Tube Fab is proud to be able to offer our clients the advantages of Cold Metal Transfer Welding.
Traditionally, the joining of tubes to brackets, or tube-to-tube joints have utilized either resistance welding or tack welding followed by a copper braze process. Brazing can have significant drawbacks pertaining to cost, lead time and warpage requiring post process manipulation to meet gauging requirements after the assembly has been brazed.
The Furnace brazing process heats the entire part, not just the joint area. The impact of this heat, anneals sections previously cold worked during fabrication. This relieves the stress in the part and causes relaxation between the brazed joints, changing the geometry of the parts.
Copper Furnace Brazing also requires tight fitting joints to allow for the capillary action or “wicking” of braze material into the joint. To achieve this, additional sizing operations are often required to meet the joint requirements; adding additional cost. The addition of a braze process increases both lead time and cost due to the extra logistics and packaging involved.
CMT welding on the other hand imparts minimal heat to create the weld joint and has a minute impact on the geometry of the assembly once it is welded. This eliminates warpage and the need for manipulation of the assembly to again meet the required geometry.
Joining Aluminum – because the aluminum oxide layer’s melting point is much higher than the aluminum/alloys melting points it can be difficult to join without burning through the parent metal. Often, torch brazing is utilized. However, this is relatively inconsistent in producing sound, leak free joints. It also requires a caustic cleaning process to remove scale.
A solution to this is Tube Fab’s Robotic CMT Welding cell. It is especially suitable for joining thin materials, dissimilar materials, and aluminum components together to form an assembly.