Patent ID: 6337042
Filing Date: 2002-01-08
Classification: B30B

Abstract:
A method of manufacturing pressed products characterized by manufacturing the pressed products by performing press work by using a press machine having a plurality of fixed molds and a plurality of motors provided on a common stand, wherein said plurality of motors individually drive moving molds respectively in pairs with said plurality of fixed molds to perform press work, said method comprising:providing a plurality of amplifiers for passing cut individually through said plurality of motors; and individually controlling said plurality of amplifiers to realize weighing operation of moving said plurality of moving molds in mold-closing direction and pressing said plurality of moving molds respectively against said plurality of fixed molds and withdrawing operation of moving said plurality of moving molds in mold-open direction, wherein each of said plurality of amplifiers performs the steps of: calculating an amount of current to be passed through a corresponding one of said plurality of motors so that a measured value of operating position of the corresponding motor follows a directing value, and sending said amount of said current calculated by said control portion to said corresponding motor while limiting the same so that torque of said corresponding motor does not exceed a limit value, and wherein in said weighting operation, said amplifier control portion further advances said directing value for each of said plurality of amplifiers in said mold-closing direction after said torque reaches said limit value.