Working machinery

Abstract

To provide a machine tool that can automatically measure the position of a measurement object provided on a workpiece, and measure the position of the workpiece. [Solution] The machine tool 100 comprises a manual pulse generator 50 that manually controls the feed axis that moves the spindle 112 and table 106 relative to one another, an imaging device 30 that can be attached to the spindle of the machine tool and that images the surface of a workpiece W fixed to the table, a display device 28 that displays the image of the surface of the workpiece W imaged by the imaging device, and a processing unit 12 that extracts a measurement object from image data of the workpiece surface imaged by the imaging device and determines the coordinates of the measurement object by calculation, and the processing unit determines the coordinate values ​​of the reference point of the measurement object from image data of the workpiece surface imaged by the imaging device attached to the spindle that is positioned relative to the table by the manual pulse generator so that the center Om of the measurement object is located approximately at the center Oc of the image of the workpiece surface displayed on the display device.

Description

[Technical Field]

[0001] The present invention relates to a machine tool capable of measuring the position of a workpiece on the machine. [Background technology]

[0002] Patent Document 1 describes a machine tool in which a vision measuring head device is attached to a spindle and image measurements such as edge detection and circle measurement are performed from image data captured by the vision measuring head device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-026913 Summary of the Invention [Problem to be solved by the invention]

[0004] When the workpiece requires precise positioning, such as a semiconductor wafer, measurement using a microscope attached to the machine tool is necessary. However, with the machine tool described in Patent Document 1, when the workpiece to be machined changes, it is extremely difficult to position the image measuring head relative to the workpiece.

[0005] Furthermore, when measuring workpieces using a microscope, the operator must perform the measurement manually each time. Furthermore, when performing manual measurements, the measurement target, such as a hole or alignment mark, must be aligned with the center of the image, but the accuracy of alignment to the image center varies depending on the operator's skill, which causes variations in measurement results.

[0006] The present invention aims to solve the problems of the conventional technology by providing a machine tool that can automatically measure the positions of holes formed in a workpiece, the edges of the workpiece, and alignment marks provided on the surface of the workpiece.Alignment marks are marks that come in various shapes, such as crosses and squares, provided on the surface of the workpiece. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, according to the present invention, there is provided a machine tool comprising: a spindle on which a tool is attached; a table facing the spindle and on which a workpiece is attached; a feed axis for relatively moving the spindle and the table; an imaging device that can be attached to the spindle of a machine tool and that images the surface of a workpiece fixed to the table; a display device that displays an image of the surface of the workpiece imaged by the imaging device; a processing unit that extracts a measurement object from image data of the surface of the workpiece imaged by the imaging device and calculates the coordinate values ​​of the center of the measurement object; and a data storage unit that stores the coordinate values ​​of the center of the measurement object as measurement information, A machine tool is provided in which, when the center of the object to be measured is positioned relative to the table at a temporary position that is located within the range of the image of the workpiece surface displayed on the display device, the processing unit determines the position of the reference point of the object to be measured on the image data of the workpiece surface imaged by the imaging device attached to the spindle, moves the feed axis relatively so that the measurement point of the object to be measured on the image data is at the center position of the image captured by the imaging device, and measures the coordinate value of the feed axis as the coordinate value of the reference point of the object to be measured. [Effects of the Invention]

[0008] According to the present invention, when machining a new workpiece for which no measurement information related to the object to be measured has been registered, the coordinate values ​​of the reference point of the object to be measured are determined from image data of the surface of the workpiece captured by an imaging device attached to a spindle positioned relative to the table by a manual pulse generator so that the center of the object to be measured is positioned approximately in the center of the image of the surface of the workpiece displayed on the display device.This makes it possible to perform accurate measurements without being affected by errors in the angle of view size of the imaging device or aberrations of the lens of the imaging device. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing an example of a machine tool according to the present invention. [Figure 2]FIG. 1 is a schematic block diagram showing an example of a workpiece measuring device. [Figure 3] 1 is a flowchart showing a workpiece measuring method. [Figure 4] 10 is a schematic diagram of a screen displayed on a display unit. [Figure 5] 10 is a schematic diagram of a screen displayed on a display unit. [Figure 6] 10 is a schematic diagram of a screen displayed on a display unit. [Figure 7] 10 is a schematic diagram of a screen displayed on a display unit. [Figure 8] 10 is a schematic diagram of a screen displayed on a display unit. [Figure 9] 10 is a schematic diagram of a screen displayed on a display unit. [Figure 10] 10 is a schematic diagram of a screen displayed on a display unit. [Figure 11] 10 is a schematic diagram of a screen displayed on a display unit. [Figure 12] 10 is a schematic diagram for explaining alignment of the center of an image with the center of a non-circular alignment mark. [Figure 13] 10 is a schematic diagram for explaining alignment of the center of an image with the center of a non-circular alignment mark. [Figure 14] 10 is a schematic diagram of a screen displayed on a display unit. [Figure 15] 10 is a schematic diagram of a screen displayed on a display unit. [Figure 16] 10 is a schematic diagram of a screen displayed on a display unit. [Figure 17] 10 is a schematic diagram of a screen displayed on a display unit. [Figure 18] 10 is a schematic diagram of a screen displayed on a display unit. [Figure 19] 10 is a schematic diagram of a screen displayed on a display unit. [Figure 20] 10 is a schematic diagram for explaining a measurement method when a workpiece has multiple non-circular alignment marks. [Figure 21] 10 is a schematic diagram for explaining a measurement method when a workpiece has multiple non-circular alignment marks. [Figure 22]10 is a schematic diagram for explaining a measurement method when a workpiece has multiple non-circular alignment marks. [Figure 23] 10 is a schematic diagram for explaining a measurement method when a workpiece has multiple non-circular alignment marks. DETAILED DESCRIPTION OF THE INVENTION

[0010] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Referring to Figure 1, an example of a machine tool to which the present invention is applicable is shown. In Figure 1, machine tool 100 according to a preferred embodiment of the present invention constitutes a vertical machining center and includes: a bed 102 as a base fixed to the factory floor; a table 106, which is mounted on the upper surface of the front portion (left side in Figure 1) of bed 102 and movable in the front-rear direction or the Y-axis direction (left-right direction in Figure 1) and to which a workpiece W is fixed; a column 104, which is fixed to the upper surface of bed 102 at the rear end (right side in Figure 1) of bed 102; an X-axis slider 108, which is mounted in front of column 104 and movable in the left-right direction or the X-axis direction (direction perpendicular to the plane of the paper in Figure 1); and a spindle head 110, which is mounted in front of X-axis slider 108 and movable in the up-down direction or the Z-axis direction, and rotatably supports a spindle 112. Machine tool 100 also includes an operation panel 200 for an operator to operate machine tool 100. Although not limited thereto, the present invention is particularly advantageous when the workpiece W is a thin workpiece such as a semiconductor wafer.

[0011] A tool (not shown) for machining workpiece W fixed to table 106 can be attached to the tip of spindle 112. In FIG. 1, instead of a tool, an imaging device 30 for measuring workpiece W is attached to the tip of spindle 112. Although imaging device 30 can be attached manually by an operator of machine tool 100, it is preferably attached to the tip of spindle 112 automatically by automatic tool changer 40 (FIG. 2) of machine tool 100.

[0012] Table 106 is provided so as to be able to reciprocate along a pair of Y-axis guide rails (not shown) that extend in the horizontal Y-axis direction (left and right direction in FIG. 1) on the upper surface of bed 102, and bed 102 is provided with a Y-axis feed device that drives table 106 reciprocally along the Y-axis guide rails, which includes a ball screw (not shown) that extends in the Y-axis direction and a Y-axis servo motor My connected to one end of the ball screw, and a nut (not shown) that engages with the ball screw is attached to table 106. Also attached to table 106 is a Y-axis scale 120 that measures the position of table 106 in the Y-axis direction.

[0013] X-axis slider 108 is provided to be able to reciprocate along a pair of X-axis guide rails (not shown) that extend in the X-axis direction on the front surface of the upper part of column 104. Column 104 is provided with an X-axis feed device that drives X-axis slider 108 reciprocally along the X-axis guide rails. The X-axis feed device includes a ball screw (not shown) that extends in the X-axis direction and an X-axis servo motor Mx connected to one end of the ball screw, and X-axis slider 108 is fitted with a nut (not shown) that engages with the ball screw. Column 104 is also fitted with an X-axis scale 116 that measures the position of X-axis slider 108 in the X-axis direction.

[0014] The spindle head 110 is provided so as to be able to reciprocate along a pair of Z-axis guide rails that extend in the Z-axis direction (vertical direction in FIG. 1) in front of the X-axis slider 108. The X-axis slider 108 is provided with a Z-axis feed device that drives the spindle head 110 back and forth along the Z-axis guide rails. The Z-axis feed device includes a ball screw (not shown) that extends in the Z-axis direction and a Z-axis servo motor Mz connected to one end of the ball screw, and a nut (not shown) that engages with the ball screw is attached to the spindle head 110. A Z-axis scale 118 that measures the position of the spindle head 110 in the Z-axis direction is also attached to the X-axis slider 108.

[0015] The servo motors 140 for the X-axis, Y-axis, and Z-axis feed axes (X-axis servo motor Mx, Y-axis servo motor My, and Z-axis servo motor Mz) and the X-axis scale 116, Y-axis scale 120, and Z-axis scale 118 are connected to a control device 150 of the machine tool 100. The imaging device 30 is also connected to the control device 150. The control device 150 includes an NC device that controls the power (current value) supplied to the servo motors 140 for the X-axis, Y-axis, and Z-axis feed axes (X-axis servo motor Mx, Y-axis servo motor My, and Z-axis servo motor Mz).

[0016] The operation panel 200 includes a display panel 202 that forms the display device 28 (FIG. 4) of the measuring device, which will be described later. In this embodiment, the display panel 202 can be formed as a touch panel that allows an operator to select a touched area or input information corresponding to the touched area by touching the screen with a finger or a touch pen. The operation panel 200 also includes a key input unit 204. A plurality of key switches are arranged on the key input unit 204. By pressing the key switches of the key input unit 204, predetermined numbers and characters can be input. The operation panel 200 can also include operation switches (not shown) for selecting predetermined operations, an override setting unit (not shown) for setting override values, and an emergency stop button (not shown). The override setting unit can set, for example, an override value for the spindle rotation speed or the machining feed rate.

[0017] Machine tool 100 further includes a manual pulse generator 50, which is a manual operation unit that allows an operator to manually operate and input servo motors 140 for the X-, Y-, and Z-axis feed axes (X-axis servo motor Mx, Y-axis servo motor My, and Z-axis servo motor Mz). Machine tool 100 also includes manual pulse generator 50 connected to an operation panel 200. Manual pulse generator 50 is provided so that, by sending command pulses, it can manually drive, as needed, the servo motors 140 for the X-, Y-, and Z-axis feed axes (X-axis servo motor Mx, Y-axis servo motor My, and Z-axis servo motor Mz), which are normally driven based on commands from a control device (NC device) 150. For this reason, manual pulse generator 50 is configured to be able to send command pulses. Instead of manual pulse generator 50, an operating device that performs jog feed may be used as the manual operation unit.

[0018] Machine tool 100 can be a machining center further equipped with peripheral devices such as a tool magazine (not shown) that stores a plurality of tools used in machining, an automatic tool changer 40 that changes tools between the tool magazine and spindle 112, and a coolant supply device (not shown) that supplies coolant to the machining area of ​​machine tool 100, and a machine control device that controls the peripheral devices. Control device 150 can include a machine control device.

[0019] The workpiece measuring device 10 is connected to the control device 150. It comprises, as its main components, a processing unit 12, a data storage unit 14, an input unit 24, a display control unit 26, a display device 28, and an imaging device 30. The data storage unit 14 includes a measurement program storage unit 16, a measurement point coordinate storage unit 18, a measurement object storage unit 20, and a measurement information storage unit 22.

[0020] The workpiece measuring device 10, particularly the processing unit 12, data storage unit 14, and display control unit 26, can be configured as a computer including a CPU (Central Processing Unit), memory devices such as RAM (Random Access Memory) and ROM (Read-Only Memory), storage devices such as HDDs (Hard Disk Drives) and SSDs (Solid State Drives), input / output ports, and a bidirectional bus interconnecting these, and associated software. The processing unit 12, data storage unit 14, and display control unit 26 can be configured as software as part of the control device 150 of the machine tool 100 shown in FIG. 1, particularly an NC device or machine control device. As described below, in addition to measurement information, the data storage unit 14 can also store a pre-stored reference position of the workpiece W and image data captured by the imaging device 30, linked to the reference position of the workpiece.

[0021] Processing unit 12 performs processing in accordance with a flowchart described below. Input unit 24 can be formed, for example, by a touch panel constituting display panel 202 of operation panel 200 of machine tool 100 in Fig. 1, a key input unit 204, a plurality of key switches, etc. Display device 28 can be formed, for example, by display panel 202 of operation panel 200 of machine tool 100 in Fig. 1. Display control unit 26 generates a screen to be displayed on display device 28 in accordance with a command from processing unit 12.

[0022] The imaging device 30 can be formed by, for example, a digital color camera mounted on the spindle 112 of the machine tool 100 in Fig. 1. The imaging device 30 is connected to the processing unit 12 by a wired communication means such as Ethernet conforming to IEEE802.3, or a wireless communication means such as a wireless LAN conforming to IEEE802.11 or Bluetooth (registered trademark) conforming to IEEE802.15.1.

[0023] The X-axis, Y-axis, and Z-axis motors 34 can be formed by servo motors 140 for the X-axis, Y-axis, and Z-axis feed axes (X-axis servo motor Mx, Y-axis servo motor My, and Z-axis servo motor Mz) of the machine tool 100 in Figure 1. The X-axis, Y-axis, and Z-axis scales 36 can be formed by an X-axis scale 116, a Y-axis scale 120, and a Z-axis scale 118.

[0024] A method for measuring a workpiece on the machine tool 100 according to this embodiment will now be described. 4 shows a screen, window 300, displayed on display device 28. Window 300 includes a plurality of function buttons 302, 304, 308, and 310, including a work measurement button 306. When the operator taps work measurement button 306, work measurement starts according to the flowchart in FIG. 3 (step S10), and a work measurement window 312 is displayed within window 300.

[0025] As one example, the workpiece measurement window 312 includes a New button 314, an Edit button 316, and an Execute button 318. The workpiece measurement window 312 may include text adjacent to the New button 314, the Edit button 316, and the Execute button 318 that describes the content of each button, as shown in FIG.

[0026] When the workpiece measurement window 312 is displayed on the display device 28, the flowchart waits for the operator to select and tap one of the New button 314, Edit button 316, and Execute button 318 (step S12). That is, when the operator taps the New button 314, it is determined that no measurement information has been registered (No in step S12), and the flowchart proceeds to step S14, and when the operator taps the Execute button 318, it is determined that measurement information has already been registered (Yes in step S12), and the flowchart proceeds to step S36.

[0027] When the operator taps the New button 314 (No in step S12), the flowchart proceeds to step S14, and a measurement information creation dialog box 320 prompting the operator to create measurement information is displayed in the work measurement window 312. The measurement information creation dialog box 320 can display text declaring that new measurement information is about to be created. In the example of FIG. 5, the measurement information creation dialog box 320 includes the text display "The following measurement information will be created."

[0028] The measurement information creation dialog box 320 also includes a number box 322, a comment box 324, and an input confirmation button 326. A unique number to be assigned to the newly created measurement information can be entered in the number box 322. In the comment box 324, text that will help the operator understand the content of the measurement information when viewed, such as the name of the workpiece measured using the measurement information, can be entered.

[0029] Here, the measurement information will be explained. The measurement information is information related to the measurement required to execute the work measurement method of the present invention, and can include, for example, the machine coordinate values ​​of the camera when measuring, the shape of the measurement object (mark or hole) when measuring the template, the number of measurement objects, the method for calculating the measurement center (for example, in the case of a two-point measurement, should one point or the midpoint of the two points be used?), the method for calculating the inclination (for example, in the case of a three-point measurement, which two points should be used?), the macro variable in which the machine coordinate values ​​(X, Y) of the measurement point should be registered, comments to be attached to the macro variable, etc.

[0030] The measurement object is a feature on the surface of the workpiece that indicates the reference position of the workpiece to be measured. In the embodiment described below, the measurement object includes a circular hole formed in the workpiece, a circular alignment mark (circular alignment mark) on the surface of the workpiece, an alignment mark of any shape other than circular (non-circular alignment mark), and the edge of the workpiece. Of these, the circular hole, circular alignment mark, and workpiece edge are measurement objects having typical shapes, and can be stored in advance in the measurement object memory unit 20.

[0031] If the measurement target is a non-circular alignment mark having a shape other than circular, the non-circular alignment mark must be registered as a template in the measurement target storage unit 20. In this application, measurement using a non-circular alignment mark registered in the measurement target storage unit 20 as a template is referred to as "template measurement." In template measurement, the operator manually moves the spindle 112 and the table 106 relative to each other in the X-axis and Y-axis directions so that the alignment mark of an arbitrary shape to be used as a reference is positioned at the center of the image captured by the imaging device (camera). The coordinates of the center of the alignment mark of the arbitrary shape are measured, and the coordinate values ​​of the reference point of the arbitrary shape are stored as the measurement result. In this way, the machine coordinate values ​​of the center position determined by template measurement can be used as the reference point of the alignment mark when the alignment mark is registered as a template.

[0032] The measurement information can further include setting parameters for the imaging device (camera), such as a parameter (flag) for manually or automatically setting the exposure time of the imaging device, the exposure time when manually set, a parameter (flag) for manually or automatically setting the gain of the imaging device, a work offset for registering the measurement center and tilt, a parameter (flag) for determining whether to register the measurement center and tilt in the work offset, the offset amount when registering the measurement center and tilt in the work offset, the minimum and maximum diameter of the hole to be measured when the measurement object is a hole, and the minimum and maximum contrast when extracting the hole to be measured.

[0033] The measurement information can further include the width (length in the X-axis direction) and height (length in the Y-axis direction) of the area in which the non-circular alignment mark is placed in the case of template measurement, and the minimum and maximum contrast values ​​when creating the mark as a template.

[0034] After the operator enters a number in number box 322 and text in comment box 324, he or she taps input confirmation button 326 to open measurement information input window 328. As an example, measurement information input window 328 shown in FIG. 6 includes an origin calculation method selection box 332, an origin measurement method input box 334, a tilt calculation method input box 336, a setting confirmation box 338, and a measurement result registration box 340.

[0035] The origin calculation method selection box 332 includes a one-point measurement button 332a, a two-point measurement button 332b, and a three-point measurement button 332c. The one-point measurement button 332a is used when one measurement point is used as the origin. The two-point measurement button 332b is used when the midpoint between two points is used as the origin. The three-point measurement button 332c is used when the center of three points on a circle is used as the origin. There are five types of calculation methods: when one measurement point is used as the origin, when the midpoint between two points is used as the origin, when the center of three points on a circle is used as the origin, when three vertices of a rectangle are used as the origin, and when four measurement points are used as the origin.

[0036] The origin measurement method input box 334 is used to select the calculation method for the workpiece coordinate system offset Y,Y from a drop-down list. The tilt calculation method input box 336 is used to input the calculation method for the tilt angle of the workpiece relative to the X axis in the XY plane. For example, the tilt calculation method may be the tilt angle relative to the Y axis as well as the tilt angle relative to the X axis. For example, "First point P1 (X p1 ,Y p1 ) and the second point P2(X p2 ,Y p2 ) The angle θ of the line connecting θ=ACOS((Xp1 -X p2 ) / ((X p1 -X p2 ) 2 +(Y p1 -Y p2 ) 2 ) 1 / 2 ) This becomes:

[0037] The setting confirmation box 338 graphically displays the settings for newly created measurement information. The example in Fig. 6 indicates that a measured point is to be set as the origin of the workpiece in the XY plane. The measurement result registration box 340 includes a macro variable input box 340a for registering the measurement result and a comment input box 340b. The example in Fig. 6 indicates that the X and Y coordinate values ​​of the measured point are to be registered in macros indicated by numbers 100 and 101, respectively.

[0038] After inputting required values ​​into each input box in the measurement information input window 328 via the input unit 24, the operator taps the measurement button 342 to open a manual measurement window 344 (FIG. 7). By opening a camera condition setting tab 346 in the manual measurement window 344, it is possible to set the conditions of the imaging device (camera) as measurement information. In the example of FIG. 7, the camera condition setting tab 346 includes an exposure time selection box 346a for selecting whether the exposure time, as an imaging device condition, is to be set automatically by the system or manually by the operator, and a gain selection box 346b for selecting whether the gain of the imaging device is to be set manually or automatically.

[0039] After setting the imaging device conditions, it becomes possible to set the measurement target by opening the detection condition tab 348. The detection condition tab 348 includes a plurality of measurement target selection buttons for selecting the measurement target. In the example shown in Fig. 8, the measurement target selection buttons include a hole button 348a, a circle outline button 348b, a template measurement button 348c, and an edge button 348d.

[0040] Tapping the Hole button 348a selects a hole (round hole) formed in the workpiece as the measurement object. Tapping the Circular Contour button 348b selects a circular alignment mark provided on the workpiece surface as the measurement object. At this time, a predetermined frame that can surround the measurement object may be displayed in the manual measurement window 344. This frame is called a template frame, and is shown by a rectangular frame 210 in FIG. 11, for example. Tapping the Template Measurement button 348c selects a non-circular alignment mark provided on the workpiece surface that has a shape other than circular as the measurement object. Tapping the Edge button 348d selects the edge of the workpiece as the measurement object.

[0041] Circular holes, circular alignment marks, and edges as measurement targets have already been registered and stored in the measurement target storage unit 20. Non-circular alignment marks are measurement targets that can be registered arbitrarily by the operator. When the detection conditions tab 348 is opened, the flowchart determines in step S15 whether or not template measurement is being performed.

[0042] As an example, tapping the hole button 348a selects a hole that has already been registered as a measurement target. Since the measurement of the hole is not a "template measurement" that uses a non-circular alignment mark as a template, the determination in step S15 is No, and the flowchart proceeds to step S18. At this time, the workpiece surface imaged by the imaging device 30 is displayed in the image display area 350 (FIG. 9). The image of the workpiece surface includes a circular hole 361.

[0043] In step S18, the operator uses manual pulse generator 50 to relatively move spindle 112 and table 106 of machine tool 100 in the X-axis and Y-axis directions so that center Om of hole 361 to be measured is located near intersection Oc of the cross lines while viewing the image of the workpiece surface displayed in image display area 350. Note that imaging device 30 is previously adjusted so that intersection Oc of the cross lines is located on the rotation axis of spindle 112 of machine tool 100 when it is attached to spindle 112.

[0044] When aligning the center Om of the circular hole 361 with the intersection Oc of the cross lines, the center Om of the hole 361 is not actually displayed, so the intersection Oc of the cross lines and the center Om of the hole 361 are in temporary positions that do not necessarily coincide. Next, when the operator taps the detection button 372, the processing unit 12 detects the hole 361 in the image data captured by the imaging device 30, reads the coordinate values ​​of the intersection Oc of the cross lines from the X-axis scale 116 and the Y-axis scale 120, and calculates the coordinate value of the center Om of the hole 361. Based on the calculated coordinate value of the center Om of the hole 361 in the image data, the X-axis and Y-axis feed axes are automatically driven until the center Om of the circular hole 361 coincides with the intersection Oc of the cross lines. The coordinate values ​​of the intersection Oc of the cross lines are read from the X-axis scale 116 and the Y-axis scale 120 and acquired as the coordinate value of the center Om of the circular hole 361. The obtained coordinate values ​​of the center Om of the circular hole 361 are stored in the measurement point coordinate storage unit 18 as the coordinate values ​​of the reference point of the hole 361 to be measured (step S20), and are also displayed in the measurement result display area 352 as the measurement result.

[0045] In step S15, if the operator taps the circular contour button 348b, the measurement target is a circular alignment mark. Since measurement using a circular alignment mark is not a "template measurement," the determination in step S15 is No, and the flowchart proceeds to step S18. At this time, the workpiece surface imaged by the imaging device 30 is displayed in the image display area 350 (FIG. 10). The image of the workpiece surface includes the circular alignment mark 363.

[0046] In step S18, while viewing the image of the workpiece surface displayed in image display area 350, the operator uses manual pulse generator 50 to move spindle 112 and table 106 of machine tool 100 relatively in the X-axis and Y-axis directions so that center Om of circular alignment mark 363 is near intersection Oc of the cross lines.

[0047] Next, when the operator taps the detection button 372, the processing unit 12 detects the circular alignment mark 363 in the image data captured by the imaging device 30, reads the coordinate values ​​of the intersection Oc of the cross lines from the X-axis scale 116 and the Y-axis scale 120, and calculates the coordinate value of the center Om of the circular alignment mark 363. Based on the calculated coordinate value of the center Om of the circular alignment mark 363 on the image data, the X-axis and Y-axis feed axes are automatically driven until the center Om of the circular hole 363 coincides with the intersection Oc of the cross lines. The coordinate value of the intersection Oc of the cross lines is read from the X-axis scale 116 and the Y-axis scale 120 and obtained as the coordinate value of the center Om of the circular alignment mark 363. The obtained coordinate value of the center Om of the circular alignment mark 363 is stored in the measurement point coordinate storage unit 18 as the reference point of the circular alignment mark 363 to be measured (step S20), and is also displayed as the measurement result in the measurement result display area 352.

[0048] In step S15, even if the operator selects an edge as the measurement target and taps the edge button 348d, the determination in step S15 is No, and the flowchart proceeds to step S18. The workpiece surface imaged by the imaging device 30 is displayed in the image display area 350. The image of the workpiece surface includes the edge portion of the workpiece (not shown).

[0049] In step S18, while viewing the image of the workpiece surface displayed in the image display area, the operator uses the manual pulse generator 50 to move the spindle 112 and the table 106 relatively in the X-axis and Y-axis directions so that the intersection of the cross lines is positioned on the edge of the workpiece to be measured.

[0050] Next, when the operator taps the detection button 372, the processing unit 12 detects the edge of the workpiece in the image data captured by the imaging device 30, reads the coordinate values ​​of the intersection point Oc of the cross lines from the X-axis scale 116 and the Y-axis scale 120, and calculates the coordinate values ​​of the edge of the workpiece. The calculated coordinate values ​​of the edge of the workpiece are stored in the measurement point coordinate storage unit 18 (step S20), and are displayed in the measurement result display area 352 as the measurement result.

[0051] Since the edge of the workpiece is a straight line, the coordinate value of the edge is the X coordinate or the Y coordinate. That is, when the processing unit 12 detects the edge of the workpiece, if the detected edge extends in the X-axis direction, the Y coordinate becomes the coordinate value of the edge, and if the detected edge extends in the Y-axis direction, the X coordinate becomes the coordinate value of the edge.

[0052] In step S15, when the operator taps the template measurement button 348c, the processing unit 12 determines that template measurement has been selected (Yes in step S15), and the flowchart proceeds to step S16. At this time, the image display area 350 displays the workpiece surface imaged by the imaging device 30. In the example of Fig. 11, the image of the workpiece surface includes a cross-shaped alignment mark 360 as a non-circular alignment mark.

[0053] If a non-circular alignment mark to be measured has been registered (Yes in step S16), the operator, while viewing the image of the workpiece surface displayed in the image display area 350, uses the manual pulse generator 50 to relatively move the spindle 112 and the table 106 in the X-axis and Y-axis directions so that the center Om of the non-circular alignment mark 360 to be measured is located near the intersection Oc of the crosslines displayed in the template frame 210 (step S18). That is, when the operator operates the manual pulse generator 50 in step S16, the processing unit 12 determines that the non-circular alignment mark 360 to be measured has been registered. What is registered in the processing unit 12 is image data of the non-circular alignment mark 360 and position information on the image data that indicates which position in the image is the center Om of the non-circular alignment mark 360.

[0054] Next, when the operator taps the detection button 372, the processing unit 12 extracts the same shape as the registered non-circular alignment mark 360 from the captured image of the workpiece surface, and automatically drives the X-axis and Y-axis feed axes until the center Om of the non-circular alignment mark 360 on the captured workpiece surface coincides with the intersection Oc of the cross lines. The coordinates of the intersection Oc of the cross lines are read from the X-axis scale 116 and the Y-axis scale 120.

[0055] When aligning the center Om of non-circular alignment mark 360 with the intersection Oc of the cross lines displayed within template frame 210, it is ideal for the intersection Oc and center Om to coincide, as shown in FIG. 12 . However, in reality, the center Om of the non-circular alignment mark is not shown on the displayed image, and the operator manually moves spindle 112 and table 106 relative to each other in the X-axis and Y-axis directions using manual pulse generator 50. Therefore, as shown in the example of FIG. 13 , in reality, the intersection Oc of the cross lines and the center Om of non-circular alignment mark 360 are in temporary positions that do not necessarily coincide.

[0056] The processing unit 12 reads the coordinate values ​​of the intersection point Oc of the cross lines from the X-axis scale 116 and the Y-axis scale 120, stores them in the measurement point coordinate memory unit 18 as the reference point of the non-circular alignment mark 361 (step S20), and displays the measurement results in the measurement result display area 354.

[0057] After the measurement results are stored in step S20, the operator taps the proceed button 356, which causes a registration dialog box 358 (FIG. 14) to be displayed. When the operator taps the OK button 358a in the registration dialog box 358, the measurement results are stored and registered in the measurement information storage unit 22 (step S22), and the flowchart proceeds to step S30. At this time, the manual measurement window 344 (FIG. 7) is displayed again on the display device 28.

[0058] In step S30, if measurement of all measurement targets has not been completed and measurement targets to be registered remain, the operator taps the hole button 348a, the circular contour button 348b, or the edge button 348d of the measurement target selection buttons in the manual measurement window 344. This causes the processing unit 12 to determine that all measurement targets have not been measured. In other words, the determination in step S30 is No, and the flowchart returns to step S15.

[0059] In this way, steps S15 to S22 are repeated until measurements are completed for all measurement targets. When measurements are completed for all measurement targets, the operator taps the proceed button 356, the determination in step S30 becomes Yes, the measurement information and measurement results are displayed in the measurement information window 370 (FIG. 15), the measurement information and measurement results are stored and registered in the measurement information storage unit 22 (step S32), and the manual measurement process ends (step S34).

[0060] When registering a new non-circular alignment mark as a measurement target, the operator taps the template measurement button 348c (FIG. 11). The processing unit 12 determines that template measurement has been selected by tapping the template measurement button 348c (Yes in step S15), and determines that the measurement target has not been registered (No in step S16).

[0061] Thus, the flow chart proceeds to step S24. As shown in Fig. 16, the work surface imaged by the imaging device 30 is displayed in the image display area 350. In the example of Fig. 16, the non-circular alignment mark 362 to be newly registered has an equilateral triangular shape.

[0062] Next, while viewing the image of the workpiece surface displayed in the image display area, the operator manually moves the spindle 112 and the table 106 relative to each other in the X-axis and Y-axis directions using the manual pulse generator 50 so that the position to be set at the center Om of the non-circular alignment mark 362 to be registered is aligned with the intersection Oc of the cross lines (step S24).

[0063] Next, by tapping the new creation button 368, a non-circular alignment mark 362 (an equilateral triangle in the example of FIG. 16) to be registered is extracted from the captured image of the workpiece surface within the template frame 210. The intersection point Oc of the cross lines and the centroid of the equilateral triangle that is the non-circular alignment mark 362 do not necessarily need to coincide, and the position of the intersection point Oc of the cross lines in the extracted alignment mark is used as the reference point of the non-circular alignment mark 362.

[0064] Next, when the detect button 372 (FIG. 11) is tapped, the processing unit 12 stores and registers the shape (an equilateral triangle in the example of FIG. 16) and center position (the position of the center Om on the image) of the alignment mark 362 as a new non-circular alignment mark in the measurement target storage unit 20 (step S22). The processing unit 12 further reads the coordinates of the intersection Oc of the cross lines from the X-axis scale 116 and the Y-axis scale 120, and automatically drives the X-axis and Y-axis feed axes based on the coordinate values ​​of the center Om of the non-circular alignment mark 362 on the image data until the center Om of the non-circular alignment mark 362 coincides with the intersection Oc of the cross lines. The coordinate values ​​of the intersection Oc of the cross lines are read from the X-axis scale 116 and the Y-axis scale 120 and acquired as the coordinate values ​​of the center Om of the non-circular alignment mark 362. The obtained coordinate values ​​of the center Om of the non-circular alignment mark 362 are stored in the measurement point coordinate storage unit 18 as coordinate values ​​of the reference point of the non-circular alignment mark 362 to be measured (step S22), and are also displayed in the measurement result display area 364.

[0065] If the measurement information has been registered (Yes in step S12), the operator can measure the workpiece using a measurement program based on the registered measurement information, as will be described below.

[0066] When the operator taps execute button 318 after workpiece measurement window 312 is displayed, processing unit 12 determines in step S12 that the measurement information has been registered, and registered measurement information list window 380 (FIG. 17) is displayed. Next, when the operator selects one or more pieces of measurement information from registered measurement information list window 380 and taps a select button included in detection condition tab 348, setup window 382 (FIG. 18) opens. At this time, the corresponding measurement information is read from measurement information storage unit 22, and the measurement program corresponding to the measurement information is read from measurement program storage unit 16, and an image representing the operation of machine tool 100 in accordance with the measurement information and measurement program is displayed in setup window 382.

[0067] FIG. 18 shows an example setup window when registered measurement information No. 1 is selected. In this example, one measurement target (hole, circular alignment mark, or noncircular alignment mark) on the workpiece surface is measured. Specifically, the imaging device 30 moves above the workpiece to a position above the reference point of the measurement target (a position retreated along the Z axis), then approaches the workpiece by 130 mm along the Z axis (moves downward), captures an image, measures it, and then moves away from the workpiece by 100 mm along the Z axis (moves upward). Furthermore, the fact that measurement information is registered indicates that a workpiece of the same shape has already been measured while inputting the measurement information, and this is intended for subsequent works of the same shape. Even when measuring workpieces of the same shape, the X-axis and Y-axis positions of the measurement target on the workpiece surface will vary for each workpiece due to errors when mounting the workpiece on the table 106.

[0068] When the operator checks the measurement information to be performed in setup window 382 and taps confirmation (Yes) button 384, a pop-up window 386 (FIG. 19) is displayed, prompting the operator to press a cycle start switch (not shown) located on operation panel 200. When the operator presses the cycle start switch located on operation panel 200, imaging device 30 moves to a predetermined measurement position in accordance with the measurement program (step S14), performs measurement, and the measurement results are stored in measurement point coordinate storage unit 18 (step S40). The operator repeats steps S36 to S40 until measurements are completed for all measurement targets (No in step S42).

[0069] For example, as shown in Figures 20 to 23, if three non-circular alignment marks 362-1, 362-2, 362-3, and 362-4 are provided on the surface of a workpiece to be measured, the measurement program can be configured to measure the positions of the centers Om-1, Om-2, Om-3, and Om-4 of the three non-circular alignment marks 362-1, 362-2, 362-3, and 362-4 one by one.

[0070] Prior to step S20, the operator manually fine-tunes the machine coordinate values ​​(X, Y) of the measurement point to position the hole or alignment mark approximately at the center of the camera image before performing the measurement (step S18). Based on the measurement results obtained by manually aligning the measurement point of the hole or alignment mark approximately at the center of the camera image, the camera position is automatically fine-tuned so that the measurement point is at the center of the camera image. This enables accurate measurements without being affected by errors in the angle of view of the digital camera (image capture device 30) or aberrations of the camera lens. Furthermore, as mentioned above, whether an operator can manually align the measurement point of the hole or alignment mark to the center of the camera image varies depending on the operator's skill. Therefore, in the present invention, the measurement point is manually aligned approximately at the center of the camera image in advance, and then the measurement is performed after automatic fine-tuning so that the measurement point is at the center of the camera image. In other words, by performing measurements multiple times, accurate measurement results can be obtained that are not affected by the operator's skill.

[0071] According to this embodiment, even if measurement information related to the object to be measured is not registered, for example, when machining a new workpiece that has not been machined before with the machine tool 100, the imaging device 30 is manually moved above the workpiece W so that the object to be measured is positioned approximately in the center within the field of view of the imaging device 30, the measurement object is extracted from the image of the workpiece surface that has been captured, its center coordinates are determined, and stored in the measurement information memory unit 22.Therefore, for workpieces to be measured using the same measurement information, for example, the second or subsequent workpieces W, a measurement program corresponding to the measurement of the workpiece W can be generated based on the measurement information read out from the measurement information memory unit 22, making automatic measurement possible.

[0072] Furthermore, while it is obvious that the center of a hole formed in a workpiece is the measurement point, in the case of an alignment mark, where the measurement point is varies depending on the shape of the mark.The shape of the alignment mark and its measurement point can be registered, and the position in machine coordinates can be determined by template measurement using an image taken with an imaging device (camera).This means that there is no need to prepare CAD drawing data of the alignment mark in advance, as was necessary in the past, and the shape of the alignment mark and the measurement point can be easily taught to the system. [Explanation of symbols]

[0073] 10 Workpiece measuring device 12 Processing section 14 Data storage unit 16 Measurement program memory section 18 Measurement point coordinate memory section 20 Measurement target memory section 22 Measurement information storage unit 24 Input section 26 Display control unit 28 Display device 30 Imaging device 50 Manual Pulse Generator 100 Machine tools 102 Same bed 102 beds 104 Column 106 Tables 108 X-axis slider 110 Spindle head 112 Main axis 140 Feed axis servo motor 150 Control device (NC device) 200 Control panel 202 Display Panel 204 Key input section

Claims

1. A spindle on which tools are attached; a table facing the spindle and on which a workpiece is mounted; a feed axis that moves the main shaft and the table relatively; an imaging device that can be attached to a spindle of a machine tool and captures an image of a surface of a workpiece fixed to the table; a display device that displays an image of the surface of the workpiece captured by the imaging device; a processing unit that extracts a measurement object from image data of the surface of the workpiece captured by the imaging device and calculates coordinate values ​​of a reference point of the measurement object; Equipped with The processing unit When the center of the object to be measured is positioned relative to the table at a temporary position that is located within the range of the image of the workpiece surface displayed on the display device, the processing unit determines the position of the reference point of the object to be measured on image data of the workpiece surface imaged by the imaging device attached to the spindle, moves the feed axis relatively so that the measurement point of the object to be measured on the image data is at the center position of the image captured by the imaging device, and measures the coordinate value of the feed axis as the coordinate value of the reference point of the object to be measured.

2. The processing unit further storing the determined coordinate values ​​of the reference point of the measurement object in a data storage unit; 2. The machine tool according to claim 1, wherein, after the workpiece is replaced with a new workpiece, the coordinate values ​​of the measurement object are read from the data storage unit, the coordinate values ​​are used as temporary positions of the new workpiece to generate a measurement program, and the new workpiece is measured in accordance with the measurement program.

3. the measurement object is a hole formed in the workpiece, a circular alignment mark provided on the surface of the workpiece, or an edge of the workpiece, the machine tool further includes a manual operation unit for an operator to control the feed axis in a manual operation mode; 2. The machine tool according to claim 1, wherein the positioning to the temporary position is performed by the manual operation unit.

4. 2. The machine tool according to claim 1, wherein the measurement object is an alignment mark of any shape provided on the surface of the workpiece.

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