Automatic pressure control in injection moulding - based on differences of actual and preset resin temps. in the injection mould and extrusion nozzle

摘要

In the regulation of the injection pressure in an injection moulding machine, in which a screw is advanced by a screw press piston, the temps. of the molten resin and the mould are measured prior to or during the injection and the pressure on the screw press-piston is regulated for the time of the injection as a function of the deviation of the measured temps. from the corresp. pre-determined temp. Provices a method of controlling the moulding pressure which is extremely effective in improving the productivity and the precision of the dimensions of weight of the injection moulded prod.