GB1438163A - Numerical automatic control - Google Patents

Abstract

1438163 Automatic control of machine tools OKUMA MACHINERY WORKS Ltd 20 June 1973 [30 June 1972] 29370/73 Heading G3N A numerical control apparatus is responsive to a tape, having stored thereon a final configuration to be imparted to a workpiece, to cyclically perform a contouring operation until the final configuration is attained. As shown, a conventional numerical control unit I provides a final configuration and comprises a tape-reader 10 deriving command signals which are processed to supply, from interpolaters 15, 16, pulse trains. A depth of cut command signal is derived by the tape-reader 10 and fed to a register 17 of a unit III. A sub-arithmetic unit receives X and Z axis commands, from registers 11, 12 through an OR-gate 27b and X, Z axes interpolated pulse trains, through an OR-gate 27a and in dependence on the set depth of cut D computes for each cycle, under control of a cycle control circuit 19, outputs such that a cut of size D is made by the tool being fed horizontally along the Z-axis and kept in a constant position with respect to the X axis in each contouring cycle. The output P for servo positioning the tool is derived in a judging and selecting unit IV comprising final and midway judgement circuits 23, 24, which, through an OR-gate 27c, AND-gates 28a, 28b and a NOT-circuit 29, ensures that the output P is provided by interpolator 15 until the output of register 22 is of a smaller value. The cycle control circuit 19 has an internal subprogram for controlling the cycles of step contouring and is associated in an instruction unit II with a quick return circuit 21 and a tape control circuit 20. In a modification a Z-axis shift register and return cut stroke register are also associated with the sub-arithmetic unit.