Injection mould design - with automatic sprue ejection prior to opening the mould

摘要

Mould has a supplementary ejection system opposite the injection point to punch the sprue back out through the injection face platen after withdrawal of the injection nozzle and prior to opening of the mould. A separate system subsequently ejects teh moulding after the main mould is parted. Esp. for injection moulding of thermoplastics where a hole can be tolerated at the injection point, e.g. electric motor end covers. The sprue can be discharged and collected separate from the mouldings and can be severed by a relatively low power system while still soft. No further finishing of the moulding is needed.