JP2011183494A - Working position correcting device and working position correcting method of cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a working position correcting device and a working position correcting method of a cutting tool, capable of accurately correcting a working position of the cutting tool based on surface roughness in image processing. <P>SOLUTION: A CPU arithmetically operates a nose radius based on data of the image processing (Step 100), and arithmetically operates theoretical surface roughness by substituting the arithmetically operated nose radius and a feed quantity of a cutting tool in a calculation expression (a feed quantity/(8×a nose of an edge)) of the theoretical surface roughness (Step 102). This arithmetically operated theoretical surface roughness is recorded on a RAM (Step 104), and compensating processing is performed by feeding back (Step 106). That is, since the nose radius is arithmetically operated based on image processing data, a calculation error and an input error are prevented without calculating the nose radius by manual work. Thus, since the CPU can correct the working position of the cutting tool based on the theoretical surface roughness, correction processing on a lathe is facilitated and accurate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a machining position correction apparatus for a cutting tool and a machining position correction method thereof for recognizing an image of a subject such as a cutting tool and correcting a machining position based on deformation (a concept including wear).

  For example, Patent Document 1 discloses a cutting edge position measuring device that does not cause measurement errors due to machining heat or environmental temperature changes, and that can also measure the cutting edge shape, the amount of wear, the dimensions of a workpiece, and the like. Has been. Specifically, a measurement reference surface positioned with respect to a machining reference point serving as a reference for numerical control is formed on the reference piece, and the contour of the measurement reference surface and the cutting edge of the tool is captured by the camera. The captured contour is stored in the image memory as electrical image information, and the relative position calculation circuit calculates the relative distance between the machining reference point and the cutting edge based on the image information. That is, in Patent Document 1, the relative position can be measured without being affected by the displacement of the part due to heat or the like.

  And in one Example of patent document 1, the numerical control apparatus is provided with the blade edge | tip position measuring apparatus which measures those relative distance between a process reference point and the blade edge of a tool. This cutting edge position measuring device includes a reference piece having a measurement reference plane whose relative position with respect to the machining reference point is determined in advance, a camera that captures the measurement reference plane and the outline of the cutting edge as an image, and a main processor. The reference piece is held by the chuck of the main shaft (see paragraph number “0015” and FIG. 1).

  Further, Patent Document 2 discloses a blade edge contour extraction method for obtaining a blade edge contour using multi-value image data of a blade edge captured image for measuring the blade edge wear degree of a tool (summary). reference). And in patent document 2, what is called a chipping state, such as the wear condition of the blade edge part in a tool, its quantity, etc. can be easily determined on the basis of the blade edge part outline measured by the above-mentioned blade edge part outline extraction method ( (See paragraph number “0034”).

Japanese Patent Laid-Open No. 9-253979 Japanese Patent Laid-Open No. 11-351835

By the way, although patent document 1 or patent document 2 can recognize the abrasion state of a blade edge | tip, etc. with an image processing technique, the technique of correct | amending the processing position of a cutting tool based on the abrasion data is not disclosed.
The present invention provides a machining position correction device for a cutting tool and a machining position correction method thereof that can accurately correct the machining position of the cutting tool based on surface roughness in image processing.

  A cutting tool processing position correction apparatus (a concept including a cutting machine) according to the present invention includes an imaging unit that images a subject, and the imaging unit images a cutting tool as a subject, and the cutting tool is configured based on the image data. Computation means for computing the surface roughness and control means for correcting the machining position of the cutting tool based on the computation result of the computation means.

  The above-mentioned surface roughness is, for example, theoretical surface roughness (cutting tool feed amount / (8 × blade edge nose radius)) or composite edge data obtained by shifting a plurality of the image data by feed amounts. The synthetic surface roughness is defined as the distance from the protruding position of the cutting tool in the data to the maximum height position (synonymous with the valley bottom position).

  The cutting tool machining position correction method according to the present invention images a cutting tool as a subject, calculates the surface roughness of the cutting tool based on the image data, and based on the calculation result, the machining position of the cutting tool. Correct.

  In the cutting tool machining position correction apparatus and the machining position correction method according to the present invention, the calculation means calculates the surface roughness based on the image data, and corrects the machining position of the cutting tool based on the calculation result. That is, the correcting means corrects the processing position of the cutting tool in consideration of, for example, the theoretical surface roughness or the combined surface roughness in order to increase the processing accuracy of the workpiece that is the workpiece.

  According to the cutting tool machining position correction apparatus and the machining position correction method according to the present invention, the machining position of the cutting tool can be corrected based on the surface roughness, so that the correction process is simple and accurate. For example, in the case of synthetic surface roughness, even if the machining position with respect to the workpiece is displaced due to wear or the like when the theoretical surface roughness cannot be calculated, the displacement of the machining position can be corrected with high accuracy, thus improving the workpiece machining accuracy. obtain.

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 when a bite or a reference gauge and an Invar body are stored in a camera field of view with the camera shown in FIG. It is a block diagram of the turret lathe shown in FIG. It is explanatory drawing at the time of calculating | requiring the nose radius of the chip | tip shown in FIG. It is explanatory drawing at the time of calculating | requiring theoretical surface roughness. It is a flowchart figure regarding the byte image processing mode which concerns on the turret lathe shown in FIG. It is explanatory drawing at the time of calculating | requiring synthetic surface roughness. It is explanatory drawing at the time of calculating | requiring synthetic surface roughness. It is explanatory drawing at the time of calculating | requiring synthetic surface roughness. It is explanatory drawing at the time of calculating | requiring synthetic surface roughness.

  In the following, a specific embodiment 1 and embodiment 2 of the present invention will be described.

  Hereinafter, based on FIG. 1 thru | or FIG. 9, the processing position correction apparatus and the processing position correction method of the cutting tool which are one Embodiment of this invention are demonstrated. An NC lathe which is a cutting machine provided with the machining position correction device 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 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, 26 (see FIG. 5) are attached at equal angular intervals on the circumference. Further, a turret gauge (not shown) (see the specification of Japanese Patent Application No. 2009-38185) is arranged at a predetermined position (one of the cutting tool mounting positions) of the tool post 21. 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 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 arranged so as to slightly protrude from the outer periphery of the chuck 12 measures a position error of the imaging device 27 described later. It is commonly used for both of the machining tools 26. 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.

(Configuration related to imaging device 27)
As shown in FIGS. 1 and 2, an imaging device 27 is slidably disposed in the lathe S between the isolation zone S1 and the machining zone S2 (see FIG. 4). The imaging device 27 images, for example, the chips 25A and 26A shown in FIG. 5 (the cutting edge when the cutting tool is not a chip such as a cutting tool) of the cutting tools (hereinafter also referred to as cutting tools) 25 and 26 as subjects. 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. 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, corrects the machining position of the cutting tool based on the results, and controls the machining process.

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 drops a part of incident subject light.

  The full mirror 31A and the half mirror 31B described above are arranged so that the camera fields 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. The field of view has a short side of 17 mm (2000 pixels) and a long side of 21.5 mm (2500 pixels) when a 5 million pixel camera is used.

  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). Note that the imaging space is always maintained at a predetermined atmospheric pressure, for example, +0.05 MPa.

  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, the air is constantly pressurized to the lens chamber 28A.

  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 in order to prevent coolant liquid or chips from flowing into the shutter chamber 28B. The shutters 38 and 39 are always closed and do not open the optical path at the same time. As shown in FIGS. 1 and 2, illumination light sources 43 and 44 are arranged at positions on the optical path opposite to the mirrors 31 </ b> A and 31 </ b> B (see FIG. 3) of the imaging device 27, respectively. These light sources 43 and 44 are comprised by light emitting LED etc., for example.

(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). .

(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. In other words, the tip 47A of the invar body 47, the reference gauge 18 and the tip 26A of the bit 26 are housed in the field of view of the image pickup device 27 and can be imaged (synonymous with a single view). 26 is arranged. It should be noted that the byte 26 moves to a predetermined position in the one-view A area (referred to as “A frame” in the figure) or the one-view B area (referred to as “B frame” in the figure) of the image pickup device 27 when detecting the chip. Is set in advance.

  The invar body 47 is made of a material having a smaller thermal expansion coefficient than the heat-treated steel constituting the lathe S (see FIG. 1) (for example, invar which is an invariant steel or aluminum whose thermal expansion coefficient is twice that of iron). For example, it is formed in a prismatic shape. 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 47 </ b> A side of the invar body 47 in a state slightly separated from the invar body 47. The counterweight 72 for preventing vibration is arranged on the opposite side of the place where the invar body 47 is arranged.

(Configuration for control system of lathe S)
As shown in FIG. 6, 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 that is the calculation means and the control means 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 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 57 as display means displays image data captured by the camera 30. 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. 5, 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. 3A) 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. 5, the camera 30 images the free end 47 </ b> A of the invar body 47, the reference gauge 18, and the tip 26 </ b> A of the bite 26, which is a subject located in the one-view vision A area. In the present embodiment, only the chip 26 </ b> A may be positioned in the one vision A area of the camera 30 and the image may be taken.

(Procedure for obtaining surface roughness of a cutting tool)
Based on FIG. 7, the procedure for obtaining the surface roughness of the cutting tool 26, that is, the nose radius R of the tip 26 will be described first. Here, the nose radius R is the radius of the contour curve portion (synonymous with the curve portion of the rake face) of the tip 26A, and by obtaining the contact point of the X direction cutting line or the Z direction cutting line (also simply referred to as cutting line). Obtained (see, for example, the specification of Japanese Patent Application No. 2008-274049).

  Next, the well-known theoretical surface roughness θ1 (see FIG. 8) is obtained by the feed amount f / (8 × the nose radius R of the cutting edge) of the cutting tool 26. The feed amount f is a distance for feeding the cutting tool 26 to the workpiece W as shown in FIG. For example, when the feed amount f is 0.2 (mm / rev) and the nose radius R is 0.4 (mm), the theoretical surface roughness is 12.5 (μm).

(Byte image processing mode)
The byte image processing mode will be described below with reference to the flowchart of FIG. In step 100, the CPU 60 (see FIG. 6) captures the chip 26A, which is a subject located in the single vision A area shown in FIG. 5, by the camera 30 (see FIG. 3A) and performs image processing. As described above, this imaging may include the reference 26 and the free end 47A of the invar body 47 close to the reference gauge 18 in addition to the chip 26A.

  In step 102, the CPU 60 calculates the theoretical surface roughness based on the image processing data. Specifically, first, the nose radius R (see FIG. 7) is calculated based on the image processing data. In addition to the calculation method described above, this calculation may be performed, for example, by an algorithm for obtaining the center of the curved portion of the rake face. Next, the CPU 60 substitutes the feed amount f of the cutting tool 26 inputted in advance and the nose radius R calculated above into the formula for calculating the theoretical surface roughness (feed amount f / (8 × the nose R of the cutting edge)). And calculate. Note that the feed amount f may be input by the operator through the operation unit 56 (see FIG. 6) at every calculation.

  In step 104, the CPU 60 records the theoretical surface roughness in the RAM 64 (see FIG. 6). In step 106, the CPU 60 performs a compensation process with feedback. That is, in this embodiment, the theoretical surface roughness is calculated and the machining position of the cutting tool 26 is corrected at the time of non-cutting during lathe operation, so even if the tip 26A is displaced during lathe operation, The displacement of the machining position can be corrected with high accuracy, and the machining accuracy of the workpiece W can be improved.

  Here, even if it is a new bit 26, since there is generally an error in the outer shape of the nose radius R, it is necessary for the CPU 60 to calculate the nose radius R based on the image processing data. In particular, when the cutting line position of the cutting tool 26 is set as the cutting position of the workpiece W (see FIG. 8), the processing position correction data of the cutting tool 26 considering the surface roughness is important.

  The routine shown in FIG. 9 is an example that is performed at the time of a calibration cycle, for example, every processing, that is, every time cutting. In the present embodiment, the routine shown in FIG. 9 may be performed with a predetermined interval (after a predetermined number of workpieces are cut or for a predetermined time). Here, in the calibration cycle, in order to obtain a compensation value for maintaining the cutting accuracy at a predetermined level, the lathe S shown in FIG. (Time) to perform the inspection. That is, the calibration cycle is an inspection performed after the operation of the lathe S is started.

  In the present embodiment, the nose radius R is calculated based on the image processing data, and the calculated nose radius R and the feed amount f of the cutting tool 26 are calculated using the formula (feed amount f / (8 × tooth nose R)). ) To calculate the theoretical surface roughness θ1 (see FIG. 8). That is, according to the present embodiment, since the nose radius R is calculated based on the image processing data, calculation errors and input errors are prevented without manually calculating the nose radius R.

  That is, according to the present embodiment, since the CPU 60 can correct the machining position of the cutting tool 26 based on the above-described theoretical surface roughness, the correction process related to the lathe S becomes simple and accurate. As for thermal displacement, the byte image processing mode described in the specification of Japanese Patent Application No. 2009-38185 or Japanese Patent Application No. 2009-198604 is performed.

  A second embodiment of the calculation method related to surface roughness will be described with reference to FIGS. 10 to 13. This surface roughness is different from the theoretical surface roughness θ1 (see FIG. 8) of the first embodiment, so-called synthetic surface roughness that can be applied even when the nose radius R is not sufficient due to wear as shown in FIG. θ2. The same parts as those of the lathe S and the related portions shown in FIGS. 1 to 6 of the first embodiment described above are denoted by the same reference numerals, description thereof is omitted, and a calculation method mainly related to different surface roughness will be described.

  Here, when the nose radius R is not sufficient and cutting is performed at the portion of the outline tangent indicated by the broken line in FIG. 7 (the surface roughness at this time is referred to as the combined surface roughness θ2, shown in FIG. 10), the theoretical surface roughness The degree calculation formula is not applicable. Therefore, it can be said that the composite surface roughness is a concept including the theoretical surface roughness. Further, since the finished dimension of the workpiece W is generally the dimension of the maximum protruding portion of the surface roughness, it can be calculated by the protruding position B processed by the cutting line of the cutting tool (such as the cutting tool 26) + the composite surface roughness θ2. Since the protruding position B and the valley bottom position are reversed between the workpiece W and the cutting tool 26, the cutting line position is set to the protruding position B from the stand of the cutting tool 26 in this embodiment.

  Hereinafter, a calculation method related to the composite surface roughness will be described with reference to FIGS. In step 100 shown in FIG. 9, the CPU 60 (see FIG. 6) images the chip 26A with the camera 30 (see FIG. 3A) and performs image processing. In step 102, the CPU 60 calculates the composite surface roughness based on the image processing data. Specifically, the CPU 60 pattern-matches the outline of the chip 26A and calculates the position of the cutting line (see, for example, the specification of Japanese Patent Application No. 2008-274049).

  Next, the width of the surface roughness is calculated. As shown in FIG. 11, the height of the surface roughness, that is, the height of the protruding position B of the chip 26A is set to 30 μm, for example. Originally, the height of the surface roughness is required by the size of the cutting tool 26 (see FIG. 10), but in actuality, it may be several times the surface roughness. Further, if the height of the surface roughness is increased, the amount of processing data increases, so that the calculation time by the CPU 60 becomes longer.

  Then, the CPU 60 calculates the width of the range having the height of the surface roughness from the protruding position B shown in FIG. 11 (synonymous with the width of the surface roughness). Specifically, scanning is performed in the horizontal direction from the protruding position B shown in FIG. 11 by the height of the surface roughness, and the width of the maximum dark portion in each pixel is obtained and set as the width of the surface roughness. Note that the interval between the seek lines CL in FIG. 11 is set to one pixel.

  Subsequently, the CPU 60 obtains each edge of the seek line group perpendicular to the cutting line. Specifically, the edge position is set over a predetermined range of surface roughness in the horizontal direction from the protruding position B shown in FIG. 12 (the position of the cutting line, that is, the position where the tip 26A contacts the workpiece not shown). In this edge position setting, the seek line CL is set to an equal pitch (for example, 10 μm), and the edge position for each seek line CL (see the black dots in FIG. 12) is set based on the brightness of the pixels between the seek lines CL. To do.

  The pitch of the seek line CL may be a divisor of the cutting feed pitch (synonymous with the feed amount f of the tip 26A shown in FIG. 8). For example, if the cutting feed pitch is 100 μm, each pitch 10 μm is a divisor. Further, the phase of the seek line CL is adjusted to the protruding position B of the chip 26A.

  Here, the MS pattern matching technique is applied to subject position recognition, but pattern matching based on normalized correlation may be used. For example, as other edge recognition means, a caliper line for edge detection (a modified one of the seek line CL) or the like may be applied.

  Finally, the CPU 60 calculates the composite surface roughness by superimposing a plurality of blade edge shapes. In this example, as shown in FIG. 13, a plurality of, for example, four cutting edge shapes are overlapped by being shifted by a cutting feed pitch f (see LL, L, R, and RR in FIG. 13). Specifically, the protruding position B of the cutting edge (see FIG. 13) is used as a reference of the phase of the seek line CL, and sequentially shifted in the horizontal direction as shown in FIG. In addition, since the pitch of the seek line CL is a divisor of the cutting feed pitch f, each seek line CL overlaps without shifting. Further, the number of overlaps is required to be at least two for the cutting feed pitch, but may be arbitrarily changed, for example, six.

  As shown in FIG. 13, the combined cutting edge shape (hereinafter also referred to as “combined blade shape data”) for calculating the combined surface roughness θ <b> 2 is from the protruding position B of the cutting edge shape L to the protruding position B of the cutting edge shape R. A curve (also referred to as a “polygonal line”) connecting the ones having the lowest edge position (see FIG. 13) among the seek lines CL. The combined surface roughness θ2 is a distance from the protruding position B to the maximum height position (synonymous with the valley bottom position) M among the edge positions in each combined blade shape (see FIG. 13). In the example shown in FIG. 13, the cutting edge shape LL and the cutting edge shape RR do not affect the combined cutting edge shape, so the CPU 60 calculates the combined surface roughness θ2 even with the cutting edge shape L and the cutting edge shape R. obtain.

  In the present embodiment, the CPU 60 calculates the composite surface roughness θ2 by superimposing only the data of the seek line CL in which the edge position is set in advance. That is, according to this embodiment, since the seek line CL set on the virtual screen is virtually compared, the CPU 60 can calculate the composite surface roughness θ2 with high accuracy.

  As another method of calculating the composite surface roughness, a plurality of cutting edge images are shifted by the cutting feed pitch, and each pixel is superimposed to give priority to a low luminance (synonymous with “dark”), and from a plurality of image data You may make it based on the synthetic | combination blade shape data which synthesize | combined one image data. According to this calculation method, since it depends on the size of the pixel, the processing accuracy tends to be wider than when a seek line is used.

  In step 104, the CPU 60 records the composite surface roughness in the RAM 64 (see FIG. 6). In step 106, the CPU 60 performs a compensation process with feedback. That is, in the present embodiment, since the composite surface roughness is calculated and the machining position of the cutting tool 26 is corrected during non-cutting during lathe operation, the nose radius R of the tip 26A during lathe operation (FIG. 7). If the theoretical surface roughness cannot be calculated in (see Fig. 1), or even if the machining position with respect to the workpiece W (see Fig. 1) is displaced due to wear or the like, the displacement of the machining position can be corrected with high accuracy. Can be improved. Other functions and effects are the same as those of the first embodiment.

  The present invention is not limited to the short-axis lathe described in the first embodiment. For example, the machining position correction device for various cutting tools such as a 2-axis front lathe or a milling machine (processing is performed by relatively moving the cutting tool and the workpiece). Machine). In the present invention, Example 1 and Example 2 may be combined.

  DESCRIPTION OF SYMBOLS 12 ... Chuck, 25 ... Bit (cutting tool) for inner diameter processing, 25A ... Tip (subject), 26 ... Bit (cutting tool) for outer diameter processing, 26A ... Tip (subject), 27 ... Imaging device (imaging means) ), 60... CPU (calculation means and control means), 64... RAM (recording means), S... Lathe (cutting tool machining position correction device), W .. work (workpiece), R. Projection position of cutting tool, M: Maximum height position (valley bottom position), θ1: Theoretical surface roughness, θ2: Composite surface roughness

Claims (3)

Imaging means for imaging a subject;
The imaging means images a cutting tool as a subject, and calculating means for calculating the surface roughness of the cutting tool based on the image data;
Control means for correcting the machining position of the cutting tool based on the calculation result of the calculation means;
A machining position correction device for a cutting tool comprising:   2. The cutting tool machining position correction apparatus according to claim 1, wherein the surface roughness is obtained by calculating theoretical surface roughness (cutting tool feed amount / (8 × nose radius of cutting edge)) or a plurality of the image data. A machining position correction device for a cutting tool having a combined surface roughness that is a distance from a protruding position of the cutting tool to a maximum height position in the combined blade shape data as the combined blade shape data shifted in feed amount.   A machining position correction method for a cutting tool that images a cutting tool as a subject, calculates the surface roughness of the cutting tool based on the image data, and corrects the processing position of the cutting tool based on the calculation result.

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