JP5337330B2 - Cutting machine and machining position correction method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting machine accurately detecting the amount of displacement of the tailstock spindle relative to the chuck, and also to provide a method of correcting the working position of the cutting machine. <P>SOLUTION: The movement amount (Geometric-Offset value) of a cutter moved from the origin of a NC table toward the axis of a test material 66 and an inclination angle &theta; (namely, the virtual data on the virtual moving path of a tip 26A relative to a long workpiece) are set in X- and Z-directions. Namely, based on the virtual data on the virtual moving path of the cutter 26, a CPU corrects the inclination &theta; of the chuck 12 and the axis of the tailstock spindle 89 and the inclination of an unshown NC slider for working the long workpiece. Specifically, the CPU corrects the cutter 26, based on the virtual data on the virtual moving path for working the long workpiece. Since the virtual data on the virtual moving path of the cutter 26 is accurately detected, the machining accuracy is increased even when the long workpiece is machined. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a cutting machine such as an NC lathe, and more particularly to a cutting machine that measures the amount of displacement of a cutting tool or the like by image processing of the cutting tool or the like and a processing 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.

  In particular, when a long workpiece is machined, the distance between the chuck that supports the workpiece at two points and the core press stand (synonymous with the core pressing shaft) becomes long. For this reason, an error in machining dimensions is likely to occur, and machining accuracy is lowered. As shown in FIGS. 11A to 11C, for example, when a reference point serving as a reference of a camera (not shown) is provided on the outer edge of the chuck, the long workpiece is separated from the chuck in the Z direction. That is, as shown in FIG. 11 (A), when the workpiece center and the shaft center of the chuck and the core pushing shaft all coincide, the workpiece can be processed with high accuracy.

  On the other hand, as shown in FIG. 11B, when the cutting shaft including the chuck itself is displaced relatively in the X direction due to thermal displacement or the like, the other end of the workpiece (end edge on the core pressing shaft side) ) Toward the taper, and become defective. In addition, when the cutting machine itself including an X-axis slider and a Z-axis slider (also referred to as an NC slider) that moves a turret device (not shown) in the X direction or the Z direction is displaced to an upward slope due to thermal displacement, etc. As shown in FIG. 11 (C), the workpiece is cut into a tapered shape toward the other end of the workpiece, resulting in a defective product. Note that FIGS. 11B and 11C are illustrated so that they can be easily grasped visually, but in reality, the displacement and the inclination are very small.

  An object of the present invention is to provide a cutting machine capable of accurately detecting a displacement amount of a core pushing shaft or the like with respect to a chuck and a machining position correction method thereof.

  The cutting machine according to the present invention has a first position detecting means for detecting a position of a chuck for holding a workpiece with respect to a cutting tool based on an imaging process, and an imaging process for a position of a core support shaft for supporting the workpiece with respect to the cutting tool. Based on the image data obtained by the second position detecting means, the first position detecting means, and the second position detecting means, and the inclinations of the center axes of the chuck and the core pressing shaft, and the above. Control means for calculating virtual data of a virtual movement locus in the cutting tool indicating the inclination of the slider for moving the cutting tool, and controlling the movement of the cutting tool based on the virtual data.

  The first position detecting means includes a first imaging means for imaging a subject, a reference gauge disposed on the chuck for measuring a position error of the first imaging means, and one end of the chuck. The second position detecting means includes a reference body that is fixed and has a free end corresponding to the reference gauge and that serves as a reference for the amount of thermal displacement of the reference gauge. The image pickup means and a reference mark arranged on the core pressing shaft for measuring the position error of the second image pickup means may be provided.

  The first imaging means includes the reference gauge at the imaging position in the optical path, the free end of the reference body corresponding to the reference gauge, and the cutting tool at the imaging position within the same imaging area. The second imaging means captures the virtual movement locus by imaging the reference mark at the imaging position in the optical path and the cutting tool at the imaging position as a subject in the same imaging area. The control means calculates the virtual data based on the image data of the first imaging means and the image data of the second imaging means.

  Further, the machining position correction method for a cutting machine according to the present invention is based on the first position detecting means for detecting the position of the chuck with respect to the cutting tool based on the imaging process and the position of the core shaft relative to the cutting tool based on the imaging process. The image data of the second position detection means to be detected is recorded in the recording means, and the control means is based on these image data, and the slider for moving the inclination of the center of the chuck and the core pushing shaft and the cutting tool. The virtual data of the virtual movement locus in the cutting tool indicating the inclination of the cutting tool is calculated, and the movement of the cutting tool is corrected based on the virtual data.

  In the cutting machine and the machining position correction method according to the present invention, the virtual data of the virtual movement locus in the cutting tool is calculated based on the image data of the first position detection means and the second position detection means, and the virtual data Based on the above, the movement of the cutting tool is corrected. Here, the virtual movement trajectory takes into account the amount of movement from the origin of the cutting tool toward the axis of the workpiece (workpiece), and performs cutting with the inclination of the axis of the chuck and the centering shaft and the inclination of the slider. This is the trajectory that the tool will move. In other words, the virtual movement trajectory is a virtual line indicating the inclination of the axis between the chuck and the core pushing shaft and the inclination of the slider.

  In the cutting machine and the machining position correction method according to the present invention, based on virtual data (including tilt angle data) related to the virtual movement locus of the cutting tool, the control means includes the tilt of the shaft center of the chuck and the core shaft and the slider. A long workpiece is machined to correct the tilt. That is, the control means processes a long workpiece while correcting the cutting tool based on the virtual data of the virtual movement locus. Therefore, according to the cutting machine and the machining position correction method according to the present invention, the virtual data of the virtual movement locus in the cutting tool can be detected with high accuracy, so that the machining accuracy is improved even when a long workpiece is cut.

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 a diagram related to the imaging device shown in FIG. 2, (A) is an end view of the imaging device, and (B) is a plan view of the shutter. FIG. 4 is an end view showing a state in which the imaging device shown in FIG. It is a figure explaining the positional relationship at the time of imaging each to-be-photographed object with a pair of imaging device shown in FIG. Fig. 6 is an arrow view taken along line 6-6 in Fig. 5. It is a figure explaining the correction algorithm at the time of a test cut. It is a block diagram of the turret lathe shown in FIG. It is a figure which shows the modification regarding a chuck | zipper. FIG. 10 is a side view of FIG. 9. It is a figure which shows the processing state of a workpiece | work, (A) is a figure which shows a state without a displacement and inclination, (B) or (C) is a figure which shows a state with a displacement or inclination.

  Hereinafter, a specific embodiment of a mode for carrying out the present invention will be described.

  Hereinafter, based on FIG. 1 thru | or FIG. 8, the cutting machine which is one Embodiment of this invention, and its processing position correction method are demonstrated. The NC lathe which is the cutting machine of 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 a lathe S, a headstock 10 fixed so that its axis line is parallel to the Z-axis direction, and a direction parallel to the Z-axis direction and perpendicular to the Z-axis direction and perpendicular to the Z-axis direction. The turret device 20 that is movable in a direction parallel to the X-axis direction inclined backward by 60 degrees is disposed so as to face the turret device 20. 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. 8) 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.

  That is, the turret device 20 has a ball screw mechanism (not shown) by an NC motor 52 of the NC table shown in FIG. 8 (a table on which an X-axis slider and a Z-axis slider for moving the turret device 20 in the X direction or Z direction) are mounted. Move through. Here, the X-axis slider and the Z-axis slider are also referred to as NC sliders. In addition, as shown in FIG. 1, the turret apparatus 20 moves with respect to the headstock 10 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 mainly made of cutting powder or cutting fluid that scatters when the outer periphery or end surface 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 5, the reference gauge 18 disposed so as to slightly protrude from the outer periphery of the chuck 12 measures a position error of the imaging device 27 described later. 25 and the outer diameter cutting tool 26 are used in common. The reference gauge 18 is formed of heat-treated steel in order to prevent wear due to chips or the like.

  Since the reference gauge 18 has a small amount of protrusion from the outer peripheral surface of the chuck 12, the rotation range of the reference gauge 18 when the chuck 12 rotates is small. Further, since the reference gauge 18 is fixed to the chuck 12, it is easy to align the position when taking an image. Further, on the coaxial line of the chuck 12, a core presser base 88 (see a two-dot chain line in FIG. 1) for supporting a long workpiece WL (see FIG. 5) is slidably disposed on the turret device 20 side. As shown in FIG. 5 and FIG. 6, this core presser 88 supports a cylindrical core pressing shaft 89 so as to be slidable, and a conical center 90 is disposed at the tip of the core pressing shaft 89. ing.

(Configuration related to imaging devices 27 and 68)
As shown in FIG. 5, in the lathe S, a pair of imaging devices 27 and 68 are slidably arranged. First, the imaging device 27 disposed on the chuck 12 side will be described. As shown in FIGS. 1 and 2, the imaging device 27 is slidably disposed between the isolation zone S1 and the processing zone S2, that is, through the partition wall 15 (see FIGS. 4 and 5). This imaging device 27 images, for example, chips 25A and 26A shown in FIG. 9 of cutting tools (hereinafter also referred to as cutting tools) 25 and 26 that are subjects, and cutting edges when cutting tools such as cutting tools are not used.

  That is, the imaging device 27 slides toward the processing zone S2 when imaging the chips 25A, 26A, and the like, and slides toward the isolation zone S1 when imaging is completed. Further, the imaging device 27 is capable of imaging in two series. For example, when the chip 25A is imaged in the area of B frame shown in FIG. 9, the reference gauge 18 and the tip 86A of the invar body 86 are imaged in the area of A frame almost simultaneously. . The image data picked up by the image pickup device 27 is configured to be output to the CPU 60 shown in FIG. Then, the CPU 60 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. 3A, the housing 27A of the imaging device 27 is partitioned into an imaging space (also referred to as a lens chamber) 28A and a dust-proof space (also referred to as a shutter chamber) 28B. Specifically, the lens chamber 28A of the rectangular tubular casing 27A includes, for example, a 5 million pixel camera (including a CCD 30A as an image sensor) 30, an imaging lens body 29, a full mirror 31A, and a half mirror 31B. And are stored.
The half mirror 31B is disposed between the imaging lens body 29 and the full mirror 31A, and is a mirror that partially reflects and partially transmits incident subject light.

  The full mirror 31A and the half mirror 31B described above are arranged so that the fields of view of the respective imaging optical systems have the same size. That is, the full mirror 31A and the half mirror 31B are provided so that each subject can be alternately imaged. For example, when the subject (chip) 23A indicated by the two-dot chain line in FIG. 3A is imaged with the full mirror 31A, the optical path of the half mirror 31B is blocked, and when the subject (chip) 24A is imaged with the half mirror 31B. The optical path of the full mirror 31A is configured to be blocked.

  Accordingly, the optical path between the imaging lens body 29 of the camera 30 and two subjects (for example, bytes 23, 24, etc.) is bent at a right angle by the pair of mirrors 31A and 31B, respectively, so that one visual field region (synonymous with imaging region). The subject is imaged within the range of. Then, as shown in FIG. 3, for example, the chip 23A of the bite 23 is first imaged in one visual field area, and the chip 24A of the bite 24 is continuously imaged in one visual field area after the above imaging.

  Between the lens chamber 28A and the shutter chamber 28B, the focusing lens 33 is disposed on the optical path corresponding to the full mirror 31A, and the transparent protective glass 34 is disposed on the optical path corresponding to the half mirror 31B. Here, the focusing lens 33 adjusts two series of focal lengths LA (for example, 100 mm).

  A hole 27B is formed between the lens chamber 28A and the shutter chamber 28B, and compressed air (hereinafter also referred to as air) is sent from the hole 27B to the shutter chamber 28B. That is, the shutter chamber 28B is always pressurized to a pressure state lower than that of the lens chamber 28A, for example, +0.11 MPa. Therefore, since the shutter chamber 28B is pressurized, it prevents the coolant liquid or chips from flowing into the shutter chamber 28B. In addition, an air connection port (not shown) is arranged in the lens chamber 28A, and an air passage for supplying air generated by the compressor is provided between the air connection port and the compressor (not shown). Then, air is continuously blown out to the lens chamber 28A from before the shutter 38 or 39, which will be described later, is opened until the closing is completed.

  Openings 27C and 27D are formed in portions of the shutter chamber 28B facing the focusing lens 33 and the protective glass 34, respectively. Shutters 38 and 39 as switching means are slidably disposed between the casing 27A and the support piece 27E, and open or close the opening 27C or 27D. That is, the shutter 38 or 39 that blocks the optical path described above is configured to slide using the air in the air passage described above. Further, openings 27F and 27G are formed in the support piece 27E so as to face the openings 27C and 27D.

  As shown in FIG. 3B, the planar shape of the shutter 38 is a strip shape, and the planar shape of the shutter 39 is a substantially L-shape. The shutters 38 and 39 move so as to face the openings 27G and 27F, and open and close the openings 27C and 27D. That is, the shutters 38 and 39 open the respective optical paths, and the camera 30 captures an image of the tip 24A (indicated by a two-dot chain line in the drawing) of the cutting tool 24 that is the subject shown in FIG. The shutters 38 and 39 are closed to prevent coolant liquid or chips from flowing into the shutter chamber 28B. The shutters 38 and 39 always close the optical path and do not open the optical path at the same time.

  Next, as shown in FIG. 5, the imaging device 68 disposed on the core presser 88 side will be described. Since this imaging device 68 targets only one series of imaging, only the full mirror 31A is arranged as a mirror. 3 is the same as the configuration shown in the imaging device 27 except that the two-series optical configuration shown in FIG. 3 is changed to a single-line optical configuration. Note that the shutter 69 shown in FIG. 5 is a flat plate having a planar shape, that is, a long plate shape, like the shutter 38 of FIG.

  As shown in FIG. 5, the image pick-up device 68 and the core pressing shaft 89 of the core pressing table 88 are connected by a connecting rod 70, and both operate in synchronization. That is, the core presser 88 slides in the retracting direction (the direction opposite to the chuck 12 side) when removing the long workpiece WL. For this reason, the imaging device 68 connected to the core push bar 88 by the connecting rod 70 is also retracted in synchronization. In this embodiment, the imaging device 68 and the core presser 88 may be configured to operate separately without using a connecting means such as the connecting rod 70. In this case, the interference between the imaging device 68 and the tool mounted on the turret device 20 is prevented, and the visual trouble of the imaging device 68 during the cutting operation is avoided, thereby improving workability.

  Further, as shown in FIG. 6, a reference mark 91 having an isosceles trapezoidal plan shape is provided on the core pressing shaft 89 so as to protrude from the connecting rod 70 with an angular range of 90 degrees. This reference mark 91 measures the position error of the imaging device 68 shown in FIG. 5, and is common to both the outer diameter machining bit 26 (see FIG. 6) or the inner diameter machining bit 25 (not shown in FIG. 6). To use. The reference mark 91 is formed of heat-treated steel in order to prevent wear due to chips or the like. In addition, since the reference mark 91 protrudes from the core pressing shaft 89, alignment during imaging is facilitated.

  Then, as shown in FIG. 6, the cutting tool 26 is moved so that the reference mark 91 and the chip 26 </ b> A of the cutting tool 26 can be captured in the field of view of the imaging device 68 (synonymous with a single view). In other words, the bit 26 is set in advance so as to move to a predetermined position in the one-view C area (referred to as “C frame” in the drawing) of the imaging device 68 when the chip is detected.

  In this embodiment, since the reference mark 91 and the chip 26A of the bit 26 can be seen from a single view, high recognition accuracy can be obtained even if the stop position accuracy of the imaging device 68 is low. As shown in FIGS. 1 and 5, light sources 43 to 45 for illumination are arranged at positions on the optical path facing the mirrors 31A and 31B (see FIG. 5) of the imaging devices 27 and 68, respectively. These light sources 43 to 45 are composed of light emitting LEDs, for example. The light source 45 is a long light-emitting surface that can accommodate the movement range of the core pressing shaft 89. Further, in the light sources 43 to 45, for example, a mirror or the like may be used so that any one of the light sources 43 to 45 can be made unnecessary.

(Schematic configuration regarding the slide mechanism of the imaging device 27)
As shown in FIGS. 1 and 4, the imaging device 27 is disposed at a predetermined location of the partition wall 15 and is connected to a slide mechanism (not shown) (for example, a cylinder that is operated by air in an air passage). Therefore, as described above, the imaging device 27 slides between the isolation zone S1 and the processing zone S2, and retracts from the processing zone S2 to the isolation zone S1 immediately before the cutting process. The reason for retracting the imaging device 27 is to prevent interference with a cutting tool or the like mounted on the cutting turret device 20 and to improve the workability of the imaging device 27 by avoiding the visual disturbance of the operator during the cutting operation. It is.

  As shown in FIG. 4, a synthetic resin (for example, urethane rubber) seal cover 40 is disposed between the imaging device 27 and the partition wall 15. That is, the imaging device 27 is held in a state of being fitted into the seal cover 40. The seal cover 40 prevents the image pickup device 27 during the slide from pinching chips in the processing zone and prevents the coolant from seeping into the isolation zone S1.

  Furthermore, a guide port 40 </ b> A that surrounds the imaging device 27 is opened. Then, air is sent out from an air passage (not shown) to the guide port 40A (see the arrow in FIG. 4), and the air is blown out from the gap between the imaging device 27 and the seal cover 40 (see the thick arrow in FIG. 4). . Note that, at the position where the imaging device 27 is retracted to the isolation zone S <b> 1 (the standby position indicated by the solid line in FIG. 4), the tip of the imaging device 27 (the portion facing the seal cover 40) is slightly processed zone from the seal cover 40. It is set in advance so that it protrudes to S2 or is flush with the surface.

(Schematic configuration regarding chuck)
As shown in FIG. 5, an invar body 47, which is a reference body, is disposed on the outer peripheral side of the chuck 12 so as to face the reference gauge 18 described above. That is, the cutting tool 26 is moved so that the tip 47 A of the invar body 47, the reference gauge 18, and the tip 26 A of the cutting tool 26 are accommodated in the field of view of the image pickup device 27 and can be imaged (first view). That is, the byte 26 or 25 is a predetermined area in the one-view A area (referred to as “A frame” in FIGS. 7 and 9) or the one-view B area (referred to as “B frame” in FIG. 9) when the chip is detected. It is preset to move to a position.

  The invar body 47 shown in FIG. 5 has a material whose thermal expansion coefficient is smaller than that of the heat-treated steel constituting the lathe S (see FIG. 1) (for example, invar which is an invariant steel or thermal expansion coefficient is twice that of iron). For example, a prismatic shape is used. The invar body 47 has one end fixed by a fastening member (such as a bolt) not shown. Therefore, a stopper (not shown) for preventing popping out is arranged on the free end side of the invar body 47 in a state slightly separated from the invar body 47.

  The chuck 12 is provided with a plurality of claws 12A having a predetermined angular range. And the nail | claw 12A pinches and hold | maintains several types of work W (refer FIG. 1) or WL (refer FIG. 5 thru | or FIG. 7) long and short. In the long workpiece WL shown in FIGS. 5 to 7, one end is held by the chuck 12, and the other end is supported by the tailstock 88. Note that a counterweight 72 for preventing vibration is disposed on the chuck 12 on the side opposite to the position where the invar body 47 is disposed.

(Configuration for control system of lathe S)
As shown in FIG. 8, the lathe S (see FIG. 1) is arranged in the CPU 60, ROM 62 and RAM 64 that are nonvolatile memories, the motor driver 51 and NC motor 52 arranged in the NC table 50, and the turret device 20. A motor driver 53, a turret motor 54, an operation unit 56, a display unit 57, and a buzzer 58. The CPU 60 as the control means and the correction means controls the overall operation of the lathe S, and performs processing based on the operation when an operation key arranged on the operation unit 56 is operated, for example. The CPU 60 is connected to a pair of cameras 30 that constitute part of the position detection means and the imaging means, and image data captured by the camera 30 is input to the CPU 60, respectively.

  The ROM 62 records a program for controlling various processes in 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)
First, at the time of chip detection, as shown in FIG. 7, the reference gauge 18, the invar body 47, and the chip 26 </ b> A of the bite 26 are housed in the one viewing A area of the camera 30 (see FIG. 5) of the imaging device 27. In this case, the heights of the upper surfaces of the reference gauge 18 and the cutting edge 26A of the cutting tool 26 are set to the same height. At the time of chip detection, as shown in FIG. 4, the imaging device 27 is slid from the isolation zone S1 to the processing zone S2, and the light source 43 shown in FIG.

  When detecting the chip 26A of the cutting tool 26 shown in FIG. 5, the image pickup device 27 at the image pickup position (state shown by the broken line in FIG. 4) slides the shutter 38 as shown in FIG. Open the light path. Since the optical path on the side of the shutter 39 is blocked, the half mirror 31B reflects the subject light in the single vision A area to the camera 30. As shown in FIG. 7, the camera 30 images the tip 47 </ b> A of the invar body 47, the reference gauge 18, and the tip 26 </ b> A of the bite 26, which are subjects located in the first-view vision A area. Subsequent verification processing and correction processing are the same as the processing described in the specification of Japanese Patent Application No. 2009-38185.

  By the way, in the short workpiece W as shown in FIG. 1, the processing surface is in the vicinity of the reference gauge 18 disposed on the chuck 12, so that the processing accuracy can be improved by the above correction processing. On the other hand, in the long workpiece WL as shown in FIGS. 5 and 7, the other end (the end on the side of the tailstock 88) is separated from the reference gauge 18.

  However, in the present embodiment, the camera 30 (see FIG. 5) of the imaging device 68 includes the reference mark 91 and the bit 26 that are disposed on the core pressing shaft 89 located in the one-view vision C area, as shown in FIG. The chip 26A is imaged. Therefore, based on the image data on the chuck 12 side and the core pressing shaft 89 side, the CPU 60 shown in FIG. 8 can accurately detect the wear of the chip 26A, the displacement of the shaft pressing shaft 89, and the like.

(Procedure for obtaining correction data)
A procedure for acquiring correction data will be described with reference to FIG. This correction data acquisition mode is a process performed in an adjustment process (initialization) or maintenance at the time of machine manufacture in the lathe S shown in FIG. Based on the correction data, the CPU 60 shown in FIG. 8 calculates and corrects the displaced vector value during a calibration cycle. Here, the calibration cycle is to inspect at a predetermined interval forcibly when the lathe S shown in FIG. 1 is operated in order to obtain a compensation value for maintaining the cutting accuracy at a predetermined level. That is, the calibration cycle is an inspection performed after the operation of the lathe S is started.

  First, in the correction data acquisition mode, for example, a test cut is performed using a test material 66 shown in FIG. This test cut is performed by making the cut and feed smaller at the corner 1 (C1 in the drawing) and the corner 2 (C2 in the drawing) of the test material 66 (synonymous with finishing cutting). Here, the test material 66 is a long circular rod in which large diameter rings (A wheel and B wheel) are formed near both ends thereof. And the corner 1 and the corner 2 are the outer peripheral ends in a pair of wheel parts (refer to Drawing 7). The user uses a measuring instrument such as a micrometer (not shown) in advance, and Z4L (the axial length from one end to the A wheel), X4L (the radius of the A wheel) and Z4R (from one end to the B wheel) of the test material 66. ) And X4R (the radius of the B wheel) are measured, and these numerical values are recorded in the RAM 64 shown in FIG.

  After that, the CPU 60 shown in FIG. 8 causes the imaging device 27 to image the tip 47A of the invar body 47, the reference gauge 18, and the tip 26A of the bite 26 in the single vision A area, and the imaging device 68 to capture the reference in the single vision C area. The mark 91 and the chip 26A of the byte 26 are imaged. That is, the CPU 60 moves, for example, the byte 26 from the NC table origin shown in FIG. 7 to the single vision C area via the single vision A area. It should be noted that the moving order of the bite 26 can be changed as appropriate, for example, by moving to the first viewing A area via the first viewing C area. Here, in FIG. 7, an arrow mark from a black circle represents a vector, and there are a positive number and a negative number. In FIG. 7, the arrow marks in both directions represent scalars and are only positive numbers.

  Then, based on the above-described image processing, the CPU 60 calculates X2R (distance of the chip 26A in the C frame from the tip of the reference mark 91 in the X direction) in the single vision C area, and X2L (in the X direction in the X direction). The distance of the tip 26A in the A frame from the outer peripheral surface of the invar body 47) and Z2 (the distance of the tip 26A in the A frame from one end of the reference gauge 18 in the Z direction) are calculated. Here, the outer peripheral surface of the invar body 47 in the X direction means the outer peripheral surface of the chuck 12, and the outer peripheral surface of the invar body 47 and the outer peripheral surface of the reference gauge 18 in the X direction are the same distance from the chuck axis. ing.

(Calculation in X direction)
The moving amount (synonymous with the Geometric-Offset value) of the cutting tool 26 moving from the NC table origin (synonymous with the starting point of the cutting tool 26) to the center point of the workpiece (axial center of the test material 66) shown in FIG. It is obtained by the following formula 1. That is, the geometric-offset value is obtained by XLgo = X1L + X2L + X3L and XRgo = X1R + X2R + X3R (formula 1). Here, XLgo and XRgo are equivalent to the Geometric-Offset value in the X direction, respectively, in a normal NC lathe.

  If the inclination (θ) of the workpiece is not taken into consideration (that is, if the inclination θ is set to 0), the cutting position on the A wheel side (corner 1 or X5L) is XLgo + X4L = X5L (Formula 2). Here, X5L is the distance from the origin of the chip 26A to the corner 1 in the X direction. On the other hand, XRgo + X4R = X5R (formula 3) at the cutting position on the B-wheel side (corner 2 or X5R). Here, X5R is the distance from the origin of the chip 26A to the corner 2 in the X direction.

(Calculation on the A wheel side in consideration of inclination)
If the inclination (θ) of the workpiece is taken into consideration, the share ratio (XLgo and XRgo share ratios BLL and BLR) to the cutting position on the A wheel side is BLL = (HH−HL) / HH and BLR = HL / HH (Formula 4) Here, HH is the distance from the reference point (see FIG. 7) of the reference gauge 18 to the tip 26A in the Z direction to the central axis of the reference mark 91 of the core push rod 89. HL is a distance from the reference point in the Z direction to the corner 1 of the A wheel. In addition, since BLL and BLR are sharing ratios, BLL + BLR = 1.

  When Expression 2 and Expression 3 are substituted into Expression 4, (XLgo × BLL + XRgo × BLR) + X4L = X5L (Expression 5). Further, when Expression 1 and Expression 4 are substituted into Expression 5, {(X1L + X2L + X3L) * (HH-HL) / HH + (X1R + X2R + X3R) * HL / HH} + X4L = X5L (Expression 6). Here, X1L is the distance from the origin of the chip 26A in the X direction to the chip 26A in the A frame, and X3L is the radius of the chuck 12. X1R is the distance from the origin of the tip 26A to the tip 26A in the C frame in the X direction, and X3R is the distance from the center of the core pressing shaft 89 to the tip of the reference mark 91.

  In Expression 6, X1L, X1R, and X5L are obtained by values that the NC table (see FIG. 8) moves, and X2L and X2R are obtained by image processing based on the imaging devices 27 and 68. That is, the unknowns are X3L and X3R.

(Calculation on the B-wheel side in consideration of inclination)
Considering the workpiece inclination (θ), the sharing ratio (XLgo and XRgo sharing ratio BRL and BRR) to the B-wheel side cutting position is BRL = (HH−HR) / HH and BRR = HR / HH (Formula 7) Here, HR is the distance from the reference point in the Z direction to the corner 2 of the B wheel. Since BRL and BRR are sharing ratios, BRL + BRR = 1.

  When Expression 2 and Expression 3 are substituted into Expression 7, (XLgo × BRL + XRgo × BRR) + X4R = X5R (Expression 8). Further, when Expression 1 and Expression 7 are substituted into Expression 8, {(X1L + X2L + X3L) * (HH-HR) / HH + (X1R + X2R + X3R) * HR / HH} + X4R = X5R (Expression 9). In Expression 9, X1L, X1R, and X5R are obtained from values by which an X-axis slider (not shown) on which the bit 26 is mounted, and X2L and X2R are obtained by image processing based on the imaging devices 27 and 68. That is, the unknowns are X3L and X3R.

  The unknowns X3L and X3R are obtained by solving Equations 6 and 9 as simultaneous equations (the simultaneous equations are omitted). If the unknowns X3L and X3R are obtained, XLgo and XRgo (geometric-offset value in the X direction) are obtained according to equations 2 and 3.

(Calculation in the Z direction)
If Zgo, which is the Geometric-Offset value in the Z direction, is Zgo = Z1 + Z2 + Z3 (Formula 10), then Zgo + Z4L = Z5L or Zgo + Z4R = Z5R (Formula 11) holds. Here, Z1 is the distance from the origin of the chip 26A in the Z direction to the chip 26A in the A frame, and Z3 is the distance from the reference point of the reference gauge 18 (see FIG. 7) to the claw 12A. Z5L is the distance from the origin of the tip 26A to the corner 1 of the test material 66 in the Z direction, and Z5R is the distance from the origin of the tip 26A to the corner 2 of the test material 66 in the Z direction.

  If Expression 10 is substituted into Expression 11, Z1 + Z2 + Z3 + Z4L = Z5L or Z1 + Z2 + Z3 + Z4R = Z5R (Expression 12). Here, in Expression 12, Z1, Z2, Z4L, Z5L, Z4R, and Z5R are obtained by values that a Z-axis slider (not shown) on which the cutting tool 26 is mounted moves. Therefore, since the unknown is only Z3, it is obtained by Equation 12. Note that the unknown value Z3 may be an average value of two expressions of Expression 12.

  If the unknown number Z is obtained, Zgo (Geometric-Offset value in the Z direction) is obtained by Equation 10. If the Geometric-Offset value obtained in a so-called wizard format is determined for the X direction and the Z direction, NC machining can be performed. In the Z direction, the displacement of the tailstock 88 and the inclination of the Z-axis slider (not shown) are so-called cosine errors at a very small angle, and thus are as close as possible to COSθ = 1. That is, the influence of the cutting correction value in the Z direction may be equally ignored.

(Calculation for tilt angle θ)
The tilt angle θ of the center axis of the chuck 12 and the core pressing shaft 89 (or the tilt angle θ of the NC slider is the same) is obtained by Expression 13 where θ = tan ⁻¹ (XRgo−XLgo / HH). When cutting the corner 1 or the corner 2 shown in FIG. However, in the case of a cylinder or an end face (and also a taper face), the cutting is performed by offsetting the θ angle obtained by Expression 13. In the example shown in FIG. 7, the core pushing shaft 89 is displaced in the X direction. In this case, the displacement in the Z direction is a cosine error at a minute angle as described above. Accordingly, the case where the Z-axis slider (not shown) in the Z direction is tilted may be similarly ignored. However, since the influence of the cutting correction value is greater in the X direction than in the Z direction, processing is performed using the above-described equations.

  In this embodiment, if the above-described Geometric-Offset value is determined and the tilt angle θ is determined in the X direction and the Z direction (that is, by recording these numerical values in the RAM 64 shown in FIG. 8). NC machining corresponding to a long workpiece WL (see FIG. 5) can be performed as appropriate. Therefore, according to the present embodiment, virtual data of the virtual movement trajectory of the tip 26A (see FIG. 7) for various long workpieces having different lengths, that is, the Geometric-Offset value and the axis of the chuck 12 and the core shaft 89 are measured. Since the inclination or the inclination angle θ of the NC slider can be detected with high precision (concept including calculation), the machining accuracy of the long workpiece is improved even when cutting a long workpiece.

  Here, the virtual movement trajectory takes into account the amount of movement from the origin of the cutting tool 26 toward the axis of the workpiece (synonymous with the workpiece), and the inclination of the axis of the chuck 12 and the core pushing shaft 89 and the NC. This is a trajectory that the cutting tool 26 will move with the inclination of a slider (not shown). That is, the virtual movement trajectory is a virtual line indicating the inclination of the axis of the chuck 12 and the core pushing shaft 89 and the inclination of the NC slider.

  In the present embodiment, based on virtual data (including data on the tilt angle θ) regarding the virtual movement locus of the bit 26, the CPU 60 shown in FIG. 8 tilts the axis of the chuck 12 and the core pushing shaft 89 and the tilt of the NC slider. The long workpiece WL is processed so as to correct the above. That is, the CPU 60 processes the long workpiece WL while correcting the bit 26 based on the virtual data of the virtual movement locus. Therefore, according to the present embodiment, since the virtual data of the virtual movement trajectory in the cutting tool 26 can be detected with high accuracy, the processing accuracy is improved even when the long workpiece WL is cut. According to the present embodiment, since the imaging device 68 slides in conjunction with the core pushing shaft 89 of the tailstock 88, the imaging device 68 is automatically adapted to handle various long workpieces having different lengths. Can stop.

(Modifications related to chuck)
Hereinafter, based on FIG.9 and FIG.10, the modification regarding the chuck | zipper 17 is demonstrated. However, substantially the same parts as those in the configuration of the chuck 12 shown in FIG. 5 of the first embodiment described above are denoted by the same reference numerals, description thereof is omitted or simplified, and different parts are mainly described.

  As shown in FIGS. 9 and 10, the tip of the chuck 17 has a small diameter portion 17 </ b> A. The chuck 17 is formed with a notch 17B (see FIG. 10) along the axial direction of the chuck 17. As shown in FIG. 9, the cutout portion 17 </ b> B is formed from the outer periphery of the small diameter portion 17 </ b> A to the large diameter base end portion (this portion becomes a “through hole”).

  The columnar invar body 86 is fixed at the proximal end portion of the chuck 17 by a bolt 49A, which is a fastening member, at one end thereof. The tip 86A of the invar body 86 has a semicircular shape as shown in FIG. That is, as shown in FIG. 9, the tip 86A of the invar body 86, the reference gauge 18, and the tip 26A of the cutting tool 26 are captured in, for example, the visual field region (one-viewer A area) of the imaging device 27 shown in FIG. .

  Then, when detecting the chip 25A of the cutting tool 25 shown in FIG. 10 (in this case, the cutting tool 26 is not in the first view A area), as shown in FIG. 3, the shutter 38 is first slid to change the optical path on the half mirror 31B side. Open. The camera 30 images the tip 47A of the invar body 47 and the reference gauge 18, which are subjects located in the single vision A area shown in FIG. That is, as shown in FIG. 3, since the optical path on the shutter 39 side is blocked, the half mirror 31 </ b> B reflects the subject light in the single vision A area to the camera 30.

  Immediately after imaging, the shutter 38 is closed and the shutter 39 is slid to open the optical path on the full mirror 31A side. The shutters 38 and 39 are switched at a time difference (synonymous with substantially the same time), for example, 0.5 seconds. Subsequently, as shown in FIG. 9, the camera 30 captures an image of the chip 25 </ b> A of the bite 25 that is a subject located in the single vision B area. That is, as shown in FIG. 3, since the optical path on the shutter 38 side is blocked, the full mirror 31A reflects the subject light in the single vision B area to the camera 30. At this time, since the half mirror 31B transmits the subject light reflected by the full mirror 31A, the camera 30 images only the subject in the single vision B area.

  The present invention is not limited to the short-axis lathe described in the first embodiment, and can be applied to various cutting machines (machines that move a cutting tool and a workpiece relative to each other) such as a 2-axis front lathe or a milling machine. .

  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, 27, 68 ... Imaging device (Imaging means), 30 ... camera, 47, 86 ... Invar body (reference body), 47A, 86A ... tip of Invar body, 60 ... CPU (collation means, calculation means, correction means), 62 ... ROM (storage means) 64 ... RAM (recording means), 66 ... test material, 70 ... connecting rod, 88 ... core press, 89 ... core press shaft, S ... lathe (cutting machine), W ... workpiece (workpiece)

Claims (3)

First position detecting means for detecting a position of a chuck for holding a workpiece with respect to a cutting tool based on an imaging process;
Second position detecting means for detecting the position of the core support shaft for supporting the workpiece with respect to the cutting tool based on an imaging process;
The cutting tool indicating the inclination of the center of the chuck and the centering shaft and the inclination of the slider for moving the cutting tool based on the respective image data by the first position detecting means and the second position detecting means. Calculating the virtual data of the virtual movement trajectory in the control means for controlling the movement of the cutting tool based on the virtual data;
A cutting machine comprising: The first position detection means includes a first imaging means for imaging a subject, a reference gauge disposed on the chuck for measuring a position error of the first imaging means, and one end fixed to the chuck. And a reference body that is arranged so that a free end thereof corresponds to the reference gauge and serves as a reference for the amount of thermal displacement of the reference gauge,
The second position detection means includes a second imaging means for imaging a subject, and a reference mark disposed on the core pressing shaft for measuring a position error of the second imaging means,
The first imaging means images the reference gauge at the imaging position in the optical path, the free end of the reference body corresponding to the reference gauge, and the cutting tool at the imaging position as a subject in the same imaging area. At the same time, the second imaging means captures the reference mark at the imaging position in the optical path and the cutting tool at the imaging position as a subject in the same imaging area, thereby virtualizing the virtual movement trajectory. The cutting machine according to claim 1, wherein the control unit calculates data based on image data of the first imaging unit and image data of the second imaging unit. Image data of first position detecting means for detecting the position of the chuck with respect to the cutting tool based on imaging processing and image data of the second position detecting means for detecting the position of the core shaft relative to the cutting tool based on imaging processing Record each in
Based on these image data, the control means calculates virtual data of the virtual movement locus in the cutting tool indicating the inclination of the axis of the chuck and the core pushing shaft and the inclination of the slider for moving the cutting tool. A machining position correction method for the cutting machine, wherein the movement of the cutting tool is corrected based on virtual data.

Images