Comparing Electron Beam Welding & Laser Welding
At first glance electron beam welding and laser welding may appear to be similar processes. Both are welding applications that can be fully automated with industrial robots and are often the go to for those needing precision welds. The beams emitted from each provide pinpoint accuracy, small heat affected zones, and ensure weld purity. This makes both methods ideal for delicate and small parts, but they both have the versatility to weld large workpieces too. You may be wondering how one decides which process to select. While these robotic welding applications share some similarities there are also some key differences that come down to their advantages and disadvantages. Understanding these will help users determine which method will be best for their operations.
Robotic EBWElectron beam welding is automated through the integration of a welding robot, electron gun, power supply, and robotic positioner. The FANUC Arcmate 120ic and the ABB 2400-16 can both automate electron beam welding applications. Metals are welded together through the electron beam method when a stream of electrons are emitted from the robot’s EOAT to the workpiece. The kinetic energy of the electron beam heats and melts metals. Robotic EBW does not require a shielding gas of filler material. However, these welds must be completed through a vacuum chamber to prevent the weld pool from being contaminated.
EBW robots are capable of welding a variety of metals and can even weld dissimilar metals together. Even parts with different thicknesses can be joined with an EBW robot. This robotic welding method is the preferred choice for welding dissimilar metals. It is also better than laser welding for thicker parts since the electron beam is very powerful with the ability to infiltrate metals up to a half inch thick.
In terms of weld quality, EBW articulated robots have the advantage over laser welding robots. While both methods have a small heat affected zone that limits part distortion, the vacuum environment of EBW ensures no atmospheric contaminates resulting in a pure, clean weld.
Drawbacks to robotic EBW include the cost and limitations to part size. Robotic EBW can be more expensive to implement since it requires specialized equipment such as a vacuum chamber. In addition, parts that do not fit into the chamber cannot be welded with an EBW robot.
Robotic Laser WeldingLaser welding is automated through integrating a six axis robot with a laser cutting head and a laser generator. Laser welding allows metals to be joined together without contact from the laser head. Laser welding robots can weld parts from over a foot away, making this method ideal for hard to reach parts. When the laser beam is emitted to the metal, radiant heat will melt it forming the weld pool. Unlike EBW, the amount of power emitted from the beam can vary from low to high. Robotic laser welding does require the use of shielding gas to prevent weld contamination. The FANUC Arcmate 100ic and the Motoman HP20D can be deployed for laser welding applications.
Like EBW robots, laser welding robots can weld dissimilar metals together. Cycle times are shorter with laser welding robots since the laser melts metals quickly. It is also more cost-effective than robotic EBW mostly because the equipment required is less complex.
The drawbacks to robotic laser welding are related to metal thickness and reflectivity. Laser welding robots are best for welding thinner metals which limits workpiece flexibility. Reflective metals are also not suitable as the beam may be focused away from the joint, preventing infiltration and potentially damaging the part. With either form, welding automation is a great way to optimize production.