TWI Frequently asked questions
In joining thermoplastics, electromagnetic energy is employed for a number of welding techniques, for example dielectric (HF) welding, infrared welding and laser welding. However, microwave welding in amultimode cavity offers one clear advantage over all other techniques: it is capable of welding thermoplastic components of any shape. Provided that the thermoplastic is, to a first order, transparent to the microwave radiation, theonly part to be heated will be a prepositioned implant at the joint line. The joint may have features in two or three dimensions but the microwave energy will still heat only the implant, thus creating a two or three dimensional weld.This makes the process unique and is expected to give designers considerable freedom to generate thermoplastic components of increasing complexity.
The other potential benefits of this technique over conventional methods are shorter weld times and non-contact processing. Commercially, the benefits of this new technique will be in terms of a reduction in capital cost ofequipment, particularly for welding complex components. For example, a typical automotive component such as a bumper or dashboard assembly may require several welding operations. Welding equipment to carry out these operations can costover £100,000. Microwave implant welding should reduce the entire process to a single operation, with the capital cost of equipment only half that of the original technique. A further saving will be gained because the equipment isnot dedicated to one application and can be used to process a variety of components without major tooling costs and changes.
It should be emphasised that microwave welding is still under development and is not currently a commercially available process. Therefore, the feasibility of each potential application must be investigated thoroughly at the presenttime.
TWI is equipped to carry out feasibility trials and can also help companies design and manufacture microwave welding equipment specifically for their own applications.
Further information can be obtained from Mike Troughton
