From Technology to Technical Support: Welding in Today’s Automotive Industry

Worldwide, companies serving the automotive industry have faced a unique set of challenges in the last several years, including changes in material types, a lack of skilled labor and initiatives by OEMs to decrease the weight of vehicles. Still, as the economy continues to rebound, each must find ways to maintain their productivity and profitability — often with fewer employees than before the recent recession.

A large part of maintaining that productivity is to ensure high levels of uptime in the robotic welding operations in order to maximize net throughput. It is equally important to find ways to minimize errors and obtain predictive weld data to help anticipate problems in the operation. Conventional issues like spatter, burn-through and poor part fit-up often hinder these attempts, as can the need to manage large amounts of inventory and contend with downtime to service welding equipment. That’s why it’s so important, too, for companies to find equipment that minimizes the total cost of ownership.

Unfortunately, there is no single answer to these challenges. There are, however, some considerations that may help reduce automotive suppliers’ pains and assist in other interrelated parts of the process.

Best practice meetings: When possible, suppliers in the automotive industry should work with original equipment manufacturers (OEMs) and vendors or welding distributors who can engage regularly in best practice meetings. These meetings can occur by conference call, webinar or in person, and can help determine what practices in the welding operation are working most effectively and what areas need improvement. “Open issues” can be prioritized in order to determine time-phased solutions.

These meetings can be especially helpful to companies with multiple locations (even globally), since they help identify opportunities for changes that could positively affect other facilities. They are also an excellent platform for brainstorming error-proofing ideas and serve to open communication among the parties involved in the success of a company’s welding operation. Ultimately, the goal is to spread an assessment of the operation to a broader peer group, extending the company’s core competencies to gain solutions from others’ input.

Streamline vendors: Automotive suppliers, particularly those with multiple locations, may want to consider purchasing their robotic gas metal arc welding (GMAW) guns, peripherals, consumables and other welding supplies from a single-source vendor via a welding distributor. Having multiple vendors may appear to provide cost savings on the surface; however, a per-item approach can actually increase the total spend.

Instead, by single sourcing a product line, a company is better poised to maximize their purchasing power with one vendor and gain loyalty discounts. The vendor may also be more inclined to aid in new efficiencies and groundbreaking technologies. Plus, a trusted single-source vendor can often help automotive suppliers assess their total weld spend, streamline inventory and reduce costly paperwork. The goal is to work with a vendor who can “own the arc,” providing assistance throughout the whole welding operation by assessing predictive data and offering suggestions for ongoing improvements.

“Co-opetition”: If you already work with several welding vendors, co-opetition is your next best option to maintaining an effective welding operation and in some cases can occur as part of best practice meetings. This term refers, in short, to cooperation that occurs between the various equipment manufacturers who are building the end user’s welding solution. Sometimes these companies have competitive product overlap. For example, the manufacturer of the robotic GMAW gun or welding wire may be in direct competition with the company whose power sources are in an automotive supplier’s weld cell. Even so, finding equipment manufacturers who are willing to work together to address problems in the welding operation is key to resolving issues when they arise.

A problem with the contact tip, for example, is usually a barometer of other things happening in the process. In short, it is very often a symptom of a problem, as opposed to the root cause. Having partners who are willing to put aside competitive differences for the good of resolving problems like these is important to gaining good welding performance. If this co-opetition is not feasible, companies may want to consider moving to a single-source vendor.

Equipment standardization: Recent increases in demand for production have caused some automotive suppliers, especially those in North America, to make capital investments that they previously postponed during the recession. When possible, standardizing on a single brand and style of welding power source, robotic controller, and GMAW gun and consumables during this investment can streamline inventory and maintenance procedures, thereby lowering management costs. It can also help companies avoid long lead times associated with specialty products and improve access to spare parts.    

For companies in an organic growth mode with new programs and/or greenfield operations, this standardization can help in long-term equipment re-deployment to other facilities, as well as streamline the learning curve among employees, and improve adoption rates and costs.

For companies that are in acquisition mode, however, this standardization may not be feasible. Instead, these suppliers should, at a minimum, consider standardizing on a single brand and style of robotic GMAW guns and consumables to minimize inventory. Doing so can also reduce the risk of improper consumable installation, which often leads to unscheduled downtime to rectify.

Appropriate welding technology: Many automotive suppliers rely on tandem- welding operations as a means to generate greater productivity. Companies can use this process for line production in the cells housing the majority of the welds. The benefit is that these operations require less floor space and can simultaneously improve throughput.

Advancements in single arc pulsed technology have also proven very efficient in providing faster travel speeds and minimizing spatter. This single arc technology, which effectively lowers the average amperage level during welding (by regularly switching the current between high peak amperages and low background amperages), is also quite easy to operate. Given the reduction in workforce in the automotive industry, combined with an overall shortage of skilled labor, this less complex (but highly efficient) technology has already proven beneficial for many automotive suppliers.

Companies should work with an appropriate welding distributor or robotic integrator to assess the individual application in order to determine the most appropriate welding technology.

Error-proofing: In addition to standardizing equipment when possible, using welding products that minimize the opportunity for human errors is an important part of keeping the welding process flowing. For example, nozzle detection can eliminate the potential of excessive rework or scrap.  Avoiding errors in equipment installation is also critical, as missing or incorrectly installed components on the front end of a robotic GMAW gun can cause it to become electrically alive, leading to premature failure and poor welding performance.

Preventive maintenance: Even though preventive maintenance or PM may have become a commonplace buzzword in recent years, the fundamentals are still critical to providing good welding performance and reducing unscheduled downtime in the automotive industry. Companies should take care to inspect all connections in the ground cables, feeding assembly, wire feeder, GMAW gun and consumables on a regularly scheduled basis. Replacing worn components during scheduled downtime (at the beginning of a shift, for example) can help prevent problems during production. On some welding robots, “predictive maintenance” technology is available to send alerts when consumables need to be changed.

Built-in buffers: As is typical in automotive “just-in-time” applications, suppliers want to reduce work in progress (WIP) — maintaining only strategically determined micro-inventories — and keep parts flowing (Takt time). To continue that workflow but still allow for any instances of stoppage in a robotic welding cell, suppliers may consider building a buffer into production. For example, if a company has a production line of 40 welding robots, breaking that line into fifths (five sections of eight robots), allows them to address any instances of failure while causing a stoppage of only eight robots instead of shutting down production on all 40. That buffer can mean a significant difference in terms of lost production and money.

And while no single one of these considerations can ensure the levels of productivity and profitability to which automotive suppliers strive as production demands increase, they can be a step in the right direction. Automotive suppliers should consider working with a trusted welding equipment manufacturer and vendor to discuss a plan for assessing their robotic welding operation and identifying opportunities for improvement.

7 Ways to Save Money on Robotic Welding

Robotic welding systems have become an increasingly practical way for companies, large and small, to gain a competitive edge. Assistance with everything from planning and implementation to training is readily available through robotic integrators or vendors, helping make the capital investment less risky and allowing companies to safeguard better results.

In addition to programming the robot in a manner that ensures the accuracy, speed and repeatability needed to complete high-quality welds, there are also several steps that companies can take to increase the return on their investment. Saving money on the robotic welding systems is, after all, one of the primary reasons — apart from productivity gains and quality improvements — for implementing this technology.

Minimizing downtime, reducing the need for parts replacements and preventing rework are among the more important cost-saving steps companies can make. Here are some ways to achieve those goals.

Tip No. 1: Add peripherals

Peripherals — reamers, wire cutters, neck inspection tools and clutches or solid mounts — are all additional equipment that can protect the robotic welding system investment, maximize its effectiveness and reduce costs. This equipment is particularly helpful in minimizing downtime that leads to offline maintenance or repairs of the equipment or its components (e.g., the robotic MIG gun, cables or consumables). 

Unfortunately, some companies view this equipment as an unnecessary cost and don’t realize that they can play an important role in improving quality and increasing productivity. Peripherals do, of course, require an up-front investment, but the payback period is relatively short.

For example, a reamer (also called a nozzle cleaning station or spatter cleaner) minimizes spatter build-up in the nozzle and with it the opportunity for electrical resistance that could lead to premature failure of the robotic MIG gun or consumables. Failure of the gun or the consumable, of course, increases the cost for replacements and requires downtime for changeover — downtime that puts the robot offline and stops it from making parts … and making money.

A clean nozzle also allows for good shielding gas flow, thereby minimizing quality issues that could be costly to repair.

Tip No. 2: Manage and maintain your consumables properly

To protect consumables against costly damage before even placing them on the robotic MIG gun, it is important to employ proper storage and handling practices.

Always keep consumables in their original packaging until they are ready for use. Opening the packaging and placing these components in a bin can lead to scratches or dents, both factors that allow spatter to adhere the product and can lead to premature failure. Similarly, removing contact tips or retaining heads from their packaging and storing them in open or dirty containers can cause dirt and/or oil to accumulate on them, which can lead them to seat improperly together.

Regularly check that the contact tips, retaining heads and nozzles are securely connected. Solid connections help ensure reliable electrical conductivity and minimize heat, in turn providing more consistent weld quality and helping the consumables last longer.

In addition, always follow the MIG consumable manufacturer’s suggestions for installing these consumables and use the proper tools in order to gain the best performance and reduce the risk of damaging them.

While these two practices may seem simple, they can go a long way toward minimizing product replacements and preventing downtime that keeps the robot from reaching its optimal throughput during a shift. Both have measurable costs associated with them, as well, and can help companies save money. 

Tip No. 3: Implement a preventive maintenance program

Preventive maintenance (PM) is another critical way to save money on robotic welding, primarily by preventing unscheduled downtime, poor quality parts and/or costly repairs. It can even help prevent failures that require equipment replacements. The robot, as well as the robotic MIG gun, consumables and cables can all benefit, too.   

Schedule time to check connections throughout the system (from the front-end consumables through the gun and power pin). This task can easily take place during routine pauses in welding cycles to prevent unplanned downtime. To prevent debris build-up that may affect part fit-up, also remember to clean fixturing on a regular basis. Similarly, check the front-end consumables for spatter build-up and replace as necessary.

Verifying tool center point (TCP) is another important cost-saving measure, as it helps ensure that the robotic welding system continues to operate within its proper parameters and provide the same consistent weld quality — repeatedly.

Certain maintenance can occur in between shifts, such as cleaning off the robot or changing consumables, for example. Other activities, such as greasing the robot’s joints usually occur less frequently and during a longer scheduled stop. Companies should assess their individual needs and plan the preventive maintenance schedule accordingly. For larger companies, hiring a maintenance crew to take care of preventive maintenance may be desirable.

Tip No. 4: Use the best filler metal package for the job

Reducing downtime for routine filler metal package changeovers can be one of the most effective ways of maximizing return on investment and productivity. Ideally, select a package that is large enough to minimize wire changeovers, but not so large that the same wire will remain on the shop floor for more than a couple of days. Filler metal manufacturers typically ship their products in airtight or hermetically sealed containers. Once opened, the wire is at risk of absorbing moisture, dust, oil or other contaminants that can affect its welding performance and ultimately cost money to replace, not to mention downtime to change over.

It’s also important to consider the type of filler metal package being used. For instance, recyclable filler metal packaging can reduce costs and labor for properly separating and disposing of recyclable and non-recyclable packaging materials.

When possible, stocking an extra filler metal package near the robot can also contribute to cost savings by reducing downtime to transport a new package from the storage area to the weld cell.

Tip No. 5: Select, trim and install the right MIG gun liner

To prevent problems like bird-nesting (a tangle of wire in the drive rolls) or poor wire feeding — both issues that lead to downtime and added costs — it is important to select the right MIG gun liner and install it properly.

Always make sure to have the correct diameter liner for the wire being used. Using too large of a liner for too small of a wire may allow the wire to wander, causing poor wire feeding and/or premature liner failure due to excessive wear. Similarly, if a liner is too small for the wire diameter, the wire will not be able to feed smoothly, resulting in poor weld quality and potentially a clogged liner.

Tip No. 6: Select the appropriate MIG gun

Trimming the liner to the correct length is also a good cost-saving measure, since it helps prevent downtime and costs for replacing this part. Some manufacturers print markings on the outside of the weld cable to show when the cable is twisted, providing welding operators the opportunity to straighten it fully in order to measure for the correct liner length. Other manufacturers offer liner gauges as a guide. Both work well to guide in the correct trimming process. There are also spring-loaded modules available that work in conjunction with a front-loading liner to help minimize issues if a welding operator cuts the liner to an incorrect length. These modules are housed in the power pin and put forward pressure on the liner after the welding operator installs it from the front of the gun. They allow up to 1 inch of forgiveness if the liner is too short.
     
Having the right style and amperage MIG gun for the application can help minimize downtime for overheating and potential failure of this equipment. It can also save money by preventing the purchase of a larger (and more costly) gun than necessary for the job.

Air-cooled robotic MIG guns (rated at 500 amps) operate comfortably in the range of 200 to 300 amps at approximately 60 percent duty cycle with mixed gases. They are good for welding thinner materials — typically upwards of 4 mm thick. The cost of ownership for these guns is usually relatively low since they are easier to maintain and replacement parts are less expensive than water-cooled guns. They work well for shorter welds on high-volume applications and are quite durable, especially through the neck. This durability further reduces costs because it helps the guns maintain their accuracy and create consistent welds.

For higher-amperage applications, applications with thicker materials (1/4-inch or more) or those requiring prolonged welding, it’s necessary to have a gun capable of withstanding the increased heat. A water-cooled MIG gun offering 300 to 600 amps of power and 60 to 100 percent duty cycle is a good option to help reduce costs by preventing gun failure or downtime for overheating. These guns cost more to maintain, however, so it’s important to implement a good PM program for them to avoid any costly surprises.

Hybrid robotic MIG guns are another option to help reduce costs, particularly when it comes to maintenance. These guns are a mix between an air-cooled and a water-cooled gun, and feature water lines that run independently of the power cable, making them more accessible to repair than on a standard water-cooled MIG gun. These guns can also remain on the robot for maintenance, too, which reduces downtime for removal. Plus, if there are issues with water circulation, these guns can rely on an underlying air-cooled unicable to provide enough current-carrying capacity to avoid a catastrophic failure such as destroying a power cable or other components.

Tip No. 7: Take advantage of training opportunities

Many robotic integrators offer training opportunities not just up front, but also throughout the course of ownership of the robotic welding cell. Because robotic welding systems require properly trained operators to oversee them, it is important to make sure these individuals continue to gain knowledge that will increase their programming, troubleshooting and preventive maintenance knowledge and skills. In many cases, robotic integrators offer online tutorials, troubleshooting information and/or additional on-site training as aftercare support. By taking advantage of such opportunities, it will be easier for those who oversee the robotic welding cell to act quickly should a problem result and get the robot back online to product parts. It also empowers them to take preventive care to prevent downtime in the first place.

What You Should Know About Shielding Gas

Consistent productivity, high quality and low costs are all key components in a successful welding operation. Gaining these advantages depends on everything from the equipment and filler metals to the skill of the welding operators and the techniques being used in the process. The shielding gas also plays a critical role.

Both the gas metal arc welding (GMAW) process (using solid or metal-cored wires) and the gas-shielded flux-cored arc welding (FCAW) process require the use of an external shielding gas, each type of which offers distinct characteristics. Knowing how to select the appropriate one for the application can go far in helping obtain the desired welding performance and minimizing the downtime for rework caused by poor weld quality.

To help, following are some basics of what you should know about shielding gases.

The role of shielding gases

The primary purpose of shielding gas is to protect the molten weld pool against elements in the atmosphere, including oxygen, nitrogen and hydrogen. The reaction of these elements with the weld pool can create a host of problems, including (but not limited to) porosity and excessive spatter.

Shielding gas also plays an important role in determining weld penetration profiles, helping maintain arc stability and achieving the desired mechanical properties in the finished weld. Shielding gas can also affect the transfer of the filler metal from the arc to the weld joint, which in turns contributes to the efficiency of the welding process and the quality of the weld. Other important factors that shielding gas help determine include the weld bead appearance, and weld toughness and strength.

Selecting the right shielding gas

The four most common shielding gases used in the welding process are carbon dioxide, argon, helium and oxygen. Each has specific characteristics and factors such as cost, available labor (i.e., for weld preparation) and the weld properties desired — all considerations when selecting which shielding gas is best for a given welding application.

Carbon dioxide (CO2): This gas is the most common of the reactive gases used in the welding process and also the least expensive of the shielding gases. It is also the only one able to be used without the addition of an inert gas. One of the biggest advantages of pure CO2 is that it provides deep weld penetration, which is useful when welding thick material. It does, however, tend to create a less stable arc and more spatter than when it is mixed with other gases, including argon. This additional spatter can lead to downtime for post-weld cleaning. Pure CO2 is also limited to use in short circuit welding processes.

Argon: When welding aluminum, magnesium or titanium, it is common to use 100 percent argon as a shielding gas due to its stable arc features. Adding argon to a CO2 shielding gas is also an option for materials like carbon steel. It provides consistent weld quality and appearance and good weld pool control, and can help minimize post-weld cleanup. Argon also produces a narrow penetration profile, making it useful for fillet and butt welds.

Typical mixtures include a balance of 75 to 95 percent argon with 25 to 5 percent CO2. An argon/CO2 shielding gas mixture allows the use of a spray transfer process, which lends itself to high productivity rates and visually appealing welds.

Helium: Helium is generally used when welding non-ferrous metals. It is also used in a tri-mix formula of argon and CO2 for welding stainless steels. The gas produces a wide, deep penetration profile, making it suitable for welding thick materials, and also creates a hot arc, which helps increase travel speeds and productivity rates. Helium is typically used in ratios of 25 to 75 percent helium with an appropriate balance of argon. Adjusting these ratios changes the weld penetration, bead profile and travel speeds.

It’s important to note that helium is more expensive than other gases and requires a higher flow rate than argon (because it is so light).  For this reason, it’s imperative that companies calculate the value of the productivity increase against the increased cost of this gas.

Oxygen: Oxygen is a reactive gas typically used in ratios of 9 percent or less. The addition of the gas to a mixture with argon helps to improve weld pool fluidity, weld penetration and arc stability, particularly when welding carbon, low alloy and stainless steels. Because the gas causes oxidation of the weld metal, it is not recommended for use with aluminum, magnesium, copper or other exotic metals.

Tips for getting the most out of your shielding gas

To achieve the best results out of a chosen shielding gas, it’s important to select the proper front-end consumables. These consumables — the gas diffuser, contact tip and nozzle — play a critical role in delivering the shielding gas to the weld pool and also protecting it from the atmosphere. Consider these tips to help with the selection.

1.    Choose consumables that have a smooth surface to help resist spatter build-up that could block shielding gas flow and lead to issues, such as porosity.

2.    Choose an appropriate size nozzle for the application. A nozzle that is too narrow for the application can easily become clogged with spatter, again, hindering its ability to deliver enough shielding gas to the weld pool to protect it.

3.    Consider using nozzles with a built-in spatter guard. These designs add a second phase of shielding gas diffusion, resulting in even smoother, more consistent shielding gas flow.

4.    Be certain to select quality gas diffusers to ensure smooth and balanced gas flow. Consult with a trusted welding distributor for recommendations.

7 Things To Know About Robotic Welding Systems

Implementing a robotic welding system isn’t something that happens on a whim — at least not successfully. Converting to this technology can help companies gain greater productivity, improve quality and reduce costs in the welding operation, but the process requires thorough planning to gain those results. Working closely with a robotic integrator is a good step to ensure every aspect of the implementation is carefully orchestrated and that the robotic welding system works properly for the given application — in reality, not just theory. Before adding a robotic welding system, it’s helpful to know some key factors that can maximize the return on investment (ROI) in the technology and also help prevent potential problems.

1. Part repeatability is critical to successful automation

The quality of part produced by a robotic welding system depends on the quality of the part that enters the weld cell. That’s why it’s not uncommon to hear the phrase “garbage in, garbage out” when it comes to robotic welding systems — if the part entering the welding cell is flawed, the subsequent weld will be, too.

To protect against poor weld quality, it is critical to have simple, consistent parts that allow the robot to execute the weld in the same location, repeatedly. Having a blueprint or electronic CAD drawing is helpful for confirming that repeatability. Robotic integrators can review the blueprint or they may want to create a software simulation that assesses the suitability of the part for the robotic welding system. After the assessment, they can advise of any adjustments that need to be made prior to implementation.

Proper fixturing is also critical to achieving part repeatability, regardless of whether the application is high volume/low variety or low volume/high variety. Parts that meet the exact specifications can easily be welded incorrectly if they are not held in an exact position during the process. Many robot manufacturers offer vision systems to aid in part recognition and to ensure that the weld path can be altered in real time if part fit-up issues exist. These systems usually work very well, but may cost more.

2. Training is essential

Robotic welding systems require a properly trained operator to oversee them. A skilled welding operator or an individual with previous robotic welding management experience is a good candidate for the job. Again, a trusted robotic integrator is an excellent resource to provide the necessary training, which should cover proper programming, troubleshooting and preventive maintenance. As a best practice, companies should also consider ongoing training support to keep the operator’s knowledge of the system up to date. In many cases, robotic OEMs offer online tutorials, troubleshooting information and/or additional on-site training as aftercare support.

3. Additional safety equipment may be necessary

Many facilities already have fume extraction systems in place for manual welding operations, but converting to a robotic welding system may require additional equipment to help maintain a healthy work environment.  With the increased production brought forth by a robotic welding system, there is also an increase in fume generation. Given the stringent regulations and recommendations from OSHA (Occupational Safety and Health Administration) and other safety regulatory bodies, proper equipment is necessary to maintain compliance.

For larger facilities with higher production robotic welding applications, a centralized fume extraction system is a good option. These systems involve the installation of ductwork throughout the facility and the placement of fume extraction hoods over the welding cell. Smaller shops with fewer robotic welding cells may want to consider a less expensive portable fume extraction system. Operators can wheel these systems right next to the welding cell and adjust the extendable arm toward the robot to suction the fumes. It is also critical that the proper cage and screens are in place around the robotic welding system to protect employees from the welding arc and moving parts within the cell.

4. Weld data monitoring and/or peripherals can help improve results

Adding weld data monitoring capabilities and/or peripherals into a robotic welding system can help improve weld quality and productivity. Achieving these results, however, requires an additional up-front investment.

Weld data monitoring (whether integrated in a power source or via a third party) allows companies to track the parameters of individual welds, determine the cause of weld defects and identify general inefficiencies in order to rectify those problems and optimize the process for peak quality and productivity.  This equipment requires the purchase of software and computers, as well as the establishment and maintenance of an Ethernet network throughout the facility. Companies will also need tech-savvy individuals to review the data and make the necessary adjustments to the robotic welding system according to the data provided.

Similarly, the addition of peripherals — particularly a nozzle cleaning station (also called a reamer or spatter cleaner) can improve weld quality and productivity. By cleaning spatter from the inside of the welding consumables on the front end of the GMAW welding gun, this peripheral helps extend consumable life, reduces downtime for changeover during production and also reduces the cost for replacing consumables. Nozzle cleaning stations also help minimize the loss of shielding gas coverage (due to spatter build-up) that could lead to poor weld quality and rework.

Proper maintenance can help protect the investment in automation

Preventive maintenance of the entire robotic welding system, including the robotic GMAW (gas metal arc welding) gun, consumables and cables is an important step in protecting the investment in this technology. Neglecting maintenance can easily lead to unscheduled downtime, poor quality parts and/or costly repairs. It may even lead to failures that require equipment replacements.

Scheduling time to check connections throughout the system, clean fixturing (to prevent debris that may affect part fit-up) and check TCP (tool center point) helps ensure that the robotic welding system continues to operate within its proper parameters. Certain maintenance can occur in between shifts — cleaning off the robot or changing consumables, for example — while other activities like greasing the robot’s joints may occur less frequently and during a longer scheduled stop. Companies need to assess their individual needs and plan the preventive maintenance schedule accordingly. For larger companies, hiring a maintenance crew to take care of preventive maintenance may be desirable.

6. Communication is key to proper weld quality and cost savings

Retrofitting robotic welding systems is a common practice among many companies, particularly those investing in automation for the first time or for smaller shops requiring only one or two weld cells. It’s significantly less expensive to purchase a used robot than a new one. When retrofitting a robot, however, it is absolutely essential that it is capable of communicating with the selected power source if companies are to have the entire robotic welding system function properly. New power sources feature software that may not be immediately compatible with a robot that is older, or in some cases, the robot may need a specific robotic GMAW gun that isn’t readily available at a welding distributor or possibly even discontinued.

For this reason, it is critical to contact an experienced robotic integrator who can both recommend and help set up all components in the retrofitted robotic welding system. The investment in this assistance can help ensure the proper functioning of the equipment and the long-term cost savings sought by implementing the system. Not to mention, it can also save a lot of frustration and downtime.

7. Robots can do more than just weld

Robots rely on the input of the operator to execute a given task. That task, however, doesn’t have to be limited to just welding or to welding the same part every time. Operators can program the robot to weld multiple parts over the course of a single shift, enhancing the versatility of the robotic welding system and positioning the company to produce additional output. Operators can also program robots to move parts so that a particular unit is not sitting idle when it isn’t tasked with welding; there are components that offer gripping capabilities and can be installed in addition to a welding gun. Companies may even have a tool dock that allows the robot to be fitted with a different tool and proceed with its work.  Some companies with multiple robots may also benefit from installing a vision system in order to check on the work of the others, ensuring that part fit-up is optimal and that the robot is correctly placing welds.

Given that the goal of any robotic welding system is uptime, having the versatility to use a robot for multiple tasks can contribute meaningfully to the other advantages of this technology – increased productivity, improved quality, decreased costs — and may help give companies a real competitive edge.

What You Must Know About Robotic Welding

In the fabrication and manufacturing world, quality and productivity are everything. To remain competitive, companies need to look continually for ways to increase throughput and minimize defects, while also keeping costs low for parts and labor. In many cases, turning to robotic welding is a means to achieve those goals — for both the smaller job shop and larger manufacturing facilities.

The decision to implement a robotic weld cell, however, takes a good deal of consideration and planning if the system is to function in the most efficient, productive and profitable manner. And it requires a significant investment.

Fortunately, the long-term benefits of a robotic welding operation can be very positive. For companies who have already invested in robotic welding, but are looking to improve or better understand their operations, or for those considering the investment, it is critical to consider some key factors about the technology. Here, we will explore “what you must know about robotic welding” to make the most of the process.

1. There’s more to the payback on a robotic welding system than just speed

Justifying the cost of a robotic weld cell comes down to the ability to gain (and prove) a payback on the investment. Typically, that payback comes in the form of greater productivity and higher-quality welds (which minimize instances of costly and time-consuming rework), but there are other contributing factors to the return on the investment (ROI) in this technology. Robotic welding also offers the advantage of lower energy and labor costs, and in many cases lower material costs due to fewer instances of overwelding. Overwelding is a common and costly occurrence in semi-automatic welding. A weld bead that is 1/8-inch larger than necessary can double filler metal costs, but a robot can reduce those costs by only putting down as much material as necessary. Plus, robotic welding systems use bulk filler metals (600-pound drums, for example) that companies can often purchase at a greater discount.                        

For companies just considering the investment in robotic welding, it is important to consider how to calculate the payback. Assess the current part cycle times and compare those to the potential cycle times of a robot. A trusted robotic welding integrator or OEM can often help with this calculation. During this process, also consider the possibility of reallocating existing labor to other parts of the welding operation, where these individuals can add value to the process. Remember, up to 75 percent of the cost in a semi-automatic welding operation is labor. If there is the opportunity to use that labor elsewhere to increase part production, the payback on the investment in robotic welding will increase.           

Most companies — particularly smaller ones or those with frequent production changes — seek a payback on the robotic welding investment of no greater than 12 to 15 months. That time frame is entirely possible to achieve with proper up-front planning of the part blueprints, fixturing and general setup of the system. In some cases, companies may be able to justify a longer payback period if they know that their production needs will remain relatively static for longer periods of time.

2. Parts and product flow need to be consistent

The output from a robotic welding cell is only as good as the parts fed into it. In order to gain the advantages of these systems, it is critical to have accurate, repeatable part designs. Gaps, poor fit-up or poor joint access all prevent a robot from completing its job correctly.

The best part designs for a robotic welding application are simple ones that allow the robot to execute the same weld repeatedly. High-volume applications with low-variety parts are especially poised to gain the advantages of robotic welding. Companies should try to avoid part designs that require intricate tooling or clamping to hold it in place, as both can hinder the efficiency of the robot and also add to the up-front cost of the operation. That said, in some cases, companies may still be able to gain a good payback on the investment in tooling for slightly more complex parts, but they will need to weigh out the pros and cons of that cost ahead of time.

Companies also need to be certain to assess their overall welding operation for consistent process flow. Bottlenecks upstream can easily slow down the movement of parts into the robotic work cell and the ability of the system to function to its full capacity. A robot that sits idle costs time and money. Some companies may need to reconfigure operations or set up a flexible cell that can manage quick tool and fixture changes in order to minimize bottlenecks in the process flow. It is also important to have adequate labor to supply the robot with parts.

Again, companies should consider tapping the knowledge of a robotic welding integrator for advice and assistance to optimize process flow.

3. The MIG guns and consumables on the robot can impact productivity and profitability

The robotic MIG gun and consumables on a robot together are responsible for directing the current to the arc to complete the weld, making them integral components in the whole system. To gain the best quality and to avoid expensive downtime for maintenance, repairs or replacement, companies need to select a robotic MIG gun that is suitable for the amperage, duty cycle and cooling capacity needed in the application. Using a robotic MIG gun that offers inadequate cooling or amperage can cause performance issues and lead to premature failure — both factors that increase costs and downtime. Likewise, using a robotic MIG gun that offers higher amperages than necessary raises the total cost of ownership, as typically the cost of a robotic MIG gun increases directly in proportion to its amperage.

Companies also need to select their consumables — contact tips, nozzles, retaining heads (diffusers) and liners — carefully and manage them properly in order to gain optimal productivity and lower costs.

Look for contact tips with more mass at the front end and that are buried further in the gas diffuser — both features help the tip resist heat from the arc. Consumables with tapered connections mate securely together to provide good electrical conductivity, which also reduces heat buildup and helps the consumables last longer.

Contact tips with long tails and coarse threads are also a good option to simplify installation — they virtually eliminate cross-threading because the tail concentrically aligns the contact tip within the diffuser before the threads engage. This easy-to-install design works well for operations with less experienced welding operators who may not be as familiar with consumable changeovers. It also helps reduce unplanned downtime for troubleshooting associated with cross-threading.t      

As with robotic MIG guns, carefully matching the type of consumables to the application can keep companies from having to address premature failures and/or accrue costly downtime (not to mention, lapses in production). It can also keep them from overpaying for consumables that may be too much for the application.

Companies should also consider the mode of welding when selecting consumables, as technology such as Pulsed welding tends to be especially harsh on consumables and often requires heavy-duty options to withstand the heat of the arc for longer periods of time. For these applications, look for contact tips that are engineered with a hardened insert, making them more resistant to arc erosion and wear. They typically last 10 times longer than copper or chrome zirconium tips. Companies can regain as much as 95% of lost productivity for contact tip changes with this style by reducing planned downtime for the task.

4. Peripherals can help improve the return on investment in a robotic welding operation

Peripherals refer to any additional equipment integrated into the robotic welding system to maximize its performance. They include items such as a nozzle cleaning station (sometimes called a reamer or spatter cleaner), anti-spatter sprayers, wire cutters and neck alignment tools. Unfortunately, some companies downplay the value of peripherals, viewing them as an unnecessary cost, and don’t realize that they can play an important role in reducing downtime and rework, improving quality and increasing productivity.

Consider a nozzle cleaning station, for example. As its name implies, this peripheral cleans the nozzle of dirt, debris and spatter, typically during routine pauses in the robotic welding operation. This cleaning action helps prevent shielding gas coverage loss that could lead to weld defects, expensive rework and lost productivity. The equipment also helps the front-end consumables last longer — and longer consumable life means less downtime for changeover and less expense for replacements. The addition of an anti-spatter sprayer further improves consumable life and performance by adding an anti-spatter compound that serves as a protective barrier against spatter buildup and other contaminants.

In the long run, the up-front investment in peripherals such as these can lead to measurable savings and provide a better return on investment by aiding the robot in doing what it does best: complete consistent, high-quality welds for longer periods of time than a semi-automatic welding operation. 

5. Having skilled operators with proper training to oversee the robotic weld cell is critical

Robotic welding operations require ongoing supervision and maintenance, and that job needs to be completed by a skilled operator who has undergone the proper training. When considering an investment in robotic welding, companies should take care to evaluate the available pool of talent. As a rule, skilled welding operators and/or employees with prior robotic welding experience are the best candidates to supervise the weld cell.  After the proper training, which a robotic integrator or OEM can typically provide, these employees can provide the necessary operating and troubleshooting skills to ensure the maximum uptime in the robotic welding cell.

As part of the routine training, it is absolutely necessary for the operators who will be overseeing the robot to be able to schedule and perform routine preventive maintenance on the system. Implementing preventive maintenance helps minimize unnecessary downtime and keep the robotic welding system running more smoothly. If problems can be solved before they arise and the robotic welding equipment made to last longer, it can protect the company’s investment, and ensure the productivity and profitability sought by this equipment in the first place.

Companies should consider vetting robotic welding integrators to determine the availability and costs associated with the training of personnel. Typically training lasts one to three weeks, depending on the certification level desired, and continuing tutorials are often available.

In the end, careful planning, good equipment selection and proper training are all “must-knows” for managing a profitable and productive robotic welding operation. So whether a company is new to robotic welding or trying to improve an existing operation, knowing some key factors can go a long way in helping to gain a competitive edge and to make the most out of the investment.

FAQs About Robotic Peripherals Answered

Automated welding systems add speed, accuracy and repeatability to the welding operation. They can help operations increase productivity and reduce costs in a relatively short period of time. But these results don’t happen by accident; they require careful equipment selection, system integration and training — including the selection of peripherals.

Peripherals refer to the additional equipment that is integrated into the automated welding system to maximize its performance. The selection and implementation of the proper peripherals should be a part of the welding automation plan upfront, not later after the system is in place. Incorporating peripherals early in the process can result in more efficient throughput, long-term cost savings, better quality welds and minimized downtime.

Consider these frequently asked questions about peripherals to clarify their role in the welding operation and better understand their benefits.

Why is a nozzle cleaning station important?

A nozzle cleaning station (also called a reamer) cleans spatter from the inside of the welding consumables on the front-end of the MIG welding gun, including nozzles, contact tips and retaining heads.

There are several benefits a nozzle cleaning station can offer. First, by keeping the nozzle clean, this equipment helps reduce the risk of losing shielding gas coverage that could potentially lead to expensive re-work. Secondly, it helps lengthen the life of the consumables (nozzle, contact tip and diffuser or retaining head) and the robotic MIG gun. Longer equipment life translates into less downtime and also less cost for equipment — both factors that contribute positively to a company’s ROI of its automated welding system.

What’s the benefit of adding an anti-spatter sprayer to a nozzle cleaning station?

An anti-spatter compound (typically in liquid form) can provide additional protection to consumables. A sprayer applies the anti-spatter compound to the front-end consumables after they have been cleaned. In many cases the sprayer can be mounted on the nozzle cleaning station, integrating it into the overall process of nozzle cleaning.

Recall that the rule of “less is more” applies. Excessive anti-spatter usage can lead to unnecessary costs and the compound may build up on the nozzle, the welding robot and the parts being welded. In the long term, a high spray volume could cause additional problems that are just as harmful as spatter build-up itself.

How can a wire cutter help the operation?

Many robotic welding applications require consistent welding wire stick-out (also called electrode extension) when the arc initiates. A wire cutter can help maintain that consistency.  

As its name implies, a wire cutter cuts the welding wire to a specified length and it also removes any inconsistencies at the end of the wire, resulting in more reliable and smoother arc starts. For companies that program their robot to seam track (or find the joint) through touch sensing, the consistent wire stick-out allows for more reliable and repeatable welds by helping the robot to more easily locate the correct spot to begin welding.

Most wire cutters are capable of cutting different types of welding wire, including stainless steel, flux-cored and metal-cored, usually up to 1/16-inch diameter. Companies may prefer to mount the wire cutter on a nozzle station or locate it remotely, according to their needs.??

How do neck inspection fixtures work?

This peripheral verifies that the robotic MIG gun’s neck is set to the intended tool center point (TCP), allowing it to be readjusted after a collision or if the neck becomes bent due to routine welding. Most inspection fixtures will accommodate standard necks for a particular brand of robotic gun.

After determining the tolerances for the program, a trained welding operator simply adjusts the neck to meet the correct specifications. This adjustment helps prevent costly rework due to missing weld joints and can help prevent the downtime to reprogram the robot to meet the welding specifications with the existing bent neck. For companies that maintain a large number of robots, a neck inspection fixture can also help prevent confusion when exchanging necks from one robotic MIG gun to another. Welding operators simply remove a bent neck, exchange it with a spare that has already been inspected and adjusted, and put the robot back in service immediately. The damaged neck can then be set aside for inspection while the robot is still online.

How can peripherals help protect against collisions?

In cases where collision detection is integral to the robot, a solid arm mount can help protect against a collision. As its name implies, a solid arm mount is just that: solid. It does not provide electrical feedback during an impact, but rather relies on the software to stop the robot during an impact.

For robots without collision detection, a clutch may be added to the system. The function of a clutch is both mechanical and electrical. It recognizes the physical impact of the collision and then sends an electrical signal back to the robot controller, causing the system to stop. This action prevents damage to the robot and the robotic gun. It also alerts the welding operator overseeing the operation that there is an incorrect variable in the weld cell.Both clutches and solid arm mounts require mounting arms to attach them to the robotic MIG gun and hold it in a specified position, so the robot can repeat the same weld throughout the welding process. These mounting arms are generally composed of a durable aluminum alloy that can resist breakage during an impact.                                                                                                            

Although the addition of peripherals to an automated system does add to the initial cost of automating, this equipment can lead to measurable savings in the long term. Since the goal in automated welding is repeatability and increased productivity, any additional equipment that can help achieve that result is worth the consideration.

From the Contact Tip to the Robot: Answers to Frequently Asked Questions About Welding Automation

Robotic welding systems, when implemented properly and for the right application, can add great value to a welding operation. In addition to offering faster speeds and greater productivity, robotic welding systems can improve weld cosmetics, reduce rework and repairs, lower materials costs by limiting overwelding and also reduce labor costs. The consistency of these systems and the typically rapid return on investment (ROI) make them especially appealing for companies looking to gain a competitive edge. 

Still, setting up a robot and selecting its components — the consumables and the gun, for example — can be a complicated business, especially for first-time users. In fact, the simple question of whether to automate may itself be confusing to a company that hasn’t used a robotic welding system before.

For insight into welding automation, consider these answers to some of the most frequently asked questions. 

What are the best applications for a robotic welding system?

High-volume, low-variety applications are well-suited to robotic welding; however, lower-volume, higher-variety applications may also work if implemented with the proper tooling. Companies will need to consider the additional cost for tooling to determine if the robotic welding system can still provide a solid return on the initial investment.

In either case, it is critical that the application have simple, consistent parts so that the robot can repeatedly execute the weld in the same location. Having a blueprint or electronic CAD drawing is helpful. Robotic integrators can review the blueprint or create a software simulation that can assess the suitability of the part for welding automation. These assessments can not only help to visualize the quality of the part to be welded, but they can also identify ways to fine-tune tooling to optimize the process. Workflow is also important. Companies should be certain to have a high enough flow of parts to the robotic welding cell for the application so that it can operate consistently. Delays in upstream parts fabrication can cause bottlenecks that result in costly downtime.

Is it better to use fixed automation or a robot?

Each type of automation has its own best applications. Fixed automation is an efficient and cost-effective way to weld simple repetitive straight welds or round welds, where the part is rotated. It is good for high volume applications of a single part. Fixturing for fixed automation can be expensive, however, so companies will need to factor that cost into the initial investment and determine whether this type of automation is still cost-effective for the long-term. They also need to determine if future jobs will require retooling, as that will add further to costs. 

For companies wishing to have the flexibility to weld on multiple applications, a robotic welding system is a better choice. Because a robot can be programmed for multiple jobs, it can often handle the task of many fixed-automation systems.

Who is the best candidate to operate a robotic welding system?

Robotic welding systems require a trained operator. Skilled welding operators or those with previous robotic welding management experience are good candidates. The person overseeing the robotic welding system should be able to program it, troubleshoot errors and perform preventive maintenance. Robotic OEM manufacturers can often provide the appropriate training for employees who are new to welding automation. It is recommended to look for ongoing training support. Some robotic integrators or welding solutions providers offer online tutorials, troubleshooting information and/or additional on-site training as part of their aftercare support.

Can an air-cooled robotic MIG gun be used instead of a water-cooled gun?

In many cases, yes. It is absolutely necessary, however, to ensure that the air-cooled robotic MIG gun is rated at a high enough amperage and duty cycle for the application. For example, an air-cooled robotic GMAW gun rated at 500 amps with 60 percent duty cycle using mixed gases will be capable of welding continuously for 6 minutes (out of an available 10 minutes) at about 350 amps. When welding with pulsed waveforms it is very important to review the peak currents and ensure they do not exceed 350 amps at any time during the welding process.

Air-cooled MIG guns offer the advantage of being less expensive — both to purchase and maintain — but if a company anticipates longer periods of welding or higher amperage needs, it may be necessary to shift toward a water-cooled gun. There are also “hybrid” robotic MIG guns available in the marketplace. These guns feature a durable neck similar to an air-cooled MIG gun, but offer the higher cooling capacity of a water-cooled model by way of exterior water lines. These guns can be easier to maintain than a standard water-cooled MIG gun and typically offer 300 to 550 amperage welding capacity at 60 percent duty cycle (using mixed gases), making them adequate to weld on a variety of applications.

What are the best consumables to use?

The style of consumables — contact tips, diffusers (or retaining heads) and nozzles — depends entirely on the application. Ideally, the consumables should be durable enough to last the duration of a robotic welding shift to help minimize downtime for changeover. High-amperage applications (over 300 amps) with high levels of arc-on time can often benefit from heavy-duty consumables. Chrome zirconium products are a good choice. For lower amperage applications or applications with short arc times, standard-duty consumables (often copper) are appropriate.

Companies also need to consider the access required to reach the weld joint. In some cases, it may be necessary to use a bottleneck, straight or tapered nozzle, all of which are narrower, to maneuver around tooling or into complex areas.     

It is equally important to consider the mode of welding being used. For example, pulsed welding programs can be especially harsh on consumables due to the higher levels of heat that the process generates. These applications can benefit, often, from heavier-duty consumables.

What is the benefit of touch sensing?

Touch sensing, sometimes called joint touch sensing, is a software system that employs the welding wire or nozzle to help locate the joint in a robotic welding application. This software allows the robot to store position data and send electrical impulses back to the controller once it has located the joint. For applications that have slight variations in parts, touch sensing helps maintain weld consistency. It is also more cost-effective than investing in new tooling and fixturing to hold a part in a precise location; if the part moves slightly, the robot can still locate the joint and weld accurately, as long as the joint has well-defined edges. Touch sensing does add a few seconds to the cycle time, but it is a good choice especially for companies welding large, thicker parts that would be costly to rework should the joint be welded poorly.

To gain optimal results, it is a good idea to combine touch sensing with a robotic MIG gun that has a wire brake feature. The wire brake holds the welding wire in a set position while the robot articulates and searches for the weld joint, ensuring more accurate touch sensing readings. ?

Is it necessary to add peripherals to a robotic welding system?

It is always advisable to add peripherals, particularly a nozzle cleaning station (also called a reamer or spatter cleaner), to a robotic welding system. This peripheral cleans spatter from the inside of the welding consumables on the front end of the MIG welding gun, including nozzles, contact tips and retaining heads. It helps extend consumable life, and with that, reduces downtime for changeover during production and also the cost for replacing consumables. Nozzle cleaning stations also help reduce the risk of losing shielding gas coverage (due to spatter build-up) that could potentially lead to expensive re-work.

Adding a sprayer provides additional benefits, too. This peripheral can be mounted on the nozzle cleaning station and works by applying an anti-spatter compound to the front-end consumables after they have been cleaned. This compound coats the inside and outside of the nozzle, and also the contact tip, creating a protective barrier between the consumables and spatter.

What type of payback can be expected from a robotic welding system?

The payback on a robotic welding system can be relatively quick in many cases. To determine it, companies need to assess their parts volume, as well as the amount of time it takes to weld those parts manually, and compare that information to the potential cycle times of a robotic welding system. Determining this volume is critical, given that labor comprises 75 percent of the cost of a manually welded component. Even if a company produces the same amount of parts, labor could be reallocated elsewhere to increase productivity and enhance the payback on the robotic welding system.

Companies should also calculate the savings for overwelding often associated with semi-automatic welding applications. A weld bead that is 1/8-in. larger than necessary can often double filler metal costs. Because robots are more precise in their placement, companies should calculate the potential savings for filler metals when calculating payback. Because robotic welding systems use bulk filler metal drums that require fewer changeovers (and sometimes have the perk of bulk purchasing discounts), that savings can also be considered.

As always, when companies encounter problems with a robotic welding system or have questions about a program or component, it’s best to contact a trusted robotic integrator, welding distributor or welding equipment manufacturer for support. Robotic welding systems aren’t cheap and companies should never take chances with their investment by guessing about the right course of action. The right information is the best way to gain productivity, quality and cost improvements from a robotic welding system.

Don’t Let Your Gun and Consumables Get in the Way of Your Welds

A Guide to Troubleshooting Common GMAW Gun and Consumable Problems

Making a high-quality MIG weld is no easy task. But making a high-quality MIG weld when your gun and consumables aren’t functioning properly is just about impossible. Porosity, excessive spatter, undercut and burn back are just a few of the problems that can occur when something’s not right with these components. Troubleshooting weld defects can be a difficult task, since any single problem can be caused by a variety of factors.

It is often easier to avoid weld defects from occurring by conducting a thorough check of your MIG gun and consumables prior to welding than it is to troubleshoot an existing issue. Problems will inevitably occur, however, and being able to quickly and accurately identify their source will save you both money and frustration.

The following is a guide to solving many of the most common consumables and gun-related problems associated with MIG welding.

Wire does not feed — There are a number of problems that could cause the wire to not feed, including issues related to the feeder relay, control lead, adapter connection, liner or the trigger switch.

Begin troubleshooting this problem by checking whether the drive rolls are turning when the gun trigger is pulled. If they are not turning, an electrical continuity failure is occurring. Check the terminals and connector contact pins to ensure the gun is properly connected to the wire feeder. The wire can also fail to feed if the trigger switch is broken, or control leads in the gun cable are damaged. If this is the case, they will need to be replaced.

If the drive rolls are turning but the wire is not feeding, it is usually caused by inadequate drive roll pressure or a blockage in the contact tip or liner. Check the drive rolls and contact tip before moving on to the liner, which takes more time and effort to check and replace.

If a faulty feeder relay is the cause, consult the feeder manufacturer for information on correcting the problem. A broken control lead or a poor adapter connection will require you to test and replace the leads and/or contact pins. Some guns feature a spare set of control leads that can be used to correct the problem. With others, it may be necessary to replace the entire cable.

Contact tip burnback — Burnbacks can be caused by improper equipment set-up, including incorrectly installed consumables. Look for easy-to-install contact tips, such as those with coarse threads that require only a quick turn to be properly seated. Be sure to check the following factors if you experience an increase in your contact tip burn back rates.

Improper tip recess and improper wire stick out can cause increased burnback frequency. In the case of incorrect tip recess (or stick out), you will need to install a nozzle and tip combination with a different recess. Similarly, adjusting the distance between the gun and the workpiece (tip-to-work distance) will resolve burnback problems associated with wire stick out.

A faulty work lead/ground is another possible cause of burnback. Check and possibly replace the electrical connections and cables to ensure a faulty work lead/ground will not cause any further burnback.

Erratic wire feeding, a problem with several possible causes, is a frequent source of burnback. See the section below for information on correcting erratic wire feeding.

Erratic wire feeding —Erratic wire feeding simply means that the wire is not feeding from the gun at a consistent rate. This problem is usually caused by the liner, the drive rolls or the contact tip.

A worn out or kinked liner, or build-up of debris, filings, dirt and other foreign material inside the liner, the wrong size liner and misalignments or gaps at the liner junctions caused by an improperly trimmed liner can all cause the wire to feed erratically. In each case, the liner will likely need to be replaced and properly trimmed so that it fits as tight as possible to the other components. Some liners require no measuring for error-proof installation. After being loaded through the neck of the gun, these liners are locked in place and concentrically aligned with the gas diffuser and the power pin. This creates a perfectly aligned and gap-free wire feed path for improved wire feeding.

Improper drive roll size, worn out drive rolls and improper drive roll tension are also potential causes of erratic wire feeding. Replace worn out drive rolls or those of the wrong size with correctly sized and tensioned drive rolls.

Another common cause of erratic wire feeding is a contact tip that is worn out or the wrong size for the wire being used. If you suspect the contact tip is causing the wire to feed erratically, it is best to replace the tip. To extend contact tip life and reduce the risk of erratic wire feeding, look for a consumable system that locks and aligns the contact tip to the liner. This helps ensure the wire feeds smoothly through the tip and reduces internal wear, friction and heat.

Short contact tip life —Although quality plays a critical role in contact tip service life, tip life can vary dramatically from application to application, and it is difficult to give an average longevity to expect from your tips. If you notice a change in your contact tip life from their normal life spans, however, check the following factors as necessary.

Using the wrong size contact tip, exposure to excessive heat or erosion caused by the wire are all contributing causes to premature contact tip degradation.

If your contact tip is melting due to excessive heat, it is likely a result of exceeding the product’s rated amperage or duty cycle, in which case you should replace either the tip or the tip and the MIG gun with heavy-duty equipment. You can also reduce heat exposure with a contact tip that is buried further into the diffuser. It is not only protected from the heat, but also cooled by the shielding gas. Also, look for tapered consumable designs that lock conductive parts, including the contact tip together. These help minimize electrical resistance and heat buildup that could shorten contact tip life. Locking conductive parts together provides concentricity that helps prevent keyholing (or uneven contact tip wear) that can reduce the overall life of the contact tip.

If the wire is prematurely wearing out the contact tip, the drive rolls may be creating small burrs on the wire that can erode the inside of the contact tip. Setting the drive roll tension too high can also create deformities in the wire that cause it to mechanically wear out the tip, which is especially common with knurled drive rolls. If this is the case, the drive rolls will need to be properly tensioned or replaced.

Gaps and misalignments along the feed path within the gun may also result in the wire wearing away the contact tip from the inside leading to a burnback or premature keyholing. Ensure that your MIG gun liner has been trimmed to the correct length during replacement, or use a consumables system that ensures accurate liner length without measuring to prevent these issues.

The wire can also cause premature contact tip failure if it is rusty, dirty or simply a low quality wire with excessive imperfections. If this is the case, the wire needs to be replaced.

Erratic arc — If not caused by erratic wire feeding, the most common cause of an erratic arc is usually inconsistent electrical conductivity. If the contact tip is either too big to begin with or worn out from use, it can fail to consistently conduct electricity to the wire and thereby cause an erratic arc. In either situation, the contact tip should be replaced with a new one that is the correct size.

If the gun neck being used is too straight, it could produce an erratic arc through a lack of conductivity. The bend in the neck increases electrical conductivity by creating a continuous contact point as the wire is guided along the outside of the bend in the liner and through the tip. An erratic arc caused by an insufficient bend angle needs to be addressed through the installation of a neck with a 45- or 60-degree bend. Another possible cause of an erratic arc is a worn or kinked liner, or build-up inside the liner, which should be resolved by replacing the liner and checking the condition of the wire to ensure there are no inconsistencies that will cause the problem to recur.

Also be sure to check the work lead/ground clamp and gun connections to ensure a good electrical circuit is established.

Extreme spatter — From a gun and consumables perspective, improper tip installation and improper weld puddle protection are two common causes of excessive spatter (see photo). First check to make sure the tip is installed properly and that it is at the correct recess for the application.

Next, verify that the correct shielding gas is being used and that the weld is receiving adequate shielding gas coverage. Too little or too much shielding gas can both cause poor weld puddle protection and lead to excessive spatter. Clogged nozzle and diffuser orifices could cause too little shielding gas flow, so check and clean or replace the nozzle and diffuser as necessary.

Additional non-equipment-related causes of excessive spatter can be incorrect electrical parameters or a contaminated work piece. Verify that the voltage and wire feed speed are at the recommended levels for the application and that the work piece is free of rust, mill scale and other contaminants.

Some welding factors, such as the short circuit process, using pure CO2 gas and galvanized metal have inherently higher spatter rates, which can be mitigated through using an Argon rich gas blend or a different filler metal transfer process.

Porosity in weld — Porosity, which are holes in the weld bead caused by trapped contaminants and gasses can have many causes (see photo). Exposure of the weld puddle to atmospheric air, whether as a result of plugged gas ports, a ruptured gas hose, too much or too little gas flow, or a faulty solenoid, is one of the most common causes of porosity. Ensure proper gas flow before moving on to diagnose other possible causes of porosity.

Worn out or damaged parts, including the diffuser, the insulator, o-rings and fittings can all lead to compromised gas coverage. Check each of these components and replace as necessary. Further causes of porosity include excessive wind in the welding environment blowing away the shielding gas, in which case you will need to either move to a less windy site or set up screens to block the wind.

Gun running hot — If your gun is getting too hot, it is most likely because you are either exceeding its rated amperage or duty cycle, or else loose power connections or a degraded power cable are causing excessive resistance in the weld power circuit. If you exceed the gun’s duty cycle, you can either decrease the parameters to within the gun’s rating, or use a higher rated gun.

If loose connections are causing the problem, clean and tighten connections that are in good working condition or replace ones that are worn out. One common symptom of loose power connections or a degraded power cable is a discolored liner (see photo). The discoloration is caused by heat and indicates that weld current is being carried through the liner instead of the gun’s power cable. Also check to make sure the work lead/grounding connection is tight and free of obstruction.

Although it’s clear from the above problems that there are many ways that your MIG guns and consumables can lead to poor weld quality, the good news is that most problems usually have simple and inexpensive solutions. By following these recommendations, you will be able to address and resolve the vast majority of the most frequently encountered welding problems.

For more information on troubleshooting specific welding problems, contact your nearest welding distributor or the customer service department at the equipment manufacturer.