JPS6440158A - Secondary press casting method - Google Patents

Abstract

PURPOSE:To execute a secondary press as soon as possible and with high timing accuracy after completion of the filling of a molten metal by detecting the rising pressure of the inside of a high pressure chamber of while reaching a pressure increase starting time after completion of the filling of a molten metal and starting the secondary press with the detection signal. CONSTITUTION:When the pressure of the chamber B inside faced to the opening 66 of a valve chamber 64 rises to the specified pressure it is detected by a pressure sensor 84 and a release valve 86 is opened by the detection signal. The press oil inside the chamber C partitioned by a pressure increasing piston 62 and cylinder wall is released to the external part by the release valve 86 and the pressure increasing piston 62 advances. The pressure inside a chamber D generated at the time when a rod 86 and an injection piston 58 are apart becomes larger than that of the chamber B inside, a check valve 72 is pressed to the opening 66 of the valve chamber 64 to close the opening 66 and the pressure inside the chamber D rapidly rises with the advance of the pressure increasing piston 62. At the time when the pressure inside the chamber B reaches a set pressure a sequential valve is opened, a discharging oil is fed by a hydraulic pump to the high pressure chamber of the hydraulic cylinder for secondary press and the secondary pressure is impressed on the molten metal whose solidification is not completed.