| 摘要 |
PROBLEM TO BE SOLVED: To provide a wire electric discharge machine having a tension monitoring function capable of early detecting an abnormal state of a tension generator or a tension measuring device in a state where a feedback control is maintained.SOLUTION: A wire electric discharge machine has a wire electrode 9 spanning between an upper guide 7 and a lower guide 8, generates a tension in the wire electrode 9 by a tension generator 3, has a tension controller 1 outputting a tension command value 2 to the tension generator 3 for a certain tension target value commanded by a higher-level control device which is not shown, and has a function to output a first tension measurement value 5 obtained from a tension measuring device 4 disposed on a wire. The tension command value 2 estimated in response to the tension target value output from the tension controller 1 is stored in the machine in advance, the value is compared with the actual tension command value 2 within the tension controller 1, and when a deviation increases to be equal to or higher than a certain value, an alarm signal is generated, thereby making it possible to detect an abnormality before feedback is deactivated.SELECTED DRAWING: Figure 1 |
