Aluminum welding is not as forgiving a process as steel. For optimal success, it demands unique control and presents many unique challenges. It is of the utmost importance to understand not only the process itself, but how to control it, particularly in robotics based solutions.
As temperamental as aluminum welding can be, robotics offer a precise and cost efficient solution. For example, the FANUC ARC Mate 100iC – a robot capable of doing the work of 10 welders with exceptional cosmetic and quality standards.
From a robotic perspective, the welding process can be broken down into defined steps.
Starting of the Arc: one of the most difficult steps of the aluminum MIG process. Mechanical properties of aluminum are working against the welding process.
Weld Formation: The objective is to transition from the starting sequence to weld formation. Common techniques include Run-In, Ramping or Direct Entry editing. Choosing the appropriate technique is related directly to the part. Multiple welds on a part, weld sequencing, material thickness and
fixture design all play a role in the decision. There are three primary methods to achieve this.
· Run-In is typically treated as a global condition. The robot uses a defined weld condition to start all welds for a given process.
· Ramping is a common technique used when welding thicker material. The theory behind ramping is to change gradually from the starting parameter to the welding parameter over a defined time
· Direct Entry is a common technique used on thinner material where the base metal temperature changes as welds are applied, making it necessary to have specific control at each weld.
Weld Deposition is the reward of successful starting and weld stabilization. The stability of the weld process is directly related to the ability of the robot to control the welding process. Programming techniques such as weaving may be needed to overcome part variations.
Arc ending on aluminum requires some special techniques to close the weld crater. The weld crater is the void that remains at the end of all welds.
Burn Back is the final step in making a weld, during this phase the filler wire is separated from the weld puddle and the arc is extinguished.
All of these considerations are specialties of the Aluminum welding robotic standard set at FANUC.