Circular friction welding - CircleMerge

Circular friction welding - CircleMerge

Hermetically sealing of electronic circuit carriers is a challenging task. The reason is the high number of different requirements. Electronic components must not be affected by the welding process, while at the same time the cycle time should be short and particle formation should be prevented as far as possible. In many cases, all these requirements are met by using laser transmission welding.

With circular friction welding, PolyMerge now offers a cost-effective alternative without the need for special pigmentation. In this process, unlike ultrasonic welding, the melting energy is generated by friction between the joining partners. Nothing new, you might think - right - the principle is already known from vibration welding. But unlike this technology, circular friction welding is suitable for components in dimensions up to approx. 100 x 100mm² as well as for non-symmetrical components. The generated motion is a harmonic circular movement similar to that of an excenter grinder. The advantage here are the significantly lower acceleration loads. The tool and thus the upper joining partner perform a continuous movement without being regularly accelerated in opposite directions. This results in a weld seam with an identical appearance all around. Sensors and actuators can be implemented in the upper tool and components can also be processed when having an undercut in the welding area.

PolyMerge's patent-pending approach offers very fast start-up and shutdown times. Particle formation is still present, but much less pronounced than with other setups. Since this process works independently of the attenuation behaviour of the polymer. Materials such as polyamide with and without glass fibre reinforcement can also be processed without any problems.

Between the worlds...Circular friction welding is an useful welding process wherever ultrasonic welding cannot be used due to the high-frequency excitation and laser welding cannot be used sensibly due to economic or accessibility reasons. Due to the comparatively high frequencies of up to ~300 Hz and the bidirectional motion sequence, very fine weld seams are produced with short welding times of usually ~2s. Circular friction welding is thus optimal when quality and economy are to be brought into harmony.