초록 ▼

The quality that is good or bad of an injection molded product is judged. The temperature T of a metal mold, of a resin in the mold cavity, barrel or nozzle of an injection molding machine is measured at a time t elapsed after comencement of a pressure holding step of the injection molding machine.

The quality that is good or bad of an injection molded product is judged. The temperature T of a metal mold, of a resin in the mold cavity, barrel or nozzle of an injection molding machine is measured at a time t elapsed after comencement of a pressure holding step of the injection molding machine. The present P of resin in the mold cavity or barrel or nozzle is measured at the time t, and a time function A=f(t) is calculated using the temperature T and the pressure P, where A represents a calculating parameter T/P, P/T, T×P, T+P or T±P. This is compared with a reference time function Ao=f(t) of a shot in which satisfactory products can be obtained, with a time function An=f(t) of another shot.

대표청구항 ▼

A method of judging a quality of an injection molded product, comprising the steps of: measuring a temperature T of an operating member of an injection molding machine during a pressure holding step at a time t elapsed after commencement of said pressure holding step of said injection molding machin

A method of judging a quality of an injection molded product, comprising the steps of: measuring a temperature T of an operating member of an injection molding machine during a pressure holding step at a time t elapsed after commencement of said pressure holding step of said injection molding machine; measuring a pressure P of an operating member of said injection molding machine at said time t; repeating said measuring temperature and measuring pressure steps at different times during said pressure holding step; calculating a time function A=f(t) using both said temperature T and said pressure P, where A is a function from the group consisting of T/P, P/T, T×P, T+P or T±P at said different times; obtaining a reference time function having values at said different times of said pressure holding step that represent a satisfactory product; comparing said reference time function with the calculated time functions; and determining that said injection molded product is bad when said calculated time function differs from said reference time function, at any of said different times, by more than a predetermined amount.