Patent ID: 6241003
Filing Date: 2001-06-05
Classification: B22D

Abstract:
An injection control method of a boost-type die-casting machine including an injection plunger for injecting molten material into a casting die, an injection cylinder device having an injection piston for driving the injection plunger, and a boost cylinder device for boosting hydraulic oil supplied to the injection cylinder device, comprising the steps of:Providing a flow-rate control valve to continuously regulating flow-rate of hydraulic oil discharging channel of the injection cylinder device; AndDuring boosting process by the boost cylinder device, synchronously controlling back-pressure of the injection cylinder device and back-pressure of the boost cylinder device;Wherein the flow-rate control valve is controlled so that a relationship between casting pressure and boost time in the casting die changes in accordance with a selective curve along a predetermined critical boost curve for avoiding burr occurrence to the casting die during the synchronous controlling process;Wherein the flow-rate control valve is controlled by comparing a detected pressure value detected by the injection cylinder device and the boost cylinder device with a command pressure value for every elapsed time given in accordance with a predetermined program to eliminate difference between the pressure values.