| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a numerical controller capable of detecting abnormal cutting with high precision. <P>SOLUTION: Load torque working on a motor driving a spindle motor or a feed shaft is detected to find a maximum value, a minimum value, and a mean value in a fixed section (S1). Limits of the maximum value and the minimum value and upper and lower limits of the mean value matching the degree of tool abrasion (the number and time of use of the tool, a cutting distance, and the like) are set previously. The limits of the maximum value and the minimum value and the upper and lower limits of the mean value for the degree of present abrasion are found by interpolation based on the set data (S2, S4, and S6). It is determined whether the maximum value, the minimum value, and the mean value in the fixed section of the present load torque are within the range of the limits of the maximum value and the minimum value and the upper and lower limits of the mean value for the degree of present abrasion (S3, S5, and S7). If they are not within the range, the occurrence of an abnormal condition is outputted (S8). Since the criterion determining abnormal load torque is decided according to the degree of present tool abrasion, abnormal load torque can be detected accurately, and consequently, abnormal cutting can be detected with high precision. <P>COPYRIGHT: (C)2004,JPO&NCIPI</p> |
