사출성형공정에서 금형에 전달되는 진동 신호 측정을 이용한 성형 단계별 공정시간과 공정특성의 모니터링에 대한 연구

Abstract

In this study, the vibration signal of the mold was measured and analyzed to monitoring the process time andcharacteristics during injection molding. A 5 inch light guide plate mold was used to injection molding and the vibrationsignal was measured by MPU6050 acceleration sensor module attached the surface of fixed mold base. Conditions exceptfor injection speed and packing pressure were set to the same value and the change of the vibration signal of the moldaccording to injection speed and packing pressure was analyzed. As a result, the vibration signal had a large change atthree points: “Injection start”, “V/P switchover”, and “Packing end”. The time difference between “injection start” and“V/P switchover” means the injection time in the injection molding process, and the time difference between “V/Pswitchover” and “Packing end” means the packing time. When the injection time and packing time obtained from thevibration signal of the mold are compared with the time recorded in the injection molding machine, the error of theinjection time was 2.19± 0.69% and the error of the packing time was 1.39±0.83%, which was the same level as theactual value. Additionally, the amplitude at the time of “injection start” increased as the injection speed increased. In “V/Pswitchover”, the amplitude tended to be proportional to the pressure difference between the maximum injection pressureand the packing pressure and the amplitude at the “packing end” tended to the pressure difference between the packingpressure and the back pressure. Therefore, based on the result of this study, the injection time and packing time of eachcycle can be monitored by measuring the vibration signal of the mold. Also, it was confirmed that the level and trendof process variables such as the injection speed, maximum injection pressure, and packing pressure can be evaluated asthe change of the mold vibration during injection molding.