Patent Description:
Regarding a technique for removing chip generated by machining of a workpiece with a coolant, <CIT> (PTL <NUM>) discloses a machine tool for "detect a place where the chip generated by machining adheres and accumulates inside the cover, and efficiently discharge the chip".

As another example, <CIT> (PTL <NUM>) discloses a machine tool cleaning device "capable of cleaning the chip and the like that affect tool replacement". PTL <NUM>, PTL4 and PTL5 disclose machines and methods controlling that coolant is discharged to a specific movable region of the machine.

In the machine tool, there is a portion (hereinafter, also referred to as a "discharge inhibited portion") that may fail due to the adhesion of the coolant. Desirably the coolant is prevented from adhering to such the discharge inhibited portion.

The techniques disclosed in PTLs <NUM>, <NUM> do not prevent the coolant from adhering to the discharge inhibited portion. Accordingly, a technique for preventing the coolant from adhering to the discharge inhibited portion is desired.

In an example of the present disclosure, a machine tool capable of machining a workpiece includes: a first discharge unit that discharges a coolant removing a chip of the workpiece; a portion inside the machine tool and to which the coolant should not be discharged; a first drive unit that changes a relative position between the first discharge unit and the portion by moving at least one of the first discharge unit and the portion; and a control unit that controls the machine tool. The control unit performs processing for recognizing a position in the machine tool of a moving object by the first drive unit between the first discharge unit and the portion, and processing for controlling the discharge of the coolant by the first discharge unit such that the coolant is not discharged to the portion based on the position recognized in the recognition processing.

According to an example of the present disclosure, the machine tool further includes a second drive unit that drives a discharge port of the coolant discharged by the first discharge unit. The moving object is the portion. In the control processing, drive of the discharge port by the second drive unit is controlled such that the coolant is not discharged to the position of the portion.

In an example of the present disclosure, the machine tool further includes a second discharge unit that discharges the coolant removing the chip of the workpiece. The control processing includes processing for controlling the discharge of the coolant by the first discharge unit and the discharge of the coolant by the second discharge unit such that the coolant is not discharged to the portion.

In an example of the present disclosure, the machine tool further includes a camera that photographs the portion. A position of the portion in the machine tool is recognized based on an image obtained from the camera.

In an example of the present disclosure, the position of the portion in the machine tool is recognized by analyzing a drive program of the portion by the second drive unit.

In an example of the present disclosure, the control unit further executes processing for recognizing a position of the chip of the workpiece. The control processing includes processing for causing the first drive unit to move the relative position such that the portion is not located between the first discharge unit and the chip when the portion is located between the first discharge unit and the chip, and starting the discharge of the coolant by the first discharge unit after the movement.

In an example of the present disclosure, the portion includes at least one of a sensor measuring a size of a tool for machining the workpiece, a sensor measuring a physical quantity related to the workpiece, a camera provided in the machine tool, a surface of a spindle provided in the machine tool, and a workpiece to be machined by dry machining.

An example of the present disclosure provides a method for controlling a machine tool capable of machining a workpiece. The machine tool includes a discharge unit that discharges a coolant removing a chip of the workpiece, a portion inside the machine tool and to which the coolant should not be discharged, and a drive unit that changes a relative position between the discharge unit and the portion by moving at least one of the discharge unit and the portion. The control method includes: recognizing a position in the machine tool of a moving object by the drive unit between the discharge unit and the portion; and controlling discharge of the coolant by the discharge unit such that the coolant is not discharged to the portion based on the position recognized by the recognizing.

An example of the present disclosure provides a control program for a machine tool capable of machining a workpiece. The machine tool includes a discharge unit that discharges a coolant removing a chip of the workpiece, a portion inside the machine tool and to which the coolant should not be discharged, and a drive unit that changes a relative position between the discharge unit and the portion by moving at least one of the discharge unit and the portion. The control program causes the machine tool to execute: recognizing a position in the machine tool of a moving object by the drive unit between the discharge unit and the portion; and controlling the discharge of the coolant by the discharge unit such that the coolant is not discharged to the portion based on the position recognized in the recognizing.

With reference to the drawings, an embodiment of the present invention will be described below. In the following description, the same parts and components are denoted by the same reference numeral. Those names and functions are the same. Thus, the detailed description thereof will not be repeated.

With reference to <FIG>, a machine tool <NUM> according to an embodiment will be described. <FIG> is a view illustrating an appearance of machine tool <NUM>.

The term "machine tool" used in the present specification is a concept including various devices having a function of processing a workpiece. In the present specification, a horizontal machining center will be described as an example of machine tool <NUM>, but machine tool <NUM> is not limited thereto. For example, machine tool <NUM> may be a vertical machining center. Alternatively, machine tool <NUM> may be a lathe, an additional processing machine, or another cutting machine or grinding machine.

As illustrated in <FIG>, machine tool <NUM> includes a cover <NUM> and an operation panel <NUM>.

Cover <NUM> is also called a splash guard, and forms an appearance of machine tool <NUM> and defines a machining area AR (see <FIG>) of a workpiece W.

Operation panel <NUM> is a general-purpose computer, and includes a display <NUM> displaying various types of information about processing. For example, display <NUM> is a liquid crystal display, an organic electro luminescence (EL) display, or another display device. Display <NUM> includes a touch panel, and receives various operations on machine tool <NUM> by touch operations.

With reference to <FIG> and <FIG>, an internal configuration of machine tool <NUM> will be described below. <FIG> is a view illustrating a state in machine tool <NUM>. <FIG> is a view illustrating the state in machine tool <NUM> from a direction different from that in <FIG>.

As illustrated in <FIG> and <FIG>, machine tool <NUM> includes cameras 120A, 120B, coolant discharge mechanisms 125A, 125B (first and second discharge units), a chip collection mechanism <NUM>, a spindle head <NUM>, a tool <NUM>, and a table <NUM>. Spindle head <NUM> includes a spindle <NUM> and a housing <NUM>.

For convenience of description, hereinafter, the axial direction of spindle <NUM> is also referred to as a "Z-axis direction". A gravity direction is also referred to as a "Y-axis direction". A direction orthogonal to both the Y-axis direction and the Z-axis direction is referred to as an "X-axis direction".

Furthermore, in the following description, when cameras 120A, 120B are not particularly distinguished, one of cameras 120A, 120B is also referred to as a camera <NUM>. When discharge mechanisms 125A, 125B are not particularly distinguished, one of discharge mechanisms 125A, 125B is also referred to as a discharge mechanism <NUM>.

Camera <NUM> is disposed so as to include a machining area AR of the workpiece in a field of view of camera <NUM>. For example, camera <NUM> is provided on one side surface or a ceiling surface of cover <NUM>. Camera <NUM> may be a charge coupled device (CCD) camera, an infrared camera (thermography), or another types of camera.

Discharge mechanism <NUM> is provided in machine tool <NUM>. For example, discharge mechanism <NUM> is provided on one side surface or the ceiling surface of cover <NUM>. Discharge mechanism <NUM> includes a coolant storage tank, piping, a coolant pump, a coolant nozzle (discharge port), and the like. One end of the pipe is connected to the pump, and the other end of the pipe is connected to the coolant nozzle. The pump draws the coolant from the storage tank and sends the coolant to the coolant nozzle. Thus, the coolant is discharged to machining area AR. By discharging the coolant, the chip generated by machining of workpiece W is collected by collection mechanism <NUM>. Collection mechanism <NUM> includes a conveyor, a collection unit, and the like, and conveys the chip of workpiece W to the collection unit by the conveyor.

Spindle <NUM> is provided inside housing <NUM>. A tool for machining workpiece W, which is an object to be machined, is attached to spindle <NUM>. In the examples of <FIG> and <FIG>, a tool <NUM> used for milling workpiece W is mounted on spindle <NUM>.

Although the example in which two cameras 120A, 120B are provided in machine tool <NUM> has been described above, the number of cameras is not necessarily two, but may be one or at least three.

In the above description, an example in which two discharge mechanisms 125A, 125B are provided in machine tool <NUM> has been described. However, the number of discharge mechanisms is not necessarily two, and may be one or at least three.

The definition of the term "discharge inhibited portion" used in the present specification will be described below. In the present specification, a portion that may fail due to the adhesion of the coolant is referred to as the "discharge inhibited portion". The discharge inhibited portion may be one component in machine tool <NUM> or a part of the one component.

As an example, the discharge inhibited portion is a sensor (hereinafter, also referred to as a "tool sensor") measuring a size of the tool used for machining workpiece W. The size is a concept including a diameter of the tool, a length of the tool, a wear amount of the tool, and the like. For example, the tool sensor is provided in machine tool <NUM> and measures the size of the tool before or after machining the workpiece. For example, the tool sensor is an optical distance sensor, an ultrasonic distance sensor, and a contact measurement device that measures the size of the tool.

As another example, the discharge inhibited portion is a sensor (hereinafter, also referred to as a "workpiece sensor") measuring a physical quantity related to the workpiece. The physical quantity is a concept including a height of the workpiece, a lateral width of the workpiece, a longitudinal width of the workpiece, roughness of the workpiece surface, a temperature of the workpiece, and the like. For example, the workpiece sensor is provided in machine tool <NUM>, and measures physical quantities of the workpiece before machining, the workpiece being machined, and the workpiece after machining. For example, the workpiece sensor is an optical distance sensor, an ultrasonic distance sensor, a contact measurement device that measures the size of the workpiece, or a temperature sensor such as thermography.

As another example, the discharge inhibited portion is a camera provided in machine tool <NUM>. Not only cameras 120A, 120B but also various cameras are provided in machine tool <NUM>. As an example, the camera includes a camera monitoring the machining of workpiece W, a camera monitoring the state of the tool, a camera detecting the chip of the workpiece W, and the like.

As another example, the discharge inhibited portion includes the surface of the spindle <NUM> extending in the axial direction (that is, in the Z-axis direction) of spindle <NUM>. When the coolant enters between spindle <NUM> and housing <NUM>, there is a possibility that spindle head <NUM> fails. In order to prevent this, a labyrinth structure is adopted for a connection portion between spindle <NUM> and housing <NUM>. In order to more reliably prevent the coolant from entering between spindle <NUM> and housing <NUM>, preferably the coolant is not attached to the surface portion of spindle <NUM> corresponding to the labyrinth structure. For this reason, the surface portion of spindle <NUM> corresponding to the labyrinth structure is an example of the discharge inhibited portion.

As another example, the discharge inhibited portion includes the workpiece to be machined by dry machining. The dry machining is a type of machining method in which the coolant is not attached to the workpiece. Preferably the coolant does not adhere to the workpiece used in such the dry processing. For this reason, the workpiece used in the dry machining is an example of the discharge inhibited portion. For example, whether the machining method is the dry machining is determined based on an instruction code defined in a machining program.

In the following description, the surface of spindle <NUM> will be described as an example of the discharge inhibited portion. However, the discharge inhibited portion is not limited to the surface of spindle <NUM>, but may be another example described above.

With reference to <FIG>, various drive mechanisms in machine tool <NUM> will be described below. <FIG> is a view illustrating a configuration example of a drive mechanism in machine tool <NUM>.

As illustrated in <FIG>, machine tool <NUM> includes a controller <NUM>, motor drivers 111A, 111B, servo drivers 111R, 111X to 111Z, stepping motors 112A1,112A2,112B1,112B2, servomotors 112R, 112X to 112Z, a moving body <NUM>, discharge mechanisms 125A, 125B, spindle head <NUM>, tool <NUM>, and table <NUM>.

"Controller <NUM>" used in the present specification means a device that controls machine tool <NUM>. The device configuration of controller <NUM> is arbitrary. Controller <NUM> may be constructed with a single control unit or a plurality of control units. In the example of <FIG>, controller <NUM> includes a CPU unit <NUM> as a programmable logic control unit (PLC) and a CNC unit <NUM>. CPU unit <NUM> and CNC unit <NUM> communicate with each other through a communication path B (for example, a fieldbus or a LAN cable).

CPU unit <NUM> controls various units constituting controller <NUM> according to a previously-designed PLC program. For example, the PLC program is described by a ladder program. CPU unit <NUM> controls motor driver 111A according to the PLC program, and controls the discharge of the coolant by discharge mechanism 125A and the rotational drive of discharge mechanism 125A. CPU unit <NUM> controls motor driver 111B according to the PLC program, and controls the discharge of the coolant by discharge mechanism 125B and the rotational drive of discharge mechanism 125B.

CNC unit <NUM> starts execution of a previously-designed machining program in response to reception of a machining start instruction from CPU unit <NUM>. For example, the machining program is described by a numerical control (NC) program. CNC unit <NUM> controls servo drivers 111R, 111X to 111Z according to the machining program to machine workpiece W fixed to table <NUM>.

In the example of <FIG>, motor driver 111A is illustrated as a two-shaft integrated driver. Motor driver 111A receives the input of the target rotation speed of stepping motor 112A1 and the input of the target rotation speed of stepping motor 112A2 from CPU unit <NUM>, and controls each of stepping motors 112A1, 112A2.

Stepping motor 112A1 rotationally drives a discharge port of the coolant by discharge mechanism 125A according to an output current from motor driver 111A, and changes a discharge direction of the coolant in a rotation direction (that is, in an A-axis direction) with the X-axis direction as a rotation axis.

Stepping motor 112A2 rotationally drives the discharge port of the coolant by discharge mechanism 125A according to the output current from motor driver 111A, and changes the discharge direction of the coolant in the rotation direction (that is, in a C-axis direction) with the Z-axis direction as the rotation axis.

As described above, motor driver 111A individually controls the rotational drive in the A-axis direction by stepping motor 112A1 and the rotational drive in the C-axis direction by stepping motor 112A2, thereby discharging the coolant in an arbitrary direction toward machining area AR.

Motor driver 111B is a biaxial integrated driver. Motor driver 111B receives the input of the target rotation speed of stepping motor 112B1 and the input of the target rotation speed of stepping motor 112B2 from CNC unit <NUM>, and controls each of stepping motors 112B1, 112B2. Because a method of controlling stepping motor 112B1, 112B2 by motor driver 111B is similar to that of motor driver 111A, the description thereof will not be repeated.

Servo driver 111R sequentially receives the input of the target rotation speed from CNC unit <NUM> and controls servomotor 112R. Servomotor 112R rotationally drives spindle <NUM> about the Z-axis direction.

More specifically, servo driver 111R calculates an actual rotation speed of servomotor 112R from a feedback signal of an encoder (not illustrated) detecting the rotation angle of servomotor 112R, increases the rotation speed of servomotor 112R when the actual rotation speed is smaller than the target rotation speed, and decreases the rotation speed of servomotor 112R when the actual rotation speed is larger than the target rotation speed. In this manner, servo driver 111R brings the rotation speed of servomotor 112R closer to the target rotation speed while sequentially receiving feedback of the rotation speed of servomotor 112R.

Servo driver 111X sequentially receives an input of a target position from CNC unit <NUM> and controls servomotor 112X. Servomotor 112X feeds and drives moving body <NUM> to which spindle head <NUM> is attached through a ball screw (not illustrated), and moves spindle <NUM> to an arbitrary position in the X-direction. Because a method for controlling servomotor 112X by servo driver 111X is similar to that of servo driver 111R, the description thereof will not be repeated.

Servo driver 111Y sequentially receives the input of the target position from CNC unit <NUM> and controls servomotor 112Y. Servomotor 112Y feeds and drives moving body <NUM> to which spindle head <NUM> is attached through a ball screw (not illustrated), and moves spindle <NUM> to an arbitrary position in the Y-direction. Because a method for controlling servomotor 112Y by servo driver 111Y is similar to that of servo driver 111R, the description thereof will not be repeated.

Servo driver 111Z sequentially receives the input of the target position from CNC unit <NUM> and controls servomotor 112Z. Servomotor 112Z feeds and drives moving body <NUM> to which spindle head <NUM> is attached through a ball screw (not illustrated), and moves spindle <NUM> to an arbitrary position in the Z-direction. Because a method of controlling servomotor 112Z by servo driver 111Z is similar to that of servo driver 111R, the description thereof will not be repeated.

In the above description, servomotors 112X to 112Z that drive the discharge inhibited portion are exemplified as the drive mechanism (hereinafter, also referred to as a "first drive unit") that changes the relative position between the discharge inhibited portion (in the above-described example, spindle <NUM>) and discharge mechanism <NUM>, but the drive target by the first drive unit is not limited to the discharge inhibited portion. As an example, the first drive unit may change the relative position by feeding and driving discharge mechanism <NUM> instead of the discharge inhibited portion, or may change the relative position by feeding and driving both the discharge inhibited portion and discharge mechanism <NUM>. When discharge mechanism <NUM> is fed and driven, in addition to stepping motor 112A1, 112A2, 112B1, 112B2 (hereinafter, also referred to as a "second drive unit") rotationally driving discharge mechanism <NUM>, or instead of the second drive unit, a servomotor (not illustrated) feeding and driving discharge mechanism <NUM> is provided in machine tool <NUM> as the first drive unit. In this case, for example, discharge mechanism <NUM> is driven along a rail (not illustrated) provided on the ceiling of machine tool <NUM>.

Furthermore, in the above description, the example in which the first drive unit is configured by three servomotors 112X to 112Z has been described. However, the first drive unit may be configured by at least one drive mechanism (for example, a servomotor) feeding and driving the discharge inhibited portion or discharge mechanism <NUM>.

Furthermore, in the above description, an example in which the second drive unit is configured by two stepping motors 112A1, 112A2 (or 112B1, 112B2) has been described. However, the second drive unit may be configured by at least one drive mechanism (for example, a stepping motor or a servo motor).

With reference to <FIG>, a functional configuration of machine tool <NUM> will be described below. <FIG> is a view illustrating an example of the functional configuration of machine tool <NUM>.

Machine tool <NUM> includes controller <NUM> and a storage device <NUM> as a main hardware configuration. Controller <NUM> includes a position recognition unit <NUM>, a chip recognition unit <NUM>, and a coolant control unit <NUM> as a functional configuration. These functional configurations may be implemented in CPU unit <NUM> (see <FIG>) or implemented in CNC unit <NUM> (see <FIG>).

The functional configurations of position recognition unit <NUM>, chip recognition unit <NUM>, and coolant control unit <NUM> will be sequentially described below.

With reference to <FIG>, the function of position recognition unit <NUM> will be described.

Position recognition unit <NUM> recognizes the position in machine tool <NUM> of the moving object between discharge mechanism <NUM> and the discharge inhibited portion. Hereinafter, an example in which position recognition unit <NUM> recognizes the position of the discharge inhibited portion will be described, but when discharge mechanism <NUM> is configured to be drivable, position recognition unit <NUM> recognizes the position of discharge mechanism <NUM>. A method for recognizing the position of the discharge inhibited portion described below can also be applied to the recognition of the position of discharge mechanism <NUM>.

For example, the position of the discharge inhibited portion is recognized based on an image obtained from camera <NUM>. In this case, camera <NUM> is disposed so as to include the discharge inhibited portion in the field of view of camera <NUM>.

<FIG> is a view illustrating an image <NUM> obtained from camera <NUM>. Position recognition unit <NUM> recognizes the position of the discharge inhibited portion from image <NUM> by executing predetermined image processing.

As an example, the position of the discharge inhibited portion is recognized using a learned model. The learned model is previously generated by learning processing using a learning data set. The learning data set includes a plurality of learning images in which the discharge inhibited portion is photographed. Each learning image is associated with a label (alternatively, a label indicating the type of the discharge inhibited portion) indicating whether the discharge inhibited portion is photographed. An internal parameter of the learned model are previously optimized by the learning processing using such the learning data set.

Various machine learning algorithms can be adopted as a learning method for generating the learned model. As an example, deep learning, a convolution neural network (CNN), a full-layer convolutional neural network (FCN), a support vector machine, or the like is adopted as a machine learning algorithm.

Position recognition unit <NUM> divides image <NUM> into a plurality of regions, and inputs partial images of the respective sections to the learned model. As a result, the learned model outputs a probability in which the discharge inhibited portion is included in the input partial image. Position recognition unit <NUM> recognizes the position of the partial image where the probability exceeds a predetermined value as a position P1 of the discharge inhibited portion. For example, position P1 of discharge inhibited portion <NUM> is defined by a representative point (for example, a center point of discharge inhibited portion <NUM>) in a region representing discharge inhibited portion <NUM>. Recognized position P1 is output to coolant control unit <NUM>.

The method for recognizing the position of the discharge inhibited portion is not limited to the method using the learned model, but image processing based on a rule base may be adopted. As an example, position recognition unit <NUM> previously holds a reference image representing the discharge inhibited portion, and scans the reference image in image <NUM> to calculate similarity with the reference image for each region in image <NUM>. Then, position recognition unit <NUM> recognizes a region where the similarity exceeds a predetermined value as position P1 of the discharge inhibited portion.

In the embodiment, position recognition unit <NUM> recognizes position P1 of the discharge inhibited portion using a single algorithm. However, the present invention is not limited to this configuration, but position P1 of the discharge inhibited portion may be recognized by a plurality of algorithms.

As another example, the position of the discharge inhibited portion is recognized based on a machining program <NUM> defining a drive instruction for the discharge inhibited portion. For example, machining program <NUM> defines drive instructions of servo drivers 111X to 111Z (see <FIG>).

Typically, machining program <NUM> includes an instruction code designating a movement destination of the discharge inhibited portion. Position recognition unit <NUM> recognizes the instruction code currently executed in machining program <NUM>, and recognizes the movement destination of the discharge inhibited portion included in the instruction code as position P1 of the discharge inhibited portion. Recognized position P1 of the discharge inhibited portion is output to coolant control unit <NUM>.

With reference to <FIG>, a function of chip recognition unit <NUM> will be described below.

Chip recognition unit <NUM> recognizes the position of the chip in machine tool <NUM>. The position of the chip may be recognized in any manner. As an example, the position of the chip is recognized based on the image obtained from camera <NUM>.

As an example, the position of the chip is recognized using the learned model. The learned model is previously generated by learning processing using a learning data set. The learning data set includes a plurality of learning images in which the chip is photographed. Each learning image is associated with a label (alternatively, a label indicating the type of chip) indicating whether the chip is illustrated. An internal parameter of the learned model are previously optimized by the learning processing using such the learning data set.

The learned model receives the input of the image obtained from camera <NUM> and outputs a position P2 of the chip photographed in the image. <FIG> is a view illustrating a chip region recognized from image <NUM> in <FIG>.

More specifically, chip recognition unit <NUM> divides image <NUM> into a plurality of regions, and inputs the partial image of each section to the learned model. As a result, the learned model outputs the probability that the input partial image includes the chip. Chip recognition unit <NUM> recognizes the position of the partial image in which the probability exceeds a predetermined value as chip position P2. Recognized position P2 is output to coolant control unit <NUM>.

The method for recognizing the position of the chip is not limited to the above-described method using the learned model, but the image processing based on the rule base may be adopted. As an example, a frequency component included in the partial image tends to increase as the number of chips increases. Accordingly, chip recognition unit <NUM> performs frequency analysis such as fast Fourier transform (FFT) and acquires a spectral image for each partial image. Each pixel value of the spectrum image represents a correlation value with the waveform of each frequency. Chip recognition unit <NUM> recognizes a region of the partial image in which the pixel value exceeds a predetermined value in a predetermined high-frequency band as chip position P2.

In the embodiment, chip recognition unit <NUM> recognizes position P2 of the chip using a single algorithm. However, the present invention is not limited to this configuration, but chip position P2 may be recognized by a plurality of algorithms.

A function of coolant control unit <NUM> will be described below.

Coolant control unit <NUM> controls the discharge of the coolant by discharge mechanism <NUM> such that the coolant is not discharged to the discharge inhibited portion based on position P1 (see <FIG>) of the discharge inhibited portion recognized by position recognition unit <NUM>. Accordingly, the coolant can be prevented from adhering to the discharge inhibited portion.

As more specific processing, coolant control unit <NUM> transforms position P1 indicated in the first coordinate system into the second coordinate system based on a predetermined coordinate transformation matrix for transformation from a coordinate system (hereinafter, also referred to as a "first coordinate system") based on camera <NUM> to a coordinate system (hereinafter, also referred to as a "second coordinate system") in machining area AR (see <FIG> and <FIG>). Subsequently, coolant control unit <NUM> acquires the position of discharge mechanism <NUM> from predetermined installation position information <NUM>. For example, the position of discharge mechanism <NUM> is indicated by the second coordinate system. Coolant control unit <NUM> calculates a discharge exclusion angle of the coolant by discharge mechanism <NUM> based on position P1 of the discharge inhibited portion indicated by the second coordinate system and the position of discharge mechanism <NUM> indicated by the second coordinate system. Thereafter, coolant control unit <NUM> controls the discharge direction of the coolant by discharge mechanism <NUM> so as to exclude the calculated discharge exclusion angle. The discharge direction of the coolant can be changed by controlling stepping motors 112A1, 112A2, 112B1, 112B2.

Preferably, coolant control unit <NUM> produces a coolant cleaning path R by discharge mechanism <NUM> based on each of chip positions P2 (see <FIG>) recognized by chip recognition unit <NUM>. Typically, coolant control unit <NUM> produces cleaning path R so as to pass through each of chip positions P2. <FIG> is a view illustrating cleaning path R by discharge mechanism <NUM>.

Thereafter, coolant control unit <NUM> controls the discharge direction of the coolant by discharge mechanism <NUM> according to produced cleaning path R. At this time, coolant control unit <NUM> produces cleaning path R so as to avoid position P1 of the discharge inhibited portion. Alternatively, coolant control unit <NUM> may turn off the discharge of the coolant when the discharge port of the coolant in discharge mechanism <NUM> faces the direction of position P1 of the discharge inhibited portion.

With reference to <FIG>, the function of coolant control unit <NUM> will be further described. <FIG> is a view illustrating a positional relationship among discharge mechanism 125A, discharge inhibited portion <NUM>, and a chip G of the workpiece.

As illustrated in <FIG>, sometimes discharge inhibited portion <NUM> is located between discharge mechanism 125A and chip G. In this case, when discharge mechanism 125A discharges the coolant toward chip G, the coolant adheres to discharge inhibited portion <NUM>. Accordingly, when discharge inhibited portion <NUM> is located between discharge mechanism 125A and chip G, controller <NUM> of machine tool <NUM> moves discharge inhibited portion <NUM> such that discharge inhibited portion <NUM> is not located between discharge mechanism 125A and chip G, and starts the discharge of the coolant by discharge mechanism 125A after the movement. In the example of <FIG>, coolant control unit <NUM> discharges a coolant C toward chip G after moving discharge inhibited portion <NUM> in the X-direction.

As more specific processing, coolant control unit <NUM> acquires position P1 of discharge inhibited portion <NUM> from position recognition unit <NUM>. Furthermore, coolant control unit <NUM> acquires position P2 of chip G from chip recognition unit <NUM>. Coolant control unit <NUM> further acquires information indicating the position (hereinafter, also referred to as a "position P3") of discharge mechanism 125A.

Thereafter, coolant control unit <NUM> determines whether discharge inhibited portion <NUM> is located between chip G and discharge mechanism 125A based on position P1 of discharge inhibited portion <NUM>, position P2 of chip G, and position P3 of discharge mechanism 125A. As an example, coolant control unit <NUM> calculates a first direction from position P3 of discharge mechanism 125A toward position P1 of discharge inhibited portion <NUM> and a second direction from position P3 of discharge mechanism 125A toward position P2 of chip G. Thereafter, coolant control unit <NUM> calculates an angle between the first direction and the second direction, and determines that discharge inhibited portion <NUM> is located between chip G and discharge mechanism 125A when the calculated angle is less than or equal to a predetermined angle (for example, less than or equal to <NUM> degrees). In this case, coolant control unit <NUM> starts the discharge of coolant C after driving discharge inhibited portion <NUM>. Accordingly, coolant control unit <NUM> can remove chip G while preventing coolant C from being discharged to discharge inhibited portion <NUM>.

With reference to <FIG>, the function of coolant control unit <NUM> will be further described. <FIG> is a view illustrating the positional relationship among discharge mechanism 125A, 125B, discharge inhibited portion <NUM>, and chip G of the workpiece.

As illustrated in <FIG>, when a plurality of discharge mechanisms <NUM> (for example, discharge mechanisms 125A, 125B) are provided in machine tool <NUM>, coolant control unit <NUM> selectively controls the discharge of the coolant by discharge mechanism 125A (first discharge unit) and the discharge of the coolant by discharge mechanism 125B (second discharge unit) such that the coolant is not discharged to discharge inhibited portion <NUM>.

More specifically, coolant control unit <NUM> calculates the angle between the direction from a position P3A of discharge mechanism 125A toward position P1 of discharge inhibited portion <NUM> and the direction from position P3A of discharge mechanism 125A toward position P2 of chip G. When the angle is less than or equal to a predetermined angle (for example, less than or equal to <NUM> degrees), coolant control unit <NUM> inhibits the discharge of the coolant by discharge mechanism 125A.

Similarly, coolant control unit <NUM> calculates the angle between the direction from a position P3B of discharge mechanism 125B toward position P1 of discharge inhibited portion <NUM> and the direction from position P3B of discharge mechanism 125B toward position P2 of chip G. When the angle is greater than a predetermined angle (for example, <NUM> degrees), coolant control unit <NUM> controls the angle of the discharge port of discharge mechanism 125B so as to face position P2 of chip G, and executes the discharge of the coolant by discharge mechanism 125B. The angle of the discharge port of discharge mechanism 125B is adjusted by driving and controlling stepping motors 112B1, 112B2.

As described above, coolant control unit <NUM> controls at least one of on and off of the coolant discharge and the coolant discharge direction for each of discharge mechanisms 125A, 125B such that the coolant is not discharged to discharge inhibited portion <NUM>. Accordingly, coolant control unit <NUM> can remove chip G without driving discharge inhibited portion <NUM>.

With reference to <FIG>, a hardware configuration of controller <NUM> in <FIG> will be described below. <FIG> is a view illustrating an example of the hardware configuration of controller <NUM>.

As illustrated in <FIG>, controller <NUM> includes CPU unit <NUM> and CNC unit <NUM>. For example, CPU unit <NUM> and CNC unit <NUM> are connected to each other through communication path B.

Hereinafter, the hardware configuration of CPU unit <NUM> and the hardware configuration of CNC unit <NUM> will be described in order.

CPU unit <NUM> includes a processor <NUM>, a read only memory (ROM) <NUM>, a random access memory (RAM) <NUM>, communication interfaces <NUM>, <NUM>, and an auxiliary storage device <NUM>. These components are connected to an internal bus <NUM>.

For example, processor <NUM> is constructed with at least one integrated circuit. For example, the integrated circuit may be constructed with at least one CPU, at least one graphics processing unit (GPU), at least one application specific integrated circuit (ASIC), at least one field programmable gate array (FPGA), or a combination thereof.

Processor <NUM> controls the operations of CPU unit <NUM> by executing various programs such as a control program <NUM>. Control program <NUM> defines instructions controlling various devices in machine tool <NUM>. Processor <NUM> reads control program <NUM> from auxiliary storage device <NUM> or ROM <NUM> to RAM <NUM> based on the reception of the execution instruction of control program <NUM>. RAM <NUM> functions as a working memory, and temporarily stores various data required for the execution of control program <NUM>.

Communication interface <NUM> is an interface that implements the communication using a local area network (LAN) cable, a wireless LAN (WLAN), Bluetooth (registered trademark), or the like. As an example, CPU unit <NUM> implements the communication with an external device such as motor drivers 111A, 111B through a communication interface <NUM>.

Communication interface <NUM> is an interface implementing the communication with various units connected to the fieldbus. CNC unit <NUM> or an I/O unit (not illustrated) can be cited as an example of the unit connected to the fieldbus.

The auxiliary storage device <NUM> is an example of the above-described storage device <NUM> (see <FIG>). For example, auxiliary storage device <NUM> is a storage medium such as a hard disk or a flash memory. Auxiliary storage device <NUM> stores control program <NUM> and the like. The storage location of control program <NUM> is not limited to auxiliary storage device <NUM>, but may be stored in the storage area (for example, a cache memory) of processor <NUM>, ROM <NUM>, RAM <NUM>, the external device (for example, a server), or the like.

Control program <NUM> may be provided not as a stand-alone program, but as a part of an arbitrary program. In this case, various pieces of processing of the embodiment is performed in cooperation with an arbitrary program. Even a program that does not include such a part of modules does not deviate from the purpose of control program <NUM> of the embodiment. Furthermore, some or all of the functions provided by control program <NUM> may be performed by dedicated hardware. Further, CPU unit <NUM> may be configured in a form of what is called cloud service in which at least one server executes a part of the processing of control program <NUM>.

With reference to <FIG>, the hardware configuration of CNC unit <NUM> will be described below.

CNC unit <NUM> includes a processor <NUM>, a ROM <NUM>, a RAM <NUM>, a communication interface <NUM>, a communication interface <NUM>, and an auxiliary storage device <NUM>. These components are connected to an internal bus <NUM>.

For example, processor <NUM> is constructed with at least one integrated circuit. For example, the integrated circuit may be constructed with at least one CPU, at least one ASIC, at least one FPGA, or a combination thereof.

Processor <NUM> controls the operation of CNC unit <NUM> by executing various programs such as machining program <NUM>. Machining program <NUM> is a program implementing workpiece machining. Processor <NUM> reads machining program <NUM> from ROM <NUM> in RAM <NUM> based on the reception of the execution instruction of machining program <NUM>. RAM <NUM> functions as a working memory, and temporarily stores various data required for the execution of machining program <NUM>.

Communication interface <NUM> is an interface that implements the communication using LAN, WLAN, Bluetooth, or the like. As an example, CNC unit <NUM> implements the communication with CPU unit <NUM> through communication interface <NUM>. In addition, CNC unit <NUM> implements the communication with various drive units (for example, servo drivers 111R, 111X to 111Z, and the like) for the workpiece machining through communication interface <NUM> or another communication interface.

For example, auxiliary storage device <NUM> is a storage medium such as a hard disk or a flash memory. Auxiliary storage device <NUM> stores a machining program <NUM>, various installation position information <NUM>, and the like.

For example, machining program <NUM> is described by an NC program. For example, machining program <NUM> includes an instruction code specifying a movement destination of spindle <NUM> in the X- to Z-directions, an instruction code specifying a coolant discharge direction by discharge mechanism <NUM>, and an instruction code specifying on and off of the coolant discharge by discharge mechanism <NUM>.

Installation position information <NUM> includes position information about various devices in machine tool <NUM>. As an example, installation position information <NUM> includes position information about discharge mechanism <NUM>, position information (not illustrated) about camera <NUM>, and the like.

The storage location of machining program <NUM> or installation position information <NUM> is not limited to auxiliary storage device <NUM>, but may be stored in the storage area (for example, the cache memory) of processor <NUM>, ROM <NUM>, RAM <NUM>, the external device (for example, the server), and the like.

Machining program <NUM> may be provided not as a stand-alone program, but as a part of an arbitrary program. In this case, various pieces of processing of the embodiment is performed in cooperation with an arbitrary program. Even a program that does not include such a part of modules does not deviate from the purpose of machining program <NUM> of the embodiment. Furthermore, some or all of the functions provided by machining program <NUM> may be performed by dedicated hardware. Furthermore, CNC unit <NUM> may be configured in a form of what is called cloud service in which at least one server executes a part of the processing of machining program <NUM>.

With reference to <FIG>, a flowchart related to coolant control will be described. <FIG> is the flowchart illustrating an example of the coolant control. For example, the processing in <FIG> is executed by controller <NUM> of machine tool <NUM>.

In step S110, controller <NUM> functions as position recognition unit <NUM> (see <FIG>), and recognizes position P1 of the discharge inhibited portion in machine tool <NUM>. Because the function of position recognition unit <NUM> is as described above, the description thereof will not be repeated. At the time of step S110, recognized position P1 of the discharge inhibited portion is represented by the coordinate system (that is, the first coordinate system) based on camera <NUM>.

In step S112, controller <NUM> functions as chip recognition unit <NUM> (see <FIG>) and recognizes position P2 of chip G of the workpiece in machine tool <NUM>. Since the function of chip recognition unit <NUM> is as described above, the description thereof will not be repeated. At the time of step S112, recognized position P2 of the chip is represented by the coordinate system (that is, the first coordinate system) based on camera <NUM>.

In step S114, controller <NUM> acquires position P3 of discharge mechanism <NUM> in machine tool <NUM>. Typically, position P3 of discharge mechanism <NUM> is defined by installation position information <NUM> (see <FIG>). For example, position P3 of discharge mechanism <NUM> is indicated by the coordinate system (that is, the second coordinate system) in machining area AR (See <FIG> and <FIG>).

In step S116, controller <NUM> functions as coolant control unit <NUM> (see <FIG>), and controls discharge mechanism <NUM> such that the coolant does not adhere to the discharge inhibited portion. More specifically, controller <NUM> transforms position P1 of the discharge inhibited portion recognized in step S112 and position P2 of the chip recognized in step S114 from the first coordinate system to the second coordinate system based on a predetermined coordinate transformation matrix for the transformation from the first coordinate system to the second coordinate system. Subsequently, coolant control unit <NUM> of controller <NUM> controls discharge mechanism <NUM> such that the coolant does not adhere to the discharge inhibited portion based on position P1 of the discharge inhibited portion indicated by the second coordinate system, position P2 of the chip indicated by the second coordinate system, and position P3 of discharge mechanism <NUM> indicated by the second coordinate system.

As described above, machine tool <NUM> of the embodiment recognizes the position of the discharge inhibited portion, and controls the discharge of the coolant by discharge mechanism <NUM> such that the coolant is not discharged to the discharge inhibited portion. Accordingly, machine tool <NUM> can prevent the coolant from adhering to the discharge inhibited portion in which the position changes each time.

It should be considered that the disclosed embodiment is an example in all respects and not restrictive.

Claim 1:
A machine tool capable of machining a workpiece, the machine tool comprising:
a first discharge unit (125A) that discharges a coolant removing a chip of the workpiece;
a portion inside the machine tool and to which the coolant should not be discharged;
a first drive unit that changes a relative position between the first discharge unit and the portion by moving at least one of the first discharge unit and the portion; and
a control unit that controls the machine tool,
wherein the control unit performs
processing for recognizing a position in the machine tool of a moving object by the first drive unit between the first discharge unit and the portion, and
processing for controlling the discharge of the coolant by the first discharge unit such that the coolant is not discharged to the portion based on the position recognized in the recognition processing.