Pre-assembled wire frames cut assembly times

A method has been devised that allows spring wire components to be joined by spot welding them together, with automotive seat cushions being the target market.

Engineers at William Hughes, a manufacturer of springs and formed wire components based in Dorset, can now supply the wire frames used in the manufacture of car seat cushions as a complete pre-assembled unit. The frames are welded or clipped together and the rigid assembly is supplied ready for immediate use to suit the requirements of the foam moulding process. By pre-assembling the wire components, the company stated that the effort required for assembly on a cushion production line "can be reduced by up to 75 per cent" by reducing the workload on operators and by minimising potential errors. The firm also stated that product quality and consistency should also improve and that stoppages on the production line for rectification work was also likely to be reduced. With William Hughes' process, the wire components are formed from spring steel, which is normally very difficult to weld. The new spot welding process solves this problem. The traditional method of manufacturing car seat cushions is based on wires being placed in a moulding tool. These wires are then surrounded with foam. Historically, the wire components used are individually inserted by hand along with other components. Foam is then poured into the mould and when cured, everything is held firmly in place. Clips are available as an alternative to spot welding. These can be applied quickly and could provide a lower cost option for many companies, depending on the complexity of the cushion frame. Clips are not a rigid method of fixing but this allows final adjustments to be made to the assembly before the moulding process.