Due to the size constraints of FDM systems, it is sometimes necessary to build larger parts in multiple pieces and then join them together as part of the post processing procedure. In this article we will introduce a lesser used, but highly effective method for joining parts – Hot air welding.
Hot air welding is achieved by using a hot air plastic welder to simultaneously melt the 2 pieces you are trying to join AND a piece of filament that is fed into the hot air and creates the joint. The filament is melted into the joint and fills the void between the two pieces creating a "weld". This process is similar to wire feed metal welding.
The welding process will leave flash that can easily be sanded away to produce a cleaner looking joint.
In this process it is common to design in a dove-tail feature to hold and align parts during welding. Tack welding can also be used to hold parts in place without clamping.
Hot air welding produces strong joints due to the fact that the joint material is the same as the substrate material.
Owen Lu | Applications Engineer