When choosing the best robotic welding system for your operation, make sure to pay special attention to the gun and consumables. One size does not fit all.

While the robot itself, proper programming, and oversight by a trained supervisor are all important components in the overall robotic welding operation, the robotic GMAW gun also has a direct impact on quality and productivity, as well as costs.

When it comes to robotic welding, precision, repeatability, and speed are essential to ensuring a successful outcome. Companies rely on the robot’s ability to execute the same weld, exactly the same way, and as fast as possible.

While having the robot properly programmed and monitored by a trained welding supervisor is important, the gun used also has a direct impact on quality, productivity, and costs.

Consider some of the top things to know about robotic gas metal arc welding (GMAW) guns as a way to get the most out of this equipment.

1. One size does not fit all when it comes to robotic GMAW guns.
As with any piece of welding equipment, the right robotic GMAW gun for the job depends on the application— specifically, on the material being welded, the thickness, amperage, and required arc-on time.

Air-cooled guns provide the best results for low-amperage applications on thin materials (up to 0.16 inch thick) and for applications with short welds in high volume, such as those in the automotive industry.

These guns rely on the ambient air, as well as the copper in the unicable, to cool them during the welding process and typically are quite durable. In the event of a collision, the stronger neck construction helps reduce the opportunity for bends compared to a water-cooled model. Air-cooled guns generally are available in a range of 300 to 500 amps.

Water-cooled robotic GMAW guns are better suited to applications that require high- amperage welding for longer periods of time, particularly on materials over ¼ inch thick and on longer weldments.

Models often range from 300 to 600 amps at up to 100 percent duty cycle. These guns require an external cooler and, therefore, cost more upfront and require more maintenance. To prevent overheating on high-amperage applications, however, the additional cost and upkeep may be worthwhile.

For companies welding materials of varying thicknesses requiring both high and low amperages, a hybrid air-cooled/water-cooled gun is a viable option. These guns have a durable neck like an air-cooled gun with exterior water lines to cool the front-end consumables, making them easier to maintain. Should the gun have a water-line leak, it can still operate for a time (via the cooling capacity of the air-cooled unicable), so operators can address the problem before a complete failure occurs.

2. Added features benefit performance.
Manufacturers build robotic GMAW guns with precision in mind. The goal is to complement the robot with features in the gun that help the entire system maintain its repeatability, quality, and speed. Adding options like an air blast or wire brake to the gun can help.

An air blast feature blows high-pressure air through the front of the gun (air-cooled only), helping to remove debris. The goal is to remove any contaminants that could enter the weld pool and potentially cause poor weld quality. By reducing that risk, the air blast feature also helps reduce the need for rework. It supports more arc-on time, as it can be programmed to operate between weld cycles.

Another optional feature that can add to the consistency of a robotic GMAW gun is a wire brake. This feature stops the wire from feeding through the gun when the welding stops, allowing for uniform stick-out (or extension) at the start of the next weld.

For robots that use touch-sensing software, a wire brake is invaluable; it holds the welding wire in a set position while the robot moves and searches for the weld joint, helping to ensure that the robot can accurately determine the location of the weld joint and create a consistent, high-quality weld. A wire brake also helps prevent unspooling inside the gun during each stop and start.

3. The right neck and cables can help streamline the process.
Gaining access to the weld joint is critical for a robot to execute an accurate weld time and time again. In many cases, companies are moving to smaller robots and smaller weld cells to maximize floor space so they can produce more parts and become more competitive. These changes make it increasingly necessary for the gun to have a neck design that allows it to maneuver into the weld joint unhindered. Many gun suppliers offer various neck lengths and angles (with or without requiring special orders), and some offer online configurators that customize a gun for the exact application.

Sturdy cables that are easy to change out help to create a more efficient operation. Look for cables constructed of durable materials to protect against UV damage from the arc or general wear from air movements. Features like rotating power connections also can help by minimizing stress from routine torsion.

4. Guns operate more efficiently with the right consumables.
The right consumables—nozzles, contact tips, gas diffusers (or retaining heads), and liners—are essential for achieving maximum performance and reducing downtime. Gun manufacturers offer consumables for a range of applications, including heavy-duty products, such as chrome zirconium contact tips for high-amperage robotic welding. These tips are harder and more durable than copper tips, so they tend to last longer.

Contact tips that help improve arc starting also are available.

The liner used with the robotic GMAW gun can have an impact on the overall efficiency of the operation and gun performance. It is important to cut the liner to the correct length. A liner that is too short can lead to poor wire feeding and birdnesting (a tangle of wire in the wire feeder drive rolls). A liner that is too long can cause kinking, wire feeding issues, and shortened contact tip life, all factors that can interrupt production. Always follow the manufacturer’s recommendation for trimming the liner. Use a liner gauge as a guide when possible.

The type of liner used also plays a part in keeping the system up and running more effectively. Front-loading liners help reduce downtime by allowing the gun to stay connected to the wire feeder while the operator completes the changeover from a safe zone in the robotic weld cell.

Spring-loaded modules work in conjunction with a front-loading liner to help minimize problems 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 in. of forgiveness if the liner is too short. Again, these types of liners can help reduce time for addressing wire feeding issues that could affect productivity.

5. Preventive maintenance is not optional.
Companies invest in robotic welding systems in part to seek out productivity gains in their operation. With that in mind, the goal is to keep the system running as much as possible, but scheduling downtime for gun maintenance is essential.

The scope of a preventive maintenance (PM) schedule for a gun varies according to the application, but all companies should have a general maintenance sheet that indicates how often components on the gun should be and are changed. Tracking the maintenance activities makes it easier to troubleshoot a problem should it occur; maintenance personnel can look at the last thing changed during gun PM to see if that variable is a factor in the issue.

Routinely look for secure, clean connections between the neck, the diffuser, and the contact tip. It’s important to check that the nozzle is secure and that any seals around it are in good condition. Such activities can take place during routine pauses in welding, while other, more intensive maintenance can occur offline.

An effective PM program should include an appropriate parts inventory for the gun, including consumables. If something fails or needs to be replaced during PM but is not available, it can cause significant downtime in the production.

Other items to consider.
Be sure to select a gun with the right amperage to accommodate the application at hand. If you are using a conventional robot (as opposed to a through-arm style), selecting the right cable length for the gun also is important to prevent unnecessary wear.

Training employees on the proper operation and maintenance of the gun is critical. While GMAW guns are a seemingly small part of the overall robotic welding system, when they are selected, installed, and managed properly, they can contribute positively to the overall efficiency of a robotic welding system.


Years ago Kevin O’Leary joined a job shop during a period of surging growth, so he knew all about the growing pains. The shop he used to work for hired people as it grew, but he recalled the typical challenges: not enough time in the day, not enough equipment to get the job done.

About two years ago O’Leary took a job at Ludlow Manufacturing Inc. (LMI) in Waukegan, Ill., a suburb north of Chicago. On his first day, he looked around and saw equipment everywhere—but where were the people?

He soon learned that this reflected the philosophy of the company founders, Todd and Jenny Ludlow, who launched LMI in 2005 (see Figures 1 and 2). Before launching the business, Todd Ludlow worked as an independent sales rep in stamping and metal fabrication. So why did he launch a fab shop of his own? “Like every person thinks, I thought I knew more than I did, and I could do a better job,” Ludlow said. “I have to admit, I don’t feel that way anymore.”

LMI started in 2,000 square feet with a used 1,000-W laser, one press brake, a compressor, and that’s about it. But the company grew quickly and today operates in 80,000 sq. ft. It wouldn’t be unusual to see a facility of that size employ 100 people or more. LMI, though, employs only about 45.

This goes back to Ludlow’s take on automation: He believes in it in a big way.

LMI’s Automation Philosophy
Instead of hiring people to grow, LMI acquired new equipment that helped simplify the act of cutting and bending sheet metal. Although Ludlow believes in automation, he looks at it holistically and pays attention to how technology can shorten not just a particular cutting, bending, or welding operation, but the entire order-to-ship cycle.

Lasers do have automated load/unload systems that hold enough material for unattended cutting at night (see Figure 3), but LMI doesn’t have any tower systems. About a year and a half ago, Ludlow had dreams of moving to an even larger facility and investing in a comprehensive material storage and retrieval system. “But I realized I was totally wrong about that,” he said.

Ludlow appreciated how such systems fit perfectly in other operations, but when he looked at his company’s job mix and resources, he found the investment wouldn’t make sense. The company doesn’t deal with a lot of remnants, so it couldn’t take advantage of a tower’s ability to automatically store and retrieve these remnants after cutting. With large towers, LMI’s lasers theoretically could cut unattended for days, but material handlers would still need to spend time shaking all those parts out of the cut nests. Ludlow added that investing in automated part-removal and stacker equipment didn’t make business sense either.

He emphasized that his thinking may change. But for now, material handling automation around the cutting centers isn’t a good fit. Looking at the big picture, he said that parts still need to be formed, welded, and inspected, so the order-to-ship time really wouldn’t change.

The time wouldn’t change much with a powder coat line, either. LMI is in a crowded metal fabrication market, which comes with its own challenges. Many shops chase the same work, so quite often LMI does business with companies outside Chicagoland, in Wisconsin, Indiana, even in the Southeast. But a crowded metal fabrication market also comes with benefits, and this includes custom powder coaters that serve LMI well.

Figure 2
Kevin O’Leary, vice president of operations and engineering (on left), joined LMI two years ago. He saw that the shop had plenty of machines yet few people, an unusual situation for a growing shop. The reason behind it was the company’s philosophy on automation espoused by co-founder and Vice President of Sales Todd Ludlow (on right).

Ludlow’s decision to buy or not to buy equipment and software isn’t based on conventional return-on-investment calculations. If he took a traditional ROI approach, LMI would employ many more people and have, if not less, certainly older equipment. His chief financial officer runs the ROI calculations, equipment depreciation, and other tenets of generally accepted accounting principles (GAAP). But Ludlow doesn’t run the business off those numbers.

“I run this business with a sales-based mentality rather than a traditional accounting-based philosophy,” he said. If a machine or software platform helps generate more sales than it costs, it’s a worthy investment. “And for most of our investments,” Ludlow said, “we’ve seen the benefits immediately.”

LMI employs few people relative to the sales it generates, so labor costs are low relative to revenue. Behind material, labor is a fabricator’s greatest expense, so employing relatively few individuals keeps LMI’s operating expenses low. Ludlow expects sales to exceed $13 million this year. Considering the number of full-time-equivalent employees (full-time plus part-time plus temps), this would make LMI’s sales per employee exceed $210,000. That’s much higher than the industry average of $158,000, as reported by the “2015 Financial Ratios & Operational Benchmarking Survey” from the Fabricators & Manufacturers Association International®.

O’Leary and Ludlow don’t view what they sell as simply “manufacturing capacity,” though. If it were that straightforward, they would be providing a commodity service, racing to the bottom, and dealing with razor-thin margins, an environment that makes growth difficult. They instead sell manufacturing expertise with smart engineering ideas that take advantage of the capabilities of LMI’s machines and software.

For example, why not unitize this design and combine several parts into one? Sure, the part may require 14 bends instead of four, but you eliminate welding. Besides, with offline bend programming and simulation on the shop’s new press brakes—which have touchscreen monitors that bring operators through the operation and lights that show tool placement and the bend sequence—14 bends aren’t a problem.

Of course, no matter how engineering-driven a fabricator becomes, employee engagement becomes difficult in an unsafe environment. At LMI every brake has an optical safeguard, every welding station has direct fume collection, and used compressor water is filtered for safe disposal.

You’ll rarely see an operator standing by a laser. For each shift, the company employs just one laser operator who manages the company’s five lasers. As vice president of operations and engineering, O’Leary also acts as LMI’s bending guru, working with engineers to program and run press brake simulations offline.

All of the brakes are networked. Recently one second-shift operator needed help setting up a part. The shop has overhead cameras that capture a view of most of the shop floor, so O’Leary can log on and actually see the operator standing at the machine. O’Leary asked for the part number, pulled it up online, and loaded the program onto the brake—all from his home office. The operator then asked which tools should go where.

As O’Leary recalled saying, “I told him, ‘Can you read the numbers on the tools? See the animation on the control?’” The control showed the operator where to put the tools, as did lights across the bed of the brake itself. The operator loaded the tools, performed the first bend, and told O’Leary that the angle was 2 degrees underbent. Still sitting in his home office, O’Leary input the correction in the bend program. The operator initiated the bend again, and the angle was spot on.

Bending operators need to know how to use a caliper, a height gauge, a protractor, and other basic measurement tools, but after learning these basics, they essentially can start bending good parts right off the bat. One of the company’s new Bystronic press brakes even has a table that lifts, so it’s level with the die opening. This encourages first-time operators to slide the blank parallel to the bottom die surface, not just jam the blank in at any angle (see Figure 4).

Figure 3
LMI has load/unload automation to keep up with the speed of the shop’s modern lasers.

Processing Times
Looking at the big picture involves scrutinizing both value-added (processing) and non-value-added time. LMI has squeezed plenty out of its processing time with its investment in fiber lasers and electric and hybrid brakes. Most of its parts are small and less than 0.25 in. thick; why bend small parts on a massive machine? Moreover, the cycle time of these electric and hybrid systems can be extremely short. The result: An operator can make many more bends per minute (see Figure 5).

This makes LMI’s blanking-to-bending ratio low. The industry norm (at least for operations in which most parts are formed) is about three brakes to one blanking machine. LMI instead has only six brakes handling work from its five lasers. Considering roughly 80 percent of the shop’s parts are formed, and the fact that two lasers feeding parts to the brakes are high-powered fiber machines—one of which is 6 kW—that’s saying something.

O’Leary said that the company sends work through its robotic welding systems whenever possible. Several years ago LMI purchased a small machine shop, which opened the door for more welding and subassembly fabrication work that required milled or turned components. It also opened the door for in-house fixture development. Engineers build fixtures virtually in software, specifying machined as well as laser-cut components, then run the part through offline programming and weld simulation before the job hits the floor. Programs then can be downloaded to the company’s Genesis Systems welding cells.

“Sometimes it’s cost-prohibitive to develop a fixture [for robotic welding],” O’Leary said. “Usually we try to develop a fixture that’s load-and-go, with just one setup.” On occasion engineers may decide to tack a part manually but perform the weld with a robot. This means they need to make a holding fixture only for the robot, which is usually much less involved and less expensive than a complete welding fixture for both tacking and welding.

Tackling the Non-value-added Time
As any lean manufacturing guru will tell you, when you look at the entire manufacturing process chain, from order to shipping, value-added time takes up a small portion of it all. Non-value-added time dominates.

Some may debate what “value-added time” really is, but to keep things straightforward, LMI defines it as any time a tool touches a workpiece to make a good part: the laser cutting head, the press brake tools, the welding gun, and the portable CMM touch probe. All this helps produce a part that the customer is paying for. Everything else—quoting and estimating, scheduling, nesting, cutting assist gas and other consumables, entry of quality data, machine programming, maintenance activity, and more—may be necessary activities, but they don’t directly make or inspect what the customer is buying. Customers also, of course, are not buying bad parts, so any time spent making them, be it test parts for setup or errors made during production, is also non-value-added time.

When managers were hunting for new press brakes, the short bending cycle impressed them, as did the integrated safety.ut what really caught their eye was the offline programming, simulation, and touchscreen controllers where operators can call up programs, view a simulation, and follow along during the bend sequence (see Figure 6). This helps shorten setup, improve communication, and avoid bending errors, such as bending a flange in the wrong direction. That’s all non-value-added time.

Similarly, when they purchased the new fiber laser systems, they loved the speed, especially with thinner stock. But they really took note of the software. The company now uses Bystronic Plant Manager software to automate the scheduling and nesting of every laser.

When Ludlow found a nitrogen-generation system (from Industrial Solutions LLC) that gave him the purity levels he needed for laser cutting, he bought one. Again, the customer is paying for parts, not the nitrogen to cut them, so LMI scrutinized the cost. “The quality of these [nitrogen-generation] systems have changed a lot in recent years. I’ve had a nitrogen generator here for four years, and I’m getting another one,” he said. “If I didn’t have it, my [nitrogen] bill would be about $6,000 a month. Now it’s only about $900, simply because I don’t have enough capacity in my generator to run to all the [laser] machines.”

Look up and you might think the shop has no air lines. Look closer, though, and you’ll see a 2-in.-square aluminum extrusion that runs the length of the facility. That’s for the shop air. To drop a new air line, a technician just needs to drill a new hole in the extrusion and drop an air hose. “Most shops our size run a 100-HP compressor with a 100-HP backup,” Ludlow said. “But we get only half a percent air loss [out of those aluminum extrusions], so we just run two 25-HP compressors with a 30-HP backup. We save so much money over a year by doing that.”

Figure 4
Ludlow moves a table so that it becomes parallel with the die surface, allowing the operator to simply slide the blank in against the backgauge.

This is yet another non-value-added expense LMI uncovered. Again, customers are paying for parts, not the electricity spent for compressors to pump shop air.

Quoting It Right
So many problems in fabrication begin at the very start of the process chain: quoting. As Ludlow explained, LMI quotes are based on data from past manufacturing jobs. The laser cutting data comes from XML files exported from Plant Manager, which has helped them build a library of exact processing times. If a part is complex, engineers may run the 3-D model through bend simulation to ensure tooling is available or needs to be purchased and to make sure the part can indeed be made without colliding with tools or the backgauge.

LMI also scrutinized data entry in quality assurance. Until recently a typical QA procedure at LMI went as follows: A worker delivered the part to quality for inspection. The QA person created the inspection file, performed the inspection, and then manually entered the data on the Excel sheet. When the QA tech typed in those numbers manually, the company’s portable CMM sat idle, not adding value.

So today LMI is working to eliminate all that data entry. Before a job is sent to the floor, an engineer in the front office exports the original CAD file to Faro’s CAM2 Measure software, which creates an inspection file that identifies all the part geometries that require inspection, “auto-ballooning” the drawing to identify all the inspection points. All this happens before the order hits the floor. Now when a part arrives in QA, the technician simply calls up the file and takes the measurements (see Figure 7).

“We’re taking the mundane data-entry portion of the quality role and building intelligence into the process upfront,” O’Leary said. “It does take a little more time upfront, but it cuts down the time in QA significantly, when we’re trying to get the part through production.”

Scheduling and Going Paperless
The company recently adopted OmegaCube Technologies’ enterprise resource planning (ERP) software and, at this writing, is moving toward a near-paperless environment, opting for 4- by 6-in. “move tickets” that accompany each work order. When a worker scans the ticket, the ERP platform brings up all the information about a job on the screen in front of him. This can include visual work instructions, videos, and the 3-D model (see Figure 8). A worker can print blueprints on a shared printer, if necessary. But for the most part, LMI is saying goodbye to the paper traveler.

“You can attach any file format to the job,” O’Leary said, “and you can view it, as long as the computer you’re working on has the application.”

The ERP works in concert with Plant Manager. The shop uses the ERP to schedule jobs based on the due date; then Plant Manager takes that schedule; looks out a specified number of days; and automatically nests parts based on available capacity, machine capability, grain direction requirements, and desired material utilization. Moreover, operators no longer need to manually log jobs into the ERP once they reach the laser. Once a program is executed, an XML file is sent back to the ERP to process all of the labor and material transactions.

Part revisions make up another issue that prolongs non-value-added time. Say a customer changes a material thickness requirement after a portion of the job has already been cut on the laser. If the customer says the parts are still usable, what then? The shop still could process the material, but it would need to make sure everything downstream can account for both the old and new material thickness. This includes available tooling at the press brake, fixtures at the welding cells, and inspection programs and data in QA. All this opens the door for more variation and a lot of confusion. Is it worth keeping the WIP, or to simplify things, should it just be scrapped?

Here, software has helped organize the situation. If a customer changes an order midstream, the ERP notes it and updates the work order to reflect the latest information. But if the customer says the already produced WIP is usable, then the software creates a separate work order that maintains all the previous job information at that particular revision level. This has helped reduce scrap rate and ensure LMI reprocesses only what is necessary for the job.

Figure 5
Bending this small part with multiple bends took a matter of seconds.

Down the road, LMI has plans to place monitors throughout the shop that show what jobs are where, as well as what’s on time and what’s behind schedule. If a job is behind schedule, it will become immediately apparent. “Managing the plant, I can see if someone is having a problem,” Ludlow said.

The Little Things
Perhaps nowhere is LMI’s focus on the big picture clearer than in the packaging area. After all, inefficient packaging mitigates all those efficiencies in processes upstream.

Here the company uses an automated shrink-wrap machine from Yellow Jacket for most batches of material—a big improvement over wrapping batches of product by hand. For materials shipped with strapping, the company no longer uses metal straps but instead applies heavy-duty plastic bands using a specialized hand tool from Orgapack (see Figure 9) that tightens the strapping and then ultrasonically welds the plastic ends together—no more spring-steel banding digging into the product or pinching fingers.

“It’s better, safer, faster, and cheaper,” O’Leary said.

Those four words pretty much sum up the goal of every modern fabricator.


[Companies invest in robotic welding systems to improve productivity, gain more consistent weld quality, and reduce costs. Robotic welding also can set companies apart from the competition by allowing for faster completion and delivery of products.

Because of the cost for investing in this equipment, it is important to take steps to protect the system and ensure it is operating at its maximum potential. Keep in mind these best practices and troubleshooting tips to help you avoid downtime and increase throughput in your operation.

Select the Right Products
To gain the best performance from your robotic welding application, always select the right robotic gas metal arc welding (GMAW) guns, wire, and consumables for the job.

If your operation is large and requires a variety of equipment, take steps to prevent confusion and using the wrong product, which can lead to downtime and waste. A color-coding system is a good option. For example, you could color-code a 3-foot robotic GMAW gun with a red stripe and a 4-ft. gun with a green stripe. Putting in this extra effort takes time upfront, but it can help you streamline the welding process in the long run.

Another way to prevent product confusion is to standardize consumables across the welding operation when possible, such as using the same neck or nozzles on every robotic GMAW gun. Ideally, this standardization should be addressed at the integration level when designing the robotic system.

Last, always be sure to select a gun with enough amperage to meet the requirements of the application without overheating. For instance, an air-cooled robotic gun may not be able to manage the demands of some robotic applications, which often require a 100 percent duty cycle. In this case, converting to a water-cooled gun is a better option.

Prevent Poor Wire Feeding
Erratic or poor wire feeding, a common problem in robotic welding, can be caused by numerous factors that you can easily avoid with some preventive steps.

Cutting a liner too short is particularly problematic when robotic welding with small-diameter wires, which have less column strength. If the wire isn’t supported all the way through to the contact tip, it can fold at the front end or change course, which causes poor wire feeding, as well as burnbacks— the formation of a weld inside the contact tip.

Follow the manufacturer’s instructions for trimming and installation, using a liner gauge to confirm the correct liner length. You also can use a liner system that employs a spring-loaded module to apply constant forward pressure on the liner. This module allows forgiveness for too-short liners and accommodates for liner movement during gun manipulation.

Extreme articulation of the gun also can lead to poor wire feeding. While it is important to program the robot for optimal productivity, take into account its speed, the position of the tooling, and the stress placed on the gun cable during welding. Too much bending can prevent the wire from feeding consistently through the front end of the gun.
Program the robotic GMAW cable to stay as straight as possible. The robot may not weld quite as fast, but the trade-off of proper gun orientation can help minimize downtime to address feeding problems.

Improper drive roll selection and tension setting can lead to poor wire feeding. Consider the size and type of wire being used and match that to the drive rolls. Since flux-cored wire is softer (due to the flux inside and the tubular design), it requires a knurled drive roll, which has teeth to grab the wire and help push it through. However, knurled drive rolls should not be used with solid wire, because the teeth will cause shavings to break off, clog the liner, and create resistance as the wire feeds. Use V-groove or U-groove drive rolls instead.

To gain the best performance from your robotic welding application, always select the right robotic gas metal arc welding (GMAW) guns, wire, and consumables for the job. The gun should provide the appropriate amperage to prevent overheating.

To set the proper drive roll tension, release 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.

Finally, be sure to have the correct contact tip size for the wire you use, and check that the connections between the gun and consumable are tight to avoid issues with wire feeding.

Enhance Contact Tip Life
Contact tip life depends greatly on the application; you may change contact tips daily or weekly. Some preventive maintenance tips can help improve contact tip life.

Over time, debris and spatter buildup inside the liner can contribute to shortened contact tip life. It’s important to occasionally blow any debris out of the liner using clean compressed air.

Match the wire size you are using to the contact tip to extend the consumable’s life. When there is too much space between the wire and the tip’s internal diameter, the wire can get stuck in the tip, causing a burnback.

Choose good-quality wire. Low-quality wires may not have a good lubricant coating. This factor can increase the amount of debris being pulled through the liner to the contact tip. Low-quality wires also can have a less consistent cast and helix, which can cause erratic wire feeding and keyholing—wear that results in an oval-shaped bore—in the contact tip.

Last, incorrect welding parameters can lead to burnback, excess spatter, and internal arcing, all of which can cause premature contact tip failure. Make sure voltage, wire-feed speed, and other parameters are set correctly for the application.

Use a Reamer and Antispatter Correctly
It can be tempting to avoid using a reamer (or nozzle cleaning station), or run it infrequently to reduce capital expenses and downtime during the welding cycle. However, a reamer plays a critical role in maximizing robotic welding performance.

This peripheral cleans the nozzle of debris and spatter, typically during routine pauses in the welding operation. The goal of this cleaning action is to ensure consistent shielding gas coverage, which helps reduce weld defects, expensive rework, and lost productivity. A reamer also helps extend the life of consumables.

Be sure to set the frequency and speed of the ream cycle at an adequate level to complete the job. Some applications are fine reaming once every 30 parts, while others need it after every single part. Note that accelerating the process runs the risk of stalling the unit and/or breaking a cutter blade. Both can cost time and money for downtime and repairs. Reducing the frequency of reaming can lead to excess spatter accumulation on consumables.

Another common mistake is the misuse of antispatter. Too much is just as bad as not enough, because an excess of this compound can damage the nozzle insulator. Spray the antispatter so that it nearly evaporates on contact and leaves a slight film on the consumables. Do not spray antispatter until it is dripping; it can easily drop into the weld pool, creating porosity and inclusions in the weld.

Protect the Investment
A preventive maintenance program is among the most effective best practices you can instill for a robotic welding system and is an ideal way to reduce unscheduled downtime and minimize costly repairs or equipment replacements. Tracking maintenance manually or via weld data monitoring also helps you monitor variables, such as consumable changeover, and narrow down potential problems when issues do occur.


Robotic welding can be extraordinarily efficient—until it starts producing bad welds. Weld defects have numerous causes, but one culprit can be a dirty nozzle. This is where a nozzle cleaning station, or reamer, can help.

A reamer can be integrated into an automated welding system to maximize its performance (see Figure 1). It removes accumulated spatter from inside the gas metal arc welding (GMAW) gun’s front-end consumables, including nozzles, contact tips, and retaining heads. In doing so, it extends consumables life and reduces downtime for maintenance. It also prevents the loss of shielding gas coverage, a problem that can lead to expensive rework to correct porosity and other weld defects.

The reamer typically takes about five or six seconds to clean a nozzle, while parts are cycling down the line or while the tooling is indexing. It could take more than five minutes for a welding operator to enter the weld cell and do the job manually.

A reamer significantly reduces the risk of spatter lodging between the contact tip or retaining head and the nozzle, which can result in arcing against the part. Removing the spatter frequently also ensures smooth shielding gas coverage to protect the weld pool. By minimizing spatter and debris in the nozzle, reamers help improve the overall efficiency of a robotic welding system.

Reamer Types
Reamers are either analog or digital. Analog reamers generally have a multiconductor cord set and an air supply. Each conductor relays a specific task, signaling the system to start, spray, and return to the home position.

Digital reamers use a network cable to send commands to an IP address. They can control individual functions without being limited to the number of leads in the cord set, as an analog reamer is. Beyond being told to start and spray, a digital reamer also can be told to clamp, lift, lower, and turn the motor on and off—all of the functions that make up a ream cycle.

A digital reamer also allows for remote monitoring, which streamlines troubleshooting. If a certain unit is having issues, the operator can monitor the status of each function to determine where the problem lies. This helps determine what is wrong before a part has to be pulled off the line.

Proper Alignment
A reamer can be mounted in nearly any orientation, as long as it doesn’t allow debris to collect in the clamp housing. For easy access, place the reamer close to the welding robot. If the reamer is on an angle, with the base plate not parallel to the floor, and if it has an antispatter sprayer, make sure that the spray reservoir does not leak when full.

Using a multifeed system can help, as it operates in the same manner regardless of the reamer’s orientation. A multifeed system allows for the feeding of antispatter compound to multiple reamers from a single drum placed on the floor or a nearby shelf, thereby eliminating the need for a sprayer reservoir.

Make sure that the V-block inside the top of the reamer is the correct size for the nozzle, the cutter blade is the correct size for the nozzle bore, and the insertion depth of the nozzle to the reamer is adequate (see Figure 2). Aligned properly, the nozzle should sit tangent on the two angled faces of the appropriately sized V-block.