Abstract: A cutting liquid supply device in a machine tool is configured to remove gas mixed in a cutting liquid supply line to improve the response of discharging a mist of cutting liquid. Cutting liquid is supplied from a pump (42) through a rotary joint (28) to a mist generation device (24) within a rotating spindle (29). The pressure of the cutting liquid is measured by a pressure sensor (47). An air vent device (30) for opening and closing, with respect to atmospheric pressure, piping (3) that supplies the cutting liquid is provided above the rotary joint (28). A detection signal is inputted in the control board (70) from the pressure sensor (47), and when the control board (70) detects, after the pump (42) stops the supply of the cutting liquid to the piping (3), that the pressure of the cutting liquid does not decrease to a level lower than a predetermined threshold value, the control board (70) instructs the air vent device (30) to open the piping (4) to the atmosphere.

Abstract: A cutting liquid supply device in a machine tool is configured to remove gas mixed in a cutting liquid supply line to improve the response of discharging a mist of cutting liquid. Cutting liquid is supplied from a pump (42) through a rotary joint (28) to a mist generation device (24) within a rotating spindle (29). The pressure of the cutting liquid is measured by a pressure sensor (47). An air vent device (30) for opening and closing, with respect to atmospheric pressure, piping (3) that supplies the cutting liquid is provided above the rotary joint (28). A detection signal is inputted in the control board (70) from the pressure sensor (47), and when the control board (70) detects, after the pump (42) stops the supply of the cutting liquid to the piping (3), that the pressure of the cutting liquid does not decrease to a level lower than a predetermined threshold value, the control board (70) instructs the air vent device (30) to open the piping (4) to the atmosphere.