Numerical controller, control method, control program, and storage medium

Abstract

To provide a numerical control device, a control method, a control program, and a storage medium capable of appropriately performing drive control of a cutting fluid ejection mechanism even when a machining time varies.SOLUTION: When a machining program is received and a machining condition is set in a state where reference machining information in which identification information of the machining program, the machining condition, and a machining time are associated with each other is stored, the numerical controller determines whether identical machining information in which the same identification information as the identification information of the received machining program and the same machining condition as the set machining condition are associated with each other is stored (S31). When the identical machining information is stored (S31: YES), the numerical controller drives the jetting mechanism from the specific time to the end of the machining operation when the specific time before the first predetermined time from the time when the machining operation ends is reached based on the machining time (S51) extracted from the identical machining information (S33).SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The present invention relates to a numerical control device, a control method, a control program, and a storage medium. [Background technology]

[0002] The control device described in Patent Document 1 determines whether or not there is a block in the NC program where operating parts such as the spindle and coolant are on standby during execution of the NC program. If a block on standby is present, the control device cuts off or limits the power supplied to the power sources of the operating parts on standby in this block, such as the spindle motor and coolant pump. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-067346 Summary of the Invention [Problem to be solved by the invention]

[0004] In the control device described in Patent Document 1, power is cut off or limited only in blocks that are in a standby state, which can result in an excessive supply of coolant from the coolant pump. In this case, it may not be possible to appropriately suppress the power consumed by the coolant pump. In contrast, since chips generated by machining only need to be discharged when machining is completed, it is possible to calculate the timing of machining completion based on the machining time of the machine tool and start supplying coolant a predetermined time before this timing.

[0005] However, even if the NC program commands are the same, the machining time of a machine tool may vary depending on the operating conditions set. A specific example of this is when an override function that changes the speed is used. Therefore, if the operating time of the spray mechanism that sprays cutting fluid is controlled based on the machining time, the operating time of the spray mechanism will also vary as the machining time varies depending on the operating conditions, which is a problem.

[0006] An object of the present invention is to provide a numerical control device, a control method, a control program, and a storage medium that can appropriately control the drive of a cutting fluid ejection mechanism even when the machining time varies. [Means for solving the problem]

[0007] A numerical control device according to a first aspect of the present invention is a numerical control device that controls a machine tool equipped with a spray mechanism that sprays cutting fluid into a cover, and includes: a reception unit that receives a machining program for the machine tool; a condition setting unit that sets machining conditions when the machine tool is driven to machine a workpiece based on the machining program received by the reception unit; and a machining execution control unit that executes a machining operation to drive the machine tool based on the machining program received by the reception unit to machine the workpiece under the machining conditions set by the condition setting unit, wherein the machining execution control unit includes a measurement process that measures a machining time during which the machining operation is executed by the machining execution control unit; a storage control process that, when the machining operation by the machining execution control unit is completed, stores reference machining information in a storage unit that is associated with identification information of the machining program, the machining conditions, and the machining time measured by the measurement process; When the processing program is received by the reception unit and the processing conditions are set by the condition setting unit while stored in the memory unit, the system is characterized by comprising: an information judgment process for determining whether identical processing information, which is the reference processing information associated with the same identification information as the identification information of the received processing program and the same processing conditions as the set processing conditions, is stored in the memory unit; a time extraction process for extracting the processing time associated with the identical processing information if the information judgment process determines that the identical processing information is stored in the memory unit; a first judgment process for determining whether a specific time has been reached that is a first predetermined time before the time the processing operation ends, based on the processing time extracted by the time extraction process; and a first drive process for driving the ejection mechanism from the specific time to the end of the processing operation if the first judgment process determines that the specific time has been reached.

[0008] According to the first aspect, the numerical control device extracts the machining time from the identical machining information in which the identification information of the machining program and the machining conditions match, and identifies the specific time. When the identified specific time is reached, the numerical control device drives the jetting mechanism until the end of the machining operation. In this case, even if the machining time of the common machining program fluctuates due to changes in the machining conditions, the numerical control device can accurately extract the machining time of the currently executing machining program from the identical machining information. Therefore, even if the machining time fluctuates, the numerical control device can appropriately control the drive of the jetting mechanism.

[0009] In the first aspect, the numerical control device may further include a second drive process for intermittently driving the spray mechanism while the machining execution control unit is executing the machining operation. In this case, the numerical control device can reduce the power required to spray the cutting fluid compared to when the spray mechanism is continuously driven.

[0010] The first aspect may further include a change determination process for determining whether the machining conditions have been set during execution of the machining operation by the machining execution control unit, and a third drive process for stopping intermittent driving of the jet mechanism by the second drive process and continuously driving the jet mechanism if the change determination process determines that the machining conditions have been set. If machining conditions are set during execution of the machining operation, there is a possibility that a highly accurate machining time cannot be extracted. In such a case, the numerical control device stops intermittent driving of the jet mechanism and switches to continuous driving. This prevents drive control of the jet mechanism from being performed based on a low-accuracy machining time.

[0011] In the first aspect, the machining conditions may include at least one of override, program skip, and dry run. The numerical control device extracts the machining time from identical machining information that matches any one of the machining conditions of override, program skip, and dry run, and identifies the specific time, thereby accurately extracting the machining time of the currently executing machining program from the identical machining information. Therefore, the numerical control device can appropriately perform drive control of the jetting mechanism even when the machining time fluctuates due to changes in the machining conditions including at least one of override, program skip, and dry run.

[0012] In the first aspect, when the information determination process determines that the storage unit stores a plurality of pieces of the same processing information, the time extraction process may extract the shortest processing time from among the processing times associated with each of the plurality of pieces of the same processing information. In this case, the numerical control device can prevent the drive time of the ejection mechanism from being insufficient.

[0013] In the first aspect, the second drive process may repeatedly drive the spray mechanism for a first time period and then stop the spray mechanism for a second time period after driving the spray mechanism for the first time period, and the first predetermined time period may be shorter than the first time period. Depending on the machining program, only a small amount of chips may be generated in the latter half of the machining operation. In such cases, even if the first predetermined time period is shorter than the first time period, the chips can be sufficiently flushed away by the cutting fluid. Therefore, the numerical control device can reduce the power required to spray the cutting fluid while appropriately flushing away the chips by the cutting fluid.

[0014] In a first aspect, the second driving process may repeatedly drive the jetting mechanism for a first time period and then stop the jetting mechanism for a second time period after driving the jetting mechanism for the first time period, and the first predetermined time period may be longer than the first time period. In this case, the numerical control device drives the jetting mechanism before the end of the machining operation for a time period longer than the first time period during intermittent operation. In this case, the numerical control device can more reliably wash away chips by the end of the machining operation.

[0015] In the first aspect, the method may further include a fourth drive process for continuously driving the ejection mechanism from the start to the end of the machining operation when the information determination process determines that the same machining information is not stored in the memory unit. If the same machining time is not stored in the memory unit, a specific time cannot be identified based on the machining time. In this case, the numerical control device can reliably wash away chips by continuously driving the ejection mechanism.

[0016] In a first aspect, the second drive process may include a second determination process for repeatedly driving the spray mechanism for a first time and stopping the spray mechanism for a second time after driving the spray mechanism for the first time, and determining whether a second predetermined time from the last time the spray mechanism was stopped before the end of the machining operation by the second drive process to the specific time is shorter than a predetermined reference time. If the second determination process determines that the second predetermined time is shorter than the reference time, a fifth drive process for continuously driving the spray mechanism from the last time the spray mechanism was started for the first time until the end of the machining operation may be performed. By continuously driving the spray mechanism from the end of intermittent drive until the end of the machining operation, the numerical control device can prevent the spray mechanism from being stopped for a short time and then driven again when switching from intermittent drive to continuous drive. This allows the numerical control device to reduce the power required for spraying cutting fluid.

[0017] A control method according to a second aspect of the present invention is a control method for controlling a machine tool equipped with a spraying mechanism that sprays cutting fluid into a cover, the control method comprising: a receiving step of receiving a machining program for the machine tool; a condition setting step of setting machining conditions for when the machine tool is driven to machine a workpiece based on the machining program received by the receiving step; and a machining execution control step of driving the machine tool based on the machining program received by the receiving step under the machining conditions set by the condition setting step to execute a machining operation for machining the workpiece, the machining execution control step including: a measuring step of measuring a machining time for which the machining operation is executed by the machining execution control step; a storage control step of storing, in a storage unit, reference machining information in which identification information of the machining program, the machining conditions, and the machining time measured by the measuring step are associated with each other when the machining operation by the machining execution control step is completed; and a processing program is received in the receiving step and the processing conditions are set in the condition setting step with the received processing program stored in the storage unit, the information determining step is for determining whether identical processing information, which is the reference processing information associated with the same identification information as the identification information of the received processing program and the same processing conditions as the set processing conditions, is stored in the storage unit, the information determining step is for extracting the processing time associated with the identical processing information when it is determined by the information determining step that the identical processing information is stored in the storage unit, the first determining step is for determining whether a specific time that is a first predetermined time before the time when the processing operation is to be ended has been reached based on the processing time extracted by the time extracting step, and the first driving step is for driving the ejection mechanism from the specific time to the end of the processing operation when it is determined by the first determining step that the specific time has been reached.

[0018] A control program according to a third aspect of the present invention includes a receiving step of receiving a machining program for the machine tool in a computer that controls the machine tool, the computer being provided with a spraying mechanism that sprays cutting fluid into a cover; a condition setting step of setting machining conditions for when the machine tool is driven to machine a workpiece based on the machining program received by the receiving step; and a machining execution control step of driving the machine tool based on the machining program received by the receiving step under the machining conditions set by the condition setting step to execute a machining operation for machining the workpiece, the machining execution control step including a measuring step of measuring a machining time for which the machining operation is executed by the machining execution control step; a storage control step of storing, in a storage unit, reference machining information in which identification information of the machining program, the machining conditions, and the machining time measured by the measuring step are associated with each other when the machining operation by the machining execution control step is completed; When the processing information is stored in the storage unit, the processing program is accepted in the accepting step and the processing conditions are set in the condition setting step, and the following steps are executed: an information determining step of determining whether identical processing information, which is the reference processing information associated with the same identification information as the accepted processing program and the same processing conditions as the set processing conditions, is stored in the storage unit; a time extracting step of extracting the processing time associated with the identical processing information if it is determined by the information determining step that the identical processing information is stored in the storage unit; a first determining step of determining whether a specific time, which is a first predetermined time before the time when the processing operation ends, has been reached based on the processing time extracted by the time extracting step; and a first driving step of driving the ejection mechanism from the specific time to the end of the processing operation if it is determined by the first determining step that the specific time has been reached.

[0019] A storage medium according to a fourth aspect of the present invention includes a computer for controlling a machine tool having a spray mechanism for spraying cutting fluid into a cover, the computer comprising: a receiving step for receiving a machining program for the machine tool; a condition setting step for setting machining conditions when the machine tool is driven to machine a workpiece based on the machining program received by the receiving step; and a machining execution control step for executing a machining operation for machining the workpiece by driving the machine tool based on the machining program received by the receiving step under the machining conditions set by the condition setting step, the machining execution control step including a measuring step for measuring a machining time during which the machining operation is executed by the machining execution control step; a storage control step for storing, in a storage unit, reference machining information in which identification information of the machining program, the machining conditions, and the machining time measured by the measuring step are associated with each other when the machining operation by the machining execution control step is completed; When the processing information is stored in the storage unit, the processing program is accepted in the accepting step and the processing conditions are set in the condition setting step, and the following steps are executed: an information determining step of determining whether identical processing information, which is the reference processing information associated with the same identification information as the identification information of the accepted processing program and the same processing conditions as the set processing conditions, is stored in the storage unit; a time extracting step of extracting the processing time associated with the identical processing information if it is determined by the information determining step that the identical processing information is stored in the storage unit; a first determining step of determining whether a specific time, which is a first predetermined time before the time when the processing operation is to be completed, has been reached based on the processing time extracted by the time extracting step; and a first driving step of driving the ejection mechanism from the specific time to the completion of the processing operation if it is determined by the first determining step that the specific time has been reached. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 2 is a perspective view of the machine tool 1 as seen from the rear. [Figure 2] FIG. 1 is a front view of a machine tool 1. [Figure 3] FIG. 1 is a plan view of a machine tool 1. [Figure 4] 4 is a cross-sectional view taken along line II in FIG. 3, as viewed from the direction of the arrow. [Figure 5] 1 is a diagram showing a state in which a tool T attached to a spindle 7 machines a workpiece W. FIG. [Figure 6] 2 is a block diagram showing the electrical configuration of a numerical control device 30 and a machine tool 1. FIG. [Figure 7] FIG. 10 is a diagram illustrating a history table. [Figure 8] 10 is a graph showing the first cleaning operation. [Figure 9] 10 is a graph showing the second cleaning operation. [Figure 10] 10 is a graph showing the third cleaning operation. [Figure 11] 10 is a flowchart of a main process. [Figure 12] 12 is a flowchart of the main processing, which is a continuation of FIG. 11. [Figure 13] 13 is a flowchart of the main process, which is a continuation of FIG. 12. [Figure 14] 14 is a flowchart of the main processing, which is a continuation of FIG. 13. DETAILED DESCRIPTION OF THE INVENTION

[0021] An embodiment of the present invention will be described with reference to the drawings. In the following description, the front, back, left, right, upper, and lower directions in Fig. 2 will respectively refer to the front, rear, left, right, upper, and lower directions of the machine tool 1. The left-right direction, front-rear direction, and upper and lower directions of the machine tool 1 correspond to the X-axis direction, Y-axis direction, and Z-axis direction of the machine tool 1, respectively.

[0022] The structure of the machine tool 1 will be outlined with reference to Figures 1 to 4. The machine tool 1 includes a base 2, a machine body 3, a cover 4, a table 8 (see Figure 3), a tool changer 13 (see Figure 4), a control box 15, and the like. The base 2 is a roughly rectangular parallelepiped iron base. The machine body 3 is located at the rear of the upper part of the base 2 and performs cutting operations on a workpiece W (see Figure 5) held on the upper surface of the table 8. The types of cutting operations include drilling, tapping, and milling. The cover 4 is located on top of the base 2 and is a roughly rectangular parallelepiped box that covers the periphery of the machine body 3 and the upper part of the base 2. The cover 4 prevents chips and cutting fluid from scattering to the outside. As shown in Figure 4, the table 8 is located at the center of the upper part of the base 2 and can be moved in the X-axis and Y-axis directions by an X-axis motor 53 (see Figure 6), a Y-axis motor 54 (see Figure 6), an X-axis guide mechanism, and a Y-axis guide mechanism (not shown). Each guide mechanism includes a linear guide, a ball screw, a nut (not shown), etc. The workpiece W (see FIG. 5) can be fixed to the upper surface of the table 8 with a jig or the like.

[0023] As shown in FIG. 4, the tool changer 13 is equipped with a tool magazine 14. The disk-shaped tool magazine 14 is equipped with a plurality of grip arms 14A on its outer periphery. The grip arms 14A hold a tool T (see FIG. 5) at their tips and are capable of swinging between them and a spindle 7 (see FIG. 5) of the machine body 3, which will be described later. The tool changer 13 swings the grip arms 14A, which are in the tool changing position, to attach and detach the tool T to and from the spindle 7. The tool changing position is the lowest position of the tool magazine 14 and the position closest to the spindle 7. As shown in FIG. 1, the control box 15 is provided on the rear side of the cover 4, and houses a numerical control device 30 (see FIG. 6) inside. The numerical control device 30 controls the operation of the machine tool 1.

[0024] The configuration of the machine body 3 will be described with reference to Figures 1 to 4. The machine body 3 includes a column 5, a spindle head 6, and a spindle 7 (see Figure 5). The column 5 is located at the rear of the upper part of the base 2. The spindle head 6 can be raised and lowered in the Z-axis direction along the front surface of the column 5 by a Z-axis movement mechanism (not shown). The Z-axis movement mechanism includes a linear guide, a ball screw, a nut (not shown), and the like. As shown in Figure 5, the spindle head 6 rotatably supports a spindle 7 therein. A tool T is attached to the lower end of the spindle 7, and the spindle 7 is rotated by the drive of a spindle motor 52 (see Figures 3 and 6). The machine tool 1 can perform cutting on a workpiece W (see Figure 5) held on the upper surface of a table 8 by relative movement between the workpiece W and the tool T attached to the spindle 7.

[0025] The structure of the cover 4 will be described with reference to Figures 1 to 4. The cover 4 has a front wall 41, a left wall 42, a right wall 43, a left back wall 44 (see Figures 3 and 4), and a right back wall 45 (see Figures 3 and 4), and is formed in a substantially rectangular box shape. The lower ends of each of the walls 41 to 45 are fixed to the upper part of the base 2. As shown in Figures 3 and 4, the left back wall 44 and the right back wall 45 form the back walls of the cover 4. The left back wall 44 is fixed to the front end of the left side of the column 5 and extends to the left. The right back wall 45 is fixed to the front end of the right side of the column 5 and extends to the right. The cover 4 covers the machining area of ​​the machine tool 1. The machining area is the area required by the machine tool 1 to machine the workpiece W. The cover 4 is equipped with a cutting fluid spraying mechanism (hereinafter referred to as the "spraying mechanism"). The spraying mechanism sprays cutting fluid within the cover 4. Therefore, the machine tool 1 can wash away chips that are generated during the machining of the workpiece W and that adhere to and accumulate inside the cover 4. The structure of the ejection mechanism will be described later.

[0026] As shown in FIG. 2 , the front wall 41 has an opening 46, a door 47, and an operation panel 10. The opening 46 is located approximately in the center of the front wall 41 and is rectangular in front view. The door 47 is movable left and right within the opening 46. An operator can open the door 47 to attach or detach the workpiece W on the top surface of the table 8. The operation panel 10 is located on the right side of the opening 46. The operation panel 10 is connected to the numerical control device 30 (see FIG. 6 ) via a harness (not shown). The operation panel 10 has an input unit 11 and a display unit 12. The input unit 11 is a device that allows input of various operation instructions for the machine tool 1, machining programs, tool types, tool diameters, various parameters, etc. The machining program is an NC program described in the background art, and is composed of multiple blocks containing various control commands and has block numbers. The numerical control device 30 controls the machine tool 1 based on the machining program, causing the machine tool 1 to perform machining operations including axis movement, tool replacement, etc. The display unit 12 receives instructions from the numerical control device 30 and is capable of displaying various input screens, operation screens, and the like.

[0027] The structure of the spray mechanism will be explained with reference to Figures 1, 3, and 4. The spray mechanism consists of a spray unit and a supply unit. The spray unit is located inside the cover 4 and sprays cutting fluid inside the cover 4. The supply unit is located outside the cover 4 and supplies cutting fluid to the spray unit.

[0028] The configuration of the spraying unit will be described with reference to Figure 4. The spraying unit is composed of flexible pipes 71 and 72, cutting fluid nozzles 74 and 75, cutting fluid piping 81 and 82, chip showers 83 and 84, etc. The flexible pipe 71 extends toward the top surface of the table 8 from a through hole 94 formed in the left rear wall 44. The through hole 94 is formed on the right end side of the left rear wall 44, approximately in the middle in the vertical direction. The cutting fluid nozzle 74 is formed at the tip of the flexible pipe 71. The flexible pipe 72 extends toward the top surface of the table 8 from a through hole 92 formed in the right rear wall 45. The through hole 92 is formed on the left end side of the right rear wall 45, approximately in the middle in the vertical direction. The cutting fluid nozzle 75 is formed at the tip of the flexible pipe 72. The cutting fluid nozzles 74 and 75 are formed by bending the flexible pipes 71 and 72 and pointing them toward the top surface of the table 8.

[0029] The cutting fluid pipe 81 extends horizontally and forward from a through hole 93 (see Figure 3) provided in the upper left end of the left rear wall 44. The cutting fluid pipe 82 extends horizontally and forward from a through hole 91 (see Figure 3) provided in the upper right end of the right rear wall 45. The cutting fluid pipe 81 has a plurality of holes (not shown) at predetermined intervals in its lower part. The chip showers 83 are each attached to a plurality of holes provided in the lower part of the cutting fluid pipe 81. The cutting fluid pipe 82 also has a plurality of holes (not shown) at predetermined intervals in its lower part. The chip showers 84 are each attached to a plurality of holes provided in the lower part of the cutting fluid pipe 82. The chip showers 83, 84 spray cutting fluid downward.

[0030] The configuration of the supply unit will be described with reference to Figures 1 and 3. As shown in Figure 1, the supply unit is composed of a tank 20, pumps 22 and 23, main hoses 25 and 26, branch hoses 27 and 28, T-joints 61 and 62, and joints 63 and 64 (see Figure 3), etc. The tank 20 is installed behind the base 2 and stores cutting fluid. The pumps 22 and 23 are installed adjacent to the right side of the tank 20. The main hose 25 is connected to the pump 22. The main hose 26 is connected to the pump 23. The pump 22 pumps up the cutting fluid in the tank 20 and supplies it to the main hose 25. The pump 23 pumps up the cutting fluid in the tank 20 and supplies it to the main hose 26.

[0031] The T-joint 61 is connected from outside the cover 4 to a through-hole 91 provided in the upper right end of the right back wall 45. The T-joint 62 is connected from outside the cover 4 to a through-hole 92 provided in the middle position in the vertical direction on the left end side of the right back wall 45. As shown in Figure 3, the joint 63 is connected from outside the cover 4 to a through-hole 93 provided in the upper left end side of the left back wall 44. The joint 64 is connected from outside the cover 4 to a through-hole 94 (see Figure 4) provided in the middle position in the vertical direction on the right end side of the left back wall 44.

[0032] The main hose 25 and the branch hose 27 are each connected to the T-joint 61. The branch hose 27 extends to the left side of the column 5 via the back side of the column 5 and is connected to a joint 63 provided on the left back wall 44 (see Figure 3). The main hose 26 and the branch hose 28 are each connected to the T-joint 62. The branch hose 28 is inserted through a hole 5B (see Figure 1) provided in the column 5, extends to the left side of the column 5, and is connected to a joint 64 provided on the left back wall 44 (see Figure 3). The hole 5B is provided in the middle position in the vertical direction of the column 5 and penetrates in the left-right direction.

[0033] The operation of the spray mechanism will be described with reference to Figures 1, 3, and 4. When the pump 23 is driven, the cutting fluid flows through the main hose 26. The cutting fluid branches at the T-shaped joint 62, with one branch flowing through the through-hole 92 to the flexible pipe 72 and the other flowing to the branch hose 28. The cutting fluid that flows into the flexible pipe 72 is sprayed out from the cutting fluid nozzle 75. The cutting fluid that flows into the branch hose 28 flows from the joint 64 on the opposite side of the column 5 through the through-hole 94 to the flexible pipe 71 and is sprayed out from the cutting fluid nozzle 74. The cutting fluid nozzles 74 and 75 can directly spray cutting fluid from both the left and right sides onto the workpiece W (not shown) fixed to the top surface of the table 8 with a jig or the like. The cutting fluid can wash away chips adhering to the workpiece.

[0034] When pump 22 is driven, cutting fluid flows through main hose 25. The cutting fluid branches at T-joint 61, one branch flows through through-hole 91 into cutting fluid piping 82, and the other flows into branch hose 27. The cutting fluid that flows into cutting fluid piping 82 is sprayed downward from chip shower 84. The cutting fluid that flows into branch hose 27 flows from joint 63 on the opposite side of column 5 through through-hole 93 into cutting fluid piping 81, and is sprayed downward from chip shower 83. Therefore, the cutting fluid can wash away chips that adhere to and accumulate on the inside of cover 4.

[0035] Hereinafter, the operation of driving the pump 22 of the jetting mechanism to jet cutting fluid from the chip showers 83, 84 to wash away chips will be referred to as the "washing operation."

[0036] The electrical configurations of the numerical control device 30 and the machine tool 1 will be described with reference to FIG. 6. The numerical control device 30 includes a CPU 31, a ROM 32, a RAM 33, a nonvolatile storage device 34, an input / output unit 35, motor control units 51A-55A, and drive control units 56A and 57A. The CPU 31 performs overall control of the numerical control device 30. The ROM 32 stores control programs and the like. The RAM 33 includes various storage areas, which will be described later. The nonvolatile storage device 34 stores multiple machining programs. The control programs stored in the ROM 32 may be stored in a readable external storage medium (such as a USB memory or a CD-ROM). The CPU 31 may read a program from the storage medium, store it in the nonvolatile storage device 34, and execute the control program stored in the nonvolatile storage device 34. The machine tool 1 may also be capable of communicating with other devices (such as a server) via a communication line. The control program may be stored in the storage device of the other devices. The CPU 31 may store a control program acquired by communicating with the other devices in the nonvolatile storage device 34.

[0037] Motor control unit 51A is connected to Z-axis motor 51 and encoder 51B. Motor control unit 52A is connected to spindle motor 52 and encoder 52B. Motor control unit 53A is connected to X-axis motor 53 and encoder 53B. Motor control unit 54A is connected to Y-axis motor 54 and encoder 54B. Motor control unit 55A is connected to magazine motor 55 and encoder 55B. Drive control unit 56A is connected to pump 22. Drive control unit 57A is connected to pump 23. Motor control units 51A to 55A receive commands from CPU 31 and output drive currents to the corresponding motors 51 to 55, respectively.

[0038] Motor control units 51A-55A receive feedback signals from encoders 51B-55B and perform feedback control of position and speed. Input / output unit 35 is connected to input unit 11 and display unit 12, respectively. Drive control units 56A and 57A receive commands from CPU 31 and output drive currents to corresponding pumps 22 and 23, respectively. Pumps 22 and 23 are driven by the drive currents. Z-axis motor 51, spindle motor 52, X-axis motor 53, Y-axis motor 54, and magazine motor 55 are all servo motors. In the following description, Z-axis motor 51, spindle motor 52, X-axis motor 53, Y-axis motor 54, and magazine motor 55 will be referred to collectively as motors 51-55.

[0039] When starting a machining operation using the machine tool 1, the operator first operates the input unit 11 to select a machining program. Next, the operator operates the input unit 11 to set machining conditions. The machining conditions include a rapid traverse override, a cutting feed override, a spindle override, a block skip, and a dry run. The rapid traverse override is the movement speed of the tool T relative to the workpiece W during rapid traverse operation and is set by the operator within a range of 0-100%. The cutting feed override is the movement speed of the tool T relative to the workpiece W during cutting feed operation and is set by the operator within a range of 0-100%. The spindle override is the rotational speed of the spindle 7 and is set by the operator within a range of 0-100%. The block skip is a setting that skips a specified block in the machining program. The specified block is specified by a specified command included in the machining program. The dry run is a setting that moves the tool T relative to the workpiece W at a speed set in the numerical control device 30 separately from the commands in the machining program.

[0040] The CPU 31 of the numerical control device 30 controls the machine tool 1 under the set machining conditions based on the selected machining program, thereby causing the machine tool 1 to execute a machining operation.

[0041] The history table will be described with reference to Fig. 7. The history table stores multiple pieces of reference machining information as information indicating the history of machining operations performed by the machine tool 1. Each piece of reference machining information is associated with a history number, machining time, identification information, start position, rapid traverse override, cutting feed override, spindle override, block skip, dry run, and flag information.

[0042] The history number indicates the index of the reference machining information. The machining time indicates the execution time of the machining operation by the machine tool 1. The identification information is information that identifies the machining program selected when the machine tool 1 is made to execute the machining operation, and is, for example, the file name of the machining program. Note that the identification information is not limited to the file name of the machining program, and may be other information that can identify the machining program. For example, the identification information may be simple numbers or symbols, the name of the creator of the machining program, the name of the factory, etc. The start position indicates the line number of the command that is first referenced when the machine tool 1 executes the machining operation, among the multiple commands contained in the machining program.

[0043] The rapid traverse override, cutting feed override, spindle override, block skip, and dry run each indicate the machining conditions that are set when the machine tool 1 executes a machining operation based on the corresponding machining program. In the example shown in Fig. 7, the rapid traverse override, cutting feed override, and spindle override are shown as values ​​between 0 and 100% that are set by the operator. For block skip and dry run, "enabled" is shown if the operator has set the function to ON, and "disabled" is shown if the operator has set the function to OFF.

[0044] The flag information is such that an inapplicable flag is set when the operator sets the machining conditions during the machining operation by the machine tool 1, and an applicable flag is set when the operator does not set the machining conditions during the machining operation.

[0045] The cleaning operation will be described with reference to FIGS. 8 to 10. The cleaning operation is performed during the machining operation of the machine tool 1. The CPU 31 of the numerical control device 30 switches the cleaning operation method based on the machining program selected by the operator to cause the machine tool 1 to perform the machining operation and the machining conditions set by the operator to perform the machining operation. More specifically, if machining information that matches the identification information, start position, and machining conditions of the selected machining program is not stored in the history table (see FIG. 7), the first cleaning operation shown in FIG. 8 is performed. The machining information includes the identification information, start position, and machining conditions of the machining program. On the other hand, if machining information that matches the identification information, start position, and machining conditions of the selected machining program is stored in the history table, the second cleaning operation shown in FIG. 9 or the third cleaning operation shown in FIG. 10 is performed. Hereinafter, machining information that matches the identification information, start position, and machining conditions of the selected machining program will be referred to as "identical machining information."

[0046] 8, in the first cleaning operation, the pump 22 is continuously driven from the start to the end of the machining operation. As a result, cutting fluid is continuously sprayed from the chip showers 83 and 84, washing away chips that have adhered to and accumulated inside the cover 4.

[0047] 9 and 10, in the second and third cleaning operations, the pump 22 is operated intermittently from the start of the machining operation to partway through the machining operation. More specifically, the pump 22 is stopped for a second time Toff, and then driven for a first time Ton, repeatedly. As a result, cutting fluid is intermittently sprayed from the chip showers 83 and 84, washing away chips that have adhered to and accumulated inside the cover 4. Hereinafter, the driving state in which cutting fluid is intermittently sprayed from the chip showers 83 and 84 by intermittently driving the pump 22 will be referred to as the "intermittent driving state."

[0048] Furthermore, the pump 22 is continuously driven from the middle of the machining operation (Tsp in FIG. 9) until the end of the machining operation. As a result, cutting fluid is continuously sprayed from the chip showers 83, 84, washing away chips that have adhered to and accumulated on the inside of the cover 4. Hereinafter, the driving state in which the pump 22 is continuously driven and cutting fluid is continuously sprayed from the chip showers 83, 84 is referred to as the "continuous driving state."

[0049] The duration of the continuous drive state differs between the second cleaning operation shown in FIG. 9 and the third cleaning operation shown in FIG. 10. Details are explained below. In FIGS. 9 and 10, the time from the start of the processing operation that is the processing time associated with the same processing information has elapsed is referred to as the "history end time Tprg." The time used as a reference when determining the duration of the continuous drive state is referred to as the "first predetermined time Tend." The time before the history end time Tprg by the first predetermined time Tend is referred to as the "specific time Tsp." When the pump 22 last drives for the first time Ton in the intermittent drive state and then stops, the time at which the pump 22 stops is referred to as the "end time Tsr." The time from the end time Tsr to the specific time Tsp is referred to as the "second predetermined time Tsub." The predetermined time used as a reference for determining the second predetermined time Tsub is referred to as the reference time Tref.

[0050] As shown in FIG. 9, the second cleaning operation is executed when the second predetermined time Tsub is equal to or greater than the reference time Tref. In this case, the pump 22 is finally driven for the first time Ton in the intermittent drive state, and then stops driving at the end time Tsr. When the second predetermined time Tsub has elapsed while the pump 22 is stopped, the specific time Tsp is reached. When the specific time Tsp is reached, the pump 22 starts driving, thereby entering the continuous drive state. In the continuous drive state, when the first predetermined time Tend has elapsed since the pump 22 started driving, the history end time Tprg is reached. The pump 22 continues to drive. Then, when the processing operation is completed, the pump 22 is also stopped.

[0051] As shown in FIG. 10A, the third cleaning operation is performed when the second predetermined time Tsub is shorter than the reference time Tref. In this case, as shown in FIG. 10B, the first predetermined time Tend is reset so that the start time of the first time Ton, during which the pump 22 is last driven in the intermittent drive state, coincides with the specific time Tsp. As a result, the pump 22 is continuously driven from the start of the last drive of the first time Ton in the intermittent drive state until the end of the processing operation, thereby entering a continuous drive state. Then, when the processing operation ends, the drive of the pump 22 is also stopped. Thus, in the third cleaning operation, unlike the second cleaning operation, the pump 22 is last driven for the first time Ton in the intermittent drive state, and the drive of the pump 22 is not stopped even after the end time Tsr.

[0052] 9 and 10, the first predetermined time Tend is longer than the first time Ton. Therefore, cutting fluid is continuously sprayed in the continuous drive state for the first predetermined time Tend, which is longer than the first time Ton during which cutting fluid is repeatedly sprayed in the intermittent drive state.

[0053] The magnitude relationship between the first predetermined time Tend and the first time Ton is not limited to the examples shown in Figures 9 and 10. For example, the first predetermined time Tend may be shorter than the first time Ton. In this case, cutting fluid is continuously sprayed in the continuous drive state for the first predetermined time Tend that is shorter than the first time Ton during which cutting fluid is repeatedly sprayed in the intermittent drive state.

[0054] The main processing will be described with reference to Figures 11 to 14. The main processing is started by CPU 31 of numerical control device 30 reading and executing a control program stored in nonvolatile storage device 34. Specifically, the main processing is started when machine tool 1 is powered on.

[0055] 11, the CPU 31 determines whether an operation to select a machining program has been received via the input unit 11 (S11). If the CPU 31 determines that an operation to select a machining program has not been received (S11: NO), the process returns to S11. The CPU 31 repeats the process of S11 until an operation to select a machining program is received. If the CPU 31 determines that an operation to select a machining program has been received (S11: YES), the CPU 31 reads the selected machining program from the ROM 32 and stores it in the RAM 33 (S13).

[0056] The CPU 31 determines whether an operation to input the start position of the machining program has been received via the input unit 11 (S15). The start position is a block number that the machining program has, and the first line shown in FIG. 7 is equivalent to block number 1, and the 23rd line is equivalent to block number 23. If the CPU 31 determines that an operation to input the start position has not been received (S15: NO), the process returns to S15. The CPU 31 repeats the process of S15 until an operation to input the start position is received. If the CPU 31 determines that an operation to input the start position has been received (S15: YES), the CPU 31 acquires the input start position and stores it in the RAM 33 (S17).

[0057] The CPU 31 determines whether an operation to set machining conditions (rapid feed override, cutting feed override, spindle override, block skip, dry run) has been accepted via the input unit 11 (S19). If the CPU 31 determines that an operation to set machining conditions has not been accepted (S19: NO), the process returns to S19. The CPU 31 repeats the process of S19 until an operation to set machining conditions is accepted. If the CPU 31 determines that an operation to set machining conditions has been accepted (S19: YES), the CPU 31 stores the set machining conditions in the RAM 33 (S21).

[0058] The CPU 31 reads out from the RAM 33 the machining program, start position, and machining conditions stored therein. The CPU 31 acquires the multiple commands of the read machining program in order, starting from the command for the read start position. The CPU 31 drives the machine tool 1 using a control method according to the acquired commands. The drive method of the machine tool 1 is adjusted so that the machining operation is performed under the read machining conditions. As a result, the machine tool 1 starts a machining operation to machine the workpiece W with the tool T under the set machining conditions (S23). The CPU 31 starts measuring the machining time of the started machining operation (S25).

[0059] 12, the CPU 31 refers to the processing program, start position, and processing conditions stored in the RAM 33. The CPU 31 determines whether the history table (see FIG. 7) contains identical processing information that is reference processing information including identification information that matches the identification information of the processing program selected in S11 (see FIG. 11), including a start position that matches the start position specified in S15 (see FIG. 11), and including processing conditions that match the processing conditions set in S19 (see FIG. 11), and that is associated with a target flag (S31). If the CPU 31 determines that the identical processing information is not included in the history table (S31: NO), the CPU 31 proceeds to S33 to start the first cleaning operation (see FIG. 8).

[0060] The CPU 31 controls the drive control unit 57A to start driving the pump 22 (S33). In this case, cutting fluid is sprayed from the chip showers 83 and 84, and chips that have adhered to and accumulated on the inside of the cover 4 are washed away.

[0061] The CPU 31 determines whether an operation to change the machining conditions has been received via the input unit 11 (S35). If the CPU 31 determines that an operation to change the machining conditions has been received (S35: YES), it changes and updates the machining conditions stored in the RAM 33 in S21 (see FIG. 11) with the changed machining conditions and stores them in the RAM 33 (S37). Furthermore, the CPU 31 adjusts the machining operation started in S23 (see FIG. 11) so that the machining operation is executed under the changed machining conditions. The CPU 31 proceeds with the process to S39. If the CPU 31 determines that an operation to change the machining conditions has not been received (S35: NO), it returns the process to S39.

[0062] The CPU 31 determines whether the processing operation started in S23 (see FIG. 11) is to be completed based on the processing program and processing conditions (S39). If the CPU 31 determines that the processing operation is not to be completed (S39: NO), the CPU 31 returns the process to S35. The CPU 31 repeats S35 and S37 until the processing operation is completed. As a result, the driving of the pump 22 started in S33 continues, and the first cleaning operation in which the pump 22 is continuously driven is executed.

[0063] When the CPU 31 determines that the machining operation is to end (S39: YES), it stops driving the pump 22, which was started in S33 (S41). The CPU 31 ends the measurement of the machining time, which was started in S25 (see FIG. 11) (S43). The CPU 31 acquires the identification information, start position, and machining conditions of the machining program stored in the RAM 33. The CPU 31 acquires the machining time measured in S25 and S43. The CPU 31 stores reference machining information, which associates the acquired machining time, identification information of the machining program, start position, and machining conditions, in the history table (S45). Furthermore, when the CPU 31 receives an operation to change the machining conditions during the machining operation (S35: YES), it associates a non-target flag as flag information of the stored reference machining information. On the other hand, when the CPU 31 does not receive an operation to change the machining conditions during the machining operation (S35: NO), it associates a target flag as flag information of the stored reference machining information. The CPU 31 returns the process to S11 (see FIG. 11).

[0064] When the CPU 31 determines that the same processing information is included in the history table (S31: YES), it extracts the processing time associated with the same processing information (S51). When the CPU 31 determines that the history table contains multiple pieces of the same processing information, it extracts the shortest processing time from among the processing times associated with each of the multiple pieces of the same processing information. The CPU 31 determines whether the extracted processing time is shorter than a first predetermined time Tend (S53). When the CPU 31 determines that the processing time is shorter than the first predetermined time Tend (S53: YES), it controls the drive control unit 57A to start driving the pump 22 (S33). In this case, the driving of the pump 22 started in S33 continues until the processing operation ends. This executes a first cleaning operation in which the pump 22 is continuously driven.

[0065] If the CPU 31 determines that the processing time is equal to or longer than the first predetermined time Tend (S53: NO), the CPU 31 proceeds to S61 (see FIG. 13) to start the second cleaning process (see FIG. 9) or the third cleaning process (see FIG. 10).

[0066] 13, the CPU 31 calculates the history end time Tprg as the time when the machining time extracted in S51 (see FIG. 12) has elapsed since the time when the machining operation started in S23 (see FIG. 11) (S61). The CPU 31 calculates the specific time Tsp as the time that is a first predetermined time Tend before the calculated history end time Tprg (S63). The CPU 31 calculates the end time Tsr as the time when the pump 22 drives for a first time Ton and then stops just before the specific time Tsp in the intermittent drive state that starts from the time when the machining operation started in S23 (see FIG. 11) (S65). The CPU 31 calculates the time from the end time Tsr to the specific time Tsp as the second predetermined time Tsub (S67).

[0067] The CPU 31 determines whether the calculated second predetermined time Tsub is shorter than the reference time Tref (S69). If the second predetermined time Tsub is equal to or longer than the reference time Tref, the second cleaning process (see FIG. 9) is executed. In this case, there is no need to reset the first predetermined time Tend. If the CPU 31 determines that the second predetermined time Tsub is equal to or longer than the reference time Tref (S69: NO), the process proceeds to S81 (see FIG. 14).

[0068] If the second predetermined time Tsub is shorter than the reference time Tref, the CPU 31 executes the third cleaning process (see FIG. 10). The CPU 31 resets the first predetermined time Tend so that the specific time Tsp coincides with the start time of the first time Ton, at which the pump 22 is last driven in the intermittent drive state (S71). The CPU 31 calculates the specific time Tsp based on the reset first predetermined time Tend (S73). The CPU 31 proceeds to S81 (see FIG. 14).

[0069] As shown in FIG. 14, the CPU 31 controls the drive control unit 57A to stop driving the pump 22 (S81). The CPU 31 starts measuring the stop time while the driving of the pump 22 is stopped (S83). The CPU 31 determines whether an operation to change the machining conditions (rapid-forward override, cutting feed override, spindle override, block skip, dry run) has been received via the input unit 11 (S85). If the CPU 31 determines that an operation to change the machining conditions has not been received (S85: NO), it determines whether the specific time Tsp has been reached (S89). If the CPU 31 determines that the specific time Tsp has not been reached (S89: NO), it determines whether the second time Toff has elapsed since the driving of the pump 22 was stopped, based on the stop time whose measurement started in S83 (S91). If the CPU 31 determines that the second time Toff has not elapsed since the driving of the pump 22 was stopped (S91: NO), it returns the process to S85. When the CPU 31 determines that the second time Toff has elapsed since the driving of the pump 22 was stopped (S91: YES), the CPU 31 advances the process to S101.

[0070] The CPU 31 controls the drive control unit 57A to start driving the pump 22 (S101). The CPU 31 starts measuring the driving time while the pump 22 is being driven (S103). The CPU 31 determines whether an operation to change the machining conditions (rapid-forward override, cutting feed override, spindle override, block skip, dry run) has been received via the input unit 11 (S105). If the CPU 31 determines that an operation to change the machining conditions has not been received (S105: NO), it determines whether a specific time Tsp has been reached (S109). If the CPU 31 determines that the specific time Tsp has not been reached (S109: NO), it determines whether a first time Ton has elapsed since the driving of the pump 22 was started, based on the driving time whose measurement started in S103 (S111). If the CPU 31 determines that the first time Ton has not elapsed since the driving of the pump 22 was started (S111: NO), it returns the process to S105. When the CPU 31 determines that the first time Ton has elapsed since the start of driving of the pump 22 (S111: YES), the CPU 31 returns the process to S81. The CPU 31 controls the drive control unit 57A to stop driving of the pump 22 (S81). By repeating the processes of S81 to S111, the pump 22 enters an intermittent drive state in which it is driven intermittently.

[0071] If the CPU 31 determines that the specific time Tsp has been reached in the intermittent drive state (S89: YES, S109: YES), the process returns to S33 (see FIG. 12). As shown in FIG. 12, the CPU 31 controls the drive control unit 57A to start driving the pump 22 (S33). This ends the intermittent drive state and switches to the continuous drive state. The CPU 31 determines whether the machining operation started in S23 (see FIG. 11) has ended (S39). If the CPU 31 determines that the machining operation has ended (S39: YES), it stops driving the pump 22 that was started in S33 (S41). In other words, the pump 22 continues to drive from the specific time Tsp until the machining operation ends.

[0072] The CPU 31 ends the measurement of the machining time that started in S25 (see FIG. 11) (S43). The CPU 31 stores the reference machining information, which associates the machining time, the identification information of the machining program, the start position, and the machining conditions, in the history table (S45). The CPU 31 also associates a target flag as flag information of the stored reference machining information. The CPU 31 returns the process to S11 (see FIG. 11).

[0073] As shown in FIG. 14, when the CPU 31 determines that an operation to change the machining conditions has been received in the intermittent drive state (S85: YES, S105: YES), the CPU 31 stores the changed machining conditions in the RAM 33 (S87, S107). The CPU 31 returns the process to S33 (see FIG. 12). As shown in FIG. 12, the CPU 31 controls the drive control unit 57A to start driving the pump 22 (S33). This ends the intermittent drive state and switches to the continuous drive state. The CPU 31 determines whether the machining operation started in S23 (see FIG. 11) has ended (S39). When the CPU 31 determines that the machining operation has ended (S39: YES), it stops driving the pump 22 started in S33 (S41).

[0074] The CPU 31 acquires the machining conditions stored in the RAM 33 in S87 and S107 (see FIG. 14), i.e., the changed machining conditions. The CPU 31 stores reference machining information in which the measured machining time is associated with the identification information of the machining program, the start position, and the changed machining conditions in the history table (S45). The CPU 31 associates an out-of-target flag as flag information of the stored reference machining information. The CPU 31 returns the process to S11 (see FIG. 11).

[0075] Even when machining programs with the same identification information are executed, the machining time of the machining operation may vary depending on the machining conditions. In response to this, the numerical control device 30 extracts the machining time from identical machining information whose machining program identification information matches the machining conditions (S51) and identifies the specific time Tsp (S63). When the identified specific time Tsp is reached (S89: YES, S109: YES), the numerical control device 30 sets the state of the machine tool 1 until the end of the machining operation to a continuous drive state in which the spray mechanism is continuously driven (S33). In this case, even if the machining time of machining programs with the same identification information varies depending on the machining conditions, the machining time of the currently executed machining program can be accurately extracted from the identical machining information. Therefore, even if the machining time varies depending on the machining conditions, the numerical control device 30 can start driving the pump 22 at the appropriate time and appropriately perform the cleaning operation.

[0076] The numerical controller 30 intermittently drives the pump 22 in the intermittent drive state in the second cleaning operation and the third cleaning operation (S81, S101). In this case, the numerical controller 30 can reduce the power required to eject the cutting fluid compared to when the pump 22 is continuously driven.

[0077] If the machining conditions are changed during the execution of a machining operation, the machine tool 1 will be driven under the changed machining conditions from the middle of the machining operation, which may make it impossible to extract a highly accurate machining time. In such a case, the numerical control device 30 switches from an intermittent drive state in which the pump 22 is driven intermittently to a continuous drive state in which the pump 22 is driven continuously. This allows the numerical control device 30 to prevent drive control of the pump 22 from being executed based on a machining time with low accuracy.

[0078] The machining conditions include a rapid-traverse override, a cutting feed override, a spindle override, a block skip, and a dry run. In this case, the numerical control device 30 extracts the machining time from the same machining information in which the rapid-traverse override, the cutting feed override, the spindle override, the block skip, and the dry run match, and identifies the specific time, thereby enabling the numerical control device 30 to accurately extract the machining time of the currently executing machining program from the same machining information. Therefore, the numerical control device 30 can appropriately perform drive control of the pump 22 even when the machining time varies depending on the machining conditions, such as the rapid-traverse override, the cutting feed override, the spindle override, the block skip, and the dry run.

[0079] If the history end time Tprg determined based on the machining time is set after the end time of the actual machining operation, the time for the cleaning operation by driving the pump 22 will be insufficient, which is undesirable. In response to this, when the numerical control device 30 determines that multiple identical machining information items are stored in the history table, it extracts the shortest machining time from among the machining times associated with each of the multiple identical machining information items (S51). In this case, the history end time Tprg determined based on the extracted machining time can always be set before the end time of the machining operation, regardless of the machining conditions. Therefore, the numerical control device 30 can prevent the drive time of the pump 22 in the continuous drive state from being insufficient.

[0080] The numerical control device 30 continuously drives the pump 22 in the continuous drive state for a first predetermined time Tend that is longer than the first time Ton for which the pump 22 is intermittently driven in the intermittent drive state. In this case, the numerical control device 30 can more reliably wash away chips with cutting fluid by the time the machining operation ends.

[0081] If the same machining time is not stored in the history table (S31: NO), the history end time Tprg may not be determined based on the machining time. In this case, the numerical control device 30 can reliably wash away chips by continuously driving the pump 22 (S33).

[0082] If the second predetermined time Tsub is shorter than the reference time Tref (S69: YES), the numerical controller 30 resets the first predetermined time Tend so that the start time of the first time Ton, the time at which the pump 22 is last driven in the intermittent drive state, coincides with the specific time Tsp (S71). In this case, the intermittent drive state is immediately followed by a switch to a continuous drive state, and the pump 22 continues to be driven until the end of the machining operation. This prevents the numerical controller 30 from stopping the pump 22 for a short time after the end of the intermittent drive state, and then switching to the continuous drive state to continuously drive the pump 22. This allows the numerical controller 30 to reduce the power required to spray cutting fluid.

[0083] The present invention is not limited to the above embodiment, and various modifications are possible. The numerical control device 30 may maintain the machine tool 1 in an intermittent drive state even when the machining conditions are changed during a machining operation by the machine tool 1 in the intermittent drive state. The numerical control device 30 may stop the pump 22 of the machine tool 1 without intermittently driving it during a period before the specific time Tsp is reached. The numerical control device 30 may continuously drive the pump 22 to set it to a continuous drive state only during the period from the specific time Tsp to the end of the machining operation.

[0084] The machining conditions may be at least one of rapid traverse override, cutting feed override, spindle override, block skip, and dry run, or the machining conditions may include conditions other than rapid traverse override, cutting feed override, spindle override, block skip, and dry run.

[0085] Even if the history table contains reference machining information that matches only part of the rapid traverse override, cutting feed override, spindle override, block skip, and dry run included in the machining conditions set during machining operation, the numerical control device 30 may extract the machining time by treating this reference machining information as the same machining information. Also, if the history table contains reference machining information that includes values ​​within a predetermined margin (for example, ±10%) of the range (0-100%) of the rapid traverse override, cutting feed override, and spindle override included in the set machining conditions, the numerical control device 30 may extract the machining time by treating this reference machining information as the same machining information.

[0086] When it is determined that the same machining information is stored multiple times in the history table, the numerical control device 30 may extract, as the machining time, a value statistically calculated from the machining times associated with each of the multiple pieces of the same machining information. For example, the numerical control device 30 may extract, as the machining time, an average value or a median value of the machining times associated with each of the multiple pieces of the same machining information.

[0087] The first predetermined time Tend may be shorter than the first time Ton. Depending on the machining program, only a small amount of chips may be generated in the latter half of the machining operation. In such cases, even if the first predetermined time Tend is set shorter than the first time Ton, the chips can be sufficiently flushed away by the cutting fluid. Therefore, the numerical control device 30 can reduce the power required to spray the cutting fluid while appropriately flushing away the chips by the cutting fluid.

[0088] Even when the same machining information is not stored in the history table, numerical control device 30 may first set machine tool 1 in the intermittent drive state and then in the continuous drive state.

[0089] The history table does not have to be stored in the non-volatile storage device 34 of the numerical control device 30, and may be stored in another storage unit. For example, a plurality of machine tools including the machine tool 1 may be installed in a factory. Each of the plurality of machine tools may be equipped with a network interface and be able to access an external server. The history table may be stored in a storage unit of the external server. The numerical control device 30 of the machine tool 1 may communicate with the external server and refer to the history table stored in the storage unit of the external server.

[0090] The pump 22 is an example of a "jet mechanism" of the present invention. The nonvolatile storage device 34 that stores the history table is an example of a "storage unit" of the present invention. The CPU 31 that performs the process of S11 is an example of a "receiving unit" of the present invention. The CPU 31 that performs the process of S19 is an example of a "condition setting unit" of the present invention. The CPU 31 that performs the process of S23 is an example of a "processing execution control unit" of the present invention. The CPU 31 that performs the process of S25 and S43 is an example of a "condition setting unit" of the present invention. The CPU 31 that performs the process of S45 is an example of a "storage control process" of the present invention. The CPU 31 that performs the process of S31 is an example of an "information determination process" of the present invention. The CPU 31 that performs the process of S51 is an example of a "time extraction process" of the present invention. The CPU 31 that performs the processes of S89 and S109 is an example of a "first determination process" of the present invention. The CPU 31 that performs the process of S33 is an example of a "first drive process," a "third drive process," a "fourth drive process," or a "fifth drive process" of the present invention. The CPU 31 performing the processes of S81 and S101 is an example of a "second drive process" of the present invention. The CPU 31 performing the processes of S85 and S105 is an example of a "change determination process" of the present invention. The process of S11 is an example of a "receiving process" of the present invention. The process of S19 is an example of a "condition setting process" of the present invention. The process of S23 is an example of a "processing execution process" of the present invention. The processes of S25 and S43 are an example of a "condition setting process" of the present invention. The process of S45 is an example of a "storage control process" of the present invention. The process of S31 is an example of an "information determination process" of the present invention. The process of S51 is an example of a "time extraction process" of the present invention. The processes of S89 and S109 are an example of a "first determination process" of the present invention. The process of S33 is an example of a "first drive process" of the present invention. [Explanation of symbols]

[0091] 1: Machine tool 22: Pump 30: Numerical control device 31: CPU 32:ROM 34: Non-volatile storage device Tend: First scheduled time Toff: 2nd Hour Ton: 1st hour Tprg: History end time Tref: Reference time Tsp:Specific time Tsr: End time Tsub: 2nd predetermined time W: Work material

Claims

1. A numerical control device for controlling a machine tool having a spray mechanism that sprays cutting fluid into a cover, a reception unit that receives a machining program for the machine tool; a condition setting unit that sets machining conditions when the machine tool is driven to machine a workpiece based on the machining program accepted by the accepting unit; a machining execution control unit that drives the machine tool and executes a machining operation to machine the workpiece under the machining conditions set by the condition setting unit based on the machining program accepted by the accepting unit, The processing execution control unit a measurement process of measuring a processing time during which the processing operation is executed by the processing execution control unit; a storage control process for storing, in a storage unit, reference processing information associated with identification information of the processing program, the processing conditions, and the processing time measured by the measurement process, when the processing operation by the processing execution control unit is completed; an information determination process for determining whether identical processing information, which is the reference processing information associated with the same identification information as the identification information of the received processing program and the same processing conditions as the set processing conditions, is stored in the storage unit when the processing program is received by the receiving unit and the processing conditions are set by the condition setting unit in a state where the reference processing information is stored in the storage unit by the storage control process; a time extraction process for extracting the processing time associated with the identical processing information when it is determined by the information determination process that the identical processing information is stored in the storage unit; a first determination process for determining whether a specific time that is a first predetermined time before the end of the processing operation has been reached based on the processing time extracted by the time extraction process; a first drive process for driving the ejection mechanism from the specific time until the end of the processing operation when it is determined that the specific time has been reached by the first determination process; A numerical control device comprising:

2. 2. The numerical control device according to claim 1, further comprising a second driving process for intermittently driving the ejection mechanism while the machining execution control unit is executing the machining operation.

3. a change determination process for determining whether or not the machining conditions have been set during execution of the machining operation by the machining execution control unit; a third driving process for stopping the intermittent driving of the jetting mechanism by the second driving process and continuously driving the jetting mechanism when it is determined by the change determination process that the processing conditions have been set; 3. The numerical control device according to claim 2, further comprising:

4. 2. The numerical control device according to claim 1, wherein the machining conditions include at least one of override, program skip, and dry run.

5. The time extraction process includes:

2. The numerical control device according to claim 1, characterized in that, when the information determination process determines that a plurality of pieces of the same machining information are stored in the memory unit, the smallest machining time among the machining times associated with each of the plurality of pieces of the same machining information is extracted.

6. The second driving process includes: repeatedly driving the ejection mechanism for a first time period, and stopping the ejection mechanism for a second time period after driving the ejection mechanism for the first time period; 3. The numerical control device according to claim 2, wherein the first predetermined time is shorter than the first time.

7. The second driving process includes: repeatedly driving the ejection mechanism for a first time period, and stopping the ejection mechanism for a second time period after driving the ejection mechanism for the first time period; 3. The numerical control device according to claim 2, wherein the first predetermined time is longer than the first time.

8. 2. The numerical control device according to claim 1, further comprising a fourth drive process for continuously driving the ejection mechanism from the start to the end of the machining operation when it is determined by the information determination process that the same machining information is not stored in the memory unit.

9. The second driving process includes: repeatedly driving the ejection mechanism for a first time period, and stopping the ejection mechanism for a second time period after driving the ejection mechanism for the first time period; a second determination process for determining whether a second predetermined time from the last stop of driving of the ejection mechanism before the end of the processing operation by the second driving process to the specific time is shorter than a predetermined reference time; a fifth driving process for continuously driving the jetting mechanism from a driving start time of the jetting mechanism to an end time of the processing operation in the last first time period when it is determined by the second determination process that the second predetermined time period is shorter than the reference time period; 3. The numerical control device according to claim 2, further comprising:

10. A control method for controlling a machine tool equipped with a spray mechanism that sprays cutting fluid into a cover, comprising: a receiving step of receiving a machining program for the machine tool; a condition setting step of setting machining conditions when the machine tool is driven to machine a workpiece based on the machining program received in the receiving step; a machining execution control step of driving the machine tool and executing a machining operation to machine the workpiece based on the machining program accepted by the accepting step under the machining conditions set by the condition setting step, The processing execution control step includes: a measuring step of measuring a machining time during which the machining operation is executed by the machining execution control step; a storage control step of storing, in a storage unit, reference processing information associated with identification information of the processing program, the processing conditions, and the processing time measured in the measurement step, when the processing operation by the processing execution control step is completed; an information determining step of determining whether identical processing information, which is the reference processing information associated with the same identification information as the identification information of the received processing program and the same processing conditions as the set processing conditions, is stored in the storage unit when the processing program is received in the receiving step and the processing conditions are set in the condition setting step with the reference processing information stored in the storage unit in the storage control step; a time extraction step of extracting the processing time associated with the identical processing information when it is determined by the information determination step that the identical processing information is stored in the storage unit; a first determination step of determining whether a specific time that is a first predetermined time before a time when the machining operation is to be completed has been reached based on the machining time extracted by the time extraction step; a first driving step of driving the ejection mechanism from the specific time until the end of the processing operation when it is determined in the first determining step that the specific time has been reached; A control method comprising:

11. A computer that controls a machine tool equipped with a spray mechanism that sprays cutting fluid into a cover a receiving step of receiving a machining program for the machine tool; a condition setting step of setting machining conditions when the machine tool is driven to machine a workpiece based on the machining program received in the receiving step; a machining execution control step of driving the machine tool and executing a machining operation to machine the workpiece based on the machining program accepted by the accepting step under the machining conditions set by the condition setting step, The processing execution control step includes: a measuring step of measuring a machining time during which the machining operation is executed by the machining execution control step; a storage control step of storing, in a storage unit, reference processing information associated with identification information of the processing program, the processing conditions, and the processing time measured in the measurement step, when the processing operation by the processing execution control step is completed; an information determining step of determining whether identical processing information, which is the reference processing information associated with the same identification information as the identification information of the received processing program and the same processing conditions as the set processing conditions, is stored in the storage unit when the processing program is received in the receiving step and the processing conditions are set in the condition setting step with the reference processing information stored in the storage unit in the storage control step; a time extraction step of extracting the processing time associated with the identical processing information when it is determined by the information determination step that the identical processing information is stored in the storage unit; a first determination step of determining whether a specific time that is a first predetermined time before a time when the machining operation is to be completed has been reached based on the machining time extracted by the time extraction step; a first driving step of driving the ejection mechanism from the specific time until the end of the processing operation when it is determined in the first determining step that the specific time has been reached; A control program for executing the above.

12. A computer that controls a machine tool equipped with a spray mechanism that sprays cutting fluid into a cover a receiving step of receiving a machining program for the machine tool; a condition setting step of setting machining conditions when the machine tool is driven to machine a workpiece based on the machining program received in the receiving step; a machining execution control step of driving the machine tool and executing a machining operation to machine the workpiece based on the machining program accepted by the accepting step under the machining conditions set by the condition setting step, The processing execution control step includes: a measuring step of measuring a machining time during which the machining operation is executed by the machining execution control step; a storage control step of storing, in a storage unit, reference processing information associated with identification information of the processing program, the processing conditions, and the processing time measured in the measurement step, when the processing operation by the processing execution control step is completed; an information determining step of determining whether identical processing information, which is the reference processing information associated with the same identification information as the identification information of the received processing program and the same processing conditions as the set processing conditions, is stored in the storage unit when the processing program is received in the receiving step and the processing conditions are set in the condition setting step with the reference processing information stored in the storage unit in the storage control step; a time extraction step of extracting the processing time associated with the identical processing information when it is determined by the information determination step that the identical processing information is stored in the storage unit; a first determination step of determining whether a specific time that is a first predetermined time before a time when the machining operation is to be completed has been reached based on the machining time extracted by the time extraction step; a first driving step of driving the ejection mechanism from the specific time until the end of the processing operation when it is determined in the first determining step that the specific time has been reached; A storage medium that stores a control program for executing the above.

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