Machine tool and method of cleaning machining chamber interior of machine tool

Abstract

A machine tool includes: image pickup means for picking up an image of a machining chamber interior of a machine tool that machines a workpiece; determination means for determining, based on the image obtained by image pickup, an accumulation state of chips of the workpiece in the machining chamber interior; a first nozzle that discharges a coolant to the machining chamber interior; a pump that supplies the coolant to the first nozzle; and control means for controlling an output of the pump based on the accumulation state of the chips.

Description

MACHINE TOOL AND METHOD OF CLEANING MACHINING CHAMBER INTERIOR OF MACHINE TOOL

[0001] The present disclosure relates to a machine tool and a method of cleaning a machining chamber interior of a machine tool.

[0002] For example, Japanese Patent Laying-Open No. 2021-102235 (PTL 1) discloses a machine tool including an image pickup unit, a chip recognition unit that automatically recognizes chips based on an image picked up by the image pickup unit and detects a position at which the chips are accumulated, and a coolant discharge unit that, upon input of a detection signal from the chip recognition unit, discharges a coolant along a predetermined path toward the position at which the chips are accumulated.

[0003] [PTL 1] Japanese Patent Laying-Open No. 2021-102235

[0004] The machine tool of PTL 1 described above recognizes the position at which the chips are accumulated, but it is not configured to remove the chips with consideration given to the accumulation state at this position.

[0005] The present disclosure provides a machine tool and a method of cleaning a machining chamber interior of a machine tool that are capable of cleaning a machining chamber interior with consideration given to an accumulation state of chips in a machining chamber interior.

[0006] According to an aspect of the present disclosure, a machine tool includes: image pickup means for picking up an image of a machining chamber interior of a machine tool that machines a workpiece; determination means for determining an accumulation state of chips of the workpiece in the machining chamber interior based the image obtained by image pickup; a first nozzle that discharges a coolant to the machining chamber interior; a pump that supplies the coolant to the first nozzle; and control means for controlling an output of the pump based on the accumulation state of the chips.

[0007] With the configuration described above, the coolant is discharged from the first nozzle at a pump output based on the accumulation state of the chips in the machining chamber interior. With such a configuration, thus, the machining chamber interior can be cleaned with consideration given to the accumulation state of the chips in the machining chamber interior.

[0008] Preferably, the control means sets the output of the pump to a first output when the accumulation state is at a first level. The control means sets the output of the pump to a second output, which is higher than the first output, when the accumulation state is at a second level at which the chips are accumulated more than at the first level.

[0009] With the configuration described above, the pump has a higher output as the level of the accumulation state is higher. Thus, when the accumulation state of the chips in the machining chamber interior is at the second level, the chips can be removed with a higher probability than when the output of the pump is set to the same output as that of the first level.

[0010] Preferably, the first nozzle discharges the coolant toward a first region of a plurality of regions of the machining chamber interior. The determination means determines the accumulation state in the first region. The control means sets the output of the pump to the first output when the accumulation state in the first region is at the first level. The control means sets the output of the pump to the second output when the accumulation state in the first region is at the second level.

[0011] With the configuration described above, the first region can be cleaned with consideration given to the accumulation state of the chips in the first region. Further, when the accumulation state of the chips in the first region is at the second level, the chips can be removed with a higher probability than when the output of the pump is set to the same output as that of the first level.

[0012] Preferably, the machine tool further includes: a second nozzle that is supplied with the coolant from the pump and discharges the coolant toward the second region of the plurality of regions; a first electromagnetic valve that is caused by the control means to form or block a first flow path of the coolant from the pump to the first nozzle; and a second electromagnetic valve that is caused by the control means to form or block a second flow path of the coolant from the pump to the second nozzle. The determination means further determines the accumulation state of the chips in the second region. When the accumulation state in the first region is at the second level and the accumulation state in the second region is at the first level, the control means sets the output of the pump to the second output and blocks only the second flow path of the first flow path and the second flow path over a first period.

[0013] With the configuration described above, the coolant can be discharged from only the first nozzle of the first and second nozzles in the first period. Thus, the coolant of higher pressure or higher flow rate can be discharged to the first region than when the coolant is discharged at the same timing from both the first nozzle and the second nozzle. Thus, the chips in the first region of the second level can be removed with a higher probability.

[0014] Preferably, when the accumulation state in the first region is at the second level and the accumulation state in the second region is at the first level, the control means switches the output of the pump from the second output to the first output after a lapse of the first period and blocks only the first flow path of the first flow path and the second flow path over a second period.

[0015] With the configuration described above, the coolant can be discharged from only the second nozzle of the first and second nozzles in the second period. Thus, the chips in the second region of the first level can be removed with a coolant of lower pressure than in the first region. This can reduce power consumption more than when the second region is cleaned with a coolant of higher pressure or higher flow rate.

[0016] Preferably, the second output is an output of 90% or more of a maximum output of the pump.

[0017] With the configuration described above, a coolant of higher pressure or higher flow rate can be discharged from the first nozzle.

[0018] According to another aspect of the present disclosure, a method of cleaning a machining chamber interior of a machine tool includes: picking up an image of a machining chamber interior of a machine tool that machines a workpiece; and determining an accumulation state of chips of the workpiece in the machining chamber interior based on the image obtained by image pickup. In the machining chamber interior, the coolant is discharged from a nozzle by a pump. The method of cleaning a machining chamber interior of a machine tool further includes controlling an output of the pump based on the accumulation state of the chips.

[0019] According to the method described above, the coolant is charged from the nozzle at a pump output based on the accumulation state of chips in the machining chamber interior. Therefore, the configuration described above enables cleaning of the machining chamber interior with consideration given to the accumulation state of chips in the machining chamber interior.

[0020] According to the present disclosure, the machining chamber interior can be cleaned with consideration given to the accumulation state of chips in the machining chamber interior.

[0021] Fig. 1 is a perspective view of a machine tool.Fig. 2 is a top view of a machining chamber interior of the machine tool.Fig. 3 is a diagram illustrating a device configuration for removing chips of a workpiece.Fig. 4 is a diagram showing a plurality of regions of the machining chamber interior.Fig. 5 is a diagram illustrating regions of the plurality of regions shown in Fig. 4 which are cleaned respectively by nozzles.Fig. 6 is a diagram illustrating an example accumulation state of chips.Fig. 7 is a diagram illustrating level determination of regions in Fig. 6.Fig. 8 is a diagram showing another example accumulation state of chips.Fig. 9 is a diagram illustrating level determination of regions in Fig. 8.Fig. 10 is a diagram showing still another example accumulation state of chips.Fig. 11 is a diagram illustrating level determination of regions in the case of Fig. 10.Fig. 12 is a diagram showing an accumulation level of chips in each region.Fig. 13 is a diagram illustrating a way of cleaning when level determination of Fig. 12 has been performed.Fig. 14 is a diagram showing an accumulation level of chips in each region.Fig. 15 is a diagram illustrating a way of cleaning when level determination of Fig. 14 has been performed.Fig. 16 is a block diagram illustrating a functional configuration of the machine tool.Fig. 17 is a flowchart illustrating a flow of a process performed in the machine tool.Fig. 18 is a flowchart showing details of processing of step S2 in Fig. 17.

[0022] Each embodiment according to the present invention will be described below with reference to the drawings. It will be understood that like parts and components are designated by like reference signs in the following description. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[0023] <A: Schematic Configuration of Machine Tool> Fig. 1 is a perspective view of a machine tool in the present embodiment. Fig. 2 is a top view of a machining chamber interior (machining region) of the machine tool of Fig. 1.

[0024] Referring to Figs. 1 and 2, a machine tool 100 is a machining center that machines a workpiece by bringing a rotating tool 90 into contact with the workpiece. More particularly, machine tool 100 is a machining center in which a rotation center axis 101 of the tool extends horizontally. Specifically, machine tool 100 is a 5-axis machine of swivel rotary table type. However, machine tool 100 is not limited to the 5-axis machine. Machine tool 100 is a numerically-controlled (NC) machine tool in which various operations for machining the workpiece are automated by computer-aided numerical control.

[0025] The figures show a Z axis, which is parallel to the horizontal direction and parallel to rotation center axis 101 of tool 90, an X axis, which is parallel to the horizontal direction and orthogonal to rotation center axis 101 of tool 90, and a Y axis, which is parallel to the upward-downward direction.

[0026] Machine tool 100 has a tool spindle 21. Tool spindle 21 is rotatable about rotation center axis 101 parallel to the Z axis as it is driven by a motor. Tool spindle 21 has a built-in clamping mechanism for detachably holding a tool. Tool spindle 21 rotates tool 90, such as a drill, a reamer, or a milling cutter, about rotation center axis 101. Tool spindle 21 is movable in the X-axis direction and the Y-axis direction by various feed mechanisms, guide mechanisms, servo motors, and the like.

[0027] Machine tool 100 further includes a table 41. Table 41 is a device for fixing a workpiece. A pallet 42 is detachably attached to table 41. Table 41 is movable in the Z-axis direction by various feed mechanisms, guide mechanisms, servo motors, and the like. Table 41 is rotatable about an A axis (an axis rotating about the X axis, not shown). A placement portion of table 41, on which pallet 42 is mounted, is rotatable about a C axis (not shown).

[0028] Machine tool 100 further includes an automatic pallet changer (APC) 50. Automatic pallet changer 50 changes pallet 42 between a machining chamber interior 110 and a setup station 120. Specifically, automatic pallet changer 50 has an APC arm 52. Pallet 42 is changed by APC arm 52.

[0029] Machining chamber interior 110 is the space in which a workpiece is machined. Tool spindle 21 and table 41 are disposed in machining chamber interior 110. Machine tool 100 further includes an automatic tool changer (not shown). The automatic tool changer changes tool 90 attached to tool spindle 21.

[0030] Setup station 120 is the space in which a workpiece is attached to pallet 42. A pallet placement table (not shown) on which pallet 42 is placed is provided in setup station 120.

[0031] Machine tool 100 further includes an operation panel 81. Operation panel 81 is a general-purpose computer. Operation panel 81 has an upper panel 82 and a lower panel 83. Upper panel 82 includes a touch screen that displays manuals, various application screens, or the like and that is operated in use of an application. Lower panel 83 includes a touch screen that displays the operating status of machine tool 100 or the machining status of the workpiece and that is operated for operating machine tool 100, and an operating portion, such as a button or a switch, operated for operating machine tool 100.

[0032] Machine tool 100 further includes a cover body 31. Cover body 31 partitions machining chamber interior 110 and forms the exterior appearance of machine tool 100. Machining chamber interior 110 is hermitically sealed by cover body 31 to prevent foreign matter, such as chips due to machining of a workpiece and a coolant, from leaking out of machining chamber interior 110.

[0033] Cover body 31 includes covers 32, 36, 37, 38, 65, 66, telescopic covers 34, 62, 63, a door 35, an ATC shutter 33, a protective cover 61, and a ceiling cover 39. Covers 32, 38 and telescopic covers 34, 63 are provided upright. Cover 32 and ATC shutter 33 are disposed while facing each other in the X-axis direction. Ceiling cover 39 is disposed on the ceiling of machining chamber interior 110.

[0034] Door 35 is disposed in an opening provided in cover 32. Door 35 is slidable so as to open and close the opening provided in cover 32. ATC shutter 33 is disposed in an opening provided in cover 38. ATC shutter 33 is slidable so as to open and close the opening provided in cover 38. The automatic tool changer is disposed opposite to machining chamber interior 110 with ATC shutter 33 in between.

[0035] Telescopic cover 34 is configured to be deformable along with movement of tool spindle 21 in the X-axis direction and the Y-axis direction. Tool spindle 21 projects from telescopic cover 34 in the Z-axis direction.

[0036] Covers 65, 66 are disposed on the cover 38 side. Cover 66 is located above cover 65. Cover 65 is contiguous to cover 66. Cover 65 and cover 66 are inclined downward toward a conveyor 46, which will be described later. Cover 65 extends diagonally downward from the lower end of cover 66 toward conveyor 46. Cover 65 and cover 66 form a stepped slope. The length of cover 65 in the Z-axis direction is greater than the length of cover 66 in the Z-axis direction. Cover 65 has a first part 651 on the tool spindle 21 side and a second part 652 opposite to first part 651. Second part 652 is a part located below cover 66.

[0037] Covers 36, 37 are disposed on the floor of machining chamber interior 110. Cover 36 and cover 37 are spaced apart from each other in the X-axis direction. Cover 36 extends diagonally downward from the lower end of cover 32 toward cover 37. Cover 37 extends diagonally downward from the lower end of cover 38 toward cover 36. Cover 37 is adjacent to cover 65 and cover 66 in the Z-axis direction. Cover 37 is adjacent to automatic pallet changer 50. In the Z-axis direction, cover 37 is more distant from tool spindle 21 than covers 65, 66 are from tool spindle 21.

[0038] Machine tool 100 further includes conveyor 46. Conveyor 46 is provided between telescopic cover 62 and cover 65 in the X-axis direction. Conveyor 46 extends in the Z-axis direction. Conveyor 46 transports chips, which are generated due to machining of a workpiece, out of machining chamber interior 110.

[0039] Telescopic covers 62, 63 are configured to be deformable along with movement of table 41 in the Z-axis direction. Telescopic cover 62 is disposed on the floor of machining chamber interior 110. Telescopic cover 62 is disposed in the X-axis direction between cover 36 and conveyor 46. Telescopic cover 62 has a first part 621 on the tool spindle 21 side and a second part 622 opposite to first part 621.

[0040] Protective cover 61 protects table 41 from above. Protective cover 61 is positioned in the Z-axis direction between first part 621 and second part 622.

[0041] Fig. 3 is a diagram illustrating a device configuration for removing chips of a workpiece.

[0042] As shown in Fig. 3, machine tool 100 further includes a camera 210, a cleaning device 300, a controller 500, an oil conditioner 800, and a valve 850.

[0043] Cleaning device 300 cleans machining chamber interior 110 with a coolant. Cleaning device 300 includes nozzles 301 to 309, valves 351 to 359, a coolant tank 371, and a pump 372.

[0044] Camera 210 picks up an image of machining chamber interior 110. Camera 210 periodically transmits image data of machining chamber interior 110 to controller 500. Camera 210 may be a charge coupled device (CCD) camera or another type of camera. Camera 210 is provided to be capable of picking up an image of machining chamber interior 110. Camera 210 is provided in machining chamber interior 110. In this example, camera 210 is attached to ceiling cover 39. Camera 210 may be attached to, for example, cover 32 or cover 38, not limited to ceiling cover 39. One camera may be provided, or a plurality of cameras may be provided.

[0045] Coolant tank 371 is formed of a box body capable of storing a coolant. Coolant tank 371 is placed on the floor surface of a factory or the like where machine tool 100 is provided. A coolant is stored in coolant tank 371. Pump 372 is provided in coolant tank 371. As pump 372 is driven, pump 372 delivers the coolant stored in coolant tank 371 to nozzles 301 to 309 via valves 351 to 359. Pump 372 supplies the coolant to oil conditioner 800 via valve 850.

[0046] Controller 500 obtains image data from camera 210. Controller 500 controls the operation of pump 372. Controller 500 includes a processor and a memory storing programs and various data. Controller 500 controls the operations of valves 351 to 359 and 850. Details of control by controller 500 will be described later.

[0047] Valves 351 to 359 and 850 are electromagnetic valves. In this example, valves 351 to 359 and 850 are solenoid valves. Valves 351 to 359 and 850 operate in response to commands from controller 500. Valves 351 to 359 and 850 are either opened or closed in response to commands from controller 500. Valves 351 to 359 and 850 can form or block a coolant flow path.

[0048] Nozzle 301 is attached to ceiling cover 39. Nozzle 301 can change the direction of discharge (release) of the coolant. In nozzle 301, the direction of discharge of the coolant is controlled by controller 500. Nozzle 301 is connected to pump 372 via valve 351. When valve 351 is open, the coolant is supplied to nozzle 301 as pump 372 is driven. This causes the coolant to be discharged from nozzle 301. When valve 351 is closed, the coolant is not supplied to nozzle 301 even if pump 372 is driven. Supply is stopped in this manner also for the other nozzles 302 to 309 described later.

[0049] Nozzle 302 is attached to ceiling cover 39, similarly to nozzle 301. Similarly to nozzle 301, nozzle 302 can change the direction of discharge of the coolant. In nozzle 302, the direction of discharge of the coolant is controlled by controller 500. Nozzle 302 is connected to pump 372 via valve 352. When valve 352 is open, the coolant is supplied to nozzle 302 as pump 372 is driven. This causes the coolant to be discharged from nozzle 302.

[0050] Nozzle 303 is attached to ceiling cover 39, similarly to nozzles 301, 302. Nozzle 303 has a plurality of discharge ports arranged at predetermined intervals in the Z-axis direction. Nozzle 303 is connected to pump 372 via valve 353. When valve 353 is open, the coolant is supplied to nozzle 303 as pump 372 is driven. This causes the coolant to be discharged from each discharge port of nozzle 303.

[0051] Nozzle 304 is attached to ceiling cover 39. In nozzle 304, the direction of discharge of the coolant is fixed. Nozzle 304 is connected to pump 372 via valve 354. When valve 354 is open, the coolant is supplied to nozzle 304 as pump 372 is driven. This causes the coolant to be discharged from nozzle 304.

[0052] Nozzle 305 is attached to ceiling cover 39, similarly to nozzle 304. In nozzle 305, the direction of discharge of the coolant is fixed, similarly to nozzle 304. Nozzle 305 is connected to pump 372 via valve 355. When valve 355 is open, the coolant is supplied to nozzle 305 as pump 372 is driven. This causes the coolant to be discharged from nozzle 305.

[0053] Nozzle 306 is provided to tool spindle 21. Nozzle 306 includes a first discharge portion 306a and a second discharge portion 306b located below first discharge portion 306a. First discharge portion 306a is provided at a position higher than that of tool 90 attached to the tip of tool spindle 21. Second discharge portion 306b is provided at a position lower than that of tool 90. Nozzle 306 is connected to pump 372 via valve 356. When valve 356 is open, the coolant is supplied to nozzle 306 as pump 372 is driven. This causes the coolant to be discharged from first and second discharge portions 306a, 306b of nozzle 306. Specifically, first discharge portion 306a discharges the coolant toward tool 90 (obliquely downward). Second discharge portion 306b discharges the coolant toward tool 90 (obliquely upward).

[0054] Nozzle 307 is disposed on the setup station 120 side in machining chamber interior 110. Nozzle 307 is provided on the cover 37 side. Nozzle 307 is connected to pump 372 via valve 357. When valve 357 is open, the coolant is supplied to nozzle 307 as pump 372 is driven. This causes the coolant to be discharged from nozzle 307.

[0055] Nozzle 308 is disposed on the cover 32 side in machining chamber interior 110. Nozzle 308 is provided below cover 36. Nozzle 308 has a plurality of discharge ports arranged at predetermined intervals in the Z-axis direction. Nozzle 308 is connected to pump 372 via valve 358. When valve 358 is open, the coolant is supplied to nozzle 308 as pump 372 is driven. This causes the coolant to be discharged from nozzle 308. Specifically, nozzle 308 discharges the coolant toward second part 622 of telescopic cover 62.

[0056] Nozzle 309 is disposed on the door 35 side in machining chamber interior 110. Similarly to nozzle 308, nozzle 309 is provided below cover 36. Nozzle 309 is provided on the side close to telescopic cover 34 relative to nozzle 308. Similarly to nozzle 308, nozzle 309 has a plurality of discharge ports arranged at predetermined intervals in the Z-axis direction. Nozzle 309 is connected to pump 372 via valve 359. When valve 359 is open, the coolant is supplied to nozzle 309 as pump 372 is driven. This causes the coolant to be discharged from nozzle 309. Specifically, nozzle 309 discharges the coolant toward first part 621 of telescopic cover 62.

[0057] <B: Relationship between Region of Machining Chamber Interior and Nozzle> Fig. 4 is a diagram showing a plurality of regions of machining chamber interior 110. Fig. 5 is a diagram illustrating regions that are cleaned respectively by nozzles 301 to 309 among the plurality of regions shown in Fig. 4.

[0058] Referring to Figs. 4 and 2, a region R1 is a region of a surface (upper surface) of cover 36. A region R2 is a region of a surface of second part 622 of telescopic cover 62. A region R3 is a region of a surface (upper surface) of protective cover 61. A region R4 is a region of a surface of first part 621 of telescopic cover 62.

[0059] A region R5 is a region of a surface of APC arm 52. A region R6 is a region of a surface of cover 37. A region R7 is a combined region of a region of a surface of cover 66 and a region of a surface of second part 652 of cover 65.

[0060] A region R8 is a region of table 41. Region R8 includes a region on the upper surface side of table 41. When pallet 42 is placed on table 41, region R8 includes a surface of pallet 42.

[0061] A region R9 is a combined region of a surface of cover 38, a surface of ATC shutter 33, a surface of telescopic cover 63, and a surface of first part 651 of cover 65. A region R10 is a region of a surface of telescopic cover 34. A region R11 is a region of an upper surface of tool spindle 21. A region R12 is a region of tool 90.

[0062] Referring to Figs. 3 to 5, as shown in data D1, region R1 is cleaned with the coolant discharged from nozzle 301. Region R2 is cleaned with the coolant discharged from nozzle 308. Region R3 is cleaned with the coolant discharged from nozzle 301 and / or nozzle 302. Region R4 is cleaned with the coolant discharged from nozzle 302 and / or nozzle 309. Region R5 is cleaned with the coolant discharged from nozzle 301 and / or nozzle 302. Region R6 is cleaned with the coolant discharged from nozzle 307.

[0063] Region R7 is cleaned with the coolant discharged from nozzle 303. Region R8 is cleaned with the coolant discharged from nozzles 301, 302. Region R9 is cleaned with the coolant discharged from nozzle 303. Region R10 is cleaned with the coolant discharged from nozzle 305. Region R11 is cleaned with the coolant discharged from nozzle 304. Region R12 is cleaned with the coolant discharged from nozzle 306.

[0064] Controller 500 holds data showing the relationship between nozzles and regions, as shown in Fig. 5.

[0065] <C: Determination of Accumulation State of Chips> Controller 500 determines the accumulation state of chips in each of regions R1 to R12. Specifically, controller 500 determines the accumulation state of chips of a workpiece in machining chamber interior 110 for each of regions R1 to R12 based on an image obtained by image pickup with camera 210 and two determination criteria #1, #2 different from each other. Such determination processing is typically realized as the processor included in controller 500 executes a program stored in the memory.

[0066] Specifically, controller 500 determines the accumulation level of chips in each of regions R1 to R12. Controller 500 classifies the accumulation states of the respective chips in the plurality of regions R1 to R12 into levels by use of the two determination criteria #1, #2. In this example, controller 500 classifies the accumulation states into three levels.

[0067] Hereinafter, the accumulation levels are referred to as "level 0", "level 1", and "level 2" in ascending order. Level 0 indicates no chips or a small amount of chips. Level 1 indicates a normal amount (moderate amount, moderate degree) of chips. Level 2 indicates a large amount of chips.

[0068] For convenience of description, the following description focuses on region R2 of the plurality of regions R1 to R12. Detailed description will be given using three cases as examples.

[0069] (First Case) Fig. 6 is a diagram showing an example accumulation state of chips. Specifically, Fig. 6 shows a state in which chips are accumulated throughout region R2.

[0070] Controller 500 performs the following processing when determining the accumulation level of chips in region R2. As described above, controller 500 obtains image data from camera 210. Controller 500 divides the image of region R2 in the image based on the image data into a plurality of regions (hereinafter referred to as "element regions Ei"). Controller 500 obtains the accumulation state of chips in each element region Ei. In this example, as shown in Fig. 6, region R2 is divided into 72 element regions Ei. In this case, the value of i is a natural number of 1 or more and 72 or less.

[0071] Controller 500 classifies the accumulation states in element regions Ei into three levels, similarly to the three levels (levels 0 to 2) described above. The first level (hereinafter also referred to as "level L") refers to a state in which there are no chips or only a small amount of chips. The second level (hereinafter also referred to as "level M") refers to a state in which there are a moderate amount of chips. The third level (hereinafter also referred to as "level H") refers to a state in which there are a large amount of chips.

[0072] In the example of Fig. 6, there are 37 regions of level L, 32 regions of level M, and three regions of level H among 72 element regions Ei. In Fig. 6, the spacing between the hatching lines is narrower in order of level L, level M, and level H. The same applies to Figs. 8 and 10 described later.

[0073] Fig. 7 is a diagram illustrating the level determination of region R2 in this case. Referring to Fig. 7, controller 500 assigns a weight to the number of element regions Ei at each level. In this example, controller 500 assigns weights of 0 points, 3 points, and 8 points to element regions Ei of level L, element regions Ei of level M, and element regions Ei of level H, respectively.

[0074] In the example of Fig. 6, there are 37 element regions Ei of level L. However, since the weighting point for these 37 element regions Ei is 0 points, controller 500 does not assign a score. Since there are 32 element regions Ei of level M, controller 500 assigns a weight of 3 points to these 32 element regions Ei, yielding 96 points (3 points × 32 pieces). Since there are three element regions Ei of level H, controller 500 assigns a weight of 8 points to these three element regions Ei, yielding 24 points (8 points × 3 pieces).

[0075] Controller 500 calculates the total score of the 72 element regions Ei obtained by the above-described weighting. In this example, controller 500 calculates the sum of 0 points, 96 points, and 24 points, yielding 120 points as a total score.

[0076] Subsequently, controller 500 determines the accumulation level in region R2 by use of two determination criteria #1, #2. Determination criterion #1 is a criterion for determining whether chips are accumulated throughout region R2. Determination criterion #2 is a criterion for determining whether chips are accumulated locally in region R2.

[0077] Specifically, determination criterion #1 is a criterion for determining that chips are accumulated throughout region R2 when score #1, represented by the following equation (1), is greater than or equal to the threshold for determination criterion #1 (hereinafter also referred to as a "first threshold").

[0078] Score #1 = Total Score / (Number of Element Regions Ei in Region R2 × Score of Highest Weighting) × 100 ... (1)

[0079] In this example, since the total score is 120 points, the number of element regions Ei in region R2 is 72, and the highest weighting score is 8 points, controller 500 obtains 20.8 (= 120 points / (8 points × 72 pieces) × 100) as score #1. Since score #1 is greater than or equal to the first threshold (15 in this example), controller 500 determines that chips are accumulated throughout region R2.

[0080] Determination criterion #2 is a criterion for determining that chips are accumulated locally in region R2 when score #2, represented by the following equation (2), is greater than or equal to the threshold for determination criterion #2 (hereinafter also referred to as a "second threshold").

[0081] Score #2 = Score of Level H Obtained by Weighting / (Number of Element Regions Ei in Region R2 × Score of Highest Weighting) × 100 ... (2)

[0082] In this example, since the score of level H obtained by weighting is 24 points, the number of element regions Ei in region R2 is 72, and the highest weighting score is 8 points, controller 500 obtains 4.2 (= 24 points / (8 points × 72 pieces) × 100) as score #2. Since score #2 is less than the second threshold (10 in this example), controller 500 determines that chips are not accumulated locally in region R2.

[0083] Controller 500 determines the accumulation level of chips in region R2 by use of the above-described determination results based on the two criteria #1, #2. A specific determination method is as follows.

[0084] When determining that chips are accumulated throughout region R2 and chips are accumulated locally in region R2, controller 500 determines the accumulation level in region R2 to be level 2.

[0085] When determining that chips are accumulated throughout region R2 and chips are not accumulated locally in region R2, controller 500 determines the accumulation level in region R2 to be level 1. In contrast, when determining that chips are not accumulated throughout region R2 and chips are accumulated locally in region R2, controller 500 also determines the accumulation level in region R2 to be level 1.

[0086] When determining that chips are not accumulated throughout region R2 and chips are not accumulated locally in region R2, controller 500 determines the accumulation level in region R2 to be level 0.

[0087] In this case, since controller 500 determines that chips are accumulated throughout region R2 and chips are not accumulated locally in region R2, it determines the accumulation level in region R2 to be level 1.

[0088] (Second Case) Fig. 8 is a diagram showing another example accumulation state of chips. Specifically, Fig. 8 shows a state in which chips are accumulated locally in region R2. Fig. 9 is a diagram illustrating the level determination of region R2 in this case.

[0089] Referring to Fig. 8, there are 61 regions of level L, three regions of level M, and eight regions of level H among 72 element regions Ei.

[0090] In the example of Fig. 8, though there are 61 element regions Ei of level L, the weighting point for these 61 element regions Ei is 0 points, and thus, controller 500 does not assign a score. Since there are three element regions Ei of level M, controller 500 assigns a weight of 3 points to these three element regions Ei, yielding 9 points (= 3 points × 3 pieces). Since there are eight element regions Ei of level H, controller 500 assigns a weight of 8 points to these eight element regions Ei, yielding 64 points (= 8 points × 8 pieces).

[0091] Controller 500 calculates the total score of the 72 element regions Ei obtained by weighting. In this example, controller 500 calculates the sum of 0 points, 9 points, and 64 points, yielding 73 points as a total score. Subsequently, controller 500 determines the accumulation level in region R2 by use of the two determination criteria #1, #2.

[0092] For determination criterion #1, since the total score is 73 points, the number of element regions Ei in region R2 is 72, and the highest weighting score is 8 points, controller 500 obtains 12.7 (= 73 points / (8 points × 72 pieces) × 100) as score #1 based on the above-described equation (1). Since score #1 is less than the first threshold (15 in this example), controller 500 determines that chips are not accumulated throughout region R2.

[0093] For determination criterion #2, since the score of level H obtained by weighting is 64 points, the number of element regions Ei in region R2 is 72, and the highest weighting score is 8 points, controller 500 calculates 11.1 (= 64 points / (8 points × 72 pieces) × 100) as score #2 based on the above-described equation (2). Since score #2 is greater than or equal to the second threshold (10 in this example), controller 500 determines that chips are accumulated locally in region R2.

[0094] Thus, in this case, since controller 500 determines that chips are not accumulated throughout region R2 and chips are accumulated locally in region R2, it determines the accumulation level in region R2 to be level 1.

[0095] (Third Case) Fig. 10 is a diagram showing still another example accumulation state of chips. Specifically, Fig. 10 shows a state in which chips are accumulated throughout and locally in region R2. Fig. 11 is a diagram illustrating the level determination of region R2 in this case.

[0096] Referring to Fig. 10, there are 33 regions of level L, 28 regions of level M, and 11 regions of level H among 72 element regions Ei.

[0097] In the example of Fig. 10, though there are 33 element regions Ei of level L, the weighting point for these 33 element regions Ei is 0 points. Thus, controller 500 does not assign a score. Since there are 28 element regions Ei of level M, controller 500 assigns a weight of 3 points to these 28 element regions Ei, yielding 84 points (= 3 points × 28 pieces). Since there are 11 element regions Ei of level H, controller 500 assigns a weight of 8 points to these 11 element regions Ei, yielding 88 points (8 points × 11 pieces).

[0098] Controller 500 calculates the total score of the 72 element regions Ei obtained by weighting. In this example, controller 500 calculates the sum of 0 points, 84 points, and 88 points, yielding 172 points as a total score. Subsequently, controller 500 determines the accumulation level in region R2 by use of the two determination criteria #1, #2.

[0099] For determination criterion #1, since the total score is 172 points, the number of element regions Ei in region R2 is 72, and the highest weighting score is 8 points, controller 500 obtains 29.9 (= 172 points / (8 points × 72 pieces) × 100) as score #1 based on the above-described equation (1). Since score #1 is greater than or equal to the first threshold (15 in this example), controller 500 determines that chips are accumulated throughout region R2.

[0100] For determination criterion #2, since the score of level H obtained by weighting is 88 points, the number of element regions Ei in region R2 is 72, and the highest weighting score is 8 points, controller 500 obtains 15.3 (= 88 points / (8 points × 72 pieces) × 100) as score #2. Since score #2 is greater than or equal to the second threshold (10 in this example), controller 500 determines that chips are accumulated locally in region R2.

[0101] Thus, in this case, since controller 500 determines that chips are accumulated throughout region R2 and chips are accumulated locally in region R2, it determines the accumulation level in region R2 to be level 2.

[0102] The three cases described above are merely examples, and the accumulation state of chips in region R2 can vary. Further, though description has been given using region R2 as an example, controller 500 also performs, for each of the other regions R1 and R3 to R12, the processing described based on region R2. In other words, controller 500 determines the accumulation level of chips for each of 12 regions R1 to R12.

[0103] <D: Cleaning> Controller 500 switches whether or not to perform cleaning, in accordance with the accumulation level of chips in each of regions R1 to R12. Further, in cleaning, controller 500 changes the pressure of the coolant in accordance with this accumulation level. Specifically, this is as follows.

[0104] For a region determined to be at level 0 among regions R1 to R12, controller 500 does not cause the coolant to be discharged from the nozzle corresponding to this region. For a region determined to be at level 1 or level 2 among regions R1 to R12, controller 500 causes the coolant to be discharged from the nozzle corresponding to this region.

[0105] Controller 500 discharges the coolant of higher pressure or higher flow rate to a region determined to be at level 2 than to a region determined to be at level 1 among regions R1 to R12. During this discharge, controller 500 causes the coolant to be discharged from only a nozzle for the region determined to be at level 2 among the plurality of nozzles 301 to 309 in order to discharge the coolant of higher pressure or higher flow rate. Such control of the discharge pressure of the coolant is achieved by control of an output of pump 372 and switch control of valves 351 to 359.

[0106] Fig. 12 is a diagram showing the accumulation level of chips in each of regions R1 to R12 in one aspect. As shown in Fig. 12, controller 500 temporarily stores data D2 indicating the accumulation level determined for each of regions R1 to R12 in the memory.

[0107] In this example, the accumulation levels in regions R1, R2, R6, R7, and R10 are level 0. The accumulation levels in regions R3, R5, R8, and R9 are level 1. The accumulation level in region R4 is level 2.

[0108] Fig. 13 is a diagram illustrating a way of cleaning when level determination shown in data D2 of Fig. 12 has been performed. In this example, controller 500 causes cleaning device 300 to preferentially clean region of level 2. Specifically, in this example, controller 500 causes cleaning device 300 to clean region R4 for 10 seconds, from 0 seconds to 10 seconds, with the output of pump 372 set to 95% (95% of the maximum output). Specifically, controller 500 causes cleaning device 300 to clean region R4 by causing the coolant to be discharged from nozzle 309 with only valve 359 open among valves 351 to 359.

[0109] Subsequently, controller 500 causes cleaning device 300 to continuously clean region R4 for 20 seconds, from 10 seconds to 30 seconds, with the output of pump 372 maintained at 95%. Specifically, controller 500 causes cleaning device 300 to clean region R4 by causing the coolant to be discharged from nozzle 302 with only valve 352 open among valves 351 to 359.

[0110] Subsequently, controller 500 causes cleaning device 300 to clean region R9 for 10 seconds, from 30 seconds to 40 seconds, with the output of pump 372 changed from 95% to 80%. Specifically, controller 500 causes cleaning device 300 to clean region R9 by causing the coolant to be discharged from nozzle 303 with only valve 353 open among valves 351 to 359.

[0111] Subsequently, controller 500 causes cleaning device 300 to clean region R8 for 20 seconds, from 40 seconds to 60 seconds, with the output of pump 372 maintained at 80%. Specifically, controller 500 causes cleaning device 300 to clean region R8 by causing the coolant to be discharged from nozzles 301, 302 with only valves 351, 352 open among valves 351 to 359. In this time period, cleaning device 300 cleans one region R8 by use of two nozzles 301, 302.

[0112] Finally, controller 500 causes cleaning device 300 to simultaneously clean region R3 and region R5 for 15 seconds, from 60 seconds to 75 seconds, with the output of pump 372 maintained at 80%. Specifically, controller 500 controls the directions of discharge of the coolant of nozzles 301, 302. Further, controller 500 causes cleaning device 300 to clean region R3 by causing the coolant to be discharged from nozzle 301 with only valves 351, 352 open among valves 351 to 359, and causes cleaning device 300 to clean region R5 by causing the coolant to be discharged from nozzle 302. In this time period, cleaning device 300 cleans two regions R3, R5 by use of two nozzles 301, 302. Consequently, the cleaning time can be reduced more than when two regions R3, R5 are cleaned individually.

[0113] Subsequently, controller 500 changes the output of pump 372 from 80% to 65% and continuously supplies the coolant to oil conditioner 800 via valve 850. An output of 80% is an example of the "first output" of the present disclosure. An output of 95% is an example of the "second output" of the present disclosure.

[0114] Fig. 14 is a diagram showing the accumulation level of chips in each of regions R1 to R12 in an aspect different from that of Fig. 12. As shown in Fig. 14, controller 500 temporarily stores data D3 indicating the accumulation level determined for each of regions R1 to R12 in the memory.

[0115] In this example, the accumulation levels of regions R1, R2, R6, R7, and R10 are level 0. The accumulation levels of regions R3, R4, R5, R8, and R9 are level 1. There are no regions in which the accumulation level is level 2.

[0116] Fig. 15 is a diagram illustrating a way of cleaning when level determination shown in data D3 of Fig. 14 has been performed. As shown in Fig. 15, controller 500 causes cleaning device 300 to simultaneously clean region R4 and region R9 for 10 seconds, from 00 seconds to 10 seconds, with the output of pump 372 set to 80%. Specifically, controller 500 causes cleaning device 300 to clean region R4 by causing the coolant to be discharged from nozzle 309 with only valves 353, 359 open among valves 351 to 359, and causes cleaning device 300 to clean region R9 by causing the coolant to be discharged from nozzle 303. In this time period, cleaning device 300 cleans two regions R4, R9 by use of two nozzles 303, 309.

[0117] Subsequently, controller 500 causes cleaning device 300 to clean region R8 for 20 seconds, from 10 seconds to 30 seconds, with the output of pump 372 maintained at 80%. Specifically, controller 500 causes cleaning device 300 to clean region R8 by causing the coolant to be discharged from nozzle 301 and nozzle 302 with only valves 351, 352 open among valves 351 to 359. In this time period, cleaning device 300 cleans one region R8 by use of two nozzles 301, 302.

[0118] Finally, controller 500 causes cleaning device 300 to simultaneously clean regions R3 and region R5 for 15 seconds, from 30 seconds to 45 seconds, with the output of pump 372 maintained at 80%. Specifically, controller 500 controls the directions of discharge of the coolant of nozzles 301, 302. Further, controller 500 causes cleaning device 300 to clean region R5 by causing the coolant to be discharged from nozzle 301 with only valves 351, 352 open among valves 351 to 359 and causes cleaning device 300 to clean region R3 by causing the coolant to be discharged from nozzle 302. In this time period, cleaning device 300 cleans two regions R3, R5 by use of the two nozzles 301, 302.

[0119] Subsequently, controller 500 changes the output of pump 372 from 80% to 65% and continuously supplies the coolant to oil conditioner 800 via valve 850.

[0120] Description has been given using, as examples, 95%, 80%, and 65% as the output of pump 372, but the present disclosure is not limited thereto. In the case of level 2, the output of pump 372 is preferably set to 90% or more. The order of cleaning regions is not limited to the order described above. The cleaning time of each period is not limited to the period of time described above.

[0121] <E: Functional Configuration> Fig. 16 is a block diagram illustrating the functional configuration of machine tool 100. Referring to Fig. 16, machine tool 100 includes camera 210, controller 500, and cleaning device 300, as described above. Cleaning device 300 has pump 372, the plurality of valves 351 to 359, and the plurality of nozzles 301 to 309, as described above.

[0122] Controller 500 includes an extraction unit 510, a determination unit 520, a pump control unit 530, and a valve control unit 540. Determination unit 520 includes a division unit 521, a score calculation unit 522, a first individual determination unit 523, and a second individual determination unit 524. Extraction unit 510, determination unit 520, pump control unit 530, and valve control unit 540 are functional blocks realized as a processor executes a program stored in the memory.

[0123] Extraction unit 510 extracts image portions respectively corresponding to the plurality of regions R1 to R12 from the image picked up by camera 210. Specifically, extraction unit 510 extracts pieces of image data (hereinafter "pieces of image data G1 to G12") respectively corresponding to the plurality of regions R1 to R12 from the image data obtained from camera 210. Extraction unit 510 transmits the extracted plurality of pieces of image data G1 to G12 to determination unit 520.

[0124] Determination unit 520 determines the accumulation state of chips in each of regions R1 to R12. Specifically, determination unit 520 determines the accumulation state of chips of a workpiece in machining chamber interior 110 for each of regions R1 to R12 based on the image obtained by image pickup with camera 210 and two determination criteria #1, #2 different from each other. Specifically, determination unit 520 determines the accumulation level of chips in each of regions R1 to R12.

[0125] Determination unit 520 receives the pieces of image data G1 to G12. Based on the pieces of image data G1 to G12, determination unit 520 determines the accumulation level of chips in each of regions R1 to R12. For example, based on image data G1, determination unit 520 determines the accumulation level of chips in region R1. Similarly, determination unit 520 determines the accumulation level of chips in region R2 based on image data G2.

[0126] For convenience of description, the processing by determination unit 520 will be described below using image data G2 corresponding to region R2 as an example. The same processing as that for region R2 is performed for the other regions R1 and R3 to R12. Thus, the description of the processing for the other regions R1 and R3 to R12 will not be repeated.

[0127] Division unit 521 divides the image of region R2 into a plurality of element regions Ei, as shown in, for example, Fig. 6. Division unit 521 divides the image of region R2 into 72 element regions Ei, each of which is a square. Specifically, division unit 521 extracts pieces of element image data (hereinafter "pieces of element image data GE1 to GE72") respectively corresponding to the plurality of element regions E1 to E72 from the image data of region R2. Each of the plurality of pieces of element image data GE1 to GE72 includes a plurality of pieces of pixel data (pixel values of a plurality of pixels).

[0128] Score calculation unit 522 determines the accumulation level of each element region Ei based on the plurality of pieces of element image data GE1 to GE72. Specifically, score calculation unit 522 determines the accumulation level of each element region Ei to be level L, level M, or level H. Further, score calculation unit 522 calculates each of the number of element regions Ei of level L, the number of element regions Ei of level M, and the number of element regions Ei of level H.

[0129] Subsequently, score calculation unit 522 performs the above-described weighting process. Specifically, score calculation unit 522 performs weighting by assigning 0 points to element region Ei of level L, 3 points to element region Ei of level M, and 8 points to element region Ei of level H. Thus, for example, in the first case described above, score calculation unit 522 calculates 0 points, 96 points, and 24 points, as shown in Fig. 7. Further, score calculation unit 522 sums the three calculated scores. In the first case, score calculation unit 522 sums 0 points, 96 points, and 24 points, yielding 120 points.

[0130] (Determination Based on Determination Criterion #1) The total score obtained by summing the three scores is transmitted to first individual determination unit 523. In the first case described above, score calculation unit 522 notifies first individual determination unit 523 of 120 points. First individual determination unit 523 performs a determination based on determination criterion #1 described above. In other words, first individual determination unit 523 determines whether chips are accumulated throughout region R2.

[0131] Specifically, first individual determination unit 523 determines score #1 based on the above-described equation (1). In the first case described above, first individual determination unit 523 multiplies a value "0.208" by 100, where the value "0.208" is obtained by dividing 120 points by 576 points, which is a value obtained by multiplying 72 pieces by 8 points. As a result, first individual determination unit 523 obtains "20.8" as score #1. Further, first individual determination unit 523 determines whether the calculated score #1 is greater than or equal to the first threshold (15 points).

[0132] (Determination Based on Determination Criterion #2) The total score of element region Ei of level H after weighting is transmitted to second individual determination unit 524. In the first case described above, score calculation unit 522 notifies second individual determination unit 524 of 24 points. Second individual determination unit 524 performs a determination based on determination criterion #2 described above. Specifically, second individual determination unit 524 determines whether chips are accumulated locally in region R2.

[0133] Specifically, second individual determination unit 524 determines score #2 based on the above-described equation (2). In the first case described above, second individual determination unit 524 multiplies a value "0.042" by 100, where the value "0.042" is obtained by dividing 24 points by 576 points, which is a value obtained by multiplying 72 pieces by 8 points. As a result, second individual determination unit 524 obtains "4.2" as score #1. Further, second individual determination unit 524 determines whether the calculated score #2 is greater than or equal to the second threshold (10 points).

[0134] (Overall Determination) Determination unit 520 determines the accumulation level of chips in region R2 based on the determination result by first individual determination unit 523 and the determination result by second individual determination unit 524. Specifically, determination unit 520 determines the accumulation level in region R2 to be "level 0", "level 1", or "level 2" described above.

[0135] Specifically, when first individual determination unit 523 determines that score #1 is greater than or equal to the first threshold (15 points) and second individual determination unit 524 determines that score #2 is greater than or equal to the second threshold (10 points), determination unit 520 determines the accumulation level in region R2 to be level 2.

[0136] When score #1 is greater than or equal to the first threshold and score #2 is less than the second threshold, determination unit 520 determines the accumulation level in region R2 to be level 1. Similarly, when score #1 is less than the first threshold and score #2 is greater than or equal to the second threshold, determination unit 520 determines the accumulation level in region R2 to be level 1. When score #1 is less than the first threshold and score #2 is less than the second threshold, determination unit 520 determines the accumulation level in region R2 to be level 0.

[0137] Determination unit 520 determines not only the accumulation level of chips in region R2 but also the accumulation level of chips in the other regions R1 and R3 to R12.

[0138] (Control of Cleaning Device) Pump control unit 530 operates pump 372. In this example, as shown in Fig. 3, the coolant is supplied from pump 372 to oil conditioner 800 via valve 850. Thus, as long as oil conditioner 800 is operating, pump 372 is brought into operation by pump control unit 530 regardless of the accumulation level of chips in machining chamber interior 110.

[0139] Pump control unit 530 and valve control unit 540 receive notification of the accumulation level in each of regions R1 to R12 from determination unit 520.

[0140] Pump control unit 530 controls an output of pump 372 based on the accumulation level of chips in each of regions R1 to R12. Pump control unit 530 sets the output of pump 372 to the output of 80% at the timing for cleaning a region when the accumulation level in this region (e.g., region R2) is level 1. Pump control unit 530 sets the output of pump 372 to the output of 95% at the timing for cleaning a region, when the accumulation level in this region is level 2.

[0141] Valve control unit 540 controls valves 351 to 359 and 850 to be open or closed. Valve control unit 540 controls the timing for opening each of valves 351 to 359 and the timing for closing each valve. When a valve is opened by valve control unit 540, the coolant is discharged from a nozzle connected to this valve. Consequently, the region (Fig. 5) corresponding to this valve is cleaned among the plurality of regions R1 to R12.

[0142] <F: Control Structure> Fig. 17 is a flowchart illustrating a flow of a process performed by machine tool 100. Referring to Fig. 17, in step S1, camera 210 picks up an image of machining chamber interior 110 of machine tool 100. In step S2, controller 500 determines the accumulation state (level) of chips of a workpiece in each of regions R1 to R12 of machining chamber interior 110 based on the image obtained by image pickup and the two determination criteria #1, #2.

[0143] In step S3, controller 500 determines whether there is a region of level 2 among the plurality of regions R1 to R12. When determining that there is a region of level 2 (YES in step S3), controller 500 determines in step S4 whether there is a region of level 1 among the plurality of regions R1 to R12.

[0144] When determining that there is a region of level 1 (YES in step S4), in step S5, controller 500 causes cleaning device 300 to clean the region of level 2 with the coolant of higher pressure or higher flow rate. In this example, controller 500 causes cleaning device 300 to clean the region of level 2 with the output of pump 372 set to 95%. When there are a plurality of regions of level 2, controller 500 causes cleaning device 300 to clean the regions with the coolant of higher pressure or higher flow rate one by one in order.

[0145] Subsequently, in step S6, controller 500 causes cleaning device 300 to clean a region of level 1 at normal pressure. In this example, controller 500 causes cleaning device 300 to clean the region of level 1 with the output of pump 372 set to 80%. When there are a plurality of regions of level 1, controller 500 causes cleaning device 300 to clean some or all of the regions of level 1.

[0146] When determining that there are no regions of level 1 (NO in step S4), in step S7, controller 500 causes cleaning device 300 to clean the region of level 2 with the coolant of higher pressure or higher flow rate, as in step S5.

[0147] When determining that there are no regions of level 2 (NO in step S3), in step S8, controller 500 determines whether there is a region of level 1 among the plurality of regions R1 to R12. When determining that there is a region of level 1 (YES in step S8), in step S9, controller 500 causes cleaning device 300 to clean the region of level 1 at normal pressure, as in step S6. When determining that there are no regions of level 1 (NO in step S9), controller 500 terminates the process without causing cleaning device 300 to clean any region (step S10).

[0148] Fig. 18 is a flowchart showing details of processing of step S2 in Fig. 17.

[0149] Each of steps S21 to S27 shown in Fig. 18 is performed for each of regions R1 to R12. Description will be given below using region R2 as an example. In step S21, controller 500 determines whether the accumulation state of chips in region R2 satisfies determination criterion #1. When determining that criterion #1 is satisfied (YES in step S21), controller 500 determines in step S22 whether the accumulation state of chips in region R2 satisfies determination criterion #2.

[0150] When determining that criterion #2 is satisfied (YES in step S22), controller 500 determines in step S23 that the accumulation level of chips in region R2 is level 2. When determining that criterion #2 is not satisfied (NO in step S22), controller 500 determines in step S24 that the accumulation level of chips in region R2 is level 1.

[0151] When determining that criterion #1 is not satisfied (NO in step S21), controller 500 determines in step S25 whether the accumulation state of chips in region R2 satisfies criterion #2.

[0152] When determining that criterion #2 is satisfied (YES in step S25), controller 500 determines in step S26 that the accumulation level of chips in region R2 is level 1. When determining that criterion #2 is not satisfied (NO in step S25), controller 500 determines in step S27 that the accumulation level of chips in region R2 is level 0. The same processing is performed for the other regions R1 and R3 to R12.

[0153] <G: Summary and Advantages> For convenience of description, the following description will be given by taking any one nozzle as "nozzle #1" and any other nozzle as "nozzle #2" among the plurality of nozzles 301 to 309. Similarly, the region cleaned by nozzle #1 is taken as "region #1", and the region cleaned by nozzle #2 is taken as "region #2". Further, a valve connected to nozzle #1 is taken as "valve #1", and a valve connected to nozzle #2 is taken as "valve #2", among valves 351 to 359.

[0154] (1) Machine tool 100 includes camera 210 that picks up an image of machining chamber interior 110 of machine tool 100 that machines a workpiece, determination unit 520 that determines an accumulation state of chips of the workpiece in region #1 of machining chamber interior 110 based on the image obtained by image pickup, nozzle #1 that discharges the coolant to machining chamber interior 110, pump 372 that supplies the coolant to nozzle #1, and pump control unit 530 that controls an output of pump 372 based on an accumulation state of the chips.

[0155] With this configuration, the coolant is discharged from nozzle #1 at a pump output based on the accumulation state of the chips in region #1. With such a configuration, thus, region #1 can be cleaned with consideration given to the accumulation state of the chips in region #1.

[0156] (2) Nozzle #1 discharges the coolant toward region #1. Determination unit 520 determines an accumulation state in region #1. Pump control unit 530 sets the output of pump 372 to 80% when the accumulation state of the chips in region #1 is at level 1. Pump control unit 530 sets the output of pump 372 to 95%, which is higher than 80%, when the accumulation state of the chips in region #1 is at level 2 at which the chips are accumulated more than at level 1.

[0157] With this configuration, the pump has a higher output as the level of the accumulation state is higher. Thus, when the accumulation state of the chips in region #1 is at level 2, chips can be removed with a higher probability than when the output of pump 372 is set to the same output of level 1.

[0158] (3) Machine tool 100 further includes nozzle #2 that is supplied with the coolant from pump 372 and discharges the coolant toward region #2 of the plurality of regions R1 to R12, valve #1 that is caused by valve control unit 540 to form or block a flow path (hereinafter "flow path #1") of the coolant from pump 372 to nozzle #1, and valve #2 that is caused by valve control unit 540 to form or block a flow path ("hereinafter "flow path #2") of the coolant from pump 372 to nozzle #2.

[0159] Determination unit 520 further determines the accumulation state of the chips in region #2. When the accumulation state in region #1 is at level 2 and the accumulation state in region #2 is at level 1, valve control unit 540 sets the output of pump 372 to 95% and blocks only flow path #2 of flow paths #1, #2 over a predetermined period (hereinafter "period #1").

[0160] With the configuration described above, the coolant can be discharged from only nozzle #1 of nozzles #1, #2 in period #1. Thus, the coolant of higher pressure or higher flow rate can be discharged to region #1 than when the coolant is discharged at the same timing from both nozzle #1 and nozzle #2. Thus, the chips in region #1 of level 2 can be removed with a higher probability.

[0161] (4) When the accumulation state in region #1 is at level 2 and the accumulation state in region #2 is at level 1, pump control unit 530 switches the output of pump 372 from 95% to 80% after a lapse of the above-described period #1 and blocks only flow path #1 of flow paths #1, #2 over a predetermined period (hereinafter "period #2").

[0162] With the configuration described above, the coolant can be discharged from only nozzle #2 of nozzles #1, #2 in period #2. Thus, the chips in region #2 of level 1 can be removed with the coolant of lower pressure than in region #1. This can reduce power consumption more than when region #2 is cleaned with the coolant of higher pressure or higher flow rate.

[0163] <H: Modifications> (1) The above description has been given using, as an example, the case where machining chamber interior 110 is divided into a plurality of regions R1 to R12, but the present disclosure is not limited thereto. The region of machining chamber interior 110 may be configured as one region without being divided into a plurality of regions, and this region may be cleaned with one or a plurality of nozzle coolants. In other words, the accumulation state of chips of the workpiece in machining chamber interior 110 may be determined, and cleaning device 300 may clean machining chamber interior 110 with the coolant based on the determined accumulation state.

[0164] (2) The above description has been given using, as an example, the configuration with one pump 372, but the present disclosure is not limited thereto. Machine tool 100 may include a plurality of pumps. For example, machine tool 100 may be configured such that one pump supplies the coolant to one or a plurality of nozzles of nozzles 301 to 309 and the other pumps supply the coolant to the remaining nozzles.

[0165] (3) The above description has been given using, as an example, the case where controller 500 performs the process in order of "obtaining an image", "dividing the entire region of the image into at least regions R1 to R12", and "dividing each of regions R1 to R12 into element regions Ei", but the present disclosure is not limited thereto. For example, controller 500 may perform the process in order of "obtaining an image", "dividing the entire region of the image into element regions Ei", and "dividing the entire region into at least regions R1 to R12 by grouping a plurality of element regions Ei".

[0166] (4) The above description has been given using, as an example, the case where the first threshold and the second threshold are fixed values, but the present disclosure is not limited thereto. It is preferable to configure controller 500 to allow the user to arbitrarily change the first threshold and the second threshold. Increasing the first threshold and the second threshold can reduce the cleaning frequency, thereby reducing power consumption. Further, setting the first threshold and the second threshold smaller can increase the cleaning frequency, keeping the interior of the device cleaner.

[0167] (5) Description has been given using, as an example, the case where there are two nozzles that discharge the coolant simultaneously when the level is determined to be level 1, but the present disclosure is not limited thereto. For example, there may be three or more nozzles that simultaneously discharge the coolant.

[0168] It should be understood that the embodiment disclosed herein is illustrative and is not limited to the above contents. It is therefore intended that the scope of the present invention is defined by claims and encompasses all modifications and variations equivalent in meaning and scope to the claims.

[0169] This nonprovisional application is based on Japanese Patent Application No. 2024-227377 filed on December 24, 2024 with the Japan Patent Office, the entire contents of which are hereby incorporated by reference.

[0170] 21 tool spindle; 31 cover body; 32, 36, 37, 38, 65, 66 cover; 34, 62, 63 telescopic cover; 33 ATC shutter; 35 door; 39 ceiling cover; 41 table; 42 pallet; 46 conveyor; 50 automatic pallet changer; 52 arm; 61 protective cover; 81 operation panel; 82 upper panel; 83 panel; 90 tool; 100 tool machine; 101 rotation center axis; 110 machining chamber interior; 120 setup station; 210 camera; 300 cleaning device; 301, 302, 303, 304, 305, 306, 307, 308, 309 nozzle; 306a first discharge portion; 306b second discharge portion; 351, 352, 353, 354, 355, 356, 357, 358, 359, 850 valve; 371 coolant tank; 372 pump; 500 controller; 510 extraction unit; 520 determination unit; 521 division unit; 522 score calculation unit; 523 first individual determination unit; 524 second individual determination unit; 530 pump control unit; 540 valve control unit; 621, 651 first part; 622, 652 second part; 800 oil conditioner; D1, D2, D3 data; Ei element region; R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12 region.

Claims

1. A machine tool comprising: image pickup means for picking up an image of a machining chamber interior of a machine tool that machines a workpiece; determination means for determining an accumulation state of chips of the workpiece in the machining chamber interior based the image obtained by image pickup; a first nozzle that discharges a coolant to the machining chamber interior; a pump that supplies the coolant to the first nozzle; and control means for controlling an output of the pump based on the accumulation state of the chips, wherein the control means sets the output of the pump to a first output when the accumulation state is at a first level, and sets the output of the pump to a second output when the accumulation state is at a second level at which the chips are accumulated more than at the first level, the second output being higher than the first output.

2. The machine tool according to claim 1, wherein the first nozzle discharges the coolant toward a first region of a plurality of regions of the machining chamber interior, the determination means determines the accumulation state in the first region, and the control means sets the output of the pump to the first output when the accumulation state in the first region is at the first level, and sets the output of the pump to the second output when the accumulation state in the first region is at the second level.

3. The machine tool according to claim 2, further comprising: a second nozzle that is supplied with the coolant from the pump and discharges the coolant toward a second region of the plurality of regions; a first electromagnetic valve that is caused by the control means to form or block a first flow path of the coolant from the pump to the first nozzle; and a second electromagnetic valve that is caused by the control means to form or block a second flow path of the coolant from the pump to the second nozzle, wherein the determination means further determines the accumulation state of the chips in the second region, and when the accumulation state in the first region is at the second level and the accumulation state in the second region is at the first level, the control means sets the output of the pump to the second output and blocks only the second flow path of the first flow path and the second flow path over a first period.

4. The machine tool according to claim 3, wherein when the accumulation state in the first region is at the second level and the accumulation state in the second region is at the first level, the control means switches the output of the pump from the second output to the first output after a lapse of the first period and blocks only the first flow path of the first flow path and the second flow path over a second period.

5. The machine tool according to claim 1, wherein the second output is an output of 90% or more of a maximum output of the pump.

6. A method of cleaning a machining chamber interior of a machine tool, the method comprising: picking up an image of a machining chamber interior of a machine tool that machines a workpiece; and determining an accumulation state of chips of the workpiece in the machining chamber interior based on the image obtained by image pickup, a coolant being discharged from a nozzle by a pump in the machining chamber interior, the method further comprising controlling an output of the pump based on the accumulation state of the chips, wherein controlling of the output of the pump includes setting the output of the pump to a first output when the accumulation state is at a first level, and setting the output of the pump to a second output when the accumulation state is at a second level at which the chips are accumulated more than at the first level, the second output being higher than the first output.

Images