Control process for an injection molding machine involves pressure reduction between screw and nozzle by retraction of the injection piston according to plastic pressure

摘要

Plasticized melt collects in the chamber (25) between injection piston (3) and injection nozzle (24) and is prevented from flowing out of the nozzle by retracting the piston to reduce pressure. The degree of piston retraction is determined by the pressure profile in the plastic. A pressure profile in the plastic is determined by sensor (15) measurement of the force required to retract the piston.