How to Prevent Common Causes of Poor Welding Wire Feeding

Poor wire feeding is a common problem encountered in many welding operations. Unfortunately, it can be a significant source of downtime and lost productivity — not to mention cost.

Poor or erratic wire feeding can lead to premature failure of consumables, burnbacks, bird-nesting and more. To simplify troubleshooting, it’s best to look for issues in the wire feeder first and move toward the front of the gun to the consumables.

Finding the cause of the problem can sometimes be complicated, however, wire feeding issues often have simple solutions.

What’s happening with the feeder?

When poor wire feeding occurs, it can be related to several components in the wire feeder.

1. If the drive rolls don’t move when you pull the trigger, check to see if the relay is broken. Contact your feeder manufacturer for assistance if you suspect this is the issue. A faulty control lead is another possible cause. You can test the control lead with a multimeter to determine if a new cable is needed.

2. An incorrectly installed guide tube and/or the wrong wire guide diameter may be the culprit. The guide tube sits between the power pin and the drive rolls to keep the wire feeding smoothly from the drive rolls into the gun. Always use the proper size guide tube, adjust the guides as close to the drive rolls as possible and eliminate any gaps in the wire path.

3. Look for poor connections if your MIG gun has an adapter that connects the gun to the feeder. Check the adapter with a multimeter and replace it if it’s malfunctioning.

Take a look at the drive rolls

Using the wrong size or style of welding drive rolls can cause poor wire feeding. Here are some tips to avoid problems.

1. Always match the drive roll size to the wire diameter.

2. Inspect drive rolls every time you put a new spool of wire on the wire feeder. Replace as necessary.

3. Choose the style of drive roll based on the wire you are using. For example, smooth welding drive rolls are good for welding with solid wire, whereas U-shaped ones are better for tubular wires — flux-cored or metal-cored.

4. Set the proper drive roll tension so there is sufficient pressure on the welding wire to feed it through smoothly.

Check the liner

Several issues with the welding liner can lead to erratic wire feeding, as well as burnbacks and bird-nesting.

1. Be sure the liner is trimmed to the correct length. When you install and trim the liner, lay the gun flat, making certain the cable is straight. Using a liner gauge is helpful. There are also consumable systems available with liners that don’t require measuring. They lock and concentrically align between the contact tip and power pin without fasteners. These systems provide error-proof liner replacement to eliminate wire feeding problems.

2. Using the wrong size welding liner for the welding wire often leads to wire feeding problems. Select a liner that is slightly larger than the diameter of the wire, as it allows the wire to feed smoothly. If the liner is too narrow, it will be difficult to feed, resulting in wire breakage or bird-nesting.

3. Debris buildup in the liner can impede wire feeding. It can result from using the wrong welding drive roll type, leading to wire shavings in the liner. Microarcing can also create small weld deposits inside the liner. Replace the welding liner when buildup results in erratic wire feeding. You can also blow compressed air through the cable to remove dirt and debris when you change over the liner.

Monitor for contact tip wear

Welding consumables are a small part of the MIG gun, but they can affect wire feeding — particularly the contact tip. To avoid problems:

1. Visually inspect the contact tip for wear on a regular basis and replace as necessary. Look for signs of keyholing, which occurs when the bore in the contact tip becomes oblong over time due to the wire feeding through it. Also look for spatter buildup, as this can cause burnbacks and poor wire feeding.

2. Consider increasing or decreasing the size of contact tip you are using. Try going down one size first, which can help promote better control of the arc and better feeding.

Additional thoughts

Poor wire feeding can be a frustrating occurrence in your welding operation — but it doesn’t have to slow you down for long. If you still experience problems after inspecting and making adjustments from the feeder forward, take a look at your MIG gun. It is best to use the shortest cable possible that can still get the job done. Shorter cables minimize coiling that could lead to wire feeding issues. Remember to keep the cable as straight as possible during welding, too. Combined with some solid troubleshooting skills, the right gun can keep you welding for longer.

How to Successfully Implement a Robotic Welding System

In today’s marketplace, companies continue to automate portions, if not all of their welding operation. The reasons are many: to address a shortage of skilled labour, to improve quality, to decrease waste and rework, and/or to increase productivity — in short, to seek benefits that provide a competitive edge.

Not all companies, however, are successful in the process. Those beginning without a well-thought-out roadmap risk losing valuable time during implementation and operation and may miss the full benefits provided by a robotic welding system.

Conversely, companies that begin with a careful examination of their welding needs and existing processes — and develop a detailed plan with clearly established goals — are more likely to achieve success. Planning should include an accurate assessment of parts, work flow and the current facility, as well as an evaluation of the potential return on investment (ROI).

Companies should not only look at current needs, but also consider future opportunities to determine the best robotic welding system to scale for potential growth or changes to products they may produce later.

Why robotic welding?

In an economy where orders are increasing and welding positions are hard to fill, robotic welding can help maintain or increase productivity. In a semi-automatic welding operation, labour accounts for approximately 70 to 85% of the total cost of welding a part. A robotic welding system can reduce that cost and increase throughput by completing the work of two to four people in the same amount of time — however, companies still require skilled welding operators to oversee the robotic cell.
In addition, the national and international marketplace has become increasingly competitive, with companies seeking contracts from any number and any size of business. Investing in welding automation can help set up a company on the path to compete at a global level.

Here are additional benefits:

1. With the right robotic welding system, companies can improve first-pass weld quality and reduce the amount of rework or scrap parts. Depending on the welding wire and mode used, the system may also minimize or eliminate spatter, which reduces the need to apply anti-spatter compound or perform post-weld clean up.

2. A robotic welding system can reduce over-welding, a common and costly occurrence associated with the semi-automatic process. For example, if a company has welding operators who weld a bead that is 1/8-inch too large on every pass, it can potentially double the cost of welding (both for labour and for filler metals). Over-welding may also adversely affect the integrity of the part.

3. Companies can reallocate skilled employees to other production areas to fill open positions and gain additional productivity and efficiencies.

4. Welding automation can also provide a competitive advantage as it may be considered attractive to customers. The improvement in quality may prompt new customers to place orders or lead existing customers to increase their orders with the objective of growing their own businesses.

5. Finally, robots are fast. They don’t have to weld all day to be profitable. That fact improves productivity and the bottom line by making the same number of parts as in a semi-automatic process in less time.

Repeatability is key

When considering an investment in a robotic welding cell, companies should have part blueprints, preferably in an electronic format. Without a blueprint, the part likely won’t meet the basic criterion necessary to ensure repeatability during the manufacturing process.

A robotic welding system welds in the same place every time. When a part’s tolerances are unable to hold its position — if there are gap and/or fit-up issues — the company will simply be automating a broken process. This can increase rework or scrap.

If a company currently relies on its welding operators to compensate for fit-up issues, it will need to look upstream in the manufacturing process to establish consistency. What processes need to change so these welding operators send uniform parts downstream? Or, if vendors supply the parts, can they guarantee consistency?

Assess the workflow

A streamlined workflow is one of robotic welding’s benefits. To achieve it, companies need to look beyond the weld cell, making certain the facility can accommodate a smooth flow of materials. It makes little sense, for example, to invest in a robotic welding system to increase productivity, but then place it in a corner where employees may have to handle each part multiple times.

There should be a consistent supply of parts to avoid moving a bottleneck from one area to another. It is also important to look at the expected cycle time of the robot. Can personnel supply parts to keep up with the demand of the robot’s cycle time? If not, the supply of parts, including where the company stores them and how it moves them, will need to be adjusted. Otherwise, a robot will sit idle waiting for components to come down the line.

Robotics or fixed automation?

There is no single welding automation solution that is best for every company. When a company is considering the investment, it should factor in the expected lifetime of the job, the cost of tooling and the flexibility the equipment offers.

Fixed automation is the most efficient and cost-effective way to weld parts with simple, repetitive, straight welds or round welds, where the part is rotated with a positioner. If a company wants to reuse the equipment when the current job ends, however, a robotic welding system offers more flexibility. A single robot can store programs for multiple jobs, so it may be able to handle the tasks of several fixed-automation systems.

There is a certain volume of parts that justify the investment of welding automation for each company. An accurate assessment of goals and workflow can help determine what that volume is. If a company makes only small runs of parts, robotic welding becomes more challenging. But, if a company can identify two or three components that can be automated, a robot can be programmed to manufacture those parts, offering greater versatility and boosting productivity. This may benefit even small companies that may not have significant volume of a single part.

Although a robot is more expensive than a fixed-automation system, it is important to consider the cost of the tooling before deciding between the two. Fixed automation systems can become quite expensive if they require extensive changes to retool a new part so it can be welded consistently.

Consider the available space

The physical footprint for a robotic welding system and the area needed for parts to flow into the welding cell is typically greater than that of a semi-automatic welding operation. The available space needs to be adequate for the robot, welding power source and other equipment. This helps minimize the need to customize products, such as cables, nozzle cleaning stations (or reamers) or the robotic MIG gun to fit the work envelope.

A company with less space can still make welding automation work. One option is to purchase fewer pieces of robotic welding equipment that are capable of performing multiple tasks, such as material handling or vision/scanning systems.

A third-party integrator can help determine whether a facility suits the installation of a robotic welding system. System integrators are knowledgeable about facility modifications, including important safety regulations that apply in a company’s region, country or state — in addition to those specified by OSHA and RIA (Robotic Industries Association).

Integrators and equipment selection

In addition to offering advice on facility modifications and helping a company select the right robot, a robotic systems integrator or welding automation specialist can:

1. Help determine if parts are suitable for automation, and, if not, what is required to make them suitable

2. Analyze the workflow and facility to identify potential roadblocks

3. Analyze the true costs involved with the investment, including facility updates and tooling

4. Determine the potential payback of the investment

5. Help identify goals and develop a precise plan and timetable to achieve those goals

6. Explain automation options and help select those that best fit the company’s needs

7. Help select a welding equipment that has the flexibility to maximize travel speed, minimize spatter, eliminate over-welding, provide great arc stability and increase first-pass weld quality

Integrators can also help select additional equipment for the robotic welding cell, including positioners, tooling, the robotic MIG gun, welding wire and peripherals. Each item serves a distinct function.

The positioner turns, rotates or otherwise moves the part into an optimal position for welding. In many cases, this involves moving the part so that the system can weld in a flat position for optimal deposition efficiency. A positioner can also allow for coordinated motion between the robot and weldment.

The tooling holds the part in place during welding and is a critical component of a robotic welding system. The robot arm and robotic MIG gun travel a programmed path each cycle. If the weld joint is out of place because the part is misaligned, it can result in inadequate fusion or penetration and rework or scrap. It is important to design the tooling correctly upfront when investing in a robotic welding cell and monitor it for mechanical wear or heat distortion once it has been put into operation. This helps ensure consistent part fit up so that weld quality doesn’t suffer.

The robotic MIG gun should never be an afterthought when considering an investment in welding automation, nor should the welding wire. Both can have a significant impact on productivity and profitability. An integrator can help with the selection based on how the gun and wire perform in conjunction with the rest of the system’s components. The gun will be subject to intense heat and spatter, so it must be durable. It also needs to be the appropriate size to maneuver around the tooling and gain proper joint access.

Finally, peripherals, such as reamers, an anti-spatter sprayer and wire cutter are good options to discuss with an integrator prior to making the investment in welding automation. These devices can improve uptime and welding performance by keeping the welding gun consumables free of spatter, operators out of the weld cell and providing consistent wire stickout during welding.

Employee training

Companies cannot simply purchase a robotic welding system and let it go. They need a welding operator or other employee skilled in robotic welding programming. This will likely involve additional training to upgrade his or her skill sets. The good news is, programming a robot today is much quicker than in the past. Simplified teach pendants, along with the availability of desktop programming, help expedite the process and reduce downtime. Despite the ease of programming, however, companies may need to alleviate some existing tasks to allow time for the employee to oversee the robotic welding cell without becoming overloaded with too many responsibilities.

Most robot OEMs offer a weeklong training course explaining how to operate the equipment. This course, followed by a week of advanced programming, is recommended when implementing welding automation.

Justifying the expense and calculating payback

If the personnel investigating the prospect of robotic welding determine it’s a good fit, they will likely need to justify the investment to upper management or an owner. Calculating the potential payback is essential. There are several steps to consider.

First, determine whether the volume of parts the company needs to produce requires the speed of welding automation. Remember, the key benefit of a robotic welding system is the ability to produce high volumes of quality welds or in smaller facilities to offer the flexibility to weld smaller volumes of multiple parts.

Calculate payback by assessing the current volume of semi-automatic parts and cycle times. Compare these to the potential cycle times of a robotic welding system. Again, an integrator or welding automation specialist can help. Establishing the comparison is critical to estimating the potential return on investment.

That said, even if a company will produce the same number of parts with a robot, it could justify the investment by the amount of labour it can reallocate elsewhere in the operation for jobs that boost production, eliminate bottlenecks or increase quality. For example, a company could utilize the skills of semi-automatic welding operators to complete challenging welds that are too complicated for a robot to manage.

It’s important to factor the bulk cost of shielding gas and welding wire when looking at the potential payback. While there is an initial cost for a shielding gas/manifold system, it can help optimize a company’s robotic welding capabilities in the long term by minimizing downtime for cylinder changeover. The same is true for welding wires. The larger drums — typically ranging from 500 to 1500 pounds — can further reduce costs in a robotic welding cell since they require fewer changeovers and often come with purchasing discounts.

Companies need to keep in mind that the benefits of robotic welding can be significant. However, those benefits come at an upfront price. Many companies, especially smaller ones or those that frequently change production lines, need a faster payback — no more than 12 to 15 months is common to justify the investment. If a company will have the same production needs for many years, it can typically justify a longer payback period. Management and owners should discuss their payback goals with a trusted robotic welding integrator as part of the assessment process. 

Improving Welding Automation Safety With Risk Assessment and Training

Robotic welding systems continue to gain in popularity due to their ability to increase productivity, improve quality and decrease costs in the right application. But they also offer a way to address a shortage of skilled labor for manual operations. Welding automation provide companies with a means of staying competitive in a demanding marketplace, while using their existing and potential workforce to oversee the weld cell.

With more and more robotic welding systems being implemented — the Robotics Industries Association (RIA) cited that 20% of all industrial applications had robotic welding cells as of 2017 — comes the need for increased attention to safety. From the robotic welding gun and peripherals to the robot itself, following safety best practices is essential. 

Robotic welding safety hazards and resources

Statistically, welding automation is safer than manual or semi-automatic welding. However, operators overseeing the robotic welding cell must still remain vigilant. This is particularly true when performing nonstandard operations; these include programming, maintenance and any other tasks that involve direct human interaction with the robot. 

Conducting a thorough welding risk assessment helps identify potential safety hazards associated with a specific robotic welding system (whether it is a pre-engineered or custom cell) and is a critical first step in establishing a safer welding environment. This assessment provides a baseline for implementing solutions for identified risks and establishing appropriate welding safety training. In addition, it helps companies maintain compliance with safety standards, which most importantly protects employees but also protects the bottom line. Noncompliance and/or safety violations that can lead to injury become can be costly in terms of fines and workers’ compensation. 

Companies can obtain welding safety resources through the American Welding Society (AWS), including Safety in Welding, Cutting, and Allied Processes, ANSI Standard Z49.1, a free download at aws.org. The National Fire and Protection Association (NFPA) also offers resources. RIA follows American National Standards Institute (ANSI) standards and offers safety seminars and webinars. RIA also provides information on industrial machinery and guarding, as well as guidelines to help companies, including the American National Standard for Industrial Robots and Robot Systems – Safety Requirements, ANSI/RIA R15.06-2012. The Occupational Safety and Health Administration (OSHA) is another valuable safety resource.

Many robotic welding integrators or robotic welding system manufacturers offer training for the safe use of their equipment, including how to test safety functions and at what frequency. They also provide manuals and safety standards for their systems. It is critical to read and follow these thoroughly.

Safe use of robotic welding guns, consumables and reamers

Manufacturers of robotic MIG welding guns often integrate design elements into these products to aid in their safe use. These elements are intended to protect operators during routine maintenance and minimize or eliminate the need to enter the weld cell to complete tasks.

For example, guns that are compatible with front-loading liners help improve safety in a robotic welding cell. These liners can be installed from outside the weld cell — there is no need to climb over tooling or maneuver around the robot to complete replacement. Operators or maintenance personnel also don’t need to remove electrical connections to replace components during the process.

An insulating disc is another important safety feature in select guns. It helps protect operators from the welding current during maintenance and protects the robot from the current, limiting potential damage.

In addition to integrated safety features, there are some key best practices for working with robotic welding guns, consumables and reamers (or nozzle cleaning stations). First and foremost, always de-energize the robotic welding system when installing a robotic MIG gun or consumables, and follow all lockout/tagout procedures.

When possible, it’s ideal to have a window or opening that allows consumables to be changed or inspected from outside the weld cell.

When possible, it’s ideal to have a window or opening that allows consumables to be changed or inspected from outside the weld cell. If this isn’t feasible, programming the robot to stop near the weld cell door simplifies consumable changeover and eliminates the need for the operator to enter the cell, maneuver around tooling or climb on anything to complete the job.

The appropriate personal protective equipment (PPE) is also important when changing over consumables or the welding wire. The nozzle and contact tip may be hot, and there is the risk of the welding wire puncturing the operator. Leather or other thick work gloves are a must, and safety glasses should be worn at all times. Always use the proper tool to change over the nozzle and contact tip. A pair of welpers is recommended.

When performing maintenance on a reamer, begin by resetting the equipment to a home state, de-energizing it and following lockout/tagout procedures. Be certain there is no air or electricity supplied to the reamer. When changing over cutter blades, always wear gloves and use two wrenches to remove and install them. Reset the reamer to a home state when finished. This is an important last step, as the reamer will automatically complete a cycle as soon as it receives a start signal and is reenergized.

Navigating the robotic welding cell safely

Welding operators and maintenance personnel should familiarize themselves with the emergency stops on a robotic welding system as a first safety step. The number and location of these stops varies by system. For example, welding cells typically have an operator station emergency stop that ceases all robot functions and turns off the robot servo power, along with an emergency stop on the teach pendant. Operators should test these emergency stops periodically, although testing too frequently is stressful on the mechanics of the robotic welding system.

Understanding brake release procedures is also critical. RIA sets standard requirements for these; however, every robotic welding system is different, and the location of the override buttons may vary.

As when interacting with a robotic MIG welding gun, consumables or reamer, always follow proper lockout/tagout procedures before entering the robotic welding cell. Many systems have multiple lockout/tagout locations that are indicated by stickers. Some pre-engineered welding cells feature sliding programming access doors with magnetic keys that indicate that they are fully open and ready to be locked out prior to maintenance, helping to prevent pinch points or a trap hazard.

A built-in awareness barrier in pre-engineered cells is another means of aiding operator safety. This hooped barrier inside the weld cell covers the sweep area of the indexing table. Its purpose is to protect the operator from pinch points during teaching operations by separating the him or her from the space between the robot and the wall of the weld cell.

For robotic systems that are not enclosed, guards around the cell are necessary. These can take the form of physical barriers, like perimeter fencing or light curtains and/or electronic guarding such as area scanners that stop the robot when an operator is present in a specific area of the system.

Lastly, robotic integrators and robotic welding system manufacturers provide risk assessment documentation, typically in the operator’s manual. It is important to review this assessment thoroughly and train employees on the proper techniques to mitigate any identified risks. For example, programming the robot introduces mechanical hazards such as the potential for pinching or impact, which can be addressed by standing a safe distance outside of the weld cell or by using a slower teach speed if offered on the teach pendant.

Other safety considerations

In addition to the best practices outlined for robotic MIG welding guns, consumables and systems, there are steps to further protect employees.

Creating a culture of safety

Safety in welding automation should be top of mind among operators, management and maintenance personnel. Ongoing training needs to be a priority, whether it is conducted through company programs or seminars offered by outside resources. The goal is to ensure that everyone involved with the robotic welding system is playing an active role in employing best practices. When they are followed properly, the result is a safer work environment and a stronger bottom line.

Optimizing Shielding Gas Performance in MIG Welding

Using the wrong shielding gas for MIG welding applications — or having improper gas flow — can significantly impact weld quality, costs and productivity. Shielding gas protects the molten weld pool from outside contamination, so it’s critical to choose the right gas for the job.

Learn more about which gases and gas mixes are best suited for certain materials, along with some tips for optimizing gas performance — and saving money — in your welding operation.

This article was published in The WELDER. To read the entire story, please click here.