The average arc-on time in a semi-automatic welding operation is typically 10 to 12 percent — much lower than many manufacturing operations assume it to be. Finding ways to improve arc-on time can result in better throughput and cost savings.
Learn how paying attention to four key factors can help improve arc-on time in MIG welding — and allow operations to get more parts out of the door.
Is it the Right Welding Process?
Making a change to the welding process can result in significant benefits in the right applications. A switch from standard MIG to modified short-circuit MIG, for example, can be helpful when an operation has big part gaps that can’t be fixed in fit-up, since modified short-circuit MIG offers better gap-filling capabilities.
Pulsed MIG processes can help boost productivity through less spatter and faster travel speeds. Compared to standard MIG, a pulsed process can deliver 10 percent faster travel speeds using the same heat input.
The choice of filler metal and shielding gas can also affect arc- on time and productivity. While solid wire is commonly used for MIG applications, metal-cored and flux-cored wires might provide more benefits for productivity. It all depends on the welding process, the shielding gas and the base material.
Many manufacturing operations use a 100 percent carbon dioxide shielding gas. However, a mixed gas such as 90 percent argon/10 percent CO2 results in much less spatter — so there is less time spent on post-weld grinding — in addition to faster travel speeds.
Be aware that some of these changes may require re-approval of the Welding Procedure Specification (WPS) for operations that are working with one.
Part Fit-Up is Important
When operations measure arc-on time, that figure doesn’t include the time spent on part fit-up or material prep. But these factors can have a significant affect on overall productivity and efficiency in the welding process.
Large or uneven gaps between the parts being welded can slow down the welder and increase spatter, resulting in more time spent on post-weld grinding.
The welder may or may not be the person responsible for part fit-up. In some operations, issues with poor part fit-up might even trace back to the engineering or design phase. Taking the time to ensure consistent part fit-up helps eliminate gaps and saves time in the long run.
Check the Consumables and Parameters
When welders spend time troubleshooting problems like wire feeding issues, it reduces arc-on time. If the gun liner or contact tip is too worn or the drive roll tension isn’t properly adjusted, it can contribute to wire feeding issues and result in increased spatter and poor weld quality. Worn weld cables or poor cable connections are also common causes of weld quality issues.
Properly maintaining the MIG gun and checking all consumable connections before each shift can help decrease the time spent troubleshooting.
It’s also important to make sure welding parameters are set correctly. This helps operators produce good welds and avoid time-consuming rework. Check for proper heat input, wire stick out and travel speeds, which are all factors that affect the occurrence of weld defects or issues that require rework or additional post-weld cleanup.
Producing a bad weld that requires rework can more than triple the amount of time spent in the process, greatly impacting efficiency and throughput.
Let Newer Technology Help
Welding power sources that are easier to use for welders of all skill levels can help improve productivity and arc-on time. Some newer machines are designed with synergic control, simplified setup and other technologies that can help operators save time and produce high-quality welds.
With synergic control, the power source will automatically make changes to correspond to any adjustments made by the operator. This helps ensure optimal parameters are used for the job. Simplified setup is another way to help operators get welding faster. The operator inputs the thickness of the material being welded, and the power source automatically sets the other parameters.
In addition, investing in weld data monitoring can allow manufacturers to track performance metrics and see what factors may be negatively affecting arc-on time and productivity. From basic systems to more advanced tracking and reporting, digital weld monitoring is available on a wide range of power sources.
Optimizing Arc-On Time
There are many factors in the manufacturing operation that play a role in arc-on time and productivity. Be sure to consider the process from start to finish, and don’t look only at the welding itself. Activities performed before and after welding, such as part fit-up and post-weld grinding, also have a significant impact on how much time welders are actually spending under the hood.
For more information, visit www.millerwelds.com.