Patent ID: 8404991
Filing Date: 2013-03-26
Classification: B23H

Abstract:
1. A wire-cut electric discharge machine, comprising: a machining vessel having a discharge machining section placed therein for machining a workpiece by electric discharges using a wire electrode; a first fluid vessel for collecting and storing a machining fluid from the machining vessel; a second fluid vessel for storing the machining fluid from the first fluid vessel after filtering the machining fluid with a filter; a supply line for supplying the machining fluid from the second fluid vessel to upper and lower wire guides; a first temperature sensor configured to measure an ambient temperature of the wire-cut electric discharge machine; a second temperature sensor configured to measure a temperature of the machining fluid; a cooling device for controlling the temperature of the machining fluid by cooling the machining fluid in the second fluid vessel and supplying the cooled machining fluid to at least one of the machining vessel, the first fluid vessel, the second fluid vessel, or the supply line; and a controller for controlling the cooling operation of the cooling device to control the temperature of the machining fluid, wherein the controller is configured to automatically switch, depending on a relationship between the ambient temperature measured by the first temperature sensor and the temperature of the machining fluid measured by the second temperature sensor, between a constant temperature control mode for maintaining the temperature of the machining fluid at a preset value and a differential temperature control mode for causing the temperature of the machining fluid to follow the ambient temperature such that a difference between the temperature of the machining fluid and the ambient temperature falls within a preset range, when the ambient temperature measured by the first temperature sensor is lower than a predetermined temperature, the controller is configured to control the temperature of the machining fluid in the constant temperature control mode so as to be maintained equal to or higher than the predetermined temperature, and when the ambient temperature measured by the first temperature sensor is higher than the predetermined temperature, the controller is configured to control the temperature of the machining fluid in the differential temperature control mode so as to be maintained higher than the ambient temperature.