What Is the Right Plastics Joining Process for You: Part 2—Available Technologies
The four primary joining technologies—vibration, clean vibration, infrared, hot-gas/convection—offer different benefits and challenges for different applications.
Vibration welding uses heat energy generated when one part is held stationary while the other part is moved in a linear, back-and-forth motion. The heat generated initiates a controllable meltdown at the interface of the parts. Vibration welding requires that the part interface accommodate the relative motion inherent in the process. Typical motion is 1 mm in each direction for 240 Hz welding and 2 mm in each direction for 100 Hz welding.
Figure 2 shows an air intake manifold made from PA6 GF30. While the geometry is complex, the parts are designed so that there is a part-to-part orientation that will accommodate the linear motion required by the process. Jagged weld flash and particulates are typical byproducts of vibration welding. “Flash traps” are designed into the parts—Figure3—to contain the flash produced during the weld. However, in some designs, part geometry does not always allow for this method of flash containment.
Infrared welding uses energy that is radiated by gray body emitters mounted on a movable platen. It is a non-contact process in which the parts to be joined are brought close to the emitter platen (approximately 1 mm) as energy is absorbed at the weld interface. The parts are then pressed together, achieving a bond that is controlled during meltdown.