GB1427955A - Numerical automatic control - Google Patents

Abstract

1427955 Automatic control of contouring OKUMA MACHINERY WORKS Ltd 20 June 1973 [30 June 1972] 29369/73 Heading G3N A numerical control apparatus permits automatic cycling of contouring operation until the configuration of the workpiece agrees with that stored on a tape. As shown, a contouring control unit I, providing signals P to a servo drive for a machine-tool conventionally by use of rate and position registers 13, 11, 12 and interpolators 14-16, is associated with a contouring cycle instruction unit II and a variable computing unit III. The tape, read by a reader 10, in addition to information for unit I contains a value D for a depth of cut during a contouring operation additionally, for threadcutting an initial cut value E and a finish coefficient K are recorded on the tape. The cycle instruction unit II has a cycle control circuit 19 with a built-in sub-program relating to movement of the tool; a tape control circuit 21 whereby the tape is returned to the beginning of a cycle and a quick return circuit 20 whereby the tool is positioned at the start of a cut. The computing unit III comprises registers 17, 27 and 28 for the values D, E and K respectively and a sub-arithmetic unit, which receives the contents of registers 11, 12 through an OR-gate 24a of unit 1, and is controlled by the cycle control circuit, 19 of unit II. The unit 18 provides signals whereby each cycle in a contouring operation is effected at a cut D, the total cut being stored in a register 22 and fed-back through an AND gate 25. The final cut is judged by a circuit 23 which opens gate 23 through a NOT-circuit 26. During thread-cutting the first cut is taken in accordance with the value stored in register 17, subsequent cuts in accordance with value D and the finishing cuts, as assessed by circuit 23, reducing in accordance with the coefficient K stored in register 28.