Preventive Maintenance for Reamers, Accessories and Other Peripherals

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.

PM tips for reamers and accessories

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:

1. Check that the consumables are aligned properly to the reamer. This helps ensure that the jaws of the reamer clamp the nozzle to the V-block correctly and that the consumables are lined up concentric and parallel to the cutter blade for optimal spatter cleaning.
    
2. Clean the spindle cover shroud free of spatter and also clean the clamp jaw and V-block surfaces to gain proper nozzle alignment. Use a brush or compressed air. Look for any signs of wear on these components.
    
3. Make sure the air lines connected to the reamer are free of frays, as leaks will prevent the reamer from receiving enough air to remove spatter properly. Look for any damage to the interface cable.
    
4. Check the oil level in the lubricator reserve — the reamer motor depends on a consistent supply of oil. Also check the level of anti-spatter liquid in the anti-spatter sprayer. Fill as needed. An option to simplify PM of the anti-spatter sprayer is to employ a multi-feed system that allows 5- or 55-gallon drums of anti-spatter liquid to be connected to a manifold system to feed multiple sprayers on multiple reamers. This eliminates the need for daily reservoir fills.

On a weekly basis, continue to examine the integrity of the consumables and follow these guidelines:

1. Inspect the cutter blades for dullness, clogging and possible breakage, replacing as necessary. Note the service life of cutter blades will vary based on the application.
    
2. Again, check that the lubricator is working properly with the right level of oil, and clean or replace the filter as needed.
    
3. Check the LEDs to ensure reamer and controller communication, and wipe the nozzle detect proximity sensors clean so they can function properly.
    
4. Look over the spray head on the anti-spatter sprayer to be sure it is delivering a normal amount of liquid spray. Clean the head and adjust as necessary.

Monthly PM for reamers and accessories requires less steps but is more intensive. It may require scheduling a time off cycle to complete.

1. Check that the belt tension lock screw and bolt are securely tightened.
    
2. Examine the spindle unit for wear, replacing if necessary, and inspect the solenoids, spooling them to prevent leaks and to make sure they are operating properly.

Lastly, on an annual basis:

1. Inspect the drive belt for signs of fraying and replace as necessary.
    
2. Replace the spindle cap seal and repair any visible damage.
    
3. Perform a complete cleanup of the reamer and anti-spatter sprayer.

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.

PM tips for wire cutters

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.

1. On a daily basis, check the airlines and interface cable for leaks or frays. Be sure that the solenoid valve is providing air to the system.
    
2. Weekly, check that the cutter blades are sharp enough to cut the wire. Look for signs of dullness, looseness or breaks. Replace as needed. Also empty the wire catcher basket.
    
3. Quarterly, apply general purpose grease (NLGI Grade 1-1) through the grease fittings on the sides of the main body of the wire cutter. This helps lubricate the sliding surfaces of the equipment.

The value of peripherals

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. 

Robotic Welding: Troubleshooting FAQs

Every operation wants to avoid downtime, as well as the cost for troubleshooting problems in the robotic 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.

Q: What are causes of poor consumable performance?

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.

Q: What causes poor wire feeding?

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.

Q: Why is the cable prematurely failing?

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.
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)?

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.

Q: How do I fix poorly performing peripherals?

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:

1. Improperly taught position of the robotic MIG gun nozzle in relation to the reamer. This position should be concentric to the cutting blade on the reamer at the proper insertion depth to ensure thorough cleaning of the nozzle.
   
2. Too much or too little anti-spatter spray in the wrong location. Anti-spatter spray should cover the inside of the nozzle and the outside should be covered within 3/4 of an inch from the bottom of the nozzle. Spray for only a half-second. In production, the anti-spatter should evaporate on contact with a hot nozzle — if your nozzle is dripping, you’re spraying too long.
   
3. Using the wrong cutting blade or improper insertion depth will not allow for proper removal of accumulated welding spatter.

Correcting common problems

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.

7 Tips for Implementing a Robotic Welding Cell

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.

Tip No. 1: Use proper weld settings

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.

Tip No. 2: Choose the right wire

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.

Tip No. 3: Consider the gun and consumables

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.

Tip No. 4: Reduce cable wear

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.

Tip No. 5: Establish TCP

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.

Tip No. 6: Program the robot path  

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.

Tip No. 7: Ensure proper fit-up

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.

Closing

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 FAQs Answered

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.

1. What drive roll should I use, and how do I set the tension?

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.

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.

2. How do I get the best results from my MIG welding wire?

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.

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.

3. What contact recess should I use?

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.

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.

4. What shielding gas is best for my MIG welding wire?

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.

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.

5. What is the best way to control my weld puddle?

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.

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.

5 Common Failures in Robotic Welding and How to Prevent Them

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. 

Failure No. 1: Burnback and contact tip wear

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. 

Failure No. 2: Broken cutter blades in the reamer

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.

Failure No. 3: Loss of tool center point

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. 

Failure No. 4: Broken discs

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. 

Failure No. 5: Incorrect tool path

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.

Maintenance is key

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. 

Anti-Spatter Sprayer: How to See the Best Results

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.

Follow these best practices for anti-spatter liquid usage

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.
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.

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.

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

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
• Easy cleanup and no residue
• Compatibility with the nozzle cleaning station or reamer being used

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.

Safety Tips

Even though the more popular water-based anti-spatter compound is non-toxic, you should always take care when handling and using it.
Consider these tips:

1. Avoid breathing in spray mists, and always wash your hands after encountering the compound. or example, when filling the sprayer or setting up an anti-spatter multi-feed system.
   
2. Use a NIOSH-certified (or equivalent) respirator during spraying.
   
3. Wear Nitrile or Butyl gloves and wear chemical safety goggles for the best protection.
   
4. Utilize local exhaust ventilation near the sprayer.
   
5. Store anti-spatter compound containers according to the temperatures recommended by the manufacturer.
   
6. Consult the SDS sheet for complete recommendations for proper anti-spatter liquid usage.

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

Spatter in Welding: Should You Consider Anti-Spatter Liquid?

Are you losing money and arc-on time for excessive contact tip changeovers? Anti-spatter liquid may be an option to help.

What is anti-spatter liquid?

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
• Lowers cost for consumable inventory and management
• Reduces operating costs by improving weld quality and lowering rework

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.

Does my operation need to use anti-spatter liquid?

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.

Ethernet vs Standard Reamer: Making the Selection 

Uptime is key in any robotic welding system. Not only does it help companies increase productivity, but it also supports a solid return on investment in the equipment. The addition of peripherals, like a nozzle cleaning station or reamer, can help further those goals.

A reamer cleans the consumables on a robotic gas metal arc welding (GMAW) gun to prevent spatter buildup that could lead to porosity. This consumable cleaning reduces downtime for changeover, improves weld quality and minimizes costs. There are two main styles to choose from: standard- or Ethernet-based. Both provide the same function of cleaning the nozzle free of spatter, with the Ethernet-based reamer providing additional functionalities that some companies find beneficial to their robotic welding operation.

During cleaning, the robot is programmed so that it will dock the nozzle of the GMAW gun against a v-block on top of the reamer, typically during routine pauses in welding cycles. Once the nozzle is in place, a signal is relayed to the reamer to close its clamps. When the clamps hold onto the nozzle, concentric to the cutter blade, another signal is sent to the unit telling the spindle to rise and spin the cutter blade, removing the spatter from the nozzle and gas diffuser.

Many companies also employ an anti-spatter sprayer that applies a coating of anti-spatter compound to the front-end consumables after every cleaning cycle. Usually this spray only lasts a half second to avoid saturating the nozzle and wasting the anti-spatter compound.

Standard versus Ethernet

A standard reamer features inputs and outputs that are plugged into a Program Logic Controller (PLC), including the inputs that control the nozzle clamping, cutter actions and anti-spatter spray process. These are the traditional reamers used by many companies.

A standard reamer must be plugged in with a power cord, in addition to having several leads connected to several inputs and outputs, so it may require cord management to minimize clutter.

Ethernet reamers, a newer style, feature a single Ethernet cable that serves as a multipurpose input/output and connects to the PLC. Due to their connectivity, they enable robotic welding system operators to set a program that handles complex equations so they can easily duplicate that program to another weld cell.

Consider a robotic welding operation featuring 100 weld cells that require 50 reamers total. If there are two robots per cell sharing the same reamer, and the reamer program for all 100 weld cells is virtually identical to the first cell, operators can set the program in the first cell to alternate between the two robots and then essentially “copy and paste” that program into the next 99 cells. For this reason, an Ethernet reamer can offer time savings, especially at the integrator level.

With an Ethernet reamer, robotic welding operators can also program a double stroke. If one cleaning cycle wasn’t quite enough to remove spatter from the nozzle, a signal is sent, as the spindle unit and cutter retract, to clean again.

Ethernet reamers can come with an additional Ethernet port, which can be used to daisy chain to other Ethernet devices. This means an operator does not require an individual Ethernet cord run from the reamer to the PLC, from the robot to the PLC, or from the power source to the PLC. He or she can instead run them in a series, together. This cuts down on the number of wires and cords in the cell, further reducing clutter. They also allow operators to monitor the cycle times carefully and more easily troubleshoot any issues that arise.

That said, some older robotic welding operations are not Ethernet-ready because they use standard-based signals, and some facilities simply do not have the infrastructure, resources, capabilities or knowledge necessary to justify the higher investment of an Ethernet reamer.

As with the implementation of any robotic welding system, having a champion with a certain skillset who can oversee the implementation of an Ethernet reamer and know how to program it is incredibly helpful, and it can ensure the success of the investment.

Regardless of which style of reamer is used, standard- or Ethernet-based, it should always be programmed with the gun docking to the reamer and the height set properly, following the instructions outlined in the owner’s manual. Always dock the nozzle concentric to the cutter, and always supply the reamer with clean, dry air.

Robotic reamer accessories

Almost all reamers function the same way, but accessories can be added to make them behave differently or optimize them for a welding operation.

Wire cutter attachments, for example, cut the wire stick out to a set distance so that the robot can employ wire-touch sensing. Most operations that use a wire cutter on the reamer also use a wire brake on the GMAW gun. The wire brake then holds the wire in place at that set distance so it can’t move — keeping it from extending or retracting as the robot moves. The wire brake works well in combination with robots employing touch sensing, as it keeps the wire in a set position while the robot searches and accurately locates the weld joint.

Lubricators are yet another valuable reamer attachment. A lubricator applies oil to the air motor impeller, coating the blades so they will not absorb moisture that might be present in the air. Keeping these blades lubricated helps extend the life of the motor and protect a company’s investment in a reamer.

Reamer stands are another accessory that can be useful. They are essentially a pedestal that an operator can mount the reamer to, with a stand bolted into the floor. Options exist in the marketplace that can be customized to a specific height to help streamline the weld cell layout and those that feature quick-change base plates to facilitate reamer change-outs when necessary.

Spray containment units are also common reamer attachments designed to keep the welding cell clean of anti-spatter compound. A spray containment unit is a cylinder that mounts on top of the sprayer head to keep excess anti-spatter spray from bleeding into the open environment in the weld cell.

Another useful reamer accessory is a nozzle detect, which is a proximity switch that detects whether a nozzle is present or not. Occasionally, when a robot enters its ream cycle, there may not be a nozzle present on the GMAW gun; it may have been bumped off during routine movement of the robot arm or from accidentally hitting a fixture. Nozzle detect will recognize the absence of the nozzle or if a nozzle is pulled off during a cleaning cycle. These occurrences are especially prevalent when an operation is using a slip-on nozzle, which is more likely to disconnect.

For large robotic welding operations, a multi-feed anti-spatter sprayer system may also be useful. This attachment allows up to 10 reamers to be working off one larger container of anti-spatter compound, eliminating the need for an operator to go into the cell and fill up the smaller sprayer reservoirs attached to every reamer. This reduces how often anti-spatter levels must be checked and the associated downtime.

Although all these accessories, and the reamer itself, do add to the cost of a robotic welding system, they can also lead to measurable cost savings and profits in the long run. Remember, the goal in robotic welding is repeatability and increased productivity, and any additional equipment that can help achieve these results may be worth the investment.

In the end, reamers help clean GMAW gun consumables and prevent porosity. They also reduce downtime and labor for changeover. Since cleaner nozzles and other consumables produce cleaner welds, they can help a robotic welding system produce higher-quality products and be more productive.

Extra: Reamer maintenance

While reamers and their attachments are often afterthoughts for many operators, maintaining them properly and ensuring parts are replaced promptly can greatly improve a robotic welding operation’s overall efficiency, quality and productivity.

All limit switches on a reamer have a life expectancy and must be replaced if they don’t activate any longer, for the reamer to work properly.

Cutter blades also need to be replaced, since the edges will become dull over time and will no longer cut as effectively. In some cases, an operator might visually see that one of the flutes on the cutter is broken.

Operators must also monitor the reservoirs in anti-spatter sprayers regularly, to ensure they have anti-spatter compound in them.

Similarly, if an operation is running a lubricator over an extended period, operators will need to refill the oil reservoir on the lubricator.
 

7 MIG Welding Mistakes and How to Avoid Them

MIG welding offers numerous benefits for productivity without sacrificing quality of the finished weld, but there are many factors that can interfere with successful MIG welding performance.

You can improve performance and results in your MIG welding applications — and save money through reduced consumable waste — by taking steps to avoid common mistakes related to the MIG gun and consumables.

Consider these common causes of poor performance in MIG welding and learn how to prevent them, for a positive impact on productivity and the bottom line.  

No. 1: Improper liner length

Cutting the liner the wrong length is a common issue in MIG welding. In many cases, it’s a matter of the liner being cut too short.

When the liner is the wrong length, it can cause poor wire feeding, an erratic arc and/or wire chatter. For conventional liners, use a liner gauge as a guide when trimming and installing the liner. Another option is to employ a consumable system designed for error-proof installation that eliminates incorrect liner trimming and requires no measuring. The liner loads through the MIG gun neck and is then locked in place at the front and back of the gun while also being concentrically aligned to the contact tip and the power pin. Once locked, the welding operator simply trims the liner flush with the power pin. In addition to accurate trimming, by locking the liner at both ends of the gun, it isn’t able to extend or contract. The result is a smooth wire-feeding path.

No. 2: Overheated consumables

When a MIG gun’s consumables become overheated, they can be the source of many problems. 

To prevent consumables from overheating, use the proper wire stickout, mind the gun’s duty cycle and employ the right contact-tip-to-work distance. Any steps that keep consumables cooler will help limit the amount of vibration in the gun and reduce issues with burnback.

While a wire stickout that is too long is not desirable, keep in mind that too short of a stickout can result in the nozzle and contact tip being too close to the weld pool causing them to overheat. This impacts productivity by causing burnbacks and wire sticks, and can significantly shorten consumable life.

Also, look for consumables with a tapered design, as this helps lock conductive parts together, resulting in less electrical resistance, lower heat and a longer life. Some consumable systems feature a contact tip that is buried in the gas diffuser, which helps reduce overheating.This design also allows the shielding gas flowing through the gun to cool the tail of the contact tip for added protection against overheating.

No. 3: A bad ground

Shortened life of the contact tip and other front-end consumables can also result if a solid ground isn’t in place when MIG welding.

Without a solid ground, the arc can become erratic and ultimately cause more heat buildup in the front of the gun. Any problem that creates more heat will also create more resistance and more wear — damaging the contact tip and other front-end consumables and possibly impacting weld quality.

To prevent these problems, place the ground cable as close to the workpiece as possible. If allowable, hook the ground cable on the weldment. If that is not feasible, hook it to a bench. But remember: The closer it is to the arc, the better.

No. 4: Improper voltage or wire feed speed

An erratic arc can also be caused by setting the wrong voltage or the wrong wire feed speed.

Setting the voltage too high can create too much heat in the handle of the gun, which in turn can eventually wreak havoc on the contact tip.

When the wire feed speed is too fast, it can cause the wire to pile up instead of melting properly into the weld pool. This can also cause burnback or birdnesting. A wire feed speed that is too slow doesn’t feed the weld pool, so there is not proper penetration for a quality weld.

Always follow the manufacturer’s recommendations for the proper voltage and wire feed speed for the filler metal and thickness of the base material being welded.

No. 5: Poor cable management

Poor power cable management can lead to performance problems and cable damage.

To help prevent damage or other issues, don’t pull the welding machine around using the cable. When the gun is hot, everything is more pliable. Yanking or pulling on the cable can stretch the cable or the liner and even cause the conduit to pull away from the gas pin, which can result in shielding gas issues.

It’s also important to let the gun cool in a flat position, rather than draping or hanging the cable over a piece of plate or some other object. When a hot gun is draped or hung over something, it can bend the conduit. When the gun and consumables cool, they can be misshapen, leading to marginal shielding gas coverage.

Take care to lay the gun out properly to let it cool. Also, be sure to store the gun and cable properly when they aren’t being used to avoid damage that can occur if a cable is run over by a forklift or other heavy equipment.

No. 6: Selecting the wrong gun

A key step to prevent a MIG gun from overheating is to choose the right gun for the application. Be mindful of the requirements of the job and select a gun with enough duty cycle and amperage capacity.

If the application requires you to weld at 300 amps all day and you choose a 200-amp gun with a 30 or 40 percent duty cycle, this gun will not be up to the task. Exceeding the gun’s duty cycle leads to overheating — and doing this frequently will shorten the life of the gun.

In addition to choosing a MIG gun that has a high enough amperage rating and duty cycle rating for the job, you can also take breaks to let the gun and consumables cool to help avoid gun overheating.

A change in shielding gas can also help reduce the heat produced during welding. If you’re using an argon shielding gas, the higher the percentage of argon, the less cooling the shielding gas provides. However, keep in mind that many applications use argon shielding gas because it provides a cleaner process with much less spatter for reduced cleanup. So while reducing the argon can help the process run cooler, there are other tradeoffs that can impact productivity. 

No. 7: Drive roll issues

Using the wrong type of drive roll or setting improper drive roll tension can also be common causes of erratic or poor wire feeding in MIG welding. Consider the size and type of wire being used and match it to the correct drive roll. 

Because flux-cored wire is softer — due to the tubular design and flux inside — it requires using a knurled drive roll that has teeth that can grab the wire and help push it through. Knurled drive rolls typically should not be used with solid wire, since the teeth can cause shavings to break off of the wire, clogging the liner and creating resistance in wire feeding. Instead, use U-groove or V-groove drive rolls with solid wire.

Setting proper drive roll tension is another important step. Without proper tension, erratic feeding can cause burnback or other issues. To set the proper drive roll tension, start by releasing the drive rolls. Then increase the tension while feeding the wire into your gloved hand until the tension is one half-turn past wire slippage. Always keep the gun as straight as possible to avoid kinking in the cable that could lead to poor wire feeding.

Proper maintenance is also key

Avoiding common mistakes helps you get the best results in MIG welding. It is just as important to properly maintain the MIG gun and consumables, including the contact tip, nozzle and liner.

Whenever you change consumables, check that the gas holes in the nozzle are clean and that the seat that holds the contact tip isn’t filled with spatter or debris. A clogged contact tip or nozzle can cause overheating in the gun and handle.

Also check frequently that all connections are tight and as concentric as possible. Keeping the gun and cable as straight as possible during welding — and laying them flat to cool — makes for an effective and efficient MIG gun.

Follow these tips to minimize downtime, improve productivity and quality, and save money in your MIG welding operation.

Proper Ergonomics Improve Welding Productivity, Protect Welders

By Jack Kester, senior VP, Marsh Risk Consulting and Andy Monk, product manager, Bernard

What is ergonomics? While this term has several definitions, its practical meaning is “to adapt a task and work environment to a human.”

Despite what some think, the importance of ergonomics far surpasses comfort. A workplace environment or task that causes a welding operator to repetitively reach, move, grip or twist in an unnatural way — or even stay in a static posture for an extended time without proper rest — can do much more than become a literal pain in the neck. Over time, it can lead to repetitive stress injuries with life-long impacts that may even prevent the welding operator from working.

People are built with certain limitations, and when the design of work exceeds normal limitations, excessive wear and tear on the body occurs, accelerating damage that can lead to Work-Related Musculoskeletal Disorders (WMSDs) — injury to the muscles, tendons, ligaments, joints, nerves and/or spinal discs.

Although many welding operators may start with a dull pain that they dismiss as “just getting conditioned” or “tweaking something that will go away,” it can become more intense — and more expensive — and difficult to treat as time goes on. For example, early treatment for pain may require only ice, heat or some anti-inflammatories, and it might cost $200. However, waiting months or years to address the problem could result in invasive treatment and cost thousands of dollars. That is especially true with wrist and shoulder injuries that require surgery.

Ergonomics not only protects welding operators from injuries, but it can also improve the productivity and profitability of a welding operation. Stressful postures and motions tend to be inefficient. Lifting boxes from floor level or reaching outward beyond arm’s length, for example, takes extra time. These posture and motions repeated throughout the year by multiple employees can have a significant impact on earnings for the company.

By proactively reducing the risk of injury, companies can improve productivity, while also reducing employee absences and eliminating overtime pay for replacement workers who may not be as efficient or proficient. Eliminating stressful postures and motions can also help reduce employee turnover and training costs for replacing welding operators who quickly decide “this job isn’t for me.”

According to the Bureau of Labor statistics, WMSDs account for 29 percent of all lost workday injuries and for about 34 percent of all workers’ compensation claims — and they cost employers $20 billion each year in workers’ compensation.

Welding-related musculoskeletal disorders

Injuries ranging from mild and short-term to serious and chronic can result when the demands of a task do not naturally align with the capabilities of the welding operator. Most WMSDs develop when repetitive micro-traumas occur to the body over time.

WMSDs include strains or sprains, which can result in pain, decreased productivity, disability, medical treatment, financial stress and even a change in the quality of life for those affected. The most common symptoms among welding operators are shoulder pain, range of motion loss and reduced muscle strength. The most common injuries for welding operators include back and shoulder injuries, wrist injuries (such as tendinitis) and various knee joint disorders.

Today WMSDs are the fastest-growing disorder in the aging workforce because these illnesses have developed over time, before welding operations were as aware of them as they are today. As a result, there is the potential for an increase in claims costs in the coming 10 years as welding operators seek treatment.

The risk factors

There are three primary risk factors that increase the likelihood of developing WMSD injuries:

1) Highly repetitive tasks that keep an operator in a static posture for too long or use the same motion over and over, such as pulling a MIG gun trigger.

2) Tasks that require an operator to apply significant force or pressure, such as pushing, pulling or heavy lifting.

3) Poor or awkward postures, such as bent wrists or necks tilted backward.

In addition, environmental conditions such as extreme temperatures can also contribute to the development of WMSDs. Personal risk factors that increase the likelihood of incurring WMSDs include physical conditioning, pre-existing health problems, gender, age, work techniques and stressful hobbies.

Some common welding postures that are considered awkward and stressful include kneeling, squatting, torso twisting, leaning on a hard surface, holding the arms away from the body or above shoulder height for long periods of time, hunching or bending over, and looking upward too long.

In general, the best postures are those that are as close to neutral as possible — a natural position that the body would rest in if it were not doing anything.

Ergonomic solutions

The use of proven ergonomic principles can dramatically improve the way a welding operator performs a task, thereby reducing the exposure to risk factors and simultaneously increasing productivity. A simple work station adjustment or the use of different tools can make a big difference on an operator’s long-term health and wellbeing, as well as on the company’s bottom line.

For example, operators who weld with pistol grip tools, such as a welding gun, and use their finger to apply pressure for an extended length of time can develop “trigger finger.” This problem can be easily resolved by using a welding gun with a locking trigger.

Welding operators should position their work between the waist and shoulders, whenever possible, to ensure they are working in a close to a neutral posture. Achieving this posture may mean using work stools or height-adjustable chairs, as well as lifting tables and rotational clamps or other material-positioning equipment. All these solutions can reduce awkward postures and allow employees to work in more neutral positions.

Welding guns with rear swivels on the power cable can help reduce the stress of repetitive motions. Different combinations of handle angles, neck angles and neck lengths can also keep an operator’s wrists in a neutral position. In some cases, a welding gun with a rotatable neck can help the welding operator more easily reach a joint, with less strain on the body. Manipulators, lighter-weight welding guns, lighter power cables with low stiffness and cable supporting balancers can also be invaluable.

Remember, the working height of a welding operator’s hands should typically be at elbow height or slightly below.

The engineering controls described above are effective because they reduce or eliminate risk factors in the workplace. Administrative control measures, such as job rotation and stretching programs, can also be used to reduce the exposure time for welding operators or at least prepare their bodies for the work-related stress.

The keys to an effective ergonomics program

An effective and sustainable ergonomics process provides a structured approach to reducing risk in the workplace and preventing WMDs over the long-term. It typically includes:

1) A formal ergonomics risk assessment process to identify and prioritize high- risk work.

2) A structured task analysis process to define the causes of the risk factors, leading to the development of practical engineering controls.

3) An action plan developed by management stakeholders to set expectations and allocate resources for ergonomics in the workplace.

4) An ergonomics team trained to implement the ergonomics process and empowered to implement the action plan.

5) A formal process for developing, implementing and validating ergonomics solutions for high-risk tasks.

6) Ergonomics training for management, supervisors, the ergonomics team and other production staff members.

Once an ergonomics solution has been implemented, it is important to provide frequent reinforcement to the welding operators to ensure that the solution is utilized effectively. It can be difficult, initially, for a welding operator to get comfortable with new work practices if the job has been done a specific way for years. Therefore, it is important for welding operators to use any new welding gun and implement new best practices for at least 30 days. At that point, they can provide valid feedback on how well the new equipment or practices work for them. After all, gaining the benefits of proper ergonomics is only possible if they are used and the welding operator also sees the results.

In the end, the goal is to secure the safety of the welding operator, which requires an active commitment on the part of both the individual and management. Gaining the benefit of ergonomics is a team effort — one that ultimately provides a comfortable work environment, leads to a more productive and profitable welding operation, and provides for the long-term health of the welding operator.

Tips to Optimize the Robotic Weld Cell

Companies invest in robotic welding systems to improve productivity and gain efficiencies in their operation. But if the weld cell layout is not optimized, it can negatively impact those goals — along with the quality of the completed welds.

Poor cell layout can create a bottleneck in the process or result in parts not being properly welded —problems that cost time and money in the long term. 

When considering proper layout for a robotic weld cell — whether it’s a pre-engineered cell or a custom cell —gun and consumable selection, robot reach, parts flow in and out of the cell, and weld sequencing are all important.

Pre-engineered or custom welding cell?

Proper weld cell layout is important for both pre-engineered robotic welding systems or a custom-designed system. Determining which option is right hinges on several factors.

A pre-engineered robotic welding cell is designed for welding specific parts in a certain size range. Pre-engineered cells offer benefits for easy and fast installation and a much lower first cost, but they do have their limitations regarding the type and size of parts that can be welded. Part size is often the key determining factor when choosing between the two systems. 

If there isn’t a pre-engineered weld cell available to fit the parts — perhaps there is a reach or weight capacity issue — then a custom robotic weld cell is the better option. Custom cells have a higher initial cost and typically a longer lead time for design and installation, but the upside is they can be customized to meet specific needs.

When installing either type of robotic weld cell, the system integrator should be involved in planning and testing to ensure cell layout is optimized for the application.

Choosing the right gun and nozzle 

Having the right gun is a critical factor that can help reduce or eliminate the sources of common problems in the weld cell. Gun choice should not be an afterthought in robotic welding applications. The gun must have proper access and be able to maneuver around fixturing in the weld cell. Different choices in gun types and in consumables can help in achieving this.

Robotic welding systems are available in two styles: through-arm or conventional. Through-arm systems are gaining popularity, and most through-arm robots allow for mounting either type of gun — providing more options and flexibility depending upon the needs of the application.

As the name suggests, the power cable assembly of a through-arm MIG gun runs through the arm of the robot as opposed to over the top of it like in a conventional gun. Because of this design, the through-arm gun style is often more durable, since the power cable is protected. However, because conventional guns can be used on either type of system — a through-arm or a conventional robot — they can sometimes offer greater flexibility, and can be used with more robot makes and models. Consider which type of gun provides the best access to the welds when making the selection.

With conventional robotic welding systems especially, proper cable management is important. Once the hardware is installed and the system is set up — but before full production begins — be sure to do a test run or two through the welding sequence to determine how the gun cable moves and if it gets caught on tooling.

Another choice in selecting a gun is air-cooled versus water-cooled. This essentially comes down to the required duty cycle. The base material thickness, weld length and wire size all help determine the necessary duty cycle. Water-cooled guns are typically used in manufacturing heavy equipment and in the case of long cycle times and large wire diameters.

Once the system type and gun is chosen, it’s all about proper fit and function of the gun. It’s critical to ensure the robot arm can access all the welds — ideally in one position with one neck if possible. If not, different neck sizes, lengths and angles — and even custom necks — as well as different consumables or mounting arms can be used to improve weld access.

The choice of nozzle is another important consideration, since it can greatly hinder or improve access to the weld in a robotic cell. If a standard nozzle is not providing the necessary access, consider making a change. Nozzles are available in varying diameters, lengths and tapers to improve joint access.

While many companies like to choose a nozzle with the smallest outside diameter available, it may be necessary to size the nozzle up to avoid spatter buildup and loss of shielding gas coverage. A nozzle with a 5/8-inch bore or larger is recommended because it allows the most access. 

Key considerations for proper layout

Choosing the right gun is tied closely to proper weld cell layout — since different sizes and lengths of guns and nozzles can improve or hinder reach to the welds. However, there are also many other factors involved in proper weld cell layout. Think of weld cell layout as the footprint of the entire process. Some important issues to keep in mind:

• Robot reach: It’s critical to match the size of the part being welded with the reach of the robot. A small robot welding on a very large part won’t work well, and a large robot shouldn’t be welding on a very small part. The robot must have the capability and position to reach all the areas on the part that require welding. If there is a weld on the edge of the reach envelope, for example, it might force a company to sacrifice optimal gun angle or work angle to reach that weld. This can impact weld quality, resulting in potential rework and added costs. It can also lead to premature gun or cable failure, if the robot is constantly trying to access a weld that isn’t accessible in the configuration. Many robotic welding cells mount the robot on a riser for better access to the part. Pay attention to proper riser height to optimize the access of the arm to the welds.
• Size and weight capacity: To ensure proper operation, the size and weight capacity of the positioners in the robotic weld cell must factor in not only the weight of the part, but also the weight of the tooling. Undersizing the positioner or weight capacity of the cell is a common mistake. To address this, design the cell for the heaviest part to be welded. Consider the project scope to ensure the welding system always has the capacity to handle the heaviest part in the operation.
• Material flow: The flow of material in and out of the weld cell, in addition to the sequencing of the welding process, are key in determining the right layout and positioning. Understand the material flow to the robot, how the material will be presented to the robot, and then how that welded component will be removed from the cell and moved to the next step in the operation. The weld sequence should be planned in advance, to ensure the robot can reach all the welds with the gun configuration being used.
• Test it with modeling: Software programs that allow virtual modeling or simulation of the weld cell provide the ability to test the many factors involved in proper robotic weld cell layout — from gun and nozzle choice to material flow. Take the time to simulate the weld cell layout and welding process during development. This helps determine which product and positions are needed — and helps avoid issues that could arise later once the weld cell is installed and running. In modeling, consider the components, gun, positioner, tooling, arm movements and the part itself. All these pieces must fit together and work properly to ensure the desired results. The beauty of offline programming and 3D modeling is that these components and factors can be tested virtually, without wasting materials or consumables. It’s better to prepare and prevent problems — rather than face repairs later.

The right choices enhance productivity and quality

Weld cell layout and the chosen components that fit inside have a significant impact on productivity, efficiency and quality of the finished welds. Weld cell layout that is not optimized can even harm the tooling or consumables, and result in increased time and money spent on maintenance and repair.

Protect the robotic weld cell investment by taking the time at the start of the process to test proper cell layout and equipment — to help ensure the end results and productivity gains being sought.