The increasing drive to reduce costs, increase functionality and miniaturise medical devices has led to considerable innovation in manufacturing processes, with one key element being the joining process. Many devices comprise multi-materials or need to be semi or permanently implantable, giving particular challenges relating to material compatibility and biocompatibility or even bioactivity.

This paper will overview a series of developments:

Lasers: rapid, low distortion welding is readily available from CO2 and YAG lasers particularly for metals, with new developments now proceeding in direct laser/metal deposition for new build and reclamation of parts. With the advent of diode and fibre optic lasers, there are new opportunities for welding thermoplastics. The interaction of laser energy with polymer type will be described, leading to the invention of the ClearweldŽ process for clear-clear plastics and textiles welding.

Adhesive bonding: the ability to join many material types at relatively low temperatures are key benefits of this technology. The selection of materials for a range of medical device applications will be introduced, with particular emphasis on materials that offer biocompatibility.

Microjoining: miniaturisation requires a range of joining technologies at the microscale. From the traditional soldering and wire bonding techniques, new processes are enabling 2.5D and 3D interconnection via flip chip and direct write technology. Once connected, encapsulation and packaging methods are required to give the mechanical and environmental protection whilst not losing functionality.