Pressing for success

Tom Shelley reports on a visit to a Midlands maker of high tech metal pressings

Very complex parts can be made by pressing them out of metal sheet, easily rivalling shapes that can be moulded out of plastic, at much higher production rates, with lower tool costs, and with final products that can be lighter, stronger, and able to provide inherent shielding against EMC problems. "Why do they make mobile phone enclosures out of plastic, and then try to make them look like metal, when they could have stronger and cheaper products pressed out of metal sheet with EMC shielding built in," asked Tim Jones, business development manager of Clamason Industries in Kingswinford, when we met him on a visit to the factory. Many of the pressings we saw being made were electronic enclosures, mainly to protect engine management systems in various cars, although the product with the highest production rate that we saw, was a small intricate component being manufactured at 385 blows per minute, two parts per blow. Despite the high production rate, each part was inspected as it emerged by a Simac Masic vision system, using two cameras to each make two measurements to an accuracy of 50 microns. Sample parts are further inspected by a Nikon Nexiv 3020 non contact laser system. We were also shown very complex CCTV camera enclosures with lots of apertures and lugs, that were formed out of single sheets, that would be impossible to make so light and thin out of plastic, with any hope of their surviving normal use. But the most difficult part to make that we were shown, was a complex curved enclosure with a crease, which allows it to be formed round another part, in such a way that various holes line up precisely to engage fixings for an automotive application that we have been asked not to disclose. The company uses IT to work with designers who can be local or in another country, and tool makers who may be based in the West Midlands or on the other side of the world. Tim Jones boasted the firm could cope with 3D CAD files in any format, whether to review and mark up designs, work with tool makers, or use them to program the company's Brown and Sharpe coordinate measuring machine. The Managing director Philip Clarke, son of Gerald Clarke, who founded the company in 1947, said he had seen the company move through predominantly making bicycle parts, through automotive and computer sub assembly enclosures, back to automotive parts and now the medical sector. A particular ability he said, was the firm's ability to innovate and make pressed parts that other companies couldn't, and also to manage the manufacture of complex parts, only part of which would be pressings, so that large customers, particularly tier one automotive, could purchase complex sub assemblies from them directly. The company is able to work with literally hundreds of different steels and metal alloys, or bimetallic combinations for special applications. Clamason Industries Limited Pointers *Metal pressings can replace plastic mouldings to achieve greater strength per unit weight, enhanced long term durability and built in EMC protection * Production rates can be up to 100s per minute and tools tend to cost less than those used to produce equivalent plastic parts by injection moulding