As aluminum welding remains a rising force in the industry, continuing to test and understand the problems that come along with it is essential. With all the advantages that aluminum brings, there are also some aspects of this material that makes it tricky to weld with. For starters, aluminum is very soft, leading to many of the issues we will discuss.
Let’s take a look at some of the most common issues that arise in aluminum welding and how your facility can get ahead of the problem.
Weld Preparation
Aluminum has a unique quality making it difficult to weld with if not taken care of properly. A thin layer of aluminum oxide will form as soon as the aluminum is exposed to ambient air. This layer of aluminum oxide is what gives aluminum it’s silver-grey appearance, as well as corrosion-resistance to water, oxygen, and many other chemicals.
In order for this part of the process to run smoothly, proper weld preparation needs to happen. You will want your surface as clean as possible. If you start welding without cleaning up your area, it can pose a threat to your weld joint or application and cause cross-contamination. To ensure your surface is ready, clean your work piece with a microfiber cloth that has been soaked with solvents such as butanol, acetone, or paint thinner. You will want to remove any dirt, grease, or other contaminants that may cause a disturbance to your process. Keep in mind that anything left behind, after your thorough cleaning, will burn into your final product during the welding process.
If you plan to weld thicker sheets of material, it is always best to preheat your workpiece. Without preheating, too much heat would leave your process and go into the workpiece during welding, which makes the formation of the weld seam more difficult.
Having a clean surface is something that people don’t always take into consideration, but is crucial to the success of your operation. Since aluminum oxidizes quickly, depending on the ambient conditions, cleaning your space may need to occur multiple times.
Feed-ability
This is more often than not the most common issue we see in the field. Incorporating wire feed assist equipment helps to eliminate the issues of improper feeding.
Tangling of the wire is a common issue, which causes the wire to get stuck in the drive roll and liner. When you take time to have your operator replace the tangled wire, it ends up becoming a time-consuming and costly investment.
This is where spool guns will come into play. They can help tremendously with pushing the wire at a more controlled rate. Otherwise, with a standard MIG gun, the process would need to be much more controlled by keeping the gun steady and pointed at a straight angle to ensure issues do not arise. A push-pull gun would be your best choice in terms of feeding aluminum, as the wire maintains control from the gun and the wire feed assist motor. In addition, the spool feeding the wire would not need to be changed as often as a typical spool gun would.
With aluminum being very soft, U-groove drive rolls are a necessity to prevent deformation of the wire during feeding.
Distance can also be a challenge when feeding aluminum. Push-pull torches, which have drive rolls and a motor within the torch itself, place tension on the wire by pulling, while the main feeder pushes. Push-pull torches are typically bulky, and provide limited access to weld joints. For this reason, we recommend using our FreedomDrive™ Push-Pull System, which places the drive rolls and motor six feet away from the torch, meaning the welder can use a lightweight MIG torch. This will provide better ergonomics and flexibility while welding.
Wire Choice
As we all know, aluminum wire is extremely soft. Usually the thicker the wire, the less likely you will run into a feeding issue. The grade of wire, like 4000-5000 series wire is very common.
Picking the right wire will make all the difference, with the thickness being especially important. Since aluminum is very easily distorted, any kind of burnback, whiplash, or really any problem can drastically affect the final product. Aluminum needs to be pushed, not pulled or dragged. It liquifies so fast that you’re having to go at travel speeds much higher than standard MIG applications.
Conclusion
Aluminum, thank to its strength and low density, is increasingly becoming an integral part of modern production. By following some of our guidelines and understanding the complex nature of aluminum, your facility can be extremely successful welding aluminum.