EBW vs GTAW Robotic Welding
When it comes to robotic welding there are many different methods to choose from. Two of those methods are EBW and GTAW. Below is an overview of each to help guide robot users to determine which method may be best for their operations.
EBWElectron beam welding (EBW) involves welding metals together through a beam of powerful electrons. To automate this process a welding robot is integrated with an electron gun for its end-effector. Six axis robots that can be used for EBW include the FANUC Arcmate 120ic and the ABB 2400. During robotic electron beam welding, an articulated robot will apply the electron gun to the workpiece at the weld joint. A chain of electrons is sped up through the weld gun, creating kinetic energy that will cause the workpieces to melt at the spot the weld gun is applied to by the robot. Once cooled the workpieces will be fused together.
One feature that is unique to EBW is that all welds take place within a vacuum chamber. The vacuum chamber protects both the electron beam and the weld pool, preventing contamination. Because of the vacuum chamber, robotic electron beam welding produces some of the purest and cleanest welds.
EBW robots can weld both thin and thick metals, as well as most types of metals. What is most advantageous about EBW robots is that they can weld dissimilar metals together and workpieces with different thicknesses together. This is extremely cost-effective as a FANUC Arcmate 120ib can weld expensive metals to inexpensive ones to help save on material costs.
Other advantages include a small heat affected zone, low distortion, and no filler metal. The disadvantages of robotic EBW include high equipment costs mostly due to the vacuum chamber and part size limitations also because of the vacuum chamber.
GTAWGas tungsten arc welding (GTAW) is one of the more traditional welding methods in manufacturing. This robotic arc welding method can be automated with the FANUC Arcmate 100ic or the ABB 1600. Instead of using a beam of electrons to create heat to melt workpieces, robotic GTAW uses a single tungsten electrode. A welding robot will be integrated with a welding torch. The robot will apply the torch to the workpiece, in which the electrode creates an arc which then generates the heat needed to melt the metals and fuse them together. Instead of a vacuum chamber, GTAW robots use shielding gas to protect the weld pool from contaminants.
GTAW robots provide precise, controlled movements, making them ideal for detailed welding. Robotic GTAW is best for welding thin metals such as aluminum, copper, and steel. Electrically resistant metals are best for this welding method since they tend to melt the fastest. This method is a slower process, so using fast melting metals will speed up the process. The Motoman MA1400 is another good choice for automating this application with robots.
The main advantages of GTAW robots are complete control of the arc, low distortion rates, high-quality bead appearance, and minimal spatter. These all result in clean, smooth welds, which is why GTAW robots are preferred for welding intricate workpieces. Disadvantages include limited metal thickness and long weld torch passes causing slower cycle times.