JP5351552B2 - Measuring device and measuring method thereof, machining position correcting device of cutting machine, and machining position correcting method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and a method capable of accurately detecting a displacement amount of a cutting tool with respect to a workpiece to accurately correct a working position. <P>SOLUTION: A turret gauge 46 comprises an invar body 47 and a gauge body 48 having a different thermal expansion ratio. An A point of the gauge body 48 and a tip 47A of the invar body are imaged in one view at initial setting time and at a time of a calibration cycle (CS), and image data are compared with one another to detect temperature of the gauge body 48. A length between the A point and a B point of the gauge body 48 at a time of CS is derived from the image data. This actual length is compared with a theoretical length between the A point and the B point at the temperature of the gauge body 48 at a time of CS, so that a thermal displacement amount of a ball screw can be accurately detected and displacement of the working position of the cutting tool can be accurately corrected, which is resulted in improvement of working accuracy of the workpiece. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a measuring device that measures the amount of displacement of a cutting tool by performing image processing on an object to be measured, such as a cutting tool, a measuring method thereof, a machining position correction device for a cutting machine, and a machining position correction method thereof.

  For example, Patent Document 1 discloses a measuring device that measures an expansion coefficient or the like based on a change amount when a sample whose expansion coefficient or contraction coefficient is unknown is set to a predetermined temperature. This measuring apparatus measures the expansion coefficient of the sample and the like based on image data of the amount of light passing through a lens positioned at a predetermined position after setting the sample to a predetermined temperature.

  In Patent Document 2, a cutting tool (hereinafter also referred to as a tool) such as a cutting tool for cutting a workpiece, which is a workpiece, is imaged with a camera, and the breakage or wear of the tool is observed based on the image data. In the tool observation method, the tool is rotated or moved at least before or after machining the workpiece, and a plurality of image data is acquired, and the focused image data is selected from the plurality of image data. A tool observing method for observing breakage or wear of a tool is described.

JP-A-4-3535751 JP 2001-269844 A

  Patent Document 1 is an apparatus that measures the expansion rate or contraction rate of a sample, and does not measure the temperature of the sample. Moreover, even if it is an apparatus which uses a camera and image-processes the tool front-end | tip and observes a tool like patent document 2, it is difficult to maintain the precision with respect to the thermal displacement of a camera itself and a camera holding bracket. That is, even if the camera is tilted slightly, the measurement error is geometrically enlarged according to the distance between the camera and the tool to be detected, and the measurement accuracy is lowered. Therefore, when the conventional technique disclosed in Patent Document 2 is applied to a cutting machine, it is difficult to accurately measure the wear amount and displacement amount of the cutting tool with respect to the original work.

  The present invention relates to a measuring apparatus capable of accurately measuring the temperature of an object to be measured, its measuring method, and a machining position correction apparatus for a cutting machine capable of accurately detecting a displacement amount of a cutting tool relative to a workpiece and correcting a machining position with high accuracy. And providing a machining position correction method thereof.

A measuring apparatus according to the present invention includes a reference body serving as a reference for the amount of thermal displacement of an object to be thermally displaced, an imaging unit that images the reference body and the object to be measured in the same imaging region, and the imaging unit. The recording means for recording the reference image data at the reference temperature generated in the above, the reference image data recorded in advance in the recording means and the image data at the time of arbitrary measurement generated by the imaging means are collated And calculating a difference value between the reference body and the measured object at the time of the arbitrary measurement based on the verification result of the verification means and the measured object at the time of the arbitrary measurement based on the difference value . Computing means for computing temperature.

In the measurement method according to the present invention, a reference body that serves as a reference for the amount of thermal displacement of an object to be measured that is thermally displaced as a subject is imaged in the same imaging area in the imaging means, and is recorded in advance in the recording means. The reference image data at the time of temperature and the image data at the time of measurement at the time of arbitrary measurement are collated by the collating means, and based on the collation result of the collating means, the difference value between the reference body at the arbitrary measurement and the object to be measured And the temperature of the object to be measured at the time of the arbitrary measurement is measured based on the difference value .

  A machining position correction apparatus for a cutting machine according to the present invention includes an imaging unit that images a subject, a reference gauge (arranged on a workpiece holding chuck) for measuring a position error of the imaging unit, and a cutting tool. Reference means for detecting the amount of displacement of the cutting tool (displaced or missing) and detecting the temperature of the mounting base, and the reference gauge and the reference means corresponding to the reference gauge are arranged on the mounting base to be mounted. Recording means for recording the reference image data at the reference temperature imaged in the same imaging area by the imaging means, the reference image data recorded in advance in the recording means, and the above-mentioned generated by the imaging means A collating unit that collates image data at the time of arbitrary measurement of an object, and a correcting unit that corrects the processing position of the cutting tool based on the collation result of the collating unit. And, equipped with a.

  The machining position correction method detects the displacement amount of a reference gauge (located on the chuck) for measuring the position error of the imaging means and the cutting tool (displaced or missing) and the temperature of the mounting base of the cutting tool. The reference means arranged on the mounting base for detecting the image, the corresponding reference gauge and the reference means are imaged in the same imaging area of the imaging means as a subject of the imaging means, and the recording means The reference image data at the reference temperature recorded in advance and the image data at the time of measurement at the arbitrary measurement are collated by the collating means, and the machining position of the cutting tool is corrected based on the collation result of the collating means. .

  The reference means having the above-described structure includes a mounting means made of the same material as the metal constituting the mounting base and having a reference portion, and has a free end fixed to only one end of the mounting means and corresponding to the reference portion. You may make it provide the reference | standard body used as the reference | standard of the thermal displacement amount of the said attachment means. Moreover, you may make it the attachment means of the said structure provide at least 2 or more measurement base points. Furthermore, the reference body having the above configuration may be formed of a material having a different coefficient of thermal expansion compared to the metal forming the mounting base, for example, a small material or a large material. Further, the reference body having the above configuration may be a bimetal body.

  Further, the machining position correction apparatus for a cutting machine according to the present invention includes an imaging means for imaging a subject, a reference gauge disposed on a workpiece holding chuck for measuring a position error of the imaging means, and one end of the chuck. Is fixed and has a free end corresponding to the reference gauge, and a reference body serving as a reference for the thermal displacement amount of the reference gauge, and the free of the reference gauge and the reference body corresponding to the reference gauge. Recording means for recording the reference image data at the reference temperature imaged in the same imaging area by the imaging means with the edge as a subject, the reference image data recorded in advance in the recording means, and generated by the imaging means A collating unit that collates image data at the time of arbitrary measurement of the subject to be measured, and a machining position of the cutting tool is corrected based on a collation result of the collating unit. Includes a correction means, the. The reference body having the above configuration may be a material having a different coefficient of thermal expansion as compared with the material holding the reference gauge. Further, the reference body having the above configuration may be a bimetal body.

  The machining position correction method includes a reference gauge arranged on a chuck for holding a workpiece for measuring a position error of an image pickup means, a reference for thermal displacement of the reference gauge, and one end fixed to the chuck and a free end. The reference body arranged so as to correspond to the reference gauge is matched, and the corresponding reference gauge and the free end of the reference body are imaged in the same imaging area of the imaging means as the subject of the imaging means. In addition, the reference image data recorded at the reference temperature recorded in advance in the recording means and the measurement image data at the time of arbitrary measurement are collated by the collating means, and the machining position of the cutting tool is based on the collation result of the collating means. Correct.

  That is, the present invention is a measuring device, a machining position correcting device for a cutting machine including the measuring device, a measuring method, and a machining position correcting method for a cutting machine using the measuring method.

In the measuring apparatus and the measuring method according to the present invention, a reference body, which is a reference for the amount of thermal displacement of an object to be measured that is thermally displaced as a subject, is imaged in the same imaging area of the imaging means and recorded in advance in the recording means. The reference image data at the reference temperature and the measurement image data at any measurement are collated by the collating means, and the difference value between the reference body and the measured object at the arbitrary measurement based on the collation result of the collating means And the temperature of the object to be measured at an arbitrary measurement is measured based on the difference value, so that the object to be measured at the time of the arbitrary measurement is based on the difference value due to the respective thermal expansion coefficients of the reference body and the object to be measured. The temperature can be measured accurately. Further, since the temperature of the object to be measured can be measured in a non-contact state where there is no connection of wiring or the like from a remote location, a member for wiring connection such as a brush holder can be eliminated, and the configuration of the measuring apparatus can be simplified.

  A machining position correction apparatus and a machining position correction method for a cutting machine according to the present invention include a reference gauge (located on a chuck) for measuring a position error of an imaging means, and a displacement of a cutting tool (displaced or missing). In order to detect the quantity and to detect the temperature of the mounting base of the cutting tool, the reference means arranged on the mounting base is made to correspond, and the corresponding reference gauge and the reference means are used as subjects of the imaging means in the imaging means. The collation means collates the reference image data at the reference temperature and the image data at the time of arbitrary measurement recorded in the same imaging area and recorded in advance in the recording means, and the collation result of the collation means Because the machining position of the cutting tool is corrected based on the above, the temperature of the feed mechanism (ball screw mechanism, etc.) such as the mounting base and the cutting work are determined, for example, during non-cutting during operation. Since the machining position is corrected by calculating the displacement amount, even if the machining position is displaced due to thermal expansion / contraction of the feed mechanism during operation, the displacement of the machining position can be accurately corrected, The machining accuracy of the workpiece can be improved.

  Further, a machining position correction apparatus and a machining position correction method for a cutting machine according to the present invention include a reference gauge disposed on a workpiece holding chuck for measuring a position error of an imaging unit, and a thermal displacement amount of the reference gauge. And a reference body disposed so that one end is fixed to the chuck and a free end corresponds to the reference gauge, and the corresponding reference gauge and the free end of the reference body are connected to the imaging means. While collating the reference image data at the reference temperature and the image data at the time of arbitrary measurement recorded in advance in the same imaging area in the imaging means as a subject and prerecorded in the recording means, Since the reference position of the cutting tool is corrected based on the collation result of the collation means, even if the machining position is displaced due to thermal expansion / contraction of the chuck, the machining position The displacement accuracy can be corrected, thereby improving the machining accuracy of the workpiece.

It is a front view which shows the single axis | shaft type turret lathe of Example 1 which concerns on this invention. It is a side view which shows the principal part of the turret lathe shown in FIG. FIG. 3 is an end view of the camera device shown in FIG. 2. It is a figure explaining the positional relationship when a byte and a reference gauge are stored in a camera visual field and imaged with the camera shown in FIG. It is a figure explaining the division | segmentation state of the visual field of the camera apparatus shown in FIG. It is a figure explaining one side of the visual field shown in FIG. It is a figure which shows the mode of an inspection of a cutting tool, (A) is a figure which shows a mode that the edge of the chip | tip is calculated | required, (B)-(D) is a figure which shows a mode that the nose of a chip | tip is calculated | required. 1 is a side view of a turret gauge according to Example 1. FIG. It is a bottom view of the turret gauge shown in FIG. It is a figure explaining the measurement base point A of the turret gauge shown in FIG. 8, and its visual field state. It is a figure explaining the measurement base point B of the turret gauge shown in FIG. 8, and its visual field state. It is a figure which shows the experimental data regarding image recognition accuracy. It is a block diagram of the turret lathe shown in FIG. It is a flowchart figure regarding the initial data setting mode of the turret gauge which concerns on the turret lathe shown in FIG. It is a flowchart figure regarding the initial data setting mode of the image taking-in position which concerns on the turret lathe shown in FIG. It is a figure explaining the processing content of the flowchart of FIG. It is a flowchart figure which shows the flow of a process in a calibration cycle. It is a subroutine figure regarding the byte image processing mode shown in FIG. It is a subroutine figure regarding the measurement mode of a turret gauge shown in FIG. It is a top view which shows the structure of the principal part of the biaxial front lathe of Example 2 which concerns on this invention. It is a front view which shows the structure of the principal part of the 2-axis front lathe shown in FIG. 6 is a side view of a turret gauge according to Embodiment 2. FIG. It is a figure explaining the measurement base point A of the turret gauge shown in FIG. 22, and its visual field state. It is a figure explaining the measurement base point B of the turret gauge shown in FIG. 22, and its visual field state. It is a side view which shows the modification of the gauge main body which comprises a turret gauge. It is a figure which shows the structure of the principal part of the chuck gauge of Example 3 which concerns on this invention. It is a flowchart regarding the initial data setting mode of the chuck gauge shown in FIG. It is a flowchart regarding the measurement mode of the chuck gauge shown in FIG. It is a figure which shows the structure of the principal part of the chuck gauge of Example 4 which concerns on this invention. It is a figure which shows the other modification of the reference | standard body which concerns on this invention, for example, an invar body. It is a figure which shows the other modification of the reference | standard means based on this invention, for example, a turret gauge.

  Hereinafter, specific Embodiments 1 to 4 will be described as modes for carrying out the present invention.

  Hereinafter, based on FIG. 1 thru | or FIG. 13, the measuring apparatus which is Example 1 of this invention, the processing position correction apparatus of a cutting machine provided with the measuring apparatus, a measuring method, and the processing position correction method of a cutting machine using the measuring method Will be described. The cutting machine according to the first embodiment will be described as a single-axis type turret lathe (hereinafter simply referred to as a lathe) S.

(Schematic configuration of lathe S)
As shown in FIG. 1, in the lathe S, a headstock 10 fixed so that its axis line is parallel to the Z-axis direction (horizontal direction), a direction parallel to the Z-axis direction, and a direction orthogonal to the Z-axis direction. A turret device 20 that is movable in a direction parallel to the X-axis direction inclined backward by 60 degrees with respect to the vertical direction is arranged so as to face. A spindle 11 is supported on the spindle stock 10 so as to be rotatable about an axis parallel to the Z-axis direction. The main shaft 11 is rotationally driven by a main shaft drive motor (not shown). A chuck 12 that holds a workpiece W, which is a workpiece, is attached to the tip of the spindle 11 on the turret device 20 side. The headstock 10 and the spindle drive motor having such a configuration are disposed on the bed 13.

  The turret device 20 is provided with a turret tool post (hereinafter simply referred to as a tool post) 21 that is a mounting base so as to be able to rotate and index around an axis parallel to the Z-axis direction. On the tool post 21, a plurality of cutting tools 25 and 26 (see FIG. 4) are attached at equal angular intervals on the circumference. The turret device 20 having such a configuration is arranged to be slidable in the X-axis direction and the Z-axis direction. The turret device 20 is moved via a ball screw mechanism (not shown) by the NC motor 52 of the NC table 50 shown in FIG. That is, the turret device 20 moves with respect to the headstock 10 that is fixedly arranged. On the other hand, the tool post 21 is rotationally driven by a turret motor 54 shown in FIG.

  As shown in FIG. 1, a cover 14 that covers the headstock 10 and the turret device 20 is provided in the lathe S, and a partition wall 15 that partitions the headstock 10 side and the turret device 20 side is provided in the cover 14. ing. The partition wall 15 is made up of cutting powder, cutting fluid, or the like that scatters when the outer periphery or end face of the workpiece W held by the chuck 12 by the cutting tools 25 and 26 shown in FIG. It is provided so as not to adhere to the table 10 or the like. That is, the headstock 10 side partitioned by the partition wall 15 is an isolation zone S1, and the turret device 20 side is a processing zone S2.

  The main shaft 11 protrudes from the hole provided in the partition wall 15 toward the machining zone S <b> 2, and a chuck 12 is attached to the tip of the main shaft 11. As shown in FIGS. 2 and 4, the reference gauge 18 arranged so as to protrude from the outer periphery of the chuck 12 measures a position error of the camera device 28 described later. Used in common for both bytes 26. The reference gauge 18 is formed of heat-treated steel in order to prevent wear due to chips or the like.

(Configuration of camera device 28)
As shown in FIGS. 1 and 2, in the lathe S, a camera device 28 as an imaging unit is fixed at a predetermined position on the machining zone S2 side. The camera device 28 images, for example, the chips 25A and 26A shown in FIG. 4 of the cutting tools (hereinafter also referred to as cutting tools) 25 and 26 (the cutting edge when the cutting tool is not a chip such as a cutting tool) and the like. Data is output to the CPU 60 (see FIG. 13). Then, the CPU 60, which is a collating unit, a calculating unit, and a correcting unit, collates and calculates the displacements of the chips 25A and 26A, and corrects the machining position of the cutting tool based on the results.

  As shown in FIG. 3, the housing 28A of the camera device 28 has a two-stage structure. The upper stage of the housing 28A is an imaging space (also referred to as a lens chamber), and the lower stage of the housing 28A is a dust-proof space (shutter chamber). It is also called). Specifically, for example, a camera 30 of 5 million pixels, a lens 29, mirrors 31A and 31B, and a focusing lens 33 are accommodated in the upper stage of the rectangular tube-shaped housing 28A. A transparent protective glass 34 is mounted on the lower surface of the upper stage of the camera case 28 </ b> A so as to face the lower side of the mirrors 31 </ b> A and 31 </ b> B and the focusing lens 33 (that is, the portion that becomes the optical path). The pair of mirrors 31A and 31B and the focusing lens 33 are positioned and fixed as a pair of mirror / lens bodies. The imaging space is always maintained at a predetermined atmospheric pressure, for example, +0.5 atmospheric pressure.

  An air connection portion 35, an air filter 36, a silencer (silencer) 37, a shutter 38, and a solenoid 39 that slides the shutter 38 are arranged at the lower stage of the housing 28A. The air connection unit 35 is connected to a compressor (not shown) that generates and outputs compressed air. The air continues to be blown out to the dust-proof space through the air filter 36 and the silencer 37 before the shutter 38 is opened and until the closing is completed.

  In the lower stage of the housing 28A, an imaging opening 28B is opened to face the protective glass 34 (a portion that becomes an optical path). The shutter 38 opens and closes the opening 28 </ b> B, and is connected to the operation unit 39 </ b> A of the solenoid 39. Further, a metal wiper 40 is fixed to the housing 28A, and the tip 40A of the wiper 40 is disposed so as to face the opening 28B and abut against the shutter 38. When the camera device 28 is used, the shutter 38 is slid to open the opening 28B, that is, the optical path of the camera 30. When the camera device 28 is not used, the shutter 38, that is, the opening 28 </ b> B is closed to cover the outer surface of the protective glass 34, and is protected from chips, oil dust, and the like scattered during cutting. When the solenoid 39 is turned on, the shutter 38 slides toward the solenoid 39, opens the opening 28B, and peels off chips adhering to the outer surface of the shutter 38 when the shutter 38 slides. This is to prevent chips and the like from being attached to the outside of the shutter 38 so that the opening and closing of the shutter 38 is not hindered later.

  That is, even if the camera device 28 is installed in the processing zone S2 (see FIG. 1) filled with chips, the camera device 28 is configured to be unaffected by the environment, and thus can reliably capture an image. Further, since a slider mechanism for moving the camera device 28 to the processing zone S2 and the isolation zone S1 is not required, the cost is reduced and the time required for sliding is not required. The means for sliding the shutter 38 is an example of the solenoid 39, but it may be changed to a pneumatic cylinder device.

  As shown in FIG. 4, the mirrors 31A and 31B described above are arranged so that the field of view of the imaging optical system is divided into two fields of view 32A and 32B and the distance between the fields of view 32A and 32B is increased. These mirrors 31A and 31B bend the optical paths between the lens 29 of the camera 30 and the two subjects (the reference gauge 18 and the bite 25 and 26) at right angles, respectively, so that one visual field area (synonymous with an imaging area) is formed. Each is divided (see FIG. 5). Then, as shown in FIG. 4, the reference gauge 18 is imaged with one divided field of view 32A, and the chips 25A and 26A of the cutting tools 25 and 26 for inner diameter processing or outer diameter processing are imaged with the other field of view 32B. Is set in advance. The imaging area shown in FIG. 5 is a case where a camera with 5 million pixels is used, and the short side is 17 mm (2000 pixels) and the long side is 21.5 mm (2500 pixels). The inner diameter machining tool 25 is indicated by a two-dot chain line in FIG. FIG. 4 is a diagram in which the lower part of the camera device 28 is omitted.

  As shown in FIG. 3, mounting plates 27 are provided at a plurality of locations on the housing 28 </ b> A, and long holes 27 </ b> A along the optical axis of the camera 30 are formed in these mounting plates 27. Then, the position of the housing 28 </ b> A is adjusted using the long hole 60 in order to adjust the position of the camera device 30 in the axial direction. Thereby, the optical system of the camera 30 can be moved in the axial direction of the camera 30 in accordance with the outer diameter of the chuck 12. This moving mechanism may be configured to automatically move the optical system of the camera 30 in the axial direction of the camera 30 by a motor or the like corresponding to the outer diameter of the chuck 12, or the operator manually operates the optical system of the camera 30. The system may be moved in the axial direction of the camera 30.

  As shown in FIG. 2, a light source 44 for illumination is disposed via a transparent tempered glass 42 at a position facing the camera device 28. In addition, a coolant ejection portion 43 is provided for allowing chips, oil dust, and the like that have fallen on the tempered glass 42 to flow away. The light source 44 may be, for example, a light emitting LED.

(Chip detection method)
As shown in FIG. 4, when the reference gauge 18 and the chips 25A and 26A of the bites 25 and 26 are stored one by one in the visual fields 32A and 32B of the camera 30, respectively, the reference gauge 18 is used. And the heights of the upper surfaces of the cutting edges 25A and 26A of the cutting tools 25 and 26 are set to the same height. The edges of the chips 25A and 26A shown in FIG. 4 can be obtained using, for example, a seek line. The seek line is a line segment having a free length and inclination set in the two-dimensional virtual screen, and obtains the position of the edge with respect to the center position in the line direction. 6 is an imaging region showing the chips 25A and 26A (see FIG. 5) in the other visual field 32B, and is a comprehensive detection area used when the chips 25A and 26A are detected as a whole. The two-dot chain line portion in FIG. 6 is a blade edge detection area used when detecting the tips of the chips 25A and 26A.

  First, the detection method of the chips 25A and 26A is performed as follows. As shown in FIG. 7A, the edges of the chips 25A and 26A are obtained by setting a plurality of seek lines La. The edges of the chips 25A and 26A before and after use are obtained and pattern matching is performed. If the positions of the edges differ below a threshold value, it is determined that the chips 25A and 26A are broken. On the other hand, when the positions of the edges are different from each other by a threshold value or more, it is determined that the chips 25A and 26A are inflated (also referred to as a component cutting edge) by cutting chips. Note that the threshold value has a width of 20 μm, for example, and the width can be arbitrarily changed.

  The tip nose can also be determined using the seek line. First, as shown in FIG. 7B, a plurality of seek lines Lb directed downward are set at predetermined intervals, and a seek line Lbm having a maximum luminance value (a point changing from dark to bright) is the lowest point. The X direction cutting line is obtained. Similarly, as shown in FIG. 7C, a plurality of seek lines Lc directed to the left are set at predetermined intervals, and a seek line in which the maximum value of luminance (a point changing from dark to bright) is the leftmost point. Lcm is calculated | required and it is set as a Z direction cutting line. Next, as shown in FIG. 7D, a distance Rz between the X direction cutting line Lbm and a line Lbp parallel to the X direction cutting line Lbm and passing through the edge Ec of the Z direction cutting line Lcm is obtained. Similarly, a distance Rx between the Z direction cutting line Lcm and a line Lcp parallel to the Z direction cutting line Lcm and passing through the edge Eb of the X direction cutting line Lbm is obtained. The larger of the distance Rz and the distance Rx is set as the nose. If the nose of the chips 25A and 26A after use is greater than the set value than the nose of the chips 25A and 26A before use, it is determined that the chips 25A and 26A are worn.

  That is, according to the first embodiment, the reference gauge 18 for measuring the position error of the camera device 28 and the chips 25A and 26A adjacent to the reference gauge 18 are imaged by the camera 30 in the same field of view, and the chips 25A, 26A and Since the image processing of the chips 25A and 26A is performed after the reference gauge 18 is set to the reference position, the state of the chips 25A and 26A can be accurately detected.

(Configuration of turret gauge 46)
The turret gauge 46 shown in FIGS. 8 and 9 includes an NC table 50 (see FIG. 13) including a ball screw mechanism (for example, X axis and Y axis) (not shown) of the lathe S (see FIG. 1) and the turret device 20 (see FIG. 1). It is a gauge for measuring the degree of thermal expansion and contraction with the lathe body including the reference. As shown in FIG. 10, the turret gauge 46 serving as the reference means is configured to be attached to a predetermined position (one of the cutting tool mounting positions) of the tool post 21.

  The turret gauge 46 includes an invar body 47 that is a reference body, and a gauge body 48 that is an object to be measured and attachment means. The invar body 47 is formed in, for example, a prismatic shape using a material (for example, invar which is invariable steel) having a smaller thermal expansion coefficient than the heat-treated steel constituting the lathe S (see FIG. 1). Note that it is sufficient that there is a difference in thermal expansion coefficient between the material to be measured and the reference body, and it is desirable that the difference is particularly remarkable as much as possible. Usually, the object to be measured is steel, which is a structure of a machine tool. Therefore, the reference body is made of invar having an extremely low coefficient of thermal expansion, an aluminum alloy that is twice the coefficient of thermal expansion of steel, or three times. A certain magnesium alloy or the like may be used. On the other hand, the gauge body 48 is formed in a substantially right triangle shape using heat-treated steel which is the same material as the turret device 20 (including the tool post 21) shown in FIG.

  As shown in FIG. 8, the gauge body 48 has a hole 48 </ b> A through which the invar body 47 is inserted. The hole 48A is slightly larger than the thickness of the invar body 47, and a gap is formed so that the invar body 47 does not interfere with the wall constituting the hole 48A. As shown in FIG. 8, one end of the invar body 47 is fixed to the gauge body 48 by a bolt 49A and a stop plate 49B. The invar body 47 has a predetermined distance L1 from the fixed end, which is one end thereof, to the oblique tip 47A that is the free end. When the invar body 47 is attached to the gauge body 48, the invar body 47 is supported by the gauge body 48 at only one point, and the other is free. The reason for this is that if the invar body 47 is fixed at two or more points, a bimetal effect is generated due to the difference in thermal expansion coefficient between the invar body 47 and the gauge body 48, which causes deformation. Because.

  As shown in FIG. 8, the gauge main body 48 is formed with right-angled edges, and the two edges are point A and point B (measurement base points) that serve as base points for measurement in the X and Z directions, respectively. . Here, the distance between the edges in the X direction at the points A and B is set to the reference dimension LX in the X direction, and the distance between the edges in the Z direction is set to the reference dimension LZ in the Z direction. The gauge body 48 is processed so that these reference dimensions LX and LZ satisfy a certain degree of accuracy (for example, ± 5 μm) at the time of manufacture. This is because the gauge body 48 becomes extremely expensive when high accuracy of ± 5 μm or more is required. Before the gauge body 48 is attached to the machine, the temperature of the gauge body 48 and the dimensions LX and LZ are measured with a precision measuring instrument and recorded in a memory such as a RAM.

  The invar body 47 has a thermal expansion coefficient of about 1/10 that of steel, and when the temperature of the turret gauge 46 changes by 1 ° C., the difference between the point A of the gauge body 48 and the tip 47A of the invar body 47 is 1.8 μm. Become. Since the CPU 60 (see FIG. 13) detects the lengths of the reference dimensions LX and LZ based on the image data at the predetermined dimensions at the predetermined temperature, the accuracy of the gauge body 48 may vary to some extent. . Here, the predetermined temperature is a predetermined temperature (20 to 22 degrees which is a normal environmental temperature) designated for inspecting and measuring the dimensions of the turret gauge 46 and the like, and the predetermined dimension is the turret gauge 46 at the predetermined temperature. And so on. At the initial setting of the machine, the temperature of the gauge body 48 is measured, and the distance between the points A and B of the gauge body 48 is acquired within 1 μm. This acquisition method is performed by performing image processing on points A and B of the gauge body 48 and the reference gauge 18 in the same imaging region. A parallelism measurement reference surface 48B is formed on the gauge body 48, and the turret gauge 46 is positioned in parallel with the tool post 21 using the parallelism measurement reference surface 48B.

  When imaging with the camera device 28, as shown in FIG. 10, the position of the point A of the gauge body 48 and the tip 47A of the invar body 47 is obtained with reference to the reference gauge 18 fixed to the chuck 12. Further, as shown in FIG. 11, the position of the point B of the gauge body 48 is obtained with reference to the reference gauge 18 fixed to the chuck 12. 10 and 11 correspond to the ranges in the visual fields 32A and 32B of the camera device 28 shown in FIGS. 4 and 5.

  Note that the 5 million pixel camera can recognize an image with an accuracy of ± 0.25 μm (= 1/34 pixel) for the positioning of the chip edge and the like described in FIG. 7A. FIG. Image recognition can be performed with an accuracy of ± 0.45 μm (= 1/19 pixel) for the cutting line Lcm or Lbm described with reference to FIG. That is, as shown in FIG. 12, even an inexpensive optical system camera with 5 million pixels (actual size per pixel is 8.6 μm) is sufficiently chipped by the improvement of the recognition accuracy of the recent image processing technology. It is possible to recognize images such as breakage, wear, etc., and to measure the temperature of the gauge body 48 in units of 1 ° C. FIG. 12 shows experimental data of the image recognition accuracy of the chip, and the vertical axis shows the pixel size (unit: μm). The horizontal axis represents the number of experiments.

(Configuration for control system of lathe S)
As shown in FIG. 13, the lathe S includes a CPU 60, ROM 62 and RAM 64 that are nonvolatile memories, a motor driver 51 and NC motor 52 arranged on the NC table 50, and a motor driver 53 arranged on the turret device 20. , A turret motor 54, an operation unit 56, a display unit 57, and a buzzer 58. The CPU 60 that is the collating unit and the correcting unit controls the overall operation of the lathe S, and performs processing based on the operation when, for example, an operation key arranged on the operation unit 56 is operated. The CPU 60 is connected to a camera 30 that constitutes a part of the imaging means, and image data captured by the camera 30 is input to the CPU 60.

  The ROM 62 as recording means records a program for controlling various processes on the lathe S, and the lathe S is controlled by the program. The RAM 64 as recording means has a recording area for reading and writing various data, for example, an image data area 65, and image data and the like are recorded in the image data area 65. The motor 52 or 54 rotates via the motor driver 51 or 53 based on the drive signal of the CPU 60. The display unit 12 serving as a display unit displays image data captured by the camera 30 and the like. A buzzer as a warning means outputs a warning sound.

(Operation of this embodiment)
A flow related to image processing will be described based on the flowcharts shown in FIGS. 14, 15, and 17 to 19. Here, the processing in the lathe S is executed by the CPU 60 and is represented by the flowcharts shown in FIGS. 14, 15, and 17 to 19. These programs are recorded in the program area of the ROM 62 in advance.

(Turret gauge initial data setting mode)
The initial data setting mode of the turret gauge (represented as TG in FIG. 14) shown in FIG. 10 or FIG. 11 is a process performed during an adjustment process or maintenance at the time of machine manufacture in the lathe S. For example, at the time of factory shipment, the temperature of the turret gauge 46 is measured by a manual measuring instrument (not shown) while the temperature of the machine is in a stable state.

  Then, as shown in FIG. 14, in step 100, the CPU 60 determines whether or not a turret gauge temperature value (temperature value measured by a manual measuring instrument) Tto is input. If step 100 is negative, that is, if the temperature value Tto is not input, it waits for input. At this time, the display unit 57 or the buzzer 58 shown in FIG. If step 100 is positive, that is, if the temperature value Tto is input, in step 102, the CPU 60 moves the A region of the turret gauge 46 to the reference gauge 18 (position shown in FIG. 10) of the chuck 12. That is, the CPU 60 turns the tool post 21 to position the turret gauge 46 to the image processing position. Here, the region A is a region where the point A of the gauge body 48 and the tip 47A of the invar body 47 can be seen from a single view.

  In step 104, image processing is performed, and in step 106, the CPU 60 calculates a difference, that is, an offset value from the visual field center (center position with reference to the reference gauge 18; Xta, Zta) shown in FIG. In step 108, it is determined whether or not the offset value is within an allowable range (for example, within 100 μm). If step 108 is negative, that is, if it is outside the allowable range, in step 110, the A region of the turret gauge 46 is moved so as to be within the allowable range. This process is continued until the area A falls within the allowable range. If step 108 is affirmative, that is, if it is within the allowable range, in step 112, the image data processed in step 104 (specifically, the tip 47A of the invar body 47 and the point A of the gauge body 48 within the allowable range are determined). CPU 60 calculates the displacement value Da of the turret gauge 46 at the temperature value Tto and records it in the RAM 64. The displacement value Da is a value of a difference in relative difference position from the point A of the gauge body 48 with the tip 47A of the invar body 47 as a reference. That is, the displacement value Da detects the dimension value resulting from thermal displacement (expansion or contraction) of the steel gauge body 48 at the temperature value Tto, and the CPU 60 detects the temperature of the gauge body 48 at the time of the subsequent measurement based on the dimension value. .

  In step 114, the CPU 60 moves the B region of the turret gauge 46 to the reference gauge 18 (position shown in FIG. 11) of the chuck 12. Here, the region B is a region where the vicinity of the point B of the gauge body 48 can be seen from a single view. In step 116, image processing is performed, and in step 118, the CPU 60 calculates a difference from the visual field center (Xtb, Ztb) shown in FIG. In step 120, it is determined whether the offset value is within an allowable range. If step 108 is negative, that is, if it is outside the allowable range, in step 122, the region B of the turret gauge 46 is moved so as to be within the allowable range. If step 120 is affirmative, that is, if it is within the allowable range, in step 124, the difference values Dtx and Dtz of the field center of the gauge body 48 at the temperature value Tto are recorded in the RAM 64. Further, if it is within the allowable range described above, the NC table position in the initial data setting mode—the offset value is regarded as the NC table position having the A area and the B area with the visual field center. The difference values are the X difference in the X direction (Dtx = Xta−Xtb) and the Z difference in the Z direction (Dtz = Zta−Ztb). That is, the reason that the gauge body 48 is provided with the points A and B as measurement base points is to detect thermal displacements in the X direction and the Z direction in the turret device 20 (including the ball screw mechanism).

(Image capture position initial data setting mode)
The initial data setting mode for the image capture position shown in FIG. 15 or FIG. 16 is a process performed in an adjustment process at the time of machine manufacture in the lathe S. First, the tools 25 and 26 are manually moved into the field of view of the camera 30 using the test material 90 shown in FIG. Hereinafter, the mode will be described with reference to FIG. The initial data of the image capture position is set after the initial data of the turret gauge is set.

  As shown in FIG. 15, in step 130, the CPU 60 (see FIG. 13) determines whether or not the bytes 25 and 26 have moved into the field of view. If step 130 is negative, that is, if the bytes 25 and 26 have not moved into the field of view, the display unit 57 shown in FIG. In step 116, image processing is performed. In step 118, the CPU 60 calculates a difference from the center of the visual field shown in FIG. In step 136, it is determined whether or not the offset value F is within an allowable range (for example, within 100 μm). If step 136 is negative, that is, if it is outside the allowable range, in step 138, the bytes 25 and 26 are moved so as to be within the allowable range. This process continues until the bytes 25 and 26 are within the allowable range.

  If step 136 is affirmative, that is, within the allowable range (the position of the visual field center at that time is C), in step 140, the CPU 60 determines whether or not the position value M of the NC table 50 (see FIG. 13) has been recorded. Judging. This process is based on the premise that the test material 90 is manually subjected to finish cutting (cutting with a reduced cutting amount) to obtain the position value M of the NC table 50 at that time and recorded in the RAM 64. Become. If step 140 is negative, that is, if the position value M has not been recorded, it is displayed on the display unit 57 and warned by the buzzer 58 in step 142.

  If step 140 is positive, that is, if the position value M is recorded, in step 144, the CPU 60 determines whether or not the measured value of the workpiece dimension WL has been recorded. This process is premised on that the dimension WL of the workpiece W (specifically, Wx and Wz values shown in FIG. 16) is obtained with a micrometer and recorded in the RAM 64. When step 144 is negative, that is, when the measured value of the dimension WL is not recorded, the display unit 57 displays the warning and the buzzer 58 warns in step 145.

  If step 144 is affirmative, that is, if the measured value of dimension WL is recorded, in step 146 the byte C value and offset value F are substituted into the vector equation (M = C + F + WL or F = M−C−WL). In step 148, the C value and the F value are recorded in the RAM 64.

  Note that the C value differs for each byte, and only one F value exists in one turret device. Further, the test material 90 can be applied if it has one diameter and one end surface. Further, the C value and M value of each byte are obtained and recorded in the RAM 64, respectively. In practice, the NC table 50 is moved to the location M shown in FIG. 16 and cut based on the M value calculated from M = C + F + WL.

(Image processing mode in calibration cycle)
The flowcharts of FIGS. 17 to 19 are routines performed in a calibration cycle (indicated as CS in FIG. 17). In the calibration cycle, in order to obtain a compensation value for maintaining the cutting accuracy at a predetermined level, the lathe S is forcibly provided with a predetermined interval for inspection. That is, the flowcharts of FIGS. 17 to 19 are processes after the operation of the lathe S is started.

  As shown in FIG. 17, in step 150, the CPU 60 determines whether or not the measurement of a calibration cycle (referred to as CS in FIG. 17) is started. Whether the measurement is started is determined by the CPU 60 by counting a preset number of cuttings (for example, 100 times) or a preset time. When step 150 is affirmative, that is, when measurement is started, in step 152, processing in the byte image processing mode is performed. This byte image processing mode is processing in a subroutine shown in FIG.

  When step 150 is negative (when measurement is not started) or after the processing of step 152 is completed, a cutting process is performed at step 154, and a counting process for counting the number of cuttings (or the number of calibrations) is performed at step 156. In step 158, the CPU 50 determines whether or not the operation of the lathe is finished (including the case where the calibration cycle is stopped). If step 158 is positive, the routine ends. If step 158 is negative, the process returns to step 150 to continue each process.

(Byte image processing mode)
The byte image processing mode of step 152 shown in FIG. 17 will be described with reference to the subroutine of FIG. In step 160, measurement mode processing is performed. This measurement mode is processing in a subroutine shown in FIG. When the process of step 160 is completed, it is determined in step 162 whether or not the cutting edge is broken. If step 160 is negative, it is determined in step 164 whether the cutting edge is expanded (synonymous with the constituent cutting edge). If step 164 is negative, it is determined in step 166 whether the cutting edge is worn. In addition, the above-mentioned seek line etc. are used for these judgment methods.

  When step 166 is affirmative, that is, when it is determined to be wear, it is determined at step 168 whether or not the wear is equal to or greater than a set value (for example, 20 μm). If step 168 is affirmative, that is, if it is equal to or greater than the set value, in step 170, the friction amount data is recorded in the RAM 64 (referred to as data for maintenance or the like). Then, when step 162 or step 164 is affirmative, or when step 168 is negative or after the processing of step 170 is completed, the operation of the lathe S is forcibly stopped in step 172 (for example, cutting is performed until the cutting tool is replaced). Including fail-safe measures such as prohibition of driving) and warning in step 174. Specifically, a warning display or buzzer 58 is activated on the display unit (see FIG. 13) to output a warning sound or a warning sound from a speaker (not shown). The operator is prompted to replace the byte by the warning. If foreign matter such as chips adheres to the imaged field of view, the CPU 60 can set an error as an image recognition function, so that fail-safe treatment can be performed. Further, if it is determined in step 166 that the cutting edge is worn, the CPU 60 stops the operation of the lathe S for chip replacement even if it is equal to or less than the set value.

  If step 166 is negative, that is, if it is determined that the cutting edge is not worn, in step 176, the CPU 60 determines whether or not the displacement of the cutting edge is equal to or greater than a set value (for example, 100 μm). The displacement of the blade edge is determined by detecting the total position of the cutting line in FIG. 7, and the wear of the blade edge may be included in addition to the thermal displacement. If step 176 is affirmative, that is, if it is equal to or greater than the set value, in step 178, the interpolation data is recorded in the RAM 64 based on the displacement data at the time of measurement (to be used for maintenance or the like). When step 176 is negative or after the processing of step 178, in step 179, field back is performed and compensation processing is performed. That is, according to the first embodiment, at the time of non-cutting during lathe operation, the temperature of the gauge main body 47 and the degree of thermal expansion / contraction of the lathe are calculated on the basis of the positions of the two points A and B. Therefore, even if the machining position is displaced due to thermal expansion / contraction of the lathe during lathe operation, the displacement of the machining position can be accurately corrected, and the machining accuracy of the workpiece W can be improved. Can do.

(Turret gauge measurement mode)
The measurement mode in step 160 shown in FIG. 18 will be described using the subroutine of FIG. Note that the measurement mode in FIG. 19 is a mode in which a turret gauge (also expressed as TG in FIG. 19) 46 is measured. As shown in FIG. 19, in step 180, the CPU 60 moves the A region of the turret gauge 46 to the reference gauge 18 (position shown in FIG. 10) of the chuck 12.

  In step 182, image processing is performed, and in step 184, the CPU 60 calculates a difference from the visual field center (Xtat, Ztat), that is, an offset value. In step 186, it is determined whether the offset value is within an allowable range (for example, within 100 μm). If step 186 is negative, that is, if it is outside the allowable range, in step 188, the A region of the turret gauge 46 is moved so as to be within the allowable range. This process is continued until the area A falls within the allowable range. If step 186 is affirmative, that is, within the allowable range, in step 190, the image data processed in step 182 (specifically, the tip 47A of the invar body 47 and the point A of the gauge body 48 within the allowable range are determined). CPU 60 calculates a displacement amount Dat of the turret gauge 46 at the time of measurement of the calibration cycle (hereinafter referred to as CS measurement) and records it in the RAM 64.

  In step 192, based on the difference between the displacement values Dat and Da (data recorded in the RAM 64 in step 112 of FIG. 14), the CPU 60 calculates the temperature of the turret gauge 46 at the time of CS measurement, and at that temperature. The length Ltt of the gauge body 48 after the thermal displacement of LX and LZ (see FIG. 8) is calculated and recorded in the RAM 64. In addition, since the steel of thickness 100mm increases / decreases 1 micrometer when it changes 1 degreeC from the thermal expansion coefficient of steel, if CPU60 calculates the difference of displacement value Dat and Da, the temperature and length Ltt of the turret gauge 46 can also be calculated. When the reference body is invariant steel such as Invar, the thermal expansion of the steel itself is measured.

  In step 194, the CPU 60 moves the B region of the turret gauge 46 to the reference gauge 18 of the chuck 12 correspondingly. In step 196, image processing is performed. In step 198, the CPU 60 calculates a difference from the center of the visual field (Xtbt, Ztbt), that is, an offset value. In step 200, it is determined whether the offset value is within an allowable range. If step 200 is negative, that is, if it is outside the allowable range, in step 202, the region B of the turret gauge 46 is moved so as to be within the allowable range. If step 200 is affirmative, that is, if it is within the allowable range, in step 204, the X difference value (Dtx = Xtat−Xtbt) of the field center of the gauge body 48 at the CS measurement (Dtx = Xtat−Xtbt) and the Z direction Z The difference value (Dtz = Ztat−Ztbt) is calculated and recorded in the RAM 64.

  That is, in step 179 shown in FIG. 18, the CPU 60 calculates the difference between the points A and B of the gauge body 48 and also considers the thermal displacement amount of the gauge body 48. Can be detected. Therefore, according to the first embodiment, the X difference value and the Z difference value described above are compared with the length Ltt, and the ratio of the compared numerical values is used to move the X axis and the Z axis of the turret device 20 (see FIG. 1). The distance that the cutting tool moves from the visual field center position shown in FIG. 16 to each cutting position in the X direction and the Z direction is corrected by two-point linear interpolation (the process in step 179 in FIG. 18 is performed).

  For example, during non-cutting (CS) during lathe operation, the temperature of the gauge body 48 and the positional difference between the points A and B (a plurality of measurement base points) of the gauge body 48, between points A and B of the gauge body 48 In addition to measuring the vector difference, the temperature during processing of the gauge body 48 is also measured, and the measured value during the processing is calculated and interpolated to almost completely compensate for the thermal expansion and contraction of the lathe itself. Even if the machining position is displaced due to the thermal expansion / contraction of the lathe (including the ball screw mechanism) during lathe operation, the displacement of the machining position can be accurately corrected and the workpiece W (see FIG. 1) can be improved.

  A second embodiment of the present invention will be described with reference to FIGS. However, substantially the same parts as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted or simplified, and different parts are mainly described. Example 2 is an example applied to a two-axis front lathe as shown in FIG. Specifically, the two main shafts 11 are provided on the left and right sides so as to extend horizontally and in parallel, and a work holding chuck 12 is provided at the front end of each main shaft 11. The tool post 21 is disposed in parallel with the axis of each spindle 11 at the left and right positions of the left and right spindles 11. Each tool post 21 is configured to be movable in the front-rear direction by the driving device 19 and rotatable about the axis of the tool post 21. Various cutting tools (for example, a cutting tool 25 for inner diameter processing, a cutting tool 26 for outer diameter processing, etc.) are held on the outer peripheral portion of each tool post 21, and by rotating each tool post 21, it is possible to cut a workpiece. The byte to be used is selected.

  As shown in FIG. 21, two camera devices 28 are horizontally arranged on the ceiling portion of the machining zone S <b> 1 of the lathe S so as to be positioned directly between each tool post 21 and each chuck 12. . In addition, the camera apparatus 28 of FIG. 21 is the figure which abbreviate | omitted the lower stage.

  The bottom surface portion of the processing zone S1 is formed so as to incline downward from both the left and right sides toward the chip conveyor 16 in the central portion, and a protective glass is provided at a position directly below each camera device 28 in the bottom surface portion of the processing zone S1. A light source 44 for illumination is provided via 42. On both the left and right sides of the bottom surface portion of the processing zone S1, there are provided coolant jetting portions 43 for allowing chips, oil dust, etc. that have fallen on the bottom surface portion of the processing zone S1 and the protective glass 42 to flow down on the chip conveyor 16. Yes.

  As shown in FIG. 22, the turret gauge 45 attached to the tool post 21 shown in FIG. 20 has a stop plate 49B embedded in the turret gauge 45 so that the stop plate 49B is flush with the turret gauge 46. Yes. That is, the turret gauge 45 corresponds to the mounting of the tool post 21 shown in FIGS. Other configurations and operational effects are the same. FIG. 23 is a diagram corresponding to FIG. 11 of the first embodiment, and FIG. 24 is a diagram corresponding to FIG. 10 of the first embodiment. As shown in FIG. 25, the gauge body 48 may be provided with a plurality of measurement points, that is, three or more points (A to H points). In this case, since there are cases where the thermal displacement differs at a plurality of locations of the gauge body 28 (including the case where a ball screw mechanism (not shown) is nonlinearly displaced), it is possible to cope with each of them, and the thermal displacement of the ball screw mechanism can be more accurately performed. It can be detected.

  A third embodiment of the present invention will be described with reference to FIGS. However, substantially the same parts as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted or simplified, and different parts are mainly described. In the third embodiment, as shown in FIG. 26, the invar body 47 is arranged on the outer peripheral side of the chuck 12 so that the reference gauge 18 and the tip 47A of the invar body 47 can be seen from a single view. One end of the invar body 47, which is a chuck gauge, is fixed by a pair of bolts 49A via a stop plate 49B. Therefore, the stopper 70 for preventing the protrusion is disposed on the free end side of the invar body 47 in a state of being slightly separated from the invar body 47. The counterweight 70 for preventing vibration is disposed on the opposite side of the place where the invar body 47 is disposed.

(Operation of this embodiment)
Based on the flowcharts shown in FIGS. 27 and 28, processing of the chuck gauge (referred to as CG in FIG. 27) initial data setting mode and chuck gauge measurement mode will be described.

(Chuck gauge initial data setting mode)
The initial data setting mode of the chuck gauge shown in FIG. 26 is a process performed during an adjustment process or maintenance at the time of machine manufacture in a lathe. For example, at the time of factory shipment, the temperature of the machine is in a stable state, and the temperature of the chuck gauge 47 is measured by a manual measuring device (not shown).

  Then, as shown in FIG. 27, in step 210, the CPU 60 shown in FIG. 13 determines whether or not the temperature value (temperature value measured by a manual measuring instrument) Tco of the chuck gauge 47 is input. If step 210 is negative, that is, if the temperature value Tco is not input, it waits for input. At this time, the display unit 57 or the buzzer 58 shown in FIG.

  If step 210 is positive, that is, if the temperature value Tco is input, in step 212, the CPU 60 rotates the chuck 12 to position it at the set position. That is, the CPU 60 brings the tip 47A of the chuck gauge 47 and the reference gauge 18 into a state in which the camera device 28 (see FIG. 3) sees a single view. In step 214, image processing is performed, and in step 216, the CPU 60 calculates a difference value Dc of a relative difference position with respect to the reference gauge 18 based on the tip 47A of the invar body 47 at the temperature value Tco and records it in the RAM 64.

(Chuck gauge measurement mode)
The chuck gauge measurement mode shown in FIG. 28 is a process performed during the calibration cycle. As shown in FIG. 28, in step 220, the CPU 60 rotates the chuck 12 to position it at the set position. In step 222, image processing is performed, and in step 224, the CPU 60 calculates a difference value Dct of a relative difference position with respect to the reference gauge 18 based on the tip 47A of the invar body 47 in the calibration cycle CS, and records it in the RAM 64.

In step 226, based on the difference between the displacement values Dct and Dc (data recorded in the RAM 64 in step 216 in FIG. 27), the CPU 60 calculates the temperature Tc of the chuck 12 at the time of CS measurement and records it in the RAM 64. In step 228, the CPU 60 calculates the position data of the reference gauge 18 based on the temperature data, and records the position data in the RAM 64. The position data is the position data of the reference gauge 18 in the X direction at the time of CS measurement. The position data of the X direction is Vc (radius position of the reference gauge) = Vcn (radius position of the reference gauge at a specified temperature) + {Tc ( Chuck temperature) −Tco (specified temperature)} × Rc (radius of reference gauge) × Αc (thermal expansion coefficient of chuck). Here, the thermal expansion coefficient Αc of the chuck 12 made of steel is 1.15 × 10 ⁻⁵ (10 to the fifth power).

  The CPU 60 moves the NC table 50 by driving the NC motor 52 (see FIG. 13) based on the position data of the reference gauge 18 described above. That is, according to the third embodiment, even if the machining position is displaced due to the thermal displacement of the chuck 12 in the X direction, the displacement of the machining position can be accurately corrected, and the machining accuracy of the workpiece W (see FIG. 1). Can be improved. Further, the measurement mode described above may be performed before the operation of the lathe S is started, and in this case, it can be corrected with high accuracy even at the time of so-called cold start. Furthermore, since Example 3 utilizes the expansion and contraction of the invar body 47 in the length direction, the rigidity is high and the configuration is simple.

  A fourth embodiment of the present invention will be described with reference to FIG. However, substantially the same parts as those in the third embodiment are denoted by the same reference numerals, description thereof is omitted or simplified, and different parts are mainly described. In the fourth embodiment, as shown in FIG. 29, the bimetal body 74, which is a chuck gauge, is arranged on the outer peripheral side of the chuck 12 so that the reference gauge 18 and the tip 74A of the bimetal body 74 can be seen from one side. The bimetal body 74 is a combination of two types of metal plates having different coefficients of thermal expansion, and one end thereof is fixed with a bolt 75. And the temperature of the chuck | zipper 12 is measured by image-processing the relative curvature (synonymous with curvature distortion) of the front-end | tip 74A of the bimetal body 74. FIG. The measurement method is performed using a difference value based on the processing of FIGS.

  The counterweight 76 for preventing vibration is disposed on the opposite side of the position where the bimetal body 74 is disposed. In the fourth embodiment, since the bimetal body 74 is smaller than the invar body 47 (see FIG. 26), the chuck gauge is small, and the mounting portion of the outer peripheral surface such as the collet chuck is smaller than that of the scroll chuck or the like. While being able to be mounted, the counterweight 76 can be made smaller than the example of FIG. Other configurations and operational effects are the same as those of the third embodiment.

  As shown in FIG. 30, the invar bodies according to the first and second embodiments are integrally formed by joining a tip portion 47B formed of steel to an invar body 47 formed into a rectangular parallelepiped by brazing or the like. You may comprise. In the turret gauge according to the first embodiment and the second embodiment, as shown in FIG. 31, a bimetal body 74 (see FIG. 29) may be attached to the gauge body 48 (see FIGS. 8 and 22). Also in this case, the same effects as those of the first and second embodiments can be obtained. The chuck 12 to which the present invention is applied may have a conical shape or the like to reduce entrainment of chips and the like. Further, the present invention can be arbitrarily selected by combining the configuration of the third or fourth embodiment with the configuration of the first or second embodiment. Furthermore, the processing flow of the program described above (see FIG. 14 and the like) is an example, and can be changed as appropriate without departing from the gist of the present invention.

The measuring apparatus of the present invention (a camera, a memory such as a RAM, a CPU, for example, an apparatus including at least an invar body) is a telephoto device in which an object to be measured disposed in parallel with the invar body at a position approximately 10 m away is disposed on the camera. If imaging is performed using a lens , the CPU, which is the collating means and the computing means, calculates the difference value between the invar body and the object to be measured at the time of arbitrary measurement, and calculates the temperature of the object to be measured at the time of arbitrary measurement based on the difference value. Since it calculates, based on the difference value by each thermal expansion coefficient of an invar body and a to-be-measured object, the temperature of the to-be-measured object at the time of arbitrary measurement can be measured correctly. That is, since the temperature of the object to be measured can be measured in a non-contact state without connection of wiring or the like from a remote place, a member for wiring connection such as a brush holder can be eliminated, and the configuration of the measurement apparatus can be simplified. Moreover, the measuring apparatus of the present invention can be applied to other than the cutting machine. Further, the present invention is not limited to the two-axis front lathe and the short-axis lathe described in the first to fourth embodiments, but various cutting machines such as a milling machine (machines that move a cutting tool and a workpiece relatively). Applicable to.

  DESCRIPTION OF SYMBOLS 12 ... Chuck, 18 ... Standard gauge, 21 ... Turret tool post (mounting base), 25 ... Inner diameter machining tool, 25A ... Cutting edge, 26 ... Outer diameter machining tool, 26A ... Cutting edge, 28 ... Camera device (Imaging) Means), 30 ... camera, 33A, 33B ... field of view, 45,46 ... turret gauge (measuring means), 47 ... invar body (reference body), 47A ... tip of invar body, 48 ... gauge body (measurement object, mounting) Means), 60 ... CPU (collation means, calculation means, correction means), 62 ... ROM (recording means), 64 ... RAM (recording means), 74 ... bimetal body (measuring device) S ... lathe (cutting machine), W …work

Claims (12)

At the time of the reference temperature generated by the reference body that is a reference for the thermal displacement amount of the object to be thermally displaced, the reference body and the object to be measured in the same imaging region, and the reference temperature generated by the imaging means Recording means for recording the reference image data, collating means for collating the reference image data recorded in advance in the recording means and image data at the time of arbitrary measurement generated by the imaging means, and the collating means A calculation means for calculating a difference value between the reference body and the object to be measured at the time of the arbitrary measurement based on the collation result, and calculating a temperature of the object to be measured at the time of the arbitrary measurement based on the difference value ; A measuring apparatus comprising: Reference image data at the reference temperature recorded in advance in the same imaging area in the imaging means and recorded in advance in the recording means is used as a reference for the amount of thermal displacement of the object to be measured that is thermally displaced as a subject. The image data at the time of arbitrary measurement is collated by the collating means, and the difference value between the reference body and the object under measurement at the time of the arbitrary measurement is calculated based on the collation result of the collating means, and the difference value is calculated. And measuring the temperature of the object under measurement at the time of the arbitrary measurement.   An image pickup means for picking up an image of a subject, a reference gauge for measuring a position error of the image pickup means, and a mounting base for mounting the cutting tool for detecting the amount of displacement of the cutting tool and detecting the temperature of the mounting base A recording means for recording reference image data at a reference temperature imaged in the same imaging region by the imaging means using the reference means corresponding to the reference gauge and the reference gauge as a subject, and the recording A collating unit for collating the reference image data recorded in advance in the unit and the image data at the time of arbitrary measurement of the subject generated by the imaging unit, and the cutting tool based on the collation result of the collating unit A processing position correction apparatus for a cutting machine, comprising: a correction unit that corrects the processing position.   A reference gauge for measuring the position error of the imaging means and a reference means arranged on the mounting base for detecting the displacement amount of the cutting tool and detecting the temperature of the mounting base of the cutting tool correspond to each other. The reference gauge and the reference means are imaged in the same imaging area of the imaging means as a subject of the imaging means, and the reference image data at the reference temperature recorded in advance in the recording means and at the time of arbitrary measurement A machining position correction method for a cutting machine, wherein the image data at the time of measurement is collated by a collating means, and the machining position of the cutting tool is corrected based on the collation result of the collating means.   4. The machining position correction device for a cutting machine according to claim 3, wherein the reference means is a fixing means made of the same material as the metal constituting the mounting base and having a reference portion, and is fixed only to one end of the mounting means. And a reference body that has a free end corresponding to the reference portion and serves as a reference for the amount of thermal displacement of the attachment means.   6. The machining position correction device for a cutting machine according to claim 5, wherein the attachment means includes at least two measurement base points.   6. The machining position correction apparatus for a cutting machine according to claim 5, wherein the reference body is made of a material having a coefficient of thermal expansion different from that of the metal constituting the mounting base. Processing position correction device.   6. The machining position correction device for a cutting machine according to claim 5, wherein the reference body is a bimetal body.   Imaging means for imaging a subject, a reference gauge disposed on a workpiece holding chuck for measuring a position error of the imaging means, one end fixed to the chuck, and a free end corresponding to the reference gauge The reference body that is disposed in the base and serves as a reference for the amount of thermal displacement of the reference gauge, and the reference gauge and the free end of the reference body corresponding to the reference gauge are taken as subjects in the same imaging region. The recording means for recording the reference image data at the reference temperature, the reference image data recorded in advance in the recording means and the image data at the time of arbitrary measurement of the subject generated by the imaging means are collated And a correction unit that corrects the machining position of the cutting tool based on the verification result of the verification unit. Engineering position correcting device.   A reference gauge disposed on the workpiece holding chuck for measuring the position error of the imaging means, and a reference for the thermal displacement amount of the reference gauge, one end being fixed to the chuck, and a free end corresponding to the reference gauge And the corresponding reference gauge and the free end of the reference body are imaged in the same imaging area of the imaging means as a subject of the imaging means, and recorded in advance in the recording means The reference image data at the reference temperature and the measurement image data at the time of arbitrary measurement are collated by the collating means, and the processing position of the cutting tool is corrected based on the collation result of the collating means. A machining position correction method for a cutting machine.   10. The machining position correction device for a cutting machine according to claim 9, wherein the reference body is a material having a coefficient of thermal expansion different from that of the material holding the reference gauge. Correction device.   10. The machining position correction device for a cutting machine according to claim 9, wherein the reference body is a bimetal body.

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