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Automotive | Two-part bumper, fuel tanks, fuel pumps, expansion vessels, instrument panels, air channels, parcel shelves, inner door panels, hermetic sealing of a length of air ducting to the internal surface of a dash-board |
Consumer | Spectacle frames, type writer cover |
Industrial | Filter housings, motor saw housings, heating valves, air induction ducting |
Orbital welding is another frictional technique for joining thermoplastic parts, where each point on the surface orbits a different point on the face of the stationary part. The orbit is of constant rotational speed and is identical for all points on the joint surface. This motion is stopped after sufficient material is melted and the thermoplastic then solidifies to form a weld.
Orbital welding is a relatively new technique, and the first welding units are being marketed as devices to fill the size gap between benchtop ultrasonic units and linear vibration welders. This means that items such as medium sized automotive components (fluid reservoirs etc.) may be joined using this process.
The principle behind spin welding is similar to that of linear friction welding. The joint areas are always circular and the motion is direct rotational.
Direct rotational friction welding (spin welding) of thermoplastics involves relatively simple pieces of equipment such as lathes or drilling machines. A lathe would produce a constant speed during the frictional heating stage (continuous drive friction welding) and a drilling machine would produce a reducing speed characteristic during the frictional heating stage (inertia friction welding). In practice, purpose built machines are generally employed for spin welding to provide greater control and they may be of either the continuous drive or inertia type.
Spin welding has been exploited for applications as diverse as the manufacture of polyethylene floats, aerosol bottles, transmission shafts and PVC pipes and fittings. Apart from being a fast technique, another particular advantage is that welds can be formed beneath the surface of a liquid.
The principle behind angular friction welding is similar to linear vibration except that the motion is angular.
In spin welding it is not possible to determine where one half of the component will end up in relation to the other half when welded. In angular welding the components are pre-assembled and vibrated in an angular motion through a few degrees. When the weld cycle is complete the component parts are returned to the pre-welded position ensuring good alignment.
The angular friction welding process is used for circular components where upper and lower component alignment is critical.
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