Maintaining quality, productivity and cost savings is important in any semi-automatic MIG welding operation, but the steps companies take to achieve those goals vary. Still, there is one constant: the value of skilled welders. They are at the heart of the operation and help ensure its success.
Having the right equipment and understanding how to care for it are also important – as is
revisiting the welding process regularly to ensure its efficiency. Companies should watch for common pitfalls that could negatively affect their progress toward streamlining and improving their operations. They should also consider the following tips to help along the way.
With the industry facing an anticipated welder shortage of 400,000 by 2024, providing training to new welders is critical to support a productive and profitable MIG welding operation. In many cases, employees are entirely new to welding or only have limited experience. Learning best practices early on is necessary to achieve the best performance and avoid excessive downtime for troubleshooting.
Achieving good weld quality depends on welders knowing proper techniques like gun angles and travel speeds and the impact of welding parameters on the process. Even if a company sets lockouts that keep welding parameters within a specific range, it’s valuable for welders to understand the impact that voltage, amperage, wire feed speed and shielding gas have on the application.
It’s also important to provide training on other best practices in the MIG welding operation, such as:
- Consulting a checklist for maintenance or equipment checks at the beginning and end of each shift. This can include items like securing weld grounding and checking for welding gun or cable damage.
- Understanding proper ergonomics to prevent repetitive stress injuries. Having welder input on gun handle types can help with this, too.
- Understanding how to correctly install consumables and at what frequency, along with how to identify the signs of contact tip wear.
- Keeping the gun uncoiled and untwisted while using it to help avoid liner movement, which typically leads to wire feeding problems.
As part of the training, encourage welders to be open to ask questions and offer refresher courses to keep skills in top shape.
Assessing the process
To support the long-term efficiency of a MIG welding operation, it’s a good idea to regularly assess each aspect of it.
Time studies, for example, offer excellent insight into the entire workflow and allow companies to record the amount of time each task takes to complete. These studies include a breakdown and analysis of parts handling, welding and more. By recording every activity in the operation, it is possible to see whether each one is adding value. If not, adjustments and re-sequencing can be made.
Analyzing the operation can also help identify the need for more welder training. For instance, if a significant amount of time is spent grinding after welding, it can indicate that there are issues contributing to over-welding or poor weld quality. The company can then take proactive steps for additional welder training to improve quality and reduce or eliminate the need for grinding and rework.
Similarly, if welders spend more time transferring parts than they spend welding or if there are bottlenecks of parts entering the welding cell, it indicates the workflow needs to be adjusted. The goal is to minimize the amount of time welders spend handling or double handling parts and to avoid parts from backing up or having welders sit idle waiting for them.
Improving the organization of the workstation as part of a general assessment can also help improve welding productivity. This could include adjusting welding tables and part racks to be more ergonomic so welders are more comfortable and can weld longer.
Having the correct welding gun for the application can help enhance performance in a MIG welding operation.
One of the first things to consider is cost. Quality welding guns carry a higher price, but they are worth it in the long run. When used properly, a better gun lasts longer and can help improve weld quality and efficiency over time. Guns that feature mechanical compression fittings, as opposed to crimped fittings, are a good choice. They typically last longer from wear and tear and can also be repaired if damaged, which saves money on replacement guns.
Be certain to choose a welding gun with the appropriate amperage rating and duty cycle for the application to prevent overheating. A lower amperage gun may be appealing to a welder due to its lighter weight and flexibility, but it will not be able to withstand an application requiring higher amperages and long arc-on times.
Effectively grounding the weld circuit is another way to gain weld quality and productivity in a semi-automatic welding operation. It can also protect the gun from overheating and from wearing out consumables too quickly. Installing the ground clamp as close to the weld as possible and limiting the amount of connections can help to prevent one or more from coming loose over time or creating electrical resistance.
Always choose correctly sized ground cables for the weld circuit and the right type of ground clamp. A C-clamp is a good option as it is a tighter connection versus a spring clamp, which helps prevent arcing at the ground that could lead to an erratic arc. As with other quality components in a MIG welding operation, C-clamps can be more expensive, but they offer a connection that can better protect the gun and save on replacement or repair costs.
Finally, inspect the welding gun cable regularly for damage and replace as necessary. Nicks or cuts in the cable can expose bare copper, causing a safety hazard of electrical shock as well as erratic welding issues. Adding a cable jacket cover is a proactive step in avoiding these problems.
Role of consumables
Contact tips, nozzles, gas diffusers and liners all affect MIG welding performance. Ideally, select consumables and wire designed to complement one another as a system. These can help maintain solid connections that provide the best electrical conductivity and arc stability.
Always trim the liner properly, per the gun’s owner manual, to avoid erratic arcs and burnback or look for liners that lock into place and require no measurement to avoid trimming them too long or too short.
For semi-automatic MIG welding, copper contact tips work well. However, if more tip life is desired or needed, chrome zirconium tips are an alternative to better resist physical tip wear (also known as keyholing). It helps to monitor how often contact tips are being changed to avoid straying too far from the originally planned frequency of tip changeover.
If contact tip changes begin to increase drastically, then this points to incorrect installation of consumables, a liner being cut too short or other damage in the system. Monitoring consumable usage can also help identify when tips could still have life left in them. If tips are changed too early, this results in unnecessary downtime.
Also consider the wire being used. Quality is key here, too. Less expensive wires often have an irregular cast or helix or an inconsistent layer of lubricant. All of these factors can lead to weld quality issues and additional wear on the contact tips.
Maintaining an efficient MIG welding operation takes time and resources, but it’s worthwhile to make an investment in welders and equipment to achieve the best results. Continue to monitor the process for improvement opportunities and engage welders whenever possible. Because welders are responsible for moving quality and productivity forward, their ideas can be a valuable asset.