Patent ID: 7281918

Claim:
An injection molding system comprising: an injection molding machine; a pressure valve; a flow ratio control valve; a frequency converter connected to the pressure valve, and the flow ratio control valve; a motor connected to and controlled by the frequency converter; a hydraulic pump connected to the motor; means for analyzing injection molding conditions and procedures for controlling operation of the pressure valve and the flow ratio control valve; and an injection molding machine controller for controlling the injection molding machine and the frequency converter, the injection molding machine controller setting a maximum output frequency for the frequency converter and a maximum flow for the hydraulic pump based on a type of the injection molding machine and procedures for injection molding, preventing inappropriate operation of a user and avoiding waste of energy; the injection molding machine controller further setting a maximum speed and a minimum speed of the motor and setting a maximum speed and a minimum speed of the hydraulic pump; wherein when a required flow is below output of the minimum speed of the hydraulic pump, the injection molding machine controller makes the frequency converter output a minimum frequency to control the motor and the hydraulic pump to operate at the minimum speeds of the motor and the hydraulic pump; wherein the injection molding machine controller controls the flow ratio control valve to control the required flow of a motion; wherein when the required flow is higher than the output of the minimum speed of the hydraulic pump, an actual flow is controlled by the frequency converter that controls operation of the motor and the hydraulic pump; wherein when a pressure required in the motion is low, the injection molding machine controller increases the frequency of the frequency converter and controls the motor and the hydraulic pump to increase the output of the hydraulic pump within the maximum speed of the hydraulic pump, thereby increasing the speed.