Injection mould for prodn. of electronic components on lead frame - has manifolds, each leading to parallel series of mould cavities arranged along straight lines and ending in homogenising bore

摘要

The plastic casing for electronic devices in injection moulded on a metal lead frame using moulds arranged in rows parallel to centre rubbers; in the process the shot is injected into separate individual rows, without angles in its flow path, and, in particular, to homogenising bores at the end of the rows also. The figure shows the lower mould tool (1) with centre manifolds (2), runners (3) to the mould cavities (5,6,7) and the futher runners (4) on the same axis (10) as the cavities themseleves. Each such axis (10) passes through the centre of the manifold (20) so that all the flow paths lie on a straight line. The end rubber (8) of each line leads to a homogenising opening (9) whose volume relates to that of the cavities and rubbers. The opening (9) tapers outwards and is best in the split plane of the mould tools. ADVANTAGE - The system shortens injection time and also increases the density of the shot in the mould. A number of mould impressions of different shaft can be reliabily filled completely. It is also of interest and the system disproves the previously held belief that show flow along straight paths was undesibrable.