trucks, including forklifts and material handling equipment for a range of industries. “We manufactured roughly 750 pieces of rolling stock last year and 40 percent to 50 percent of that is highly customized,” said Matt Hillyer, director of engineering for Taylor, based in Louisville, Mississippi. “Our job is to build products that answer the customer’s needs.” Taylor’s “Big Red” forklifts, featuring the company’s distinctive “Big Red” logo, can handle material weighing up to 125,000 pounds — everything from palleted goods and empty shipping containers in waterfront shipyards to equipment encountering brutal hot and cold environments. Many of Taylor’s customers are small operations with from one to three pieces of equipment. Just one piece going out of service reduces production capacity by a large percentage. “Having high durability, high return on investment and low cost of ownership, those are all very imperative to our customers to make them successful,” said Hillyer. “It’s important for us not only to make custom products that are advanced in technology or state-of-the-art, but we also have to make products that are very simple, easy to work on and have lots of uptime. That’s what our customers are looking for.” Taylor employs some of the best welders in the business to meet those customer demands, but even great welders can’t overcome their tools’ limitations. When Taylor decided to try Bernard® semi-automatic MIG guns and Centerfire™ consumables, they discovered their talented team could take productivity up a few notches —and still gain the best quality. Making the change “Before we changed to Bernard welding products, we didn’t really know we were having a problem,” said Steve Nazary, quality assurance supervisor at Taylor. “When we started using Bernard [MIG guns and consumables], we found that they were much easier and more economical to use for our process.” Bernard semi-automatic MIG guns at 400, 500 and 600 amperages delivered more business benefits. Savings on service repair. “We can replace the liners, the tips, the nozzles” Nazary explained. “You can replace everything on a Bernard gun instead of throwing it away and buying a new one.” The previous guns Taylor used could not be repaired and components weren’t replaceable, resulting in increased costs for new purchases for their large manufacturing operation. Productivity-boosting ergonomics. “The Bernard MIG guns have a better handle on them,” Nazary said. “It fits your hand better. It has an easier trigger to pull. It doesn’t get as hot as the guns we were using before. We were using some handles before that got so hot, you couldn’t hold them anymore.” “Those twisty necks, as I call them, we can loosen them and change the angle to get in harder places. And you can reset them back straight, turn them on any angle. The employees love them.” Easier-to-use rotatable necks. Guns with multiple neck position options that are all easy to adjust let Taylor welders operate comfortably and precisely in more situations. Rather than turning the entire gun to get the right position to reach a weld joint, welders simply adjust just the neck of the gun to a better angle. Nazary added that it’s also easy to change necks on the Bernard MIG Guns to reach into tighter spaces. “We have multiple necks and they only take two or three seconds to swap them out,” he said. Centerfire™ consumables also proved to last much longer than products Taylor had used previously, reducing the need to change contact tips from multiple times per day to just once a day, on average. These consumables feature a non-threaded contact tip that is tapered at the base to seat easily in the gas diffuser. The result is better heat dissipation and a longer life. Plus, they are quick to change over. “We can change the Centerfire consumables with ease. We don’t have to have tools. You just twist the nozzle off, pull it off and pop another contact tip in and twist the nozzle back on,” said Nazary. Centerfire consumables also provide better gas flow for better welds and less rework. “With the other consumables that we were using, you would get different gas flows,” said Nazary. “With the Bernard products, we have consistent flow all the time.” “It’s absolutely imperative to make our products successful for the customer,” said Hillyer. “We also look to our suppliers, like Bernard to provide us with the best technology. They help us incorporate the right technology to make sure that we do have the most durable truck on the market.”
Implementing robotic welding can significantly improve a manufacturing operation’s productivity and weld quality, but what are the robotic welding basics you should know to be successful? From choosing the right welding wire to establishing proper tool center point (TCP), many variables play a role in optimizing robotic welding cells to produce the best results. Shaving even a few seconds from each weld cycle can save time and money. Minimizing the unplanned downtime for adjustments or repairs in the weld cell can also have a substantial impact on your bottom line. Success with robotic welding requires a well-researched plan. The more planning done upfront, the less time and money you could spend later making fixes and process improvements. Learning some basic tips for setting up a robotic weld cell can help to establish a repeatable and consistent process — so your operation can produce quality welds, reduce rework and maximize its investment. Proper weld settings for the application are based on factors including wire size and material thickness. Some welding power sources offer technology that allows welders to simply input the wire size and material thickness, and the machine will suggest recommended parameters for the application. Without this technology, finding the correct parameters can involve a bit of trial and error. Sometimes the robot manufacturer, welding power source manufacturer or system integrator can assist in choosing and testing specific materials to provide a starting point for the proper welding parameters. Utilize the experience of these partners to help you arrive at the best starting point and be prepared for the future. The choice of filler metal for a robotic welding system can significantly impact productivity, weld quality and the overall investment. Selecting the right wire for a robotic application is typically based on the material type and thickness, as well as the expected outcomes for the welded part. Welding equipment and filler metal manufacturers often offer charts to help you match a welding wire to your process needs. While solid wire has been the industry standard in robotic welding for many years, metal-cored wire is an alternative that can offer productivity and quality improvements in some applications, particularly in the manufacture of heavy equipment and automotive exhaust, chassis and wheels. However, be aware that each wire type offers pros and cons for certain applications, so it’s important to research the type that is best suited to your application. Robotic welding guns and consumables, including the nozzle, contact tip and gas diffuser, have a huge impact on performance in a robotic weld cell. The right combination can reduce unplanned downtime and improve overall efficiency of the cell. Be sure the welding gun is rated with enough duty cycle and amperage for the application. To avoid excessive wear and premature failure, the gun should not rub against any part of the system or another robot in applications where multiple robots are being used on the same tooling. Robotic welding systems typically operate at higher duty cycles than semi-automatic welding applications, and they may utilize transfer modes that are especially harsh on consumables. Consider using heavy-duty consumables that are more heat-resistant than standard-duty consumables. Chrome zirconium contact tips or tips specifically designed for pulsed welding processes are good options. In addition, ensure all consumables are properly installed and tightened. Improper or loose connections produce more electrical resistance and heat that causes faster consumable wear with premature failures. Another common failure in robotic welding is improper liner installation. Always follow the manufacturer’s directions for liner installation and cut length. A liner that is cut too short can cause premature failures of other consumables in the system. Make sure there is good cable grounding in the weld cell to help prevent potential problems as the cell ages. There are two cables running from the welding power source; one is attached to the wire feeder and the other is grounded to the tooling. Often, these cables are long and run from the shop floor to an elevated platform or through wire trays. The section of cable running up the robot or running to a positioner will constantly move — causing greater wear over time. Using a junction with high-flex ground cable at the base of the robot or the workpiece can save time and money in downtime and repair. With this solution, there is only a 6-foot section of cable to replace when it wears out, rather than replacing possibly 50 feet or more of ground cable that runs all the way back to the power source. However, keep in mind you should have as few breaks or junctions in the grounding cable as possible to maintain a better electrical connection. When mounting a ground cable to the welding workpiece, it can be helpful to use copper anti-seize lubricant, sometimes referred to as copper slop. This supports the transfer of electrical current and helps prevent the mounting point from fusing together or deteriorating over time. The lubricant can be useful in all areas where there may be grounding current running through pins or any other semi-permanent contact points. Proper cable management for the guns can also greatly extend cable life. The more any cable bends and flexes, the more wear and tear will occur — ultimately shortening cable life due to high heat and resistance. Work to minimize cable bending and flexing in your robotic process and tooling design. For repeatable and consistent weld quality, it’s critical to establish and maintain proper TCP. Welding operations can set their own standards for the acceptable amount of TCP drift, depending on the application and type of weld being made. When considering the tolerance of TCP variation, an acceptable starting point can be half the thickness of the wire diameter. Many robotic systems today can use touch-sensing features to monitor TCP and determine how far it has moved from the original programmed settings. If a gun is determined to be out of the acceptable TCP range, the gun neck can be removed and recalibrated offline to factory specifications with a neck straightening fixture. Some systems also provide the capability to adjust TCP automatically with the robot. A third option is to leave the gun in place and adjust the robot teaching to accommodate the modified TCP. This is the most time-consuming solution and, therefore, often not acceptable for the manufacturing operation. It also requires the need to reprogram the robot if new factory specifications for TCP or a new neck are ever put into place — which is why this method is typically the last resort. Set a schedule or standard for checking TCP, whether it’s every weld cycle, once a shift or even every time the torch goes through a reamer cycle. The length of time between checks is a matter of preference and weighing your priorities. It can be time-consuming to check every weld cycle, but this can save money in lost scrap and rework if a problem is found before welding occurs. The initial programming of the robot’s welding path can also involve much trial and error. When programming the path, consider the application, material type, welding process being used and gap size that must be filled. The weld quality and amount of spatter created are also impacted by the travel angle and whether it’s a pull or push weld. It can take time to dial in the correct path to achieve the desired quality. After setting the home positions in the robotic program, it’s recommended to have the robot move to perch points or ready-to-enter points that are safely away from any potential collision points, so the system can move quickly with air cut moves to and from these points. When programming the robot to move to a weld, it’s common to set the approach point just above the weld start location. Have the robot approach the start location at a slower and safer speed with the arc on. This approach position provides a good lead-in and typically won’t require adjustment unless the weld is relocated. Some robotic welding systems include technology that aids in setting the initial robot path. The robot’s welding location can play a role in premature failure of the gun. If the robot is welding with a lot of flex in the gun at a tight angle, this can cause it to fail much faster. Minimizing robot axes five and six during welding can help extend gun life by reducing wear. Proper part fit-up in the upstream process is critical to consistent weld quality and robot path programming. Inconsistent fit-up or large gaps between the parts lead to weld quality issues such as burn-through, poor penetration, porosity and others — resulting in additional unplanned downtime to deal with these problems. Large gaps between the parts may also require double weld passes, adding to cycle times. From wire and consumable selection to proper cable management and TCP, many variables play a role in weld quality and ultimately, the success of your robotic welding system. Careful planning at the start of the process and continued monitoring of these key factors helps optimize performance — so you can get the most from your robotic welding investment.
MIG welding, like any other process, takes practice to refine your skills. For those newer to it, building some basic knowledge can take your MIG welding operation to the next level. Or if you’ve been welding for a while, it never hurts to have a refresher. Consider these frequently asked questions, along with their answers, as welding tips to guide you. The welding wire size and type determines the drive roll to obtain smooth, consistent wire feeding. There are three common choices: V-knurled, U-groove and V-groove. MIG welding wires vary in their characteristics and welding parameters. Always check the wire’s spec or data sheet to determine what amperage, voltage and wire feed speed the filler metal manufacturer recommends. Spec sheets are typically shipped with the welding wire, or you can download them from the filler metal manufacturer’s website. These sheets also provide shielding gas requirements, as well as contact-to-work distance (CTWD) and welding wire extension or stickout recommendations. Contact tip recess, or the position of the contact tip within the MIG welding nozzle, depends on the welding mode, welding wire, application and shielding gas you are using. Generally, as the current increases, the contact tip recess should also increase. Here are some recommendations. The shielding gas you choose depends on the wire and the application. CO2 provides good penetration when welding thicker materials, and you can use it on thinner materials since it tends to run cooler, which decreases the risk of burn-through. For even more weld penetration and high productivity, use a 75 percent argon/25 percent CO2 gas mix. This combination also produces less spatter than CO2 so there is less post-weld cleanup. For all positions, it is best to keep the welding wire directed toward the leading edge of the weld puddle. If you are welding out of position (vertical, horizontal or overhead), keeping the weld puddle small provides the best control. Also use the smallest wire diameter that will still fill the weld joint sufficiently.
For structural applications, some contractors have made the switch from stick welding to self-shielded flux-cored welding to increase productivity and give themselves a competitive edge. Self-shielded flux-cored welding offers much greater travel speeds and deposition rates compared to stick welding, while also eliminating the frequent stopping and starting required to change out stick electrodes. For contractors considering this conversion, there are some key factors to keep in mind to help choose the right self-shielded flux-cored welding gun for the job — and to use and maintain it properly. Gun options such as heat shields, configurable necks and adjustable cable lengths can help improve weld quality, efficiency and operator comfort in self-shielded flux-cored applications. Self-shielded flux-cored welding is becoming more common on jobsites for several reasons. In addition to the greater productivity and deposition rates of the process, it also doesn’t require a shielding gas to protect the weld pool, eliminating the hassle and cost of buying and storing gas containers on the jobsite. Not using shielding gas also eliminates the need to set up tents or wind shields to protect the weld from the elements and the need to use specialty nozzles to control gas flow as is common with a gas-shielded flux-cored process. Some training may be required for welders who are used to the stick process. The different ergonomics of the self-shielded flux-cored gun compared to the stick electrode holder require approaching the weld from different angles and using different travel angles and pressure. When stick welding, the operator typically begins with the electrode (and therefore his or her body) farther from the weld. As the rod shortens during welding, the welder gets physically closer to the weld, applying pressure to the stick electrode as it melts into the weld pool. In self-shielded flux-cored welding, the welder stays in the same spot, maintaining a consistent distance between the contact tip and the weld pool. The proper contact-tip-to-work distance depends on the application, but at least 1/2 inch is a good rule of thumb. Self-shielded flux-cored welding can be prone to slag inclusions if proper technique isn’t followed. Regularly inspect the contact tip to ensure it’s free from spatter and debris buildup, which helps ensure smooth wire feeding. Properly clean the weld between passes. Welding guns for self-shielded flux-cored applications are available in various configurations. Choosing the right gun can help contractors tailor it to their specific needs and applications. Consider these features: Heat shield: One of the most common features on self-shielded flux-cored welding guns is a hand guard or heat shield, which is available in different sizes. In applications that require access to a corner joint, choosing a smaller guard increases maneuverability and provides more access. When welders need to run at a higher voltage and deposit more filler metal into the weld, using a larger guard helps deflect the higher heat. Neck lengths and bends: Gun necks are available in varying lengths and bend angles. A slimmer neck provides a better view of the weld pool and improved access to tight areas, for example. A shorter neck typically provides more control compared to a longer neck. Lightweight, rotatable necks can also reduce operator fatigue and improve weld visibility. Replaceable or fixed cable liner: Some self-shielded flux-cored gun models are available with either a replaceable cable liner or a fixed cable liner. A replaceable cable liner provides benefits in harsh and demanding environments, since self-shielded flux-cored welding can be hard on equipment and consumables. Replaceable power cable liners provide quick and easy cable maintenance and can extend product life since welders can change out components that experience high levels of wear. In addition, choosing a replaceable cable liner with internal trigger leads means there is no external trigger cord that can catch on surrounding objects. Conversely, fixed cable liners tend to be larger, which can be an issue when welding in corners or tight spaces. Dual schedule switch: A self-shielded flux-cored gun with an optional dual schedule switch allows for wire speed adjustment while welding. In some guns, this switch is integrated into the handle to keep it protected from spatter. The ability to toggle between weld parameters easily — without having to stop welding and change settings — saves time and improves productivity. There are ways to extend the life of the gun and consumables. The necessary frequency of gun and consumable maintenance depends on the application and the welding environment. Conduct routine checks to ensure front-end consumables are in good shape and all connections are tight. This helps keep heat resistance low and ensures proper electrical conductivity so the gun and consumables last longer. Consider using a rotatable gun neck with a collet-style connection, which makes it easier to drop the neck in and tighten it. Consumables that use compression fittings also provide more efficient energy transfer and less overheating to help extend product life. Be sure to keep the contact tip clear of spatter buildup and inspect the tip for signs of wear or keyholing, and also inspect the cable for any damage or nicks. While the self-shielded flux-cored process is capable of welding material with dirt, oil or mill scale, remember that better surface preparation delivers better results in any welding application. Properly cleaning the base material will help produce better welds. Because flux-cored welding produces a slag and spatter, there is also a need to remove the slag between passes and for post-weld cleaning. Be aware that travel angles beyond 20 or 25 degrees can increase spatter and arc instability. With flux-cored welding, it’s recommended to use a drag technique with a travel angle of 5 to 15 degrees. As more contractors look for ways to increase productivity and efficiency on the jobsite, the use of self-shielded flux-cored welding grows. Choosing a welding wire designed to improve a weld’s chemical composition or deposition rates can provide even more benefits. The self-shielded flux-cored process can be a good alternative to stick welding in many outdoor applications that boosts productivity and reduces costs.
Is your robotic welding operation costing time and money for problems like burnbacks, premature contact tip wear, loss of tool center point (TCP) or other issues? These common failures in robotic welding can be costly, resulting in downtime and unplanned part replacement. Even issues that seem minor, such as the wire sticking to the contact tip and forcing tip replacement, can cost thousands of dollars per day when you consider lost consumables, cell downtime and labor costs for changeover. Beyond the time and money spent on minor issues, there’s also the risk of catastrophic failure that could short out the robot or damage system electronics — potentially costing tens of thousands of dollars. Avoiding common failures is often a matter of proper weld cell setup and robot maintenance, in addition to following some best practices for consumable installation. Operator training is also critical in preventing common failures in robotic welding. One of the most common failures in a robotic weld cell is burnback and premature contact tip wear. The top cause of burnback is an improperly trimmed gun liner. When a liner is too short, it won’t seat in the retaining head properly, causing burnback. To avoid this problem, follow the manufacturer’s recommendations for proper liner trimming. It’s also helpful to choose a high-quality liner designed for accurate liner trimming and installation. Burnback is one cause of premature contact tip wear, but wear can also result from other factors. Using low-quality wire with a lot of cast can be another cause, as it quickly wears out the contact tip compared to using a better-quality, straighter wire. Drive rolls that are too tight can also cause wire cast issues that wear the contact tip faster. Improper welding parameters — such as welding too hot or too cold — can also wear contact tips prematurely and force more frequent changeout. Adjust parameters accordingly to minimize this problem. The main cause of broken cutter blades in robotic welding is incorrect positioning or too much angle of the robotic MIG gun nozzle as it enters the reamer for cleaning. For example, if the depth of the Z axis is too deep, the torch will go in too far and may cause the reamer blades to break. To prevent this, the nozzle should be concentric to the cutting blade. Use an angle finder app on your smartphone or tablet to ensure the positioning is straight up and down on the X and Y positions. Also, be sure the insertion depth on the nozzle goes past the gas holes on the diffuser. Drag marks on the diffuser or contact tip are signs of wear that mean the nozzle is not concentric to the reamer blade. Proper setup and positioning also helps ensure consistent coverage of anti-spatter spray on the nozzle. Broken cutter blades can also result from excessive spatter in the nozzle, which can be caused by poor spraying setup, incorrect weld parameters or incorrect torch angle. Spatter sticks to spatter and as the buildup grows, it can break the cutter blade as it tries to enter the nozzle. Keep in mind that you may need to ream and spray more frequently depending on the application and the material being welded to avoid some of these issues. Problems with the contact tip, nozzle, reamer and excessive spatter can also result when there is poor grounding in the weld cell. Regularly inspect all cables for damage and be sure the ground cables are securely connected. When TCP is lost in a robotic weld cell, one common cause is improperly installed consumables. A cross-threaded consumable will angle the contact tip where it meets the retaining head, causing the tip to bend and disrupting TCP. Be sure to tighten consumables to the manufacturer’s torque specifications. The general rule of thumb is one quarter turn past finger tight. A worn clutch can also cause loss of TCP. The clutch system helps prevent damage to the robot or gooseneck during tooling collisions. After repeated incidents, the clutch may allow a few degrees of movement in either direction, which throws off TCP. Consider using a neck inspection fixture, which tests and adjusts the tolerance of a robotic MIG gun’s neck to the TCP so you can readjust it after an impact or after bending due to routine maintenance. In a robotic weld cell, the disc functions as a buffer between the mount and the robot arm. It’s designed to be sacrificial; if the torch, mount or robot arm collide, the disc will absorb the bulk of the impact. However, the disc can be broken when it’s hit hard enough by the neck or torch mount, so replace it if damaged. Set the robot path correctly to avoid neck collisions. Overtightening the screws can also break or crack the disc and cause it to fail. Discs have torque specifications from the manufacturer. Use those specifications to prevent overtightening and reduce the risk of cracking. The specification sheet also describes the order in which the screws on the disc should be tightened. Robotic weld cell failures can also be caused by programming errors. If the robot’s path to the tooling is programmed incorrectly, the arm can come into contact with the tooling or the weld cell wall. The torch rubbing on the cell wall can create holes in the cable. In addition, if the neck frequently hits the tooling, this can bend the neck or cause the disc to break. To prevent these issues, program the robot so the arm is clear of the tooling and doesn’t encounter the tooling or the wall. Preventive maintenance is key to keeping a robotic welding system and its components performing optimally — and extending consumable life. Regularly check all cables to make sure they are secure, free of damage and not rubbing anything. Establish and follow a schedule for liner changeover. The required frequency of liner changeover depends on what type of filler metal is being used, what material is being welded and shop conditions. A shop that is very dusty means liners will clog faster, for example. Consult the manufacturer’s maintenance recommendations and follow a preventive maintenance checklist to ensure all the system’s components and parts remain in good working order. Using high-quality robotic MIG guns and consumables also helps prevent problems that can arise in the weld cell. Taking steps to avoid common failures in the robotic weld cell allows your operation to improve productivity, reduce consumable costs and ensure consistent part quality.
When using anti-spatter liquid in a robotic weld cell, there are steps you can take to optimize the application of the spray. The addition of an anti-spatter sprayer to a nozzle cleaning station helps ensure delivery of consistent amounts of anti-spatter liquid, leading to longer consumable life, better weld quality and higher productivity. You can also add an anti-spatter multi-feed system to help lower costs, minimize downtime and increase safety. These systems eliminate the need to refill spray reservoirs frequently by feeding up to 10 reamers from a single 5- or 55-gallon drum of anti-spatter liquid. Position the robotic MIG Gun and front-end consumables correctly. Aligning these in the right location for the ream cycle and anti-spatter liquid application helps apply the liquid uniformly. Always follow the manufacturer’s instructions for proper setup based on the nozzle bore size. If the sprayer is too far away from the nozzle, it will not provide adequate coverage to prevent spatter buildup. If the nozzle and sprayer are too close, too much spray may saturate the nozzle insulator, which can lead to premature failure. Spray for about a half-second. If you need to spray longer, it usually means the sprayer is too far away. Never spray the liquid for three or more seconds, as it can harm the consumables, cause residue buildup in the weld cell (and with it slippery surfaces) and may damage power sources by adversely affecting the electrical circuits. Use a spray containment unit. This 3- to 4-inch unit fits over the spray head on the anti-spatter liquid sprayer to capture excess anti-spatter liquid. After the spatter has been cleared from the nozzle during the reaming cycle, the nozzle docks on the spray containment unit. An opening at the top of the cylinder allows the anti-spatter liquid to spray onto the nozzle while an O-ring seals the nozzle in place; only the outside edge and inside of the nozzle are sprayed. To care for a spray containment unit, routinely remove any spatter or debris from the bottom and clear the screen or filter inside the unit of contaminants using clean, compressed air.
Having the right products for your welding application impacts quality and productivity. Anti-spatter liquid is no exception. When selecting an anti-spatter liquid for a robotic welding application, be certain that it offers the following attributes: • Uniform coverage to protect the entire nozzle A water-soluble compound, like Tregaskiss® TOUGH GARD® anti-spatter liquid, is a popular option. This liquid is non-toxic and eco-friendly, helping companies to improve employee safety and provide a cleaner work environment. Oil-based anti-spatter liquid is also available in the marketplace, but is generally less desirable to use because it is more difficult to clean up if it settles on fixtures or other parts in the weld cell. Oil-based anti-spatter liquid is not always compatible with all nozzle cleaning stations, and it can clog this equipment. Even though the more popular water-based anti-spatter compound is non-toxic, you should always take care when handling and using it. This article is the second in a three-part series focused on the use and benefits of anti-spatter liquid. Read article one, Spatter in Welding: Should You Consider Anti-Spatter Liquid? and article three, Anti-Spatter Sprayer: How to See the Best Results
Are you losing money and arc-on time for excessive contact tip changeovers? Anti-spatter liquid may be an option to help. This compound protects the front-end consumables on your robotic MIG gun from spatter accumulation, reducing downtime for tip replacements and helping to prevent shielding gas flow restrictions that could lead to porosity. This liquid also: • Prolongs the life of the nozzle, contact tips and gas diffuser Although it resembles water in its consistency, anti-spatter liquid (when applied correctly and in the appropriate volume) will not drip like water. Rather, it creates a barrier between the nozzle and any spatter generated during the welding process. The spatter easily falls off when the nozzle cleaning station or reamer performs the reaming cycle, leaving the nozzle and other front-end consumables clean. Note, you must reapply the compound frequently to help maintain that barrier. Constant-voltage (CV) applications and those utilizing solid wire and/or the welding of galvanized steel tend to produce high levels of spatter and often benefit the most from the use of anti-spatter liquid. Anti-spatter liquid also benefits high-volume, high-production operations where the goal is to minimize potential weld quality issues, extend consumable life and reduce downtime. Its application can easily be programmed so that it is sprayed onto the consumables after each ream cycle, during routine pauses in production for part changeover. Learn about TOUGH GARD® anti-spatter liquid. This article is the first in a three-part series focused on the use and benefits of anti-spatter liquid. Read article two, How to Select and Use Anti-Spatter Liquid, and article three, Anti-Spatter Sprayer: How to See the Best Results.
Taylor Machine Works saves money and improves performance by welding its forklifts with Bernard MIG guns. All Bernard MIG gun parts are replaceable, and the necks adjust to fit tight joints. “You can put different necks on the guns. Those twisty necks, I call them. We can loosen them use them and change the angle to get in tighter places. The employees they love them. Bernard guns are very helpful to us and our welding process” raves Craig Callahan, Quality Control Welding Inspector for Taylor Machine Works. “When we first went to a Bernard gun, I had one man who didn’t change a tip for 27 days. They usually we’re changing tips, nozzle and diffusers multiple times a day. Now they only have to change the tips once a day”, says Steve Nazary, Quality Assurance Supervisor for Taylor Machine Works, since converting to Centerfire™ consumables. Bernard MIG welding consumables help Taylor Machine Works save time by reducing contact tip changeover in its forklift welding operations.
Optimizing the robotic weld cell helps improve productivity, allowing a manufacturing facility to save time and money. It can be especially beneficial in applications that use pulsed gas metal arc welding (GMAW-P), a process that results in rapid wear to the welding gun’s front-end consumables. While the choice of contact tip for the GMAW gun may seem like a small factor in the entire operation, consider how much time it takes for an operator to enter the weld cell and change the contact tip — and how many times per day the tip is changed in most robotic welding operations. For example, copper contact tips are changed on average four times per shift. In a three-shift operation averaging 10 minutes per tip change, that equates to spending two hours per day changing contact tips. What else could a welding operator be doing with this time to create value in the manufacturing operation? There are contact tip innovations that help significantly reduce the downtime spent on changeover — time that can be spent on other tasks in the operation, such as increasing production up-time. In addition, when the operator spends less time in the weld cell, it reduces the potential of health and safety incidents and the possibility of weld quality issues through altering weld settings and parameters such as tool center point. For these reasons, it’s important to consider the total cost of ownership when selecting the right contact tip for a robotic welding operation. As more manufacturing applications use thinner, lighter and more corrosion-resistant materials to meet industry demands, this increases the use of GMAW-P processes, which offer benefits for welding thin-gauge materials. Pulsed waveform technology continues to develop, offering faster travel speeds, reduced spatter levels and high weld quality in many robotic applications. However, pulsed processes typically require a higher frequency of contact tip changeover due to the energy of the process. Faster contact tip deterioration is caused by peaks in pulse waveforms where the energy/heat is five times greater than in traditional constant voltage (CV) GMAW. Because of this, arc erosion is a common failure for contact tips in GMAW-P. Contact tip failure increases an operation’s costs, due to the increased frequency of downtime related to tip changeover. A new contact tip design has resulted in tips with improved resistance to arc erosion that last much longer in pulsed welding. Contact tips made from copper or copper chrome zirconium are commonly used in many welding applications. However, adoption of a GMAW-P process can double contact tip replacement frequency and related downtime when using copper or chrome zirconium tips. A new innovative technology on the market today can significantly extend the time between contact tip changeover, thanks to a combination of proprietary materials and tip design. HDP contact tips from Tregaskiss last more than 10 times longer than copper or chrome zirconium tips, allowing operations to go from changing contact tips two to four times each shift to only changing the tips once every third shift or longer. HDP contact tips are engineered to resist wear better than other materials and designs previously used for contact tips, providing increased resistance to arc erosion in pulsed welding, as well as spray transfer and CV GMAW. The precise fit between the tip and the wire also results in good arc stability to help produce high-quality welds, and because the degradation of welding current from the power source to the contact tip is reduced, it provides a truer representation of the pulsed waveform program. The tips currently come in .035, .040 and .045 sizes and can be used with standard nozzles and TOUGH LOCK® retaining heads as well as with air-cooled guns or water-cooled guns. HDP contact tips can be used with Tregaskiss guns, as well as guns from other MIG welding gun manufacturers. Because the tip bore is sized so tightly to the welding wire, it’s best to use the HDP Contact Tip with good-quality welding wire that has a large cast. A high-quality wire typically has a consistent wire diameter, which promotes better feeding and optimized performance. Typically, operations conduct contact tip changeovers on a preventive maintenance schedule to avoid unplanned downtime in the manufacturing process. The necessary frequency of contact tip changeover varies based on many factors including application, wire type and quality, waveform and base material. Many robotic welding operations have 100 welding arcs or more and run three shifts per day. In robotic welding operations, copper tips are changed on average four times per shift — or 12 times per day. Chrome zirconium tips are changed about half as often, or six times per day. A scheduled contact tip change typically takes 10 to 15 minutes to complete. Compare this to real-world results from several manufacturing operations using HDP contact tips. For example, one manufacturing operation converted to HDP contact tips in a solid wire GMAW-P application. The operation produces 600 parts per shift, and the previous chrome zirconium contact tip required changeover every 60 to 80 parts — or about 10 times per shift. In the company’s trial, one HDP contact tip was still running after 2,500 parts under the same parameters. Another manufacturing operation running a standard GMAW process tried HDP contact tips on a line of 18 robots. Where previous contact tip usage for the operation was 216 per day — or about 1,500 tips per week — one HDP contact tip lasted an entire week on each cell, totaling 18 tips per week. In addition to the significant productivity gains the new contact tip design provides, there are other benefits for arc stability, productivity and operator safety. Reduced frequency in contact tip changeover not only increases throughput while saving time and money due to downtime, it also reduces the risk of safety incidents, since every time an operator enters the weld cell it increases the risk of injury. Also, each time someone touches the welding gun, there is the risk putting it out of alignment. The less frequently an operator must enter the cell, the less chance there is for human error that can disrupt tool center point that reduces part quality. Frequently changing the contact tip can cover up other issues within the weld cell. When the contact tip is changed less often, other issues such as wire feeding problems, wire routing or a loose ground can come to the forefront. With standard contact tips, changing the tip out is often the first go-to fix when there is a problem in the weld cell — even if something else is the root cause. With a longer-lasting contact tip that is not changed as frequently, other issues that may not have been noticed before can now be fixed to improve the overall efficiency of the weld cell. It’s important to consider total cost of ownership when evaluating contact tips and other consumables. The upfront cost of a contact tip is just one factor in total overall costs. A longer-lasting contact tip may be more expensive upfront, but it can provide significant payback in time and labor savings and reduced downtime. In considering a switch in consumables, an operation should also be sure there is time to conduct a trial, which should always be part of changing the type of consumable or contact tip. The numbers will often speak for themselves when vetting the option and analyzing return on investment. An operation may think the welding process is optimized, but that may not be the case if operators must frequently enter the weld cell to change the contact tip. As manufacturing operations look for ways to improve production efficiency and throughput in automated welding, choosing the right contact tip for the gun is one solution. A contact tip designed to provide significantly longer tip life saves time and money in necessary changeover and reduces the frequency of people entering the weld cell. New contact tips on the market can last days in GMAW-P applications compared to standard copper tips that may only last a few hours. *Other parameters: 450 ipm wire feed speed, 40-45 ipm travel speed, 90/10 mixed gas, 240-260 average amps on a Tregaskiss robotic MIG gun with a 22-degree neck.
Improving Welding Automation Safety With Risk Assessment and Training
Improving Welding Automation Safety With Risk Assessment and Training
Robotic welding safety hazards and resources
External Resources
Safe use of robotic welding guns, consumables and reamers
Personal Protective Equipment (PPE)
Navigating the robotic welding cell safely
Unenclosed Robotic Systems
Other safety considerations
Creating a culture of safety
Selecting the Right MIG Welding Consumables
Selecting the Right MIG Welding Consumables
Selecting contact tips
Welding nozzle options
MIG gun liner selection
This article is the third in a three-part series discussing how configuring a MIG gun can improve the welding operation, as well as what to consider in the process. Read article one, Configuring a MIG Welding Gun for Your Application and article two, How to Choose MIG Welding Gun Parts.How to Choose MIG Welding Gun Parts
How to Choose MIG Welding Gun Parts
Choosing the cable
MIG welding gun necks and handles
Configuring a MIG Welding Gun for Your Application
Configuring a MIG Welding Gun for Your Application
Why configure?
How do you get started?
What affect does the weld cell have?
Common Problems With MIG Welding Consumables and How to Fix Them
Common Problems With MIG Welding Consumables and How to Fix Them
Making sense of welding nozzles
Avoiding contact tip downfalls
Pay close attention to the contact tip material to avoid premature failure. Consider these options:
Getting it straight about liners
Final considerations
Optimizing Shielding Gas Performance in MIG Welding
Optimizing Shielding Gas Performance in MIG Welding
This article was published in The WELDER. To read the entire story, please click here.
5 Misconceptions About Robotic Welding Guns and Consumables
5 Misconceptions About Robotic Welding Guns and Consumables
This article has been published as a web-exclusive on thefabricator.com. To read the entire story, please click here.
MIG Welding Basics: Techniques and Tips for Success
MIG Welding Basics: Techniques and Tips for Success
Proper ergonomics
Some ergonomic solutions that can improve safety and productivity include:
Proper work angle, travel angle and movement
Flat position
Horizontal position
Vertical position
Overhead position
Wire stickout and contact-tip-to-work distance
Welding travel speed
Final thoughts
2. Welding Handbook, 9th ed., Vol. 2, Welding Processes, Part 1. American Welding Society: Miami, Fla., p. 184. Implementing Robotic Welding: What to Know to Be Successful
Implementing Robotic Welding: What to Know to Be Successful
Budgeting and ROI
Effective training
Avoid common mistakes
Final thoughts
Preventive Maintenance for Reamers, Accessories and Other Peripherals
Preventive Maintenance for Reamers, Accessories and Other Peripherals
PM tips for reamers and accessories
Preventive Maintenance Checklist
PM tips for wire cutters
The value of peripherals
MIG Welding Consumables Reduce Wire Feeding Issues and Downtime
MIG Welding Consumables Reduce Wire Feeding Issues and Downtime
The cost of poor consumable performance
Error-proof liner replacement
Optimize wire feeding
Maximize performance and life
Reduce wire-feeding and weld quality issues
Robotic Welding Troubleshooting FAQs
Robotic Welding Troubleshooting FAQs
Q: What are causes of poor consumable performance?
Q: What causes poor wire feeding?
Q: Why is the cable prematurely failing?
Proper cable length is also important. A cable that is too short or too long can be stretched beyond capacity or be prone to kinking.Q: Why is there a problem with tool center point (TCP)?
Q: How do I fix poorly performing peripherals?
Correcting common problems
Taylor Forklift Operation Reduces Downtime, Costs with Bernard
Taylor Forklift Operation Reduces Downtime, Costs with Bernard
According to Taylor, sometimes it takes trying a new technology to realize what you’ve been missing. That was the case with the Bernard products — the manufacturers of the Big Red material handling machines had a business epiphany.
Helping Taylor Machine Works serve customers
All the advantages found by using Bernard semi-automatic MIG guns and Centerfire consumables align perfectly with Taylor’s commitment to quality and meeting the customer needs. And the reliability of the products fits well with the company’s slogan: “Depend on Red.”7 Tips for Implementing a Robotic Welding Cell
7 Tips for Implementing a Robotic Welding Cell
Tip No. 1: Use proper weld settings
Tip No. 2: Choose the right wire
Tip No. 3: Consider the gun and consumables
Tip No. 4: Reduce cable wear
Tip No. 5: Establish TCP
Tip No. 6: Program the robot path
Tip No. 7: Ensure proper fit-up
Closing
MIG Welding FAQs Answered
MIG Welding FAQs Answered
Pair gas- or self-shielded wires with V-knurled drive rolls. These welding wires are soft due to their tubular design; the teeth on the drive rolls grab the wire and pushes it through the feeder drive. Use U-groove drive rolls for feeding aluminum welding wire. The shape of these drive rolls prevents marring of this soft wire. V-groove drive rolls are the best choice for solid wire.
To set the drive roll tension, first release the drive rolls. Slowly increase the tension while feeding the wire into your gloved hand. Continue until the tension is one half-turn past wire slippage. During the process, keep the gun as straight as possible to avoid kinking the cable, which could lead to poor wire feeding.
Following some key best practices related to welding wire, drive rolls and shielding gas can help ensure good results in the MIG welding process.
Stickout is especially important to gaining optimal results. Too long of a stickout creates a colder weld, drops the amperage and reduces joint penetration. A shorter stickout usually provides a more stable arc and better low-voltage penetration. As a rule of thumb, the best stickout length is the shortest one allowed for the application.
Proper welding wire storage and handling is also critical to good MIG welding results. Keep the spool in a dry area, as moisture can damage the wire and potentially lead to hydrogen-induced cracking. Use gloves when handling the wire to protect it from moisture or dirt from your hands. If the wire is on the wire feeder, but not in use, cover the spool or remove it and place it in a clean plastic bag.
A 1/8- or 1/4-inch recess works well for welding at greater than 200 amps in spray or high-current pulse welding, when using a metal-cored wire and argon-rich shielding gases. You can use a wire stickout of 1/2 to 3/4 inches in these scenarios.
Keep your contact tip flush with the nozzle when welding less than 200 amps in short circuit or low-current pulse modes. A 1/4- to 1/2-inch wire stickout is recommended. At 1/4-inch stick out in short circuit, specifically, allows you to weld on thinner materials with less risk of burn-through or warping.
When welding hard-to-reach joints and at less than 200 amps, you can extend the contact tip 1/8 inch from the nozzle and use a 1/4-inch stickout. This configuration allows greater access to difficult-to-access joints, and works well for short circuit or low-current pulse modes.
Remember, proper recess is key to reducing the opportunity for porosity, insufficient penetration and burn-through and to minimizing spatter.
The ideal contact tip recess position varies according to the application. A general rule: As the current increases, the recess should also increase.
Use 100 percent CO2 shielding gas or a 75 percent CO2/25 percent argon mix in combination with a carbon steel solid wire. Aluminum welding wire requires argon shielding gas, while stainless steel wire works best with a tri-mix of helium, argon and CO2. Always reference the wire’s spec sheet for recommendations.
You can gauge heat input and travel speed by the weld bead produced and adjust accordingly to gain better control and better results. For example, if you produce a weld bead that is too tall and skinny, it indicates that the heat input is too low and/or your travel speed is too fast. A flat, wide bead suggests too high of heat input and/or too slow of travel speeds. Adjust your parameters and technique accordingly to achieve the ideal weld, which has a slight crown that just touches the metal around it.
These answers to frequently asked questions only touch on a few of the best practices for MIG welding. Always follow your welding procedures to gain optimal results. Also, many welding equipment and wire manufacturers have technical support numbers to contact with questions. They can serve as an excellent resource for you.Self-Shielded Flux-Cored Welding: Choosing Your Gun
Self-Shielded Flux-Cored Welding: Choosing Your Gun
Considering self-shielded flux-cored welding
Self-shielded flux-cored gun options
Proper maintenance, cleaning and technique
Optimizing self-shielded flux-cored welding
5 Common Failures in Robotic Welding and How to Prevent Them
5 Common Failures in Robotic Welding and How to Prevent Them
Failure No. 1: Burnback and contact tip wear
Failure No. 2: Broken cutter blades in the reamer
Other Causes for Broken Cutter Blades
Failure No. 3: Loss of tool center point
Failure No. 4: Broken discs
Failure No. 5: Incorrect tool path
Maintenance is key
Anti-Spatter Sprayer: How to See the Best Results
Anti-Spatter Sprayer: How to See the Best Results
Follow these best practices for anti-spatter liquid usage
The spray containment unit also collects anti-spatter liquid runoff so it can be easily drained into a container and disposed of in accordance with federal, state and local environmental control regulations. Anti-spatter liquid cannot be reused.
Learn more about anti-spatter liquid and available accessories.
This article is the third in a three-part series focused on the use and benefits of anti-spatter liquid. Read article one, Spatter in Welding: Should You Consider Anti-Spatter Liquid? and article two, How to Select and Use Anti-Spatter Liquid.How to Select and Use Anti-Spatter Liquid
How to Select and Use Anti-Spatter Liquid
• Easy cleanup and no residue
• Compatibility with the nozzle cleaning station or reamer being usedSafety Tips
Consider these tips:Spatter in Welding: Should You Consider Anti-Spatter Liquid?
Spatter in Welding: Should You Consider Anti-Spatter Liquid?
What is anti-spatter liquid?
• Lowers cost for consumable inventory and management
• Reduces operating costs by improving weld quality and lowering reworkDoes my operation need to use anti-spatter liquid?
Save Money, Improve Performance with Bernard Replaceable MIG Gun Parts | Customer Testimonial
Save Money, Improve Performance with Bernard® Replaceable MIG Gun Parts
Bernard MIG Welding Consumables Save Time and Last Longer | Customer Testimonial
Bernard® MIG Welding Consumables Save Time and Last Longer
New HDP Contact Tips Provide Robotic Pulsed MIG Welding Benefits
New HDP Contact Tips Provide Robotic Pulsed MIG Welding Benefits
Demands of GMAW-P
Contact tip advancements
Significant productivity gains
Additional benefits
Return on investment
Be sure to look at the big picture in terms of productivity and efficiency improvements for the entire operation.Improve productivity and efficiency
