| 摘要 |
PURPOSE:To suppress generation of seizure between a guide bush and a workpiece by detecting, by an encoder, that the revolution speed of a main spindle reduces by a certain speed width or more set in unit time, and stopping the revolution drive of the main spindle, in an NC lathe. CONSTITUTION:The output pulses supplied from an encoder 10 are counted by a counter 12 into which clock pulses KL are input at every constant time, and the signal is used as speed signal as it is. In other words, the speed GS at present is input into a comparison circuit 16 and compared with the speed signal precedingly input. In a comparison circuit 17, the error speed ES as the standard for generating the error signal ER as the signal for suspending the turning opera- tion of a main spindle is set, from the parameter 18 set according to the data obtained from a number of execution examples, on the basis of the standard speed KS input from the comparison circuit 16, and the error speed ES and the speed GS at present are compared. When the speed GS at present becomes smaller than the error speed ES, an error signal ER is output. |
