Machine tool, control method of machine tool, and computer program

Abstract

To provide a machine tool which can reduce a running cost, a control method of the machine cost, and a computer program.SOLUTION: A machine tool related to the present invention comprises: one flow path (first flow path 27) in which one valve (CTS valve 41) is opened and closed; the other flow path (second flow path 28) in which the other valve (cleaning valve 42) is opened and closed; a liquid reserving tank (clean tank 24) which reserves a coolant; a pump (CTS pump 25) which force-feeds the coolant from the liquid reserving tank into the one flow path and the other flow path; and a control part which controls on / off of the pump, wherein the control part turns on the pump when the one valve is opened, measures an elapsed time from the closure of the one valve when the one valve is closed in a state that the one valve is opened and the other valve is closed, determines whether or not the elapsed time is equal to or more than a prescribed time, and executes processing of turning off the pump when the elapsed time is equal to or more than the prescribed time.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a machine tool, a method for controlling a machine tool, and a computer program. [Background technology]

[0002] Conventionally, machine tools use coolant to cool or clean tools, workpieces, and the like. In machine tools, one pump may pump coolant through two flow paths to two nozzles. One valve opens and closes one of the two paths, and another valve opens and closes the other path. When one valve opens and the other closes, the coolant sprays out from the nozzle of one path but not from the nozzle of the other path. This type of machine tool is disclosed in, for example, Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-161992 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, when a pump is turned on, a large current flows through the motor that drives the pump, so turning the pump on and off in a short period of time increases power consumption.Furthermore, frequent switching on and off of the pump requires a large amount of power consumption, which causes significant wear on the switch. As a result of the above, the running costs of the machine tool increase.

[0005] An object of the present disclosure is to provide a machine tool, a machine tool control method, and a computer program that enable reduction in running costs. [Means for solving the problem]

[0006] The machine tool according to the present disclosure includes a first flow path opened and closed by a first valve, another flow path opened and closed by another valve, a storage tank for storing coolant, a pump for pumping the coolant from the storage tank to the first flow path and the other flow path, and a control unit for controlling the on / off of the pump, wherein the control unit turns on the pump when the first valve opens, and when the first valve closes while the first valve is open and the other valve is closed, measures the elapsed time since the first valve closed, determines whether the elapsed time is equal to or greater than a predetermined time, and executes a process to turn off the pump if the elapsed time is equal to or greater than the predetermined time.

[0007] In the present disclosure, a reservoir stores coolant, and a pump pumps the coolant from the reservoir to one flow path and another flow path. One valve opens and closes one flow path, and another valve opens and closes another flow path. In the following, we will explain the case where one nozzle is connected to a portion of one flow path downstream of one valve, and another nozzle is connected to a portion of another flow path downstream of the other valve.

[0008] The control unit turns on the pump when one valve is open. When one valve is open and the other valve is closed, the pump pumps coolant, causing the coolant to pass through one flow path and spray out one nozzle, but not out the other nozzle. When the first valve closes in this state, the control unit measures the elapsed time since the first valve closed. The control unit determines whether the elapsed time is equal to or greater than a predetermined time, and if so, turns off the pump. In other words, when one valve is closed, the control unit does not turn off the pump immediately, but waits until a predetermined time has elapsed before turning off the pump.

[0009] Even if another nozzle (or the first nozzle) opens again before the specified time has elapsed, the pump remains on, so there is no need to switch the pump from off to on. As a result, the pump does not turn on and off in a short period of time, which reduces the large energy consumption that would otherwise accompany turning the pump on and off. Also, there is no need to frequently switch the pump on and off. As a result of the above, running costs can be reduced.

[0010] The machine tool according to the present disclosure further comprises a spindle to which a holder for holding a tool is detachably attached, and a cleaning nozzle facing the holder attached to the spindle, wherein the tool has an outlet and is connectable to a portion of the first flow path downstream of the first valve, and the cleaning nozzle is connected to a portion of the second flow path downstream of the second valve.

[0011] In the present disclosure, a holder that is detachably attached to a spindle holds a tool. The tool has a spray outlet. A cleaning nozzle faces the holder attached to the spindle. The tool can be connected to a portion of one flow path downstream of one valve, and the cleaning nozzle is connected to a portion of another flow path downstream of another valve. The tool connected to one flow path corresponds to the one nozzle described above. The cleaning nozzle corresponds to the other nozzle.

[0012] When the pump is on and one valve is open, coolant is sprayed through the tool nozzles, for example to wash the workpiece. When the pump is on and other valves are open, coolant sprays from the cleaning nozzle, cleaning the holder and the tool it holds.

[0013] The machine tool according to the present disclosure is characterized in that, when the pump is on and the other valve is open, the control unit does not turn off the pump even if the elapsed time is equal to or greater than the predetermined time, and executes a process to turn off the pump when the other valve is closed.

[0014] In the present disclosure, when the pump is on and the other valve is open, the pump pumps coolant, which then passes through the other flow path and is sprayed from the other nozzle. In this case, the control unit turns off the pump when the other valve is closed. In other words, the control unit does not turn off the pump even after a predetermined time has elapsed while coolant needs to be sprayed from the other nozzle.

[0015] The control method for a machine tool according to the present disclosure is a method for controlling the on / off of a pump of a machine tool that includes one flow path opened and closed by one valve, another flow path opened and closed by another valve, a storage tank for storing coolant, and a pump for pressure-feeding the coolant from the storage tank to the one flow path and the other flow path, the method being characterized in that when the one valve opens, the pump is turned on, and when the one valve closes while the first valve is open and the other valve is closed, the method measures the elapsed time from when the first valve closed and determines whether the elapsed time is equal to or greater than a predetermined time, and turns off the pump if the elapsed time is equal to or greater than the predetermined time.

[0016] In the present disclosure, when one valve is closed, the pump is not turned off immediately, but rather waits for a predetermined time to pass before turning off the pump, so the pump is not turned on and off in a short period of time. This reduces the large energy consumption that accompanies turning the pump on and off. In addition, there is no need to frequently switch the pump on and off. As a result, the running costs of the machine tool can be reduced.

[0017] A computer program according to the present disclosure is characterized in that it causes a computer to execute a process of turning on the pump when the first valve of a machine tool that includes one flow path opened and closed by one valve, another flow path opened and closed by another valve, a storage tank for storing coolant, and a pump for pressure-feeding the coolant from the storage tank to the first flow path and the other flow paths when the first valve opens, and when the first valve closes while the first valve is open and the other valve is closed, measuring the elapsed time since the first valve closed, determining whether the elapsed time is equal to or greater than a predetermined time, and turning off the pump when the elapsed time is equal to or greater than the predetermined time.

[0018] In the present disclosure, the machine tool control method according to the present disclosure can be realized in software using the hardware elements of a computer. [Effects of the Invention]

[0019] According to the machine tool, the machine tool control method, and the computer program disclosed herein, it is possible to reduce running costs. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a partial perspective view of a machine tool according to an embodiment. [Figure 2] FIG. 2 is a block diagram showing the configuration of a main part of a machine tool. [Figure 3] FIG. 2 is a block diagram showing the configuration of a main part of a control device. [Figure 4] 10 is a graph for explaining a tool replacement procedure. [Figure 5] 10 is a timing chart showing an example of the timing of turning on and off the CTS pump. [Figure 6] 10 is a timing chart showing another example of the timing of turning on and off the CTS pump. [Figure 7] 4 is a flowchart showing the procedure of workpiece machining processing executed by the control device. [Figure 8]4 is a flowchart showing the procedure of workpiece machining processing executed by the control device. [Figure 9] 10 is a flowchart showing the procedure of a timer determination process executed by the control device. [Figure 10] 10 is a flowchart showing the procedure of a tool replacement process executed by the control device. [Figure 11] 10 is a flowchart showing the procedure of a tool replacement process executed by the control device. DETAILED DESCRIPTION OF THE INVENTION

[0021] In the following description, arrows indicating up and down, front and rear, and left and right are used in the drawings.

[0022] FIG. 1 is a partial perspective view of a machine tool according to an embodiment. In the drawing, reference numeral 1 denotes a machine tool, and the machine tool 1 comprises a base 11 and a machining chamber 12. The base 11 is placed on the floor. The machining chamber 12 is provided above the base 11. A machine body 10 of the machine tool 1 machines a workpiece W (see FIG. 2 described below) in the machining chamber 12.

[0023] FIG. 2 is a block diagram showing the configuration of the main part of the machine tool 1. The machine tool 1 uses coolant to wash away chips generated during machining of the workpiece W from the object to be cleaned. The machine tool 1 further includes a dirty tank 21, a cyclone pump 22, a cyclone filter 23, and a clean tank 24 (liquid storage tank). The dirty tank 21 stores coolant. As shown in FIG. 1, the dirty tank 21 is placed on the floor and attached to the rear of the base 11. The cyclone pump 22 is located above the dirty tank 21. The clean tank 24 is adjacent to the dirty tank 21.

[0024] As shown in Figure 2, a cyclone pump 22 pumps (sends under pressure) coolant from a dirty tank 21 to a cyclone filter 23. The cyclone filter 23 captures and removes foreign matter from the coolant through solid-liquid separation using centrifugal force. Almost all of the coolant that enters the cyclone filter 23 flows from the top of the cyclone filter 23 into a clean tank 24 without containing foreign matter, while a small portion flows out from the bottom of the cyclone filter 23 into a drainage facility (not shown) containing foreign matter. Coolant that overflows from the clean tank 24 flows into the dirty tank 21.

[0025] The machine tool 1 includes a CTS pump 25 (pump), a common flow path 26, a first flow path 27 (one flow path), and a second flow path 28 (another flow path). The CTS pump 25 is connected to the upstream end of the common flow path 26, and the first flow path 27 and the second flow path 28 branch off from the downstream end of the common flow path 26. The CTS pump 25 is located above the clean tank 24 (see FIG. 1). The CTS pump 25 pumps the coolant stored in the clean tank 24 through the common flow path 26 to the first flow path 27 and the second flow path 28. A CTS filter 261 is provided midway through the common flow path 26. The CTS filter 261 collects and removes fine foreign matter from the coolant flowing through the common flow path 26.

[0026] A CTS valve 41 (first valve) that opens and closes the first flow path 27 is provided midway through the first flow path 27. A cleaning valve 42 (another valve) that opens and closes the second flow path 28 is provided midway through the second flow path 28. Both the CTS valve 41 and the cleaning valve 42 are solenoid valves. The machine body 10 is equipped with a main spindle 13. The main spindle 13 has a main spindle passage 131. The upstream end (e.g., the upper end) of the main spindle passage 131 is connected to the first passage 27. A pressure switch may be provided between the CTS valve 41 of the first passage 27 and the main spindle passage 131.

[0027] A holder 14 is detachably attached to the spindle 13. The holder 14 detachably holds a tool 15. The tool 15 is columnar and has a tool passage 151 and an ejection port 152. The tool passage 151 penetrates the tool 15 in the axial direction. The ejection port 152 is an opening on one end side of the tool passage 151. The tool 15 may have multiple ejection ports 152. When the holder 14 for holding the tool 15 is attached to the spindle 13, the opening on the other end side of the tool passage 151 communicates with the downstream end (e.g., the lower end) of the spindle passage 131. In other words, the tool 15 is connected to the portion of the first passage 27 downstream of the CTS valve 41.

[0028] The machine tool 1 is equipped with a cleaning nozzle 16. In this embodiment, the cleaning nozzle 16 is provided on the spindle 13. The base end of the cleaning nozzle 16 is connected to the downstream end of the second flow path 28 (the portion downstream of the cleaning valve 42). The tip of the cleaning nozzle 16 faces the holder 14 attached to the spindle 13. The coolant sprayed from the cleaning nozzle 16 cleans the holder 14 attached to the spindle 13 and the tool 15 held by this holder 14. The cleaning liquid stored in the clean tank 24 may be sprayed from a nozzle other than the tool 15 and the cleaning nozzle 16 toward objects to be cleaned other than the workpiece W, the holder 14, and the tool 15.

[0029] As shown in Fig. 1, the machine tool 1 is equipped with a collection tank 20. The coolant sprayed toward the object to be cleaned flows into the collection tank 20 together with foreign matter washed away from the object to be cleaned. The collection tank 20 is adjacent to the upper side of a dirty tank 21, and the coolant collected by the collection tank 20 is filtered by each of a plurality of filters (not shown) that the collection tank 20 has, before returning to the dirty tank 21.

[0030] The machine tool 1 is equipped with a control device 3. The control device 3 is located at the rear of the machining chamber 12, and is supported by a pillar 111 that rises from the top of the base 11. FIG. 3 is a block diagram showing the configuration of the main part of the control device 3. The control device 3 is a computer, and includes a main memory unit 31, an auxiliary memory unit 32, a control unit 33, and a timer .

[0031] The main memory unit 31 is volatile and is, for example, a RAM (Random Access Memory). The auxiliary storage unit 32 is nonvolatile and includes a ROM (Read Only Memory), a flash memory, a hard disk, an SSD (Solid State Drive), or the like.

[0032] The auxiliary memory unit 32 stores a program 3P (computer program) and various data required for executing the program 3P. The program 3P stored in the auxiliary memory unit 32 may be installed from a recording medium 30 such as an optical disk, flash memory, or magnetic disk, or may be installed from a server via a network. The program 3P includes a control program for the machine tool 1 created by the manufacturer of the machine tool 1, and a machining program for the workpiece W created by the user of the machine tool 1. The machining program contains a number of commands to the control device 3 arranged in the order in which they should be executed.

[0033] The control unit 33 includes one or more processors such as a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit). The control unit 33 uses the main memory unit 31 as a working area and executes various arithmetic processing and control processing in accordance with a program 3P stored in the auxiliary memory unit 32. The control unit 33 may include a logic circuit (for example, an FPGA). The control unit 33 executes a plurality of processes such as various arithmetic processes and control processes. The plurality of processes may be executed by a single processor included in the control unit 33, or may be executed in a distributed manner by a plurality of processors included in the control unit 33. There may be separate processors executing one process and other processes.

[0034] The control unit 33 controls the on / off of the CTS pump 25 via a pump drive unit (not shown). Similarly, the control unit 33 controls the on / off of the cyclone pump 22. The control unit 33 controls the on / off of the timer 34 . The control unit 33 controls the on / off of the CTS valve 41 via a valve drive unit (not shown). Turning the CTS valve 41 on (off) means opening (closing) the CTS valve 41. Similarly, the control unit 33 controls the on / off of the cleaning valve 42.

[0035] The machine tool 1 includes a Z-axis motor 43 , a tool magazine 44 , and a magazine motor 45 . The control unit 33 controls the on / off of the Z-axis motor 43 via a motor drive unit (not shown). Similarly, the control unit 33 controls the on / off of the magazine motor 45. The spindle 13 is movable in the Z-axis direction (up and down direction). When the control unit 33 turns on the Z-axis motor 43, the position of the spindle 13 in the Z-axis direction changes. The control unit 33 determines the position of the spindle 13 based on the detection result of an encoder (not shown) provided on the Z-axis motor 43, for example.

[0036] The tool magazine 44 has a plurality of arms 46. Some of the arms 46 hold holders 14, and the remaining arms 46 do not hold anything. The holders 14 held by the arms 46 hold tools 15. The arms 46 are movable along a predetermined circular movement path. The control unit 33 turns on the magazine motor 45, causing the arms 46 to move. The control unit 33 determines the position of the arm 46 based on the detection results of an encoder (not shown) provided on the magazine motor 45, for example.

[0037] Here, the procedure for changing tools will be outlined. 4 is a graph for explaining the tool change procedure, where the horizontal axis indicates time and the vertical axis indicates the position of the spindle 13 in the Z-axis direction. The space below the machining chamber 12 is the machining area. The machining position shown in Figure 4 is at the lower end of the machining area, and a workpiece W is placed at the machining position. The space above the machining chamber 12 is a tool exchange area where a tool magazine 44 is located.

[0038] For example, the Z-axis origin is set at the boundary between the machining area and the tool change area. A retraction position is set at the top end of the tool change area. A tool change position is set between the Z-axis origin and the retraction position. The tool change position is a point on the movement path of the arm 46. A tool cleaning position is set between the tool change position and the Z-axis origin. When the spindle 13 is in the machining position, the arm 46 is at the tool change position and does not hold anything. The tool 15 machines the workpiece W. When the tool 15 is changed to another tool 15, the spindle 13 rises from the machining position.

[0039] When the ascending spindle 13 passes the Z-axis origin and arrives at the tool cleaning position, coolant begins to be sprayed from the cleaning nozzle 16 (timing t3, which will be described later). The coolant sprayed from the cleaning nozzle 16 cleans the holder 14 and the tool 15 attached to the spindle 13. When the spindle 13 has passed the tool cleaning position and arrived at the tool changing position, the arm 46 receives the holder 14 attached to the spindle 13 . The spindle 13, which has risen to the retracted position, stops.

[0040] While the spindle 13 is stopped at the retracted position, the arm 46 that has received the holder 14 leaves the tool changing position, and the arm 46 holding the other holder 14 arrives at the tool changing position. Next, the spindle 13 starts to descend. When the descending spindle 13 reaches the tool change position, the arm 46 positioned at the tool change position attaches the holder 14 to the spindle 13. The coolant sprayed from the cleaning nozzle 16 cleans the holder 14 and the tool 15 attached to the spindle 13.

[0041] When the spindle 13, which has passed the tool changing position, arrives at the tool cleaning position, the spraying of coolant from the cleaning nozzle 16 stops (timing t4, which will be described later). The spindle 13 stops after descending to the Z-axis origin. Note that the spindle 13 may further descend until it reaches the processing position.

[0042] Next, the timing of turning on and off the CTS pump 25 will be described. Fig. 5 is a timing chart showing an example of the on and off timing of the CTS pump 25. Fig. 5 also shows the on and off timing of the CTS valve 41 and the on and off timing of the flush valve 42. Timings t1 to t4 are earlier in this order. Timing t5 is the point in time when a predetermined time DT has elapsed since timing t2, and is later than timing t3 and earlier than timing t4. 6 is a timing chart showing another example of the on and off timing of the CTS pump 25. Timing t6 is the point in time when a predetermined time DT has elapsed since timing t2, and is later than timing t2 and earlier than timing t3.

[0043] 5 and 6, the cleaning valve 42 is turned on at timing t3 and turned off at timing t4. If the CTS pump 25 is on, coolant is sprayed from the cleaning nozzle 16 from timing t3 to timing t4. While the workpiece W is being machined by the tool 15, coolant may spurt from the tool 15 to clean the workpiece W. In the cases of Figures 5 and 6, the CTS valve 41 is turned on at timing t1 and turned off at timing t2. If the CTS pump 25 is on, coolant spurts from the tool 15 between timing t1 and timing t2.

[0044] As shown in Figure 5, if the time from timing t2 (CTS valve 41 off) to timing t3 (cleaning valve 42 on) is short (less than the predetermined time DT), turning off the CTS pump 25 at timing t2 will increase the running costs of the machine tool 1. This is because when the CTS pump 25 is turned on, a large current flows through the motor that drives the CTS pump 25. Turning the CTS pump 25 on and off in a short period of time increases power consumption. Also, because a switch (not shown) must be frequently switched on and off to turn the CTS pump 25 on and off, the switch wears out quickly. Parts worn out by frequent switching must be replaced.

[0045] Therefore, in this embodiment, if the time from timing t2 to timing t3 is less than the predetermined time DT, the control unit 33 turns off the CTS pump 25 at timing t4 (cleaning valve 42 off).

[0046] 6, when the time from timing t2 to timing t3 is long (longer than the predetermined time DT), it is ideal to turn off the CTS pump 25 at timing t2. However, it is not realistic for the control unit 33 at timing t2 to determine whether the time from timing t2 to timing t3 is long or short. Therefore, the control unit 33 turns off the CTS pump 25 at timing t6, which is a predetermined time DT after timing t2. For example, the user sets the predetermined time DT appropriately so that the time from timing t6 to timing t3 is not too short, which would increase the running costs of the machine tool 1, and provides this to the control device 3. The predetermined time DT is, for example, 0.1 seconds.

[0047] 7 and 8 are flowcharts showing the procedure of the workpiece machining process executed by the control device 3. FIG. Before the start of workpiece machining processing, the CTS pump 25, timer 34, CTS valve 41, and cleaning valve 42 are all off. Also, a pump-on flag FP and a timer-on flag FT, which will be described later, are reset. As shown in Figure 7, the control unit 33 reads the command that has not been executed and that should be executed earliest among the multiple commands contained in the machining program (S11), and determines whether the read command is a CTS end command that commands the end of coolant spray from the tool 15 (S12).

[0048] If the command read in S11 is not a CTS end command (NO in S12), the control unit 33 determines whether the command read in S11 is a CTS start command that commands the start of coolant spray from the tool 15 (S13).

[0049] If the command read in S11 is a CTS start command (YES in S13), the control unit 33 turns on the CTS pump 25 (S14) and the CTS valve 41 (S15). As a result of the processing of S14 and S15, coolant is sprayed from the tool 15 (timing t1 shown in FIGS. 5 and 6). The control unit 33 sets the pump-on flag FP, which indicates that the CTS pump 25 is on (S16), and returns the process to S11.

[0050] If the command read in S11 is a CTS termination command (YES in S12), the control unit 33 turns off the CTS valve 41 (S17), turns on the timer 34 (S18), and sets the limit value LT of the timer 34 (S19). In the process of S19, the control unit 33 assigns a predetermined time DT to a variable indicating the limit value LT of the timer 34. The predetermined time DT may be constant, or the control unit 33 may select from multiple predetermined times DT before executing the process of S19.

[0051] As a result of the processing of S17, the spraying of coolant from the tool 15 ends (timing t2 shown in FIGS. 5 and 6). At this time, the control unit 33 does not turn off the CTS pump 25. As a result of the processing of S18, the timer 34 counts the elapsed time T from when the CTS valve 41 was closed. The control unit 33 sets a timer-on flag FT, which indicates that the timer 34 is operating (S20), and returns the process to S11.

[0052] If the command read in S11 is not a CTS start command (NO in S13), the control unit 33 determines whether the command read in S11 is a tool change command (S31), as shown in FIG. If the command read in S11 is not a tool change command (NO in S31), the control unit 33 determines whether the command read in S11 is a machining end command (S32). If the command read in S11 is not a machining end command (NO in S32), the control unit 33 executes the command read in S11 (S33) and returns the process to S11 shown in FIG. As shown in FIG. 8, when the command read at S11 is a machining end command (YES at S32), the control unit 33 ends the workpiece machining process.

[0053] When the command read at S11 is a tool change command (YES at S31), the control unit 33 executes a tool change process described later (S34), and returns the process to S11.

[0054] FIG. 9 is a flowchart showing the procedure of the timer determination process executed by the control device 3. When the timer on flag FT is set at S20 shown in FIG. 7, the control unit 33 executes the timer determination process shown in FIG. 9 in parallel with the workpiece machining processes shown in FIGS. 7 and 8. The control unit �̳ obtains the elapsed time T which is the time measurement result of the timer 34 (S51), and determines whether or not the obtained elapsed time T is equal to or greater than the limit value LT (S52). When T < LT (NO at S52), the control unit 33 determines whether or not the timer on flag FT is reset (S53). When the timer on flag FT is set (NO at S53), since the timer 34 is still operating, the process of S52 is executed again.

[0055] When T ≧ LT (YES at S52), since the predetermined time DT has elapsed since the CTS valve 41 was closed (timing t6 shown in FIG. 6), the control unit 33 turns off the CTS pump 25 (S54). Further, the control unit 33 turns off the timer 34 (S55), resets the timer on flag FT (S56), and ends the timer determination process. When the timer on flag FT is reset (YES at S53), since it is not necessary to execute the timer determination process, the control unit 33 ends the timer determination process.

[0056] FIGS. 10 and 11 are flowcharts showing the procedure of the tool change process executed by the control device 3. As shown in FIG. 10, the control unit 33 controls the operation of the Z-axis motor 43 so that the spindle 13 rises (S71), and determines whether the spindle 13 has reached the Z-axis origin (S72). If the spindle 13 has not yet reached the origin (NO in S72), the control unit 33 executes the processing of S72 again. If the spindle 13 has reached the Z-axis origin (YES in S72), the control unit 33 determines whether or not the pump-on flag FP has been set (S73).

[0057] If the pump-on flag FP is set (YES in S73), the CTS pump 25 has not yet been turned off after being turned on in S14 of FIG. 7. As shown in FIG. 10, the control unit 33 turns off the timer 34 (S74) and resets the timer-on flag FT (S75). As a result, the control unit 33 determines YES in the process of S53 shown in FIG. 9, and therefore the CTS pump 25 will not be turned off in the process of S54 shown in FIG. 9, even if the predetermined time DT has elapsed from timing t2 shown in FIG. 5 (timing t5). In this case, the CTS pump 25 will be turned off in the process of S96, which will be described later.

[0058] 10, the control unit 33 may extend the limit value LT of the timer 34 before executing the next process of S76, and may execute the processes of S74 and S75 when executing the process of S96 described below. The extended limit value LT is a sufficiently large value to prevent the CTS pump 25 from being turned off in the process of S54 shown in FIG. 9 before the CTS pump 25 is turned off in the process of S96 described below.

[0059] As shown in FIG. 10, the control unit 33 determines whether the spindle 13 has arrived at the tool cleaning position (S76), and if not (NO in S76), executes the process of S76 again. When the spindle 13 arrives at the tool cleaning position (YES in S76), the control unit 33 turns on the cleaning valve 42 (S77). As a result of the processing of S77, coolant starts to be sprayed from the cleaning nozzle 16 (timing t3 shown in FIG. 5). If the pump-on flag FP has been reset (NO in S73), the control unit 33 determines whether the spindle 13 has arrived at the tool cleaning position (S78), and if not (NO in S78), executes the processing of S78 again.

[0060] When the spindle 13 arrives at the tool cleaning position (YES in S78), the control unit 33 turns on the CTS pump 25 (S79) and proceeds to S77. As a result of the processing of S77 after the processing of S79, coolant begins to spray from the cleaning nozzle 16 (timing t3 shown in FIG. 6). After the process of S77 is completed, the control unit 33 determines whether the spindle 13 has reached the retracted position (S80), and if not (NO in S80), executes the process of S80 again. The arm 46 receives the holder 14 from the spindle 13 until the spindle 13 reaches the retracted position.

[0061] 11, the control unit 33 turns off the Z-axis motor 43 so as to stop the spindle 13 (S91). Furthermore, the control unit 33 controls the operation of the magazine motor 45 to send the arm 46, which holds the holder 14 holding the next required tool 15, to the tool change position (S92). The control unit 33 determines whether the arm 46 has arrived at the tool change position (S93), and if not (NO in S93), executes the process of S93 again.

[0062] When the arm 46 has reached the tool changing position (YES in S93), the control unit 33 controls the operation of the Z-axis motor 43 so that the spindle 13 descends (S94), and determines whether the spindle 13 has reached the tool cleaning position (S95). If the spindle 13 has not yet reached the tool cleaning position (NO in S95), the control unit 33 executes the process of S95 again. The arm 46 attaches the holder 14 to the spindle 13 while the spindle 13 is waiting to reach the tool cleaning position.

[0063] When the spindle 13 arrives at the tool cleaning position (YES in S95), the control unit 33 turns off the CTS pump 25 (S96), turns off the cleaning valve 42 (S97), and resets the pump-on flag FP (S98). As a result of the processing in S96 and S97, the CTS pump 25 and the cleaning valve 42 are turned off at timing t4 (see FIGS. 5 and 6). Therefore, it is possible to prevent the CTS pump 25 from continuing to operate when both the CTS valve 41 and the cleaning valve 42 are closed.

[0064] The control unit 33 determines whether the spindle 13 has reached the Z-axis origin (S99), and if not (NO in S99), executes the process of S99 again. When the spindle 13 reaches the Z-axis origin (YES in S99), the control unit 33 ends the tool change process and returns the process to the workpiece machining process. At this time, the control unit 33 may turn off the Z-axis motor 43 so that the spindle 13 stops at the Z-axis origin, or may wait until the spindle 13 reaches the machining position before turning off the Z-axis motor 43.

[0065] According to the machine tool 1 as described above, the control unit 33 turns on the CTS pump 25 when the CTS valve 41 opens (timing t1). When the CTS valve 41 is open and the cleaning valve 42 is closed, and the CTS valve 41 is then closed (timing t2), the control unit 33 measures the elapsed time T from when the CTS valve 41 was closed.

[0066] When the CTS valve 41 is closed, the cleaning valve 42 is closed, and the elapsed time T is equal to or greater than the predetermined time DT, the control unit 33 turns off the CTS pump 25 (timing t6). When the CTS valve 41 is closed, the cleaning valve 42 is open, and the elapsed time T is equal to or greater than the predetermined time DT, the control unit 33 does not turn off the CTS pump 25 (timing t5).

[0067] In other words, if the flush valve 42 opens before the predetermined time DT has elapsed since the CTS valve 41 closed, the CTS pump 25 remains on, so there is no need to switch the CTS pump 25 from off to on. As a result, the CTS pump 25 does not turn on and off in a short period of time, which reduces the large energy consumption that would accompany turning the CTS pump 25 on and off. Also, there is no need to frequently switch the CTS pump 25 on and off. Therefore, there is no need to replace parts that wear out due to frequent switching. As a result of the above, running costs can be reduced.

[0068] The machine tool 1 may use a coolant to cool the tool 15, the workpiece W, and the like. The first valve is not limited to the CTS valve 41, and the second valve is not limited to the cleaning valve 42. For example, the cleaning valve 42 may be the first valve at timing t4, and the control unit 33 may turn on the timer 34 at timing t4. The machine tool 1 is not limited to a configuration in which another nozzle is newly opened before the predetermined time DT has elapsed, but may be a configuration in which one nozzle is opened again. The CTS valve 41 and the cleaning valve 42 are opened exclusively, but one valve may be open while the other is open.

[0069] The coolant that has passed through the first flow path 27 is not limited to being sprayed from the tool 15 toward the workpiece W, but may be sprayed, for example, from a nozzle provided on the spindle 13 toward the workpiece W. The coolant that has passed through the second flow path 28 is not limited to being sprayed from the cleaning nozzle 16 toward the holder 14 and the tool 15, but may be sprayed, for example, from a nozzle separate from the spindle 13 toward the holder 14 and the tool 15.

[0070] The embodiments disclosed herein are to be considered as illustrative in all respects and not restrictive. The scope of the present invention is intended to include not only the above-mentioned meaning but also the meaning equivalent to the claims and all modifications within the scope of the claims. Independent and dependent claims may be combined with each other in any and all combinations, regardless of the reference format. Furthermore, while the claims may be written in a format in which a claim references two or more other claims (multiple claim format), this is not a limitation. Multiple claims that reference at least one other multiple claim (multiple multiple claim format) may also be written. [Explanation of symbols]

[0071] 1 Machine tools 13 Spindle 14 Holder 15 Tools 152 spout 16 Cleaning nozzle 24 Clean tank (liquid storage tank) 25 CTS Pump (Pump) 27 First Channel (First Channel) 28 Secondary Channel (Other Channel) 3. Control device (computer) 33 Control Unit 34 Timer 3P Program (Computer Program) 41 CTS valve (one valve) 42 Cleaning valve (other valve)

Claims

1. a flow path that is opened and closed by a valve; Other flow paths that other valves open and close; a reservoir tank for storing coolant; a pump that pumps the coolant from the reservoir tank to the first flow path and the second flow path; a control unit that controls the on / off of the pump; Equipped with The control unit turning on the pump when the one valve is open; When the one valve is closed while the other valve is open, the time elapsed since the one valve was closed is measured; determining whether the elapsed time is equal to or greater than a predetermined time; If the elapsed time is equal to or greater than the predetermined time, turn off the pump. A machine tool characterized by performing processing.

2. a spindle to which a holder for holding a tool is detachably attached; a cleaning nozzle attached to the spindle and facing the holder; Further provided with the tool has a spout; The tool is connectable to a portion of the first flow path downstream of the first valve, 2. The machine tool according to claim 1, wherein the cleaning nozzle is connected to a portion of the other flow path downstream of the other valve.

3. The control unit When the pump is on and the other valve is open, the pump is not turned off even if the elapsed time is equal to or greater than the predetermined time, and the pump is turned off when the other valve is closed.

3. The machine tool according to claim 1, wherein processing is performed.

4. a flow path that is opened and closed by a valve; Other flow paths that other valves open and close; a reservoir tank for storing coolant; a pump that pumps the coolant from the reservoir tank to the first flow path and the second flow path; A method for controlling on / off of the pump of a machine tool comprising: turning on the pump when the one valve is open; When the one valve is closed while the other valve is open, the time elapsed since the one valve was closed is measured; determining whether the elapsed time is equal to or greater than a predetermined time; A method for controlling a machine tool, comprising turning off the pump when the elapsed time is equal to or greater than the predetermined time.

5. a pump for pumping the coolant from the reservoir tank to the first flow path and the second flow path; a coolant storage tank for storing coolant; and a machine tool including the coolant storage tank and a pump for pumping the coolant from the reservoir tank to the first flow path and the second flow path. When the first valve opens, the pump is turned on. When the one valve is closed while the other valve is open, the time elapsed since the one valve was closed is measured; determining whether the elapsed time is equal to or greater than a predetermined time; If the elapsed time is equal to or greater than the predetermined time, turn off the pump. A computer program that causes a computer to execute a process.

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