Monitoring method for machine tool

Abstract

Disclosed is a monitoring device for a machine tool, which monitors operations in work machining to increase the precision level of the yield of the work. To monitor a load current supplied to a machining motor in 1-cycle units which run from the start of the machining to the end of the machining, sampling points are taken at shorter intervals along the time axis of the machining in areas where the machining is complex, and in areas where the machining is simple sampling points are taken at longer intervals along the time axis of the machining; and at each sampling point the sampling data are stored and undergo numerical processing. Then, the actually measured value of the load current is compared to determine whether or not the actually measured value is within a range of an upper and a lower limit which are determined by a standard deviation value calculated from the sampling data at each sampling point, to thereby monitor the machining process. Determination as to defective/non-defective is performed at each sampling point on the basis of the range between the upper and lower limits which model the shape of the work. As a result, the probability of non-defective products being unretrieved as data is reduced and abnormalities are detected quickly at each sampling point to allow swift handling of the problem.

Dependencies are inferred from the claim text.