JP7022243B1 - Machine tool coolant supply device and machine tool coolant supply method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coolant supply device for a machine tool capable of appropriately dealing with an abnormality generated when a coolant is supplied from a tank to a plurality of supply destinations according to the degree of urgency. SOLUTION: A pump for supplying coolant from a coolant tank, a first pressure sensor, a plurality of branch pipes and valve mechanisms for supplying coolant to a plurality of supply destinations including a machined portion of the work, and a machined portion of the work. A first allowable pressure range in which the value of the first pressure sensor is preset in a specific supply state in which the specific valve mechanism installed in the specific branch pipe to be supplied is opened and at least one of the other valve mechanisms is closed. A control circuit for outputting a stop signal for immediately stopping the machining of the work is provided when the work deviates downward from the above. [Selection diagram] Fig. 2

Description

The present invention relates to a machine tool coolant supply device and a machine tool coolant supply method.

Patent Document 1 discloses a high-pressure coolant supply device capable of detecting an abnormal state without providing a special sensor. The high-pressure coolant supply device is configured to drive a fixed-capacity pump by a motor to supply coolant from the tank to the attachment, and to control the supply of the discharge coolant to the attachment by an on-load valve.

Then, the motor is controlled by inputting the command value and the feedback value, and the control means for controlling the on-load valve and the command value and the feedback value are input, and the rotation speed of the motor is the minimum rotation speed and the maximum rotation speed. It is provided with an abnormal state detecting means for detecting an abnormal state on condition that the load torque is lower than the minimum load torque in a state where the rotation speed is between and the on-load valve is turned on.

By providing the abnormality detecting means, it is possible to detect idle operation, forgetting to attach an attachment, pipe rupture, etc. as an abnormal state.

Japanese Unexamined Patent Publication No. 2004-160617

However, when the coolant filled in the tank is supplied to multiple supply destinations such as the spindle coolant, chip flow coolant, and reverse cleaning of the chip conveyor, the load torque of the motor differs depending on the supply destination. It was difficult to uniformly detect an abnormality based on the load torque of the motor.

In the case of spindle coolant, where the liquid supply destination directly affects the machining accuracy, it is necessary to stop the machine immediately when an abnormality occurs, but back-cleaning of the chip conveyor, which does not directly affect the machining accuracy, is required. In the case of a liquid supply destination, in order to avoid a decrease in productivity, it may not be desirable to immediately stop the machine even if an abnormality occurs.

An object of the present invention is a machine tool coolant supply device and a machine tool coolant supply method that can appropriately deal with an abnormality that has occurred when a coolant is supplied from a tank to a plurality of supply destinations. Is in the point of providing.

In order to achieve this object, the coolant supply device of the machine tool according to the present invention includes a pump that supplies coolant from a coolant tank, a liquid supply pipe that supplies coolant discharged from the pump, and a discharge side of the pump. A first pressure sensor installed in the above, and a plurality of branch pipes that branch from the liquid supply pipe on the downstream side of the installation position of the first pressure sensor and supply coolant to a plurality of supply destinations including a machined portion of the work. A valve mechanism installed in each branch pipe to supply or stop coolant to each supply destination and a control circuit for controlling the pump and each valve mechanism are provided, and the control circuit is provided with at least the work of the valve mechanism. The value of the first pressure sensor is set in advance in the specific supply state in which the specific valve mechanism installed in the specific branch pipe to the processed portion is opened and at least one of the other valve mechanisms is closed. When the work deviates downward from the permissible pressure range, a stop signal for immediately stopping the machining of the work is output , and the value of the first pressure sensor deviates upward from the first permissible pressure range in the specific supply state. It is configured to output an alarm signal without outputting the stop signal, and when the alarm signal is output, a stop signal for stopping the machining of the work is output at least at the end of a series of machining processes for the workpiece. It is characterized by that.

The control circuit determines that if the value of the first pressure sensor deviates from the preset first allowable pressure range in the above-mentioned specific supply state, an abnormality has occurred in any of the valve mechanisms provided in each liquid supply pipe. can. At that time, if the value of the first pressure sensor deviates downward from the preset first allowable pressure range, it is judged that the abnormality has a high degree of urgency, and the work is machined. By immediately outputting the stop signal to stop, it is possible to prevent damage to the work and tools in which the required amount of coolant is not supplied to the machined part of the work.

Further, in the coolant supply method of the machine tool according to the present invention, coolant is supplied from the coolant tank to the liquid supply pipe via a pump, and the coolant is branched and connected to the liquid supply pipe via a plurality of branch pipes provided with a valve mechanism. It is a method of supplying coolant of a machine tool that selectively supplies coolant to a plurality of supply destinations including a machined portion of the work, and is installed in a specific branch pipe having at least the machined portion of the work as a supply destination in the valve mechanism. Immediately when the pressure on the discharge side of the pump deviates downward from the preset first allowable pressure range in the specified supply state in which the specific valve mechanism is opened and at least one of the other valve mechanisms is closed. When the machining of the work is stopped and the pressure on the discharge side of the pump deviates upward from the preset first allowable pressure range in the specific supply state, an alarm is given without stopping the machining of the work. , At least at the end of a series of machining processes for the workpiece, it is characterized by outputting a stop signal for stopping the machining of the workpiece .

According to the present invention, when a coolant is supplied from a tank to a plurality of supply destinations, a machine tool coolant supply device and a machine tool coolant supply method can be appropriately dealt with according to the degree of urgency for an abnormality that has occurred. Will be able to provide.

FIG. 1A is an explanatory view of a front view of a machine tool installed in a processing space covered with a cover body, and FIG. 1B is an explanatory view of a setup station adjacent to the machine tool. FIG. 2 is an explanatory diagram of piping of the coolant supply device. FIG. 3 is an explanatory diagram of a control circuit provided in the coolant supply device. FIG. 4 is an explanatory diagram of operating points of the pump when the coolant is selectively supplied to each branch pipe. FIG. 5 is a flowchart illustrating a coolant supply method.

Hereinafter, the coolant supply device and the coolant supply method of the machine tool will be described with reference to the drawings.

FIG. 1A shows a machine tool 200 partitioned by a cover member 300 and installed in a processing space for processing a work W. The machine tool 200 is vertically installed on the bed 201, a table 202 that moves in the Z-axis direction along the guide surface on the bed 201, a pallet 203 that rotates around the B axis in a vertical posture on the table 202, and a bed 201. It is composed of a horizontal machining center including a column 204 and a spindle head 205 that moves in the X-axis and Y-axis directions along the guide surface of the column 204. As shown by the broken line, the circumference of the machine tool 200 is covered with the cover member 300, and the cover member 300 is provided with a door (not shown) that can be opened and closed.

When the servomotor MZ is driven, the table 202 moves along the linear drive axis in the Z-axis direction on the bed 201, and when the servomotor MB is driven, the pallet 203 rotates around the B axis on the table 202. When the servomotor MX is driven, the spindle head 205 moves along the linear drive axis in the X-axis direction on the column 204, and when the servomotor MY is driven, the spindle head 205 moves in the Y-axis direction on the column 204. Moves along the linear drive axis of.

The tool 207 is held by the tool holder 206 provided on the spindle head 205, and when the servomotor MS1 is driven, the tool 207 rotates about the horizontal axis. The work W, which is the work piece, is held by a jig such as squid provided on the pallet 203, and when the servomotor MB is driven, the work W held by the jig such as squid is vertical along the B axis together with the pallet 203. Rotate around the axis.

By driving each of the above-mentioned servomotors by the NC device based on the preset NC program, the work W and the tool 207 are relatively moved, and the work W is machined into a desired shape.

A setup station 250 is installed adjacent to the side wall located on the right side of the machine tool 200 shown in FIG. 1 (a). As shown in FIG. 1 (b), the setup station 250 is provided with an accommodating portion for accommodating the work W before machining and the work after machining, and pretreats the work W before machining and the work W after machining. Post-treatment such as cleaning is performed.

The setup station 250 is partitioned by a cover member 350 adjacent to the cover member 300, and an opening / closing shutter for passing the work W between the cover members 300 and 350 is provided between the cover members 300 and 350. Further, the setup station 250 is equipped with an APC (auto pallet changer) unit for carrying the work W before machining into the machining space and carrying out the work after machining from the machining space.

The spindle head 205 is provided with a coolant nozzle 220 that discharges the coolant toward the machined portion of the work W. High machining accuracy is ensured by reducing the cutting load when the work W is machined by the tool 207, suppressing the temperature rise due to the cutting heat generated in the machined part, and removing the chips adhering to the machined part. Therefore, coolant, which is a fluid for cooling and cleaning, is sprayed toward the machined part.

Although not shown in FIG. 1, in order to collect the chips scattered by processing, the coolant is discharged toward the inner wall of the cover member 300, the table 202, or the work W housed in the setup station 250. A plurality of coolant supply nozzles are provided.

A coolant recovery unit 208 for collecting the coolant is installed below the table 202, and the chips generated by machining are collected together with the coolant in the coolant collection unit 208. A chip conveyor 209 is arranged at the bottom of the coolant collection unit 208, and the chips collected by the coolant collection unit 208 are carried out of the machine by the chip conveyor 209 and collected in the collection container 212.

The coolant collected by the coolant collecting unit 208 is circulated and supplied to the large-capacity coolant tank 1 (see FIG. 2) after foreign matter such as chips is removed through the drum filter 208F.

FIG. 2 shows a piping route diagram of the coolant supply device 100 incorporated in the machine tool 200 described above.
The coolant supply device 100 is discharged by a coolant tank 1, a liquid supply pipe 2, a first liquid supply pump P1 that discharges the coolant filled in the coolant tank 1 to the liquid supply pipe 2, and a first liquid supply pump P1. It is provided with branch pipes 6 to 14 for branching and supplying the cooling to a plurality of coolant supply destinations, a control circuit 30 (see FIG. 3), and the like.

The coolant supplied to the liquid supply pipe 2 is supplied to the branch pipes 6 to 12 via the header pipe 4. The branch pipe 6 is a first liquid supply path for showering toward the side wall of the machine, and the branch pipe 7 is a liquid supply path to which the coolant nozzle 220 arranged in the machined portion of the work is supplied, and is branched. The pipe 8 is a liquid supply path for supplying liquid to the setup station 250 for cleaning jigs and the like.

The branch pipe 9 is a second liquid supply path for showering toward the side wall of the machine, the branch pipe 10 is a liquid supply path to the protector built-in coolant, and the branch pipe 11 is to the oil pan of the setup station. The branch pipe 12 is a liquid supply route to the XY protector beside the table, the branch pipe 13 is a spare liquid supply route, and the branch pipe 14 is a liquid supply route to the coolant gun. In the branch pipes 10, 11 and 12, one branch pipe branched from the header pipe 4 is branched into three.

Valve mechanisms V6 to V12, which are electromagnetic valves, are interposed in the branch pipes 6 to 14 on the header pipe 4 side. By controlling the opening and closing of the valve mechanisms V6 to V12 by the control circuit 30 described later, the supply of the coolant to the branch pipes 6 to 12 is controlled to be allowed or stopped.

The coolant supplied from each of the branch pipes 6 to 14 is finally collected in the coolant collection unit 208, and after foreign substances such as chips are removed through the drum filter 208F, the liquid supply pump P3 is used to supply the coolant to the coolant tank 1. It is replenished.

Foreign matter that could not be completely removed by the drum filter 208F settles on the bottom of the coolant supplied to the coolant tank 1, but the liquid supply pipe 2 is connected to the side wall of the coolant tank 1 at a position above the bottom, so that the bottom The foreign matter that has settled down is not immediately discharged to the liquid supply pipe 2.

The foreign matter that has settled on the bottom of the coolant tank 1 is supplied to the wet cyclone filter 22 together with the coolant through the circulation path 15 by the liquid supply pump P2 that is driven regularly or irregularly, and after the foreign matter is removed, it is supplied to the coolant tank 1. It is circulated. The coolant from which foreign matter has been removed by the wet cyclone filter 22 may be returned to another coolant tank different from the coolant tank 1.

The first pressure sensor SE1 is arranged on the downstream side of the first liquid supply pump P1 in the liquid supply pipe 2, and the second pressure sensor SE2 is arranged on the downstream side of the valve mechanism V7 in the branch pipe 7.

FIG. 3 shows a circuit diagram of the control circuit 30 provided in the coolant supply device 100. The control circuit 30 is composed of a CPU, a memory in which a liquid supply control program executed by the CPU is stored, an input / output circuit, a communication circuit, and a like.

The plurality of output driver circuits included in the input / output circuit provided in the control circuit 30 are connected to the valve mechanism V6 to V12 and the respective liquid supply pumps P1, P2, P3 described above. Further, in the input circuit including the A / D converter included in the input / output circuit, the values of the first pressure sensor SE1 and the second pressure sensor SE2 are input, and the A / D converted values are input to the CPU. Further, the control circuit 30 and the operation panel 50 of the machine tool 200 are connected by a communication line, and the operation panel 50 and the NC device 70 are connected by a communication line.

The NC device 70 and the control circuit 30 are activated via the operation of the operation panel 50 by the operator. The machine tool is sequentially controlled via the NC device 70 according to a pre-programmed procedure, and the coolant is controlled to be supplied to a required portion via the control circuit 30.

The memory provided in the control circuit 30 stores data that defines a plurality of operation modes for the liquid supply of the coolant. The control circuit 30 controls the first liquid supply pump P1 and the valve mechanisms V6 to V12 according to each operation mode instructed from the control panel 50 operated by the operator, and the first pressure sensor SE1 or the first pressure sensor SE1 measured in each control state. Whether or not it is abnormal is diagnosed based on the value of the second pressure sensor SE2.

The control circuit 30 transmits the diagnosed abnormal state to the operation panel 50, and the operation panel 50 outputs a stop signal to the NC device 70 when it is necessary to immediately stop the machine tool 200 according to the received abnormal state. If it is not necessary to stop immediately, an alert is sounded or an alert is displayed on the operation screen of the operation panel 50.

FIG. 4 shows the operating points of the first liquid supply pump P1 in which the flow rate is represented by the horizontal axis and the required head is represented by the vertical axis. The operating point 1 is a mode for operating the chip conveyor, and is set to a flow rate of 150 L / min and a lift of 31 m. The operating point 2 is a mode in which coolant is supplied to the machined portion to operate the spindle, and the flow rate is set to 400 L / min and the lift is set to 27 m.

The operating point 3 is a mode for improving the economic efficiency of the operating point 3, and is set to a flow rate of 400 L / min and a lift of 26 m. The operating point 4 is set to a flow rate of 150 L / min and a lift of 13 m, and the operating point 5 is set to a flow rate of 200 L / min and a lift of 30 m.

That is, in the memory of the control circuit 30, the discharge pressure and the liquid supply amount of the coolant preset according to the combination of opening and closing of each valve mechanism provided in each branch pipe are specified, and are detected according to each combination. Table data defining the allowable pressure range of the pressure sensors SE1 and S2 is stored, and the control circuit 30 controls the discharge pressure and the liquid supply amount of the first liquid supply pump P1 based on the table data, and controls each valve mechanism. It is configured to control opening and closing. The above-mentioned operation modes, flow rates, and required heads are examples, and are not limited to these values.

As shown in FIG. 5, when a start command is received from the control panel 50, the control circuit 30 determines which of the plurality of operating points shown in FIG. 4 is the operation mode to be controlled based on the start command. (S1), the liquid supply pump is controlled according to the corresponding operation mode, the necessary valve mechanism among the valve mechanisms V6 to V12 is opened, and the unnecessary valve mechanism is maintained in the closed state (S2). .. Further, the values of the first pressure sensor SE1 and the second pressure sensor SE2 are read (S3).

The appropriate range of the first pressure sensor SE1, that is, the first allowable pressure range is predetermined according to each operation mode. The control circuit 30 has a low pressure abnormality in which the value of the first pressure sensor SE1 is below the lower limit of the first allowable pressure range for each operation mode, a high pressure abnormality in which the value exceeds the upper limit, or a normal range within an appropriate range. Determine if it exists.

If it is determined to be a low pressure abnormality (S4, Y) and the operating point is 3 or 4, that is, in the mode of supplying coolant to the machined portion (S5, Y), leakage has occurred in any of the paths. When a pressure abnormality is detected and the machine must be stopped, a signal regarding the pressure abnormality is transmitted from the sensor to the control circuit 30, and the control circuit 30 stops the machine. When the machine is stopped, each valve V6 to V12 is closed by a signal from the control circuit 30. When a normally closed valve is used, it can be automatically closed by shutting off the power to the valve.

When the control panel 50 receives the status signal, it outputs a stop signal to the NC device 70 in order to urgently stop the machine tool 200 (S6). In this embodiment, at least one of the other valve mechanisms is closed in the mode of supplying the coolant to the processed portion. For example, the valve V8 provided in the branch pipe 8 is closed.

When the operating point is other than 3 or 4 (S5, N), a status signal indicating that the low voltage is abnormal is transmitted to the control panel 50. When the control panel 50 receives the status signal, the NC device 70 displays an alert on the display unit without urgently stopping the machine tool 200, and sounds a buzzer to alert the operator (S7).

When the machining of the work is continued in that state, the predetermined machining process is completed, and the tool is separated from the work (S8, Y), a stop signal is output from the control circuit 30, and the control panel 50 is a machine tool. Stop 200 (S9). Further, until the predetermined processing process is completed (S8, N), the process returns to step S1 and the same process is repeated. The completion of the predetermined machining process means the termination of all the machining processes for the work or the termination of the machining process currently being executed.

In step S4, if it is not a low pressure abnormality (S4, N), it is determined whether or not it is a high pressure abnormality, if it is a high pressure abnormality (S8, Y), the alert process of step S7 is executed, and if it is normal, it is executed. (S8, N), the processing after step S8 is executed.

If a low pressure abnormality occurs in the mode of supplying coolant to the machined portion, the machine tool 200 is urgently stopped because there is a risk of damaging the work or the tool. In addition, if a high pressure abnormality occurs in the mode of supplying coolant to the machined part, the coolant is properly supplied to the machined part and the workpiece can be machined properly, but the coolant is supplied to other liquid supply destinations. It is determined that the condition has not been achieved, and an alert is issued to the operator to call attention while avoiding a decrease in processing efficiency.

In the description of FIG. 5, an example of determining the state based only on the value of the first pressure sensor SE1 has been described in step S9, but the state may be determined by adding the value of the second pressure sensor SE2. .. Specifically, when the first pressure sensor SE1 shows a high pressure abnormality exceeding the first allowable pressure range and the second pressure sensor SE2 shows a low pressure abnormality lower than the second allowable pressure range in step S9, the process of step S6 is performed. It is configured to run. Needless to say, the appropriate range of the second pressure sensor SE2, that is, the second allowable pressure range is also preset.

In addition to referring to the value of the second pressure sensor SE2, it is equipped with a position sensor that detects the operating state of the valve body of the solenoid valve, which is the valve mechanism V7, and the valve body outputs an opening command to the valve mechanism V7. Whether or not the switch to the open position may be confirmed by the value of the position sensor. That is, when the first pressure sensor SE1 indicates a high pressure abnormality and the position sensor indicates a closed position in step S9, it is determined that the liquid is not supplied to the branch pipe 7 and the process of step S6 is executed. It composes.

As the valve mechanism V7, a normally closed solenoid valve that is normally closed when the drive signal from the control circuit 30 is not input is used, but is opened when the drive signal from the control circuit 30 is not input. If a normally open type solenoid valve is adopted, coolant can be supplied to the machined part even if the control signal line is broken.

As described above, the coolant supply device 100 of the machine tool to which the present invention is applied supplies the first liquid supply pump P1 for supplying the coolant from the coolant tank 1 and the coolant discharged from the first liquid supply pump P1. The liquid supply pipe 2 is branched from the liquid supply pipe 2 on the downstream side from the installation position of the liquid supply pipe 2, the first pressure sensor SE1 installed on the discharge side of the first liquid supply pump P1, and the first pressure sensor SE1 to process the work. A plurality of branch pipes 5 to 14 for supplying coolant to a plurality of supply destinations including a unit, valve mechanisms V6 to V12 installed in each branch pipe 5 to 14 for supplying or stopping coolant to each supply destination, and a first supply. It includes a liquid pump P1 and a control circuit 30 for controlling each valve mechanism V6 to V12.

Then, the control circuit 30 opens the specific valve mechanism V7 installed in the specific branch pipe 7 whose supply destination is at least the machined portion of the work among the valve mechanisms V6 to V12, and closes at least one of the other valve mechanisms. When the value of the first pressure sensor SE1 deviates downward from the preset first allowable pressure range in the specific supply state, a stop signal for immediately stopping the machining of the work is output.

In the above-mentioned example, the control circuit 30 and the NC device 70 are configured separately, but the control circuit 30 may be incorporated into the NC device 70 and integrally configured.

The control circuit 30 is configured to output an alarm signal without outputting a stop signal when the value of the first pressure sensor SE1 deviates upward from the first allowable pressure range in the specific supply state. .. It is determined that the coolant is properly supplied to the machined portion via the specific branch pipe 7, and the machining operation is continued.

Further, when the control circuit 30 detects that the specific valve mechanism V7 is in the closed state even when the value of the first pressure sensor SE1 deviates upward from the first allowable pressure range in the specific supply state, the work immediately works. It is configured to output a stop signal to stop the machining of.

A second pressure sensor SE2 is provided on the downstream side of the specific valve mechanism V7 installed in the specific branch pipe 7, and the control circuit 30 determines the specific valve mechanism V7 when the value of the second pressure sensor SE2 deviates downward from the second allowable pressure range. Is configured to detect that is in a blocked state.

When the control circuit 30 outputs an alarm signal, it outputs a stop signal for stopping machining of the workpiece at least at the end of a series of machining processes for the workpiece.

Further, the control circuit 30 includes table data that defines the coolant discharge pressure and the liquid supply amount preset according to the combination of opening and closing of each valve mechanism provided in each branch pipe, and discharges the pump based on the table data. It is configured to control the pressure and the amount of liquid to be supplied, and to control the opening and closing of each valve mechanism.

As described above, in the coolant supply method of the machine tool according to the present invention, coolant is supplied from the coolant tank to the liquid supply pipe via a pump, and a plurality of branch pipes provided with a valve mechanism are branched and connected to the liquid supply pipe. It is a method of supplying coolant of a machine tool that selectively supplies coolant to a plurality of supply destinations including the machined part of the work through the valve mechanism, and is installed in a specific branch pipe whose supply destination is at least the machined part of the work. When the pressure on the discharge side of the pump deviates downward from the preset first allowable pressure range in the specified supply state in which the specified valve mechanism is opened and at least one of the other valve mechanisms is closed. It is configured to stop machining the workpiece immediately.

Further, when the pressure on the discharge side of the pump deviates upward from the preset first allowable pressure range in the specific supply state, an alarm is given without stopping the machining of the work.

Further, even when the pressure deviates upward from the first allowable pressure range in the specific supply state, the machining of the work is stopped when the specific valve mechanism is detected to be in the closed state.

Further, at least at the end of a series of machining processes for the workpiece, a stop signal for stopping the machining of the workpiece is output.

Although the embodiments and embodiments of the present invention have been described above, the disclosed contents may be changed in the details of the configuration, and changes in the combinations and orders of the elements in the embodiments and embodiments have been requested. It can be realized without departing from the scope and idea of the present invention.

As described above, according to the present invention, it is possible to realize a coolant supply device for a machine tool that can appropriately deal with an abnormality that has occurred according to the degree of urgency.

1: Coolant tank 2: Liquid supply pipe 4: Header pipe 6 to 14: Branch pipe 30: Control circuit 100: Coolant supply device P1; 1st liquid supply pump P2: 2nd liquid supply pump P3: 3rd liquid supply pump SE1 : 1st pressure sensor SE2: 2nd pressure sensor V6 to V12: Valve mechanism

Claims (6)

A pump that supplies coolant from the coolant tank,
A liquid supply pipe that supplies the coolant discharged from the pump, and
The first pressure sensor installed on the discharge side of the pump and
A plurality of branch pipes that branch from the liquid supply pipe on the downstream side of the installation position of the first pressure sensor and supply coolant to a plurality of supply destinations including the machined portion of the work.
A valve mechanism installed in each branch pipe to supply or stop coolant to each supply destination,
The control circuit that controls the pump and each valve mechanism,
Equipped with
The control circuit is in a specific supply state in which at least one of the other valve mechanisms is closed while opening the specific valve mechanism installed in the specific branch pipe whose supply destination is at least the machined portion of the work among the valve mechanisms. When the value of the first pressure sensor deviates downward from the preset first allowable pressure range, a stop signal for immediately stopping the machining of the work is output , and the first pressure sensor is in the specific supply state. When the value deviates upward from the first allowable pressure range, the alarm signal is output without outputting the stop signal, and when the alarm signal is output, at least a series of machining processes for the workpiece is performed. A coolant supply device for a machine tool that outputs a stop signal to stop machining of the work at the end . When the control circuit detects that the specific valve mechanism is in the closed state even when the value of the first pressure sensor deviates upward from the first allowable pressure range in the specific supply state, the control circuit immediately said. The coolant supply device for a machine tool according to claim 1 , which is configured to output a stop signal for stopping machining of the work. A second pressure sensor is provided on the downstream side of the specific valve mechanism installed in the specific branch pipe, and the control circuit uses the specific valve mechanism when the value of the second pressure sensor deviates downward from the second allowable pressure range. The coolant supply device for a machine tool according to claim 2 , which is configured to detect that it is in a blocked state. The control circuit includes table data that defines a coolant discharge pressure and a liquid supply amount preset according to a combination of opening and closing of each valve mechanism provided in each branch pipe, and discharges the pump based on the table data. The coolant supply device for a machine tool according to any one of claims 1 to 3 , which is configured to control the pressure and the amount of liquid to be supplied and to control the opening and closing of each valve mechanism. Coolant is supplied from the coolant tank to the liquid supply pipe via a pump, and is selectively connected to the liquid supply pipe to multiple supply destinations including the machined portion of the work via a plurality of branch pipes provided with a valve mechanism. It is a method of supplying coolant to a machine tool that supplies coolant to
Discharge of the pump in a specific supply state in which at least one of the valve mechanisms is opened and at least one of the other valve mechanisms is closed, which is installed in the specific branch pipe whose supply destination is the machined portion of the work. When the pressure on the side deviates downward from the preset first allowable pressure range, the machining of the work is immediately stopped , and the pressure on the discharge side of the pump is preset in the specific supply state. Machinery coolant that warns without stopping machining of the workpiece when it deviates upward from the permissible pressure range and outputs a stop signal to stop machining of the workpiece at least at the end of a series of machining processes for the workpiece. Supply method. The machine tool according to claim 5 , wherein the machining of the work is stopped when the specific valve mechanism is detected to be in a closed state even when the specified valve mechanism deviates upward from the first allowable pressure range in the specific supply state. Coolant supply method.

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