PRECISION CASTINGS OR INJECTION-MOULDINGS FROM PLASTICS

摘要

1,208,816. Moulding plastic materials. FARBENFABRIKEN BAYER A.G. 18 April, 1968 [19 April, 1967], No. 18299/68. Heading B5A. [Also in Division B3] In a process of producing from plastics material a precision casting or an injection moulding, an oversize casting or moulding is produced in a mould and is then forced through a multi-stage shaving tool to provide the finished casting or moulding. In Fig. 1 a gear-wheel 10 is injection moulded between mould parts 1 and 5 supplied with moulding material by a nozzle 7, the part 1 being carried by a movable frame 2. An ejector 9 forces the gear-wheel from the mould and through a shaving tool 12 brought into position along a guide 11. The tool comprises a number of cutting blades separated by spacers carried in a housing 12. The head of the ejector may be in the form of a punch carrying a rotary disc which abuts the gear-wheel, which is helically toothed, to force it through the shaving tool with a rotary action.