Processing method

Abstract

A machining method in which a workpiece (1) is fixed to a rotary table (35), the workpiece is positioned in a plurality of postures, a prescribed portion of the surface of the workpiece is machined by a rotary tool (2) used at the time of formal machining of the workpiece, each surface portion of the workpiece on which machining is performed is measured, and based on the results of the measurement, an error of a rotary feed axis is corrected in accordance with position information of the center of rotation of the rotary table with respect to a machine coordinate system and a correction amount of a tool length of the rotary tool.

Description

TECHNICAL FIELD

[0001] The present application relates to a machining method by a machine tool having a rotary feed axis in addition to a linear feed axis having orthogonal 3 axes. BACKGROUND

[0002] For example, in a machine tool having a rotary feed axis such as a 5-axis machining center, machining cannot be performed with high accuracy due to a position error of a rotary axis of the rotary feed axis or the like. In Patent Literature 1, a method of calculating a position error and a tilt error of a rotary axis of a rotary feed axis of such a machine tool is described.

[0003] In the method described in Patent Literature 1, a workpiece table is positioned at 3 positions of measurement different in rotation angle by relative rotation of the workpiece table with respect to a spindle, the center position of a reference ball provided on the workpiece table is measured by a contact sensor attached to the spindle, and a direction vector of the rotary axis is calculated based on the center position of the reference ball measured at each position of measurement, and a tilt error of the actual direction vector with respect to a reference direction vector of the rotary axis is calculated.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Application Laid-Open No. 2005-061834 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] In the method described in Patent Literature 1, since the measurement is performed under conditions and environments different from actual machining such as stopping of a coolant and a spindle, when machining is performed based on the measurement results, actual machining (actual machining) is performed without knowing how the actual machining accuracy is.

[0009] The present application has an object to provide a machining method capable of machining a workpiece with high accuracy even when a rotary axis of a rotary feed axis has a position error, a tilt error, and a vibration error.

[0010] MEANS FOR SOLVING THE PROBLEMS

[0011] To achieve the above object, according to the present application, there is provided a machining method in which a workpiece is machined by a machine tool having a linear feed axis and a rotary feed axis, by relatively moving a rotary tool mounted on a spindle and the workpiece fixed to a rotary table, wherein a test workpiece is fixed to the rotary table, the test workpiece is positioned in a plurality of postures, a prescribed portion of a surface of the test workpiece is machined by a rotary tool used at the time of actual machining of the workpiece, each machined surface portion of the test workpiece is measured, based on a result of the measurement, an error of the rotary feed axis is corrected based on position information of a center of rotation of the rotary table with respect to a machine coordinate system and a correction amount of a tool length of the rotary tool, and the workpiece is machined.

[0012] Effects of the Invention

[0013] According to the present application, before actual machining, a prescribed surface portion of a test workpiece is machined under the same conditions and environment as actual machining (actual machining), and the surface portion is measured, a center of a rotary axis is found, and a correction amount is found by calculation based on this, and thus, even if the rotary axis of the rotary feed axis has a position error, an inclination error, and a vibration error, the workpiece can be machined with high accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a perspective view of a machine tool to which the present application is applied.

[0015] Figure 2 is a perspective view of a rotary table of the machine tool of Figure 1

[0016] Figure 3 is a perspective view of a rotary table of the machine tool of Figure 1

[0017] Figure 4 is a perspective view of a rotary table rotated by 180° in the B-axis direction from the state of Figure 1

[0018] Figure 5 is a block diagram of a control device of a machine tool based on the embodiment of the present application.

[0019] Figure 6 is a perspective view for explaining machining of a test workpiece.

[0020] Figure 7 is a perspective view for explaining machining of a test workpiece.

[0021] Figure 8 is a perspective view for explaining machining of a test workpiece.

[0022] Figure 9 ​​​is a perspective view for explaining the machining of the test workpiece.

[0023] Figure 10 is a perspective view for explaining the measurement of the machined surface of the test workpiece.

[0024] Figure 11 is a perspective view for explaining the measurement of the machined surface of the test workpiece.

[0025] Figure 12 is a perspective view for explaining the parameters used to calculate the correction amount from the measurement results.

[0026] Figure 13 is a diagram of an input screen for inputting the machining parameters of the test workpiece.

[0027] Figure 14 is a diagram of an input screen for inputting the tool parameters and machining condition parameters used to machine the test workpiece.

[0028] Figure 15 is a diagram of a correction amount display screen for displaying the calculation results of the correction amount. DETAILED DESCRIPTION

[0029] WAYS OF CARRYING OUT THE INVENTION

[0030] Hereinafter, a preferred embodiment of the present application will be described with reference to the accompanying drawings.

[0031] First, with reference to Figure 1 , 2 , an example of a machine tool to which the present application is applied will be described.

[0032] In Figure 1 , 2 , the machine tool 11 is provided with a bed 13 that becomes a base, and a column 15 that is vertically disposed on the upper surface of the bed 13. A moving body 27 is disposed on the upper surface of the bed 13. The moving body 27 supports, via a tilting rotary table 28, a rotary table 35 that rotates the workpiece W. The rotary table 35 has a workpiece mounting surface 35a that fixes the workpiece W.

[0033] A saddle 17 is disposed on the front surface of the column 15. Further, a spindle head 21 is disposed on the front surface of the saddle 17. A spindle 25 is attached to the spindle head 21. A rotary tool T that machines the workpiece W is attached to the spindle 25. The rotary tool T rotates together with the spindle 25 while machining the workpiece W.

[0034] The machine tool 11 in the present embodiment is provided with a moving device that changes the relative positions of the rotary tool T and the workpiece W. In the present embodiment, a machine coordinate system is set with a prescribed position in the machine tool as the origin. With respect to the machine coordinate system, the X-axis, the Y-axis, and the Z-axis that are orthogonal to one another are determined in advance. When the machine tool is designed, the direction in which the axis line of the spindle 25 extends (the up-down direction in the present embodiment) is referred to as the Z-axis. In addition, the axis that extends in the horizontal direction in which the moving body 27 moves is referred to as the Y-axis. In addition, the axis that extends in the horizontal direction in which the saddle 17 moves, that is, the direction that is perpendicular to the Z-axis and the Y-axis, is referred to as the X-axis. Figure 1

[0035] The moving device enables the rotary tool T and the workpiece W to move relatively in the X-axis direction, the Y-axis direction, and the Z-axis direction. Furthermore, the moving device enables the workpiece W to move relatively in rotation with respect to the rotary tool T in the B-axis direction around the axis line 52 of the tilt rotary table 28 and in the C-axis direction around the axis line 53 of the rotary table 35.

[0036] The moving device includes an X-axis moving device that moves the rotary tool T relatively with respect to the workpiece W in the X-axis direction. The X-axis moving device includes a pair of X-axis rails 19a, 19b formed on the front face of the column 15. The saddle 17 is formed so as to be able to move reciprocally along the X-axis rails 19a, 19b. The X-axis moving device moves the saddle 17 by a ball screw mechanism. The X-axis moving device includes an X-axis servo motor 20 that rotates the screw shaft of the ball screw mechanism. The X-axis moving device moves the saddle 17 by driving the X-axis servo motor 20. The spindle head 21 and the rotary tool T move in the X-axis direction together with the saddle 17.

[0037] The moving device includes a Z-axis moving device that moves the rotary tool T relatively with respect to the workpiece W in the Z-axis direction. The Z-axis moving device includes a pair of Z-axis rails 23a, 23b formed on the front face of the saddle 17. The spindle head 21 is formed so as to be able to move reciprocally along the Z-axis rails 23a, 23b. The Z-axis moving device moves the spindle head 21 by a ball screw mechanism. The Z-axis moving device includes a Z-axis servo motor 24 that rotates the screw shaft of the ball screw mechanism. The Z-axis moving device moves the spindle head 21 by driving the Z-axis servo motor 24. The rotary tool T moves in the Z-axis direction together with the spindle head 21. Furthermore, a drive motor that rotates the spindle 25 around the axis line is disposed inside the spindle head 21.

[0038] Figure 3 is a schematic perspective view that shows the Y-axis moving device in the present embodiment. Referring to Figures 1 to 3 ​The moving device includes a Y-axis moving device that relatively moves the rotary tool T with respect to the workpiece W in the Y-axis direction. The Y-axis moving device includes a pair of Y-axis rails 29a, 29b arranged on the upper surface of the bed 13. A moving body 27 is formed so as to be able to reciprocate along the Y-axis rails 29a, 29b. A hollow portion 15a is formed in the column 15 so that the moving body 27 is able to move in the Y-axis direction.

[0039] The Y-axis moving device moves the moving body 27 by a ball screw mechanism 30. The Y-axis moving device includes a Y-axis servo motor 32 that rotates a screw shaft of the ball screw mechanism. The Y-axis moving device moves the moving body 27 by driving the Y-axis servo motor 32. The tilt swivel table 28 and the rotary table 35 move in the Y-axis direction together with the moving body 27.

[0040] The moving device includes a B-axis rotary moving device that relatively rotates the rotary tool T with respect to the workpiece W in the B-axis direction. The axis 52 of the B-axis in the present embodiment is not parallel with respect to any one of the X-axis, the Y-axis, and the Z-axis. That is, the axis 52 of the B-axis is inclined with respect to each of the three linear axes. The B-axis rotary moving device includes the tilt swivel table 28. A servo motor for rotating the tilt swivel table 28 is arranged inside the moving body 27. The tilt swivel table 28 rotates around the axis 52 of the B-axis by driving the servo motor of the tilt swivel table 28. The workpiece W rotates in the B-axis direction together with the tilt swivel table 28 and the rotary table 35.

[0041] The moving device in the present embodiment includes a C-axis rotary moving device that relatively rotates the rotary tool T with respect to the workpiece W in the C-axis direction. The axis 53 of the C-axis is designed to be parallel with the Z-axis when the tilt swivel table 28 is at a predetermined angular position in the B-axis direction. The C-axis rotary moving device includes the rotary table 35. A servo motor is arranged inside the tilt swivel table 28. The rotary table 35 rotates around the axis 53 of the C-axis by driving the servo motor. The workpiece W rotates in the C-axis direction together with the rotary table 35.

[0042] Thus, the machine tool 11 has three linear axes in which the spindle 25 relatively moves with respect to the workpiece W. That is, the machine tool 11 has the X-axis, the Y-axis, and the Z-axis as linear axes. In the present embodiment, the first linear axis is described as the Y-axis, the second linear axis is described as the Z-axis, and the third linear axis is described as the X-axis. In addition, the machine tool 11 has two rotary axes in which the spindle 25 relatively rotates with respect to the workpiece W. That is, the machine tool 11 has the axis 52 of the B-axis and the axis 53 of the C-axis as rotary axes. In the present embodiment, the first rotary direction is described as the C-axis direction, and the second rotary direction is described as the B-axis direction. In addition, the first axis is described as the axis 53 of the C-axis, and the second axis is described as the axis 52 of the B-axis.

[0043] The machine tool in this embodiment is provided with a control device 70. The control device 70 is connected to the servo motors and drive motors of the moving device. The control device 70 is capable of relatively moving the rotary tool T with respect to the workpiece W by controlling the servo motors of the moving device.

[0044] Referring to Figure 1 , 2 , it is preferable that the machine tool 11 be manufactured so that the surface of the rotary table 35 is strictly parallel to the XY plane including the X axis and the Y axis of the machine coordinate system, and the axis 52 of the B axis and the axis 53 of the C axis intersect when the rotation angle with respect to each of the rotary axes is 0°. However, due to manufacturing errors, aging, and the like, there are cases in which the surface of the rotary table 35 is slightly inclined or the axis 52 and the axis 53 are slightly apart.

[0045] The machine tool 11 is provided with an angle adjustment device as an adjustment assembly that adjusts the inclination of the moving body 27. In this embodiment, the inclination of the moving body 27 is adjusted so that the axis 52 of the B axis and the axis 53 of the C axis extend parallel to the YZ plane throughout the Y axis stroke of the moving body 27. In this embodiment, the state in which the axis 52 of the B axis and the axis 53 of the C axis extend parallel to the YZ plane during movement of the moving body 27 in the Y axis direction is referred to as the reference state.

[0046] In addition, the machine tool 11 is provided with a control device 70. The control device 70 includes a read interpreter 72, an interpolation operation section 73, and a servo motor control section 74. The read interpreter 72 reads the input program 71 and sends the programmed movement command to the interpolation operation section 73. The interpolation operation section 73 calculates the position command value for each interpolation period and sends the position command value to the servo motor control section 74. For example, the interpolation operation section 73 calculates the movement amount for each time interval set based on the movement command. The servo motor control section 74 drives each axis servo motor 75 based on the position command value. In addition, the control device 70 is provided with an operation section 76 connected to the measurement device 40 described later and a storage section 77 connected to the read interpreter 72 and the operation section 76.

[0047] Next, the effects of the present application will be described with reference to Figures 3 to 8 .

[0048] In the present application, before the actual machining of the workpiece W, a prescribed surface portion of a machining test workpiece 1 ( Figures 6 to 11 ) is machined. At this time, the rotary tool 2 used for machining the machining test workpiece 1 is the same rotary tool as the rotary tool T used at the time of actual machining. The rotary tool 2 can be made into a ball nose end mill. The test workpiece 1 has a cuboid shape. In the present application, the cuboid shape includes a square shape.

[0049] First, before machining the machining test workpiece 1, the rotary table 35 is arranged so that the axis 52 of the B axis and the axis 53 of the C axis are parallel to the YZ plane.Figure 3 position. In this position, the workpiece mounting surface 35a of the rotary table 35 is arranged perpendicularly to the Z axis. This position of the rotary table 35 is referred to as a first position. By feeding the rotary table 35 180° in the B axis direction as indicated by an arrow 105 from the first position, the rotary table 35 is arranged in Figure 4 position. At this time, the workpiece mounting surface 35a of the rotary table 35 is in a position perpendicular to the workpiece mounting surface 35a of the rotary table 35 in the first position, parallel to the Z axis which is one of the orthogonal 3 axes, and in a position perpendicular to the other axes, in this embodiment, the Y axis.

[0050] When the rotary table 35 is in the first position, the B axis is in a rotational position of 0° (zero degree). When in a rotational position of 0° of the B axis and 0° of the C axis, it is referred to as the rotary table 35 being in a first attitude. That is, when the rotary table 35 is in the first attitude, both the B axis and the C axis are in the origin position. If the rotary table 35 is caused to feed only the B axis 180° toward the second position as indicated by the arrow 105 from the first attitude without rotating the C axis, the rotary table 35 moves to a rotational position of 180° of the B axis and 0° of the C axis. This rotational position is taken as a second attitude of the rotary table 35.

[0051] A rotational position in which the C axis is rotated 90° from the second attitude is taken as a third attitude of the rotary table 35, a rotational position in which the C axis is further rotated 90° is taken as a fourth attitude of the rotary table 35, and a rotational position in which the C axis is further rotated 90° is taken as a fifth attitude of the rotary table 35.

[0052] The test workpiece 1 is arranged so that two of the facing sides are perpendicular to the X axis and the other two of the facing sides are perpendicular to the Y axis on the workpiece mounting surface 35a of the rotary table 35 in the first attitude. At this time, one side (upper surface) of the test workpiece mounted on the workpiece mounting surface 35a is perpendicular to the Z axis which is one of the orthogonal 3 axes, and faces the rotary tool 2.

[0053] The upper surface facing the rotating cutter 2 has two surface portions 1-1 and 1-2 that should be tested and machined. Additionally, in the test workpiece 1, each of the four sides perpendicularly connected to the upper surface having these two surface portions 1-1 and 1-2 has two surface portions 1-3, 1-7; 1-4, 1-8; 1-5, 1-9; 1-6, 1-10 that should be tested and machined by the rotating cutter 2. The two upper surface portions 1-1 and 1-2 can be made rectangular, preferably square, and more preferably rectangular including one edge of the cuboid-shaped test workpiece 1. The two surface portions of each of the four sides connected to the upper surface can be made into a rectangular or strip-shaped shape of a certain width.

[0054] First, the rotary table 35 is configured in a first position, and while the rotary table 35 is linearly fed in the orthogonal three-axis directions (X-axis, Y-axis, Z-axis), one of the two surface portions of the test workpiece 1 is machined by the front end of the rotary tool 2. Next, as... Figure 7 As shown, one of the two surface portions to be machined in each of the four sides perpendicularly connected to the top of the test workpiece 1 is, in this embodiment, the surface portions 1-3, 1-4, 1-5, and 1-6 adjacent to the top side, i.e., the top of the test workpiece 1. Thus, the machining mode performed by linear feed in the orthogonal three-axis (X-axis, Y-axis, Z-axis) direction is called three-axis machining.

[0055] If the four side surface portions 1-3, 1-4, 1-5, and 1-6 are machined by the side of the rotary tool 2, then the rotary table 35 is next rotated and fed in the B-axis direction, configured to the second position. Figure 4 At this point, one side of the test workpiece 1 is positioned perpendicular to the Z-axis and facing the rotary tool 2. Next, the rotary table 35 is rotated 180° in the C-axis direction, as follows. Figure 8 As shown, the two surface portions 1-1 and 1-2 that should be machined are positioned on the upper side, that is, close to the rotary tool 2. At this time, the rotary table 35 is configured in the fourth position.

[0056] With the rotary table 35 configured in this fourth position, linear feed is performed in the orthogonal three-axis (X-axis, Y-axis, Z-axis) directions, and the other side 1-2 of the two surface portions to be tested on the upper surface of the test workpiece 1 is machined by the side of the rotary tool 2. At this time, the machining parameters for surface portions 1-1 and 1-2 are set in the machining program to create machined surfaces without step differences. Then, as... Figure 9 As shown, the front end of the rotary cutter 2 processes the surface portions 1-7 of the other two of the four sides that are perpendicularly connected to the top of the test workpiece 1.

[0057] Next, after surface portions 1-7 are machined, the C-axis is rotated 90°, and the rotary table 35 is positioned in the fifth position. Surface portions 1-8 are machined by the front end of the rotary tool 2. After surface portions 1-8 are machined, the C-axis is rotated another 90°, and the rotary table 35 is positioned in the second position. Surface portions 1-9 are machined by the front end of the rotary tool 2. Similarly, after surface portions 1-9 are machined, the C-axis is rotated another 90°, and the rotary table 35 is positioned in the third position. Surface portions 1-10 are machined by the front end of the rotary tool 2. This machining mode, which involves linear feed along three orthogonal axes (X-axis, Y-axis, Z-axis) and rotary feed along two rotary feed axes (B-axis, C-axis), is called 5-axis machining. For surfaces 1-3, 1-7, 1-4, 1-8, 1-5, 1-9, 1-6, and 1-10, the machining parameters are set in the machining program to create a machined surface without step differences.

[0058] After machining all the surfaces that should be machined, the rotary table 35 is positioned in the first orientation. At this point, the top of the test workpiece 1 is positioned perpendicular to the Z-axis, and two of the four sides perpendicularly connected to the top are... Figure 9 The sides having surface portions 1-3, 1-7, and surface portions 1-5, 1-9 are arranged perpendicular to the Y-axis, and the sides having surface portions 1-4, 1-8, and surface portions 1-6, 1-10 are arranged perpendicular to the X-axis. Simultaneously, the rotating tool 2 is removed from the spindle 25, and in its place, the measuring device 40 is mounted on the spindle 25. The measuring device 40 can be made into a contact sensor that outputs a signal when the measuring probe 40a contacts the surface of the object being measured.

[0059] Next, as Figure 10 As shown, the measuring probe 40a of the measuring device 40 is positioned above each of the two surface portions 1-1 and 1-2 on the test workpiece 1, and approaches the test workpiece 1 along the Z-axis, thereby measuring the Z-coordinate Z of each of the two surface portions 1-1 and 1-2. 1-1 Z 1-2 In other words, the measuring device 40 sends the signal of each contact between the measuring probe 40a and each of the surface portions 1-1 and 1-2 to the calculation unit 76. The calculation unit 76 detects the Z coordinate of each contact between the measuring probe 40a and the surface portions 1-1 and 1-2 of the measuring ball 44 and stores it in the storage unit 77.

[0060] Next, as Figure 11As shown, the measurement probe 40a of the measurement device 40 is brought into contact with each of the surface portions 1-3, 1-4, 1-5, 1-6 and the surface portions 1-7, 1-8, 1-9, 1-10 in a direction perpendicular to each of the surface portions 1-3, 1-4, 1-5, 1-6 and the surface portions 1-7, 1-8, 1-9, 1-10 with respect to each of the four side surfaces connected to the upper surface of the test workpiece 1. Also, the coordinate values at this time are detected by the arithmetic unit 76 and stored in the storage unit 77. More specifically, the Y coordinates Y 1-3 1-5 of the surface portions 1-3, 1-5 and the Y coordinates Y 1-7 1-9 of the surface portions 1-7, 1-9 are measured, and the X coordinates X 1-4 1-6 of the surface portions 1-4, 1-6 and the X coordinates X 1-8 1-10 of the surface portions 1-8, 1-10 are measured, and stored in the storage unit 77.

[0061] The arithmetic unit 76 calculates the coordinates (X C3 , Y C3 ) = ((X 1-4 + X 1-6 ) / 2, (Y 1-3 + Y 1-5 ) / 2) of the center C3 of the surface portions 1-3, 1-4, 1-5, 1-6 machined by the 3-axis machining and the coordinates (X C5 , Y C5 ) = ((X 1-8 + X 1-10 ) / 2, (Y 1-7 + Y 1-9 ) / 2) of the center C5 of the surface portions 1-7, 1-8, 1-9, 1-10 machined by the 5-axis machining based on the measurement results. Next, the arithmetic unit 76 calculates the deviation α = ((X 1-4 + X 1-6 ) / 2) - ((X 1-8 + X 1-10 ) / 2) in the X direction and the deviation β = ((Y 1-3 + Y 1-5 ) / 2) - ((Y 1-7 + Y 1-9 ) / 2) of the center C5 based on the 5-axis machining with respect to the center C3 based on the 3-axis machining. The calculation results are stored in the storage unit 77.

[0062] Next, the arithmetic unit 76 calculates the distances in the X direction and the Y direction of the surface portions 1-3, 1-4, 1-5, 1-6 machined by the 3-axis machining, that is, the distance γ3 = |X 1-4 - X 1-6 ​​​​| and the distance δ3 between the surface portions 1-3 and 1-5 1-3 - Y 1-5 | and the distance γ5 between the surface portions 1-8 and 1-10, that is, the distance between the surface portions 1-8 and 1-10 1-8 - X 1-10 | and the distance δ5 between the surface portions 1-7 and 1-9 1-7 - Y 1-9 | and the distance δ5 between the surface portions 1-7 and 1-9

[0063] Next, the operation section 76 calculates the difference γ = γ3 - γ5 between the distance γ3 between the surface portions in the X direction based on the 3-axis machining and the distance γ5 between the surface portions in the X direction based on the 5-axis machining, the difference δ = δ3 - δ5 between the distance δ3 between the surface portions in the Y direction based on the 5-axis machining and the distance δ5 between the surface portions in the X direction based on the 5-axis machining, and stores the calculation results in the storage section 77. Further, the operation section 76 calculates the average λ = (γ + δ) / 4 of the differences between the 3-axis machining and the 5-axis machining with respect to the distance between the surface portions in the X direction and the distance between the surface portions in the Y direction, and stores the calculation results in the storage section 77.

[0064] Next, the operation section 76 calculates the difference ε = Z 1-1 - HZ of the target value HZ of the surface portion 1-1 of the test workpiece 1 machined by the 3-axis machining and the Z coordinate Z 1-1 - HZ of the surface portion 1-2 of the test workpiece 1 machined by the 5-axis machining, and stores the calculation results in the storage section 77. 1-2 - HZ of the surface portion 1-2 of the test workpiece 1 machined by the 5-axis machining, and stores the calculation results in the storage section 77. 1-2 - HZ of the surface portion 1-2 of the test workpiece 1 machined by the 5-axis machining, and stores the calculation results in the storage section 77.

[0065] Further, the operation section 76 calculates the difference Dx = Lx - γ3 between the target value Lx in the X direction of the test workpiece 1 and the distance γ3 between the surface portions in the X direction based on the 3-axis machining, and the difference Dy = Ly - δ3 between the target value Ly in the Y direction and the distance δ3 between the surface portions in the Y direction. The operation section 76 also calculates the average η = (Dx + Dy) / 4 thereof, and stores the calculation results in the storage section 77.

[0066] The operation section 76 determines the correction amount CV based on the above calculation results as follows.

[0067] CV1 = α

[0068] CV2 = β

[0069] CV3 = - (ζ + η) / 2

[0070] CV4 = λ + CV3

[0071] CV5 = ((ζ + CV3) + (ε + CV4)) / 2

[0072] Here, CV1 is an X-direction correction amount of the rotation center of the rotary table 35, CV2 is a Y-direction correction amount of the rotation center of the rotary table 35, CV3 is a Z-axis correction amount, CV4 is a correction amount of the tool measuring device to the tool length direction of the rotary tool 2, and CV5 is a correction amount of the Z coordinate in the workpiece coordinate system (calibration value in the Z direction of the measuring device 40).

[0073] The measurement of the test workpiece 1 described above can be automatically performed by inputting the automatic measurement program to the control device 70 as the input program 71. If the control device 70 executes the automatic measurement program, the input screen shown in Figure 13 is displayed on a display device such as a touch panel provided on a control panel (not shown) of the machine tool 11.

[0074] The input screen 100 has regions 102, 104, 106, 108 for inputting machining parameters such as the dimensions of the X direction, Y direction, and Z direction of the test workpiece 1, and the depth from the surface of the test workpiece 1 (cutting amount). One of these regions 102, 104, 106, 108 is activated, and a value is input to each region 102, 104, 106, 108 using an input device such as a keyboard (not shown). The input machining parameters of the test workpiece 1 are stored in the storage section 77. In addition, the input screen 100 can include a region 120 for displaying the machining process of the test workpiece 1 such as the workpiece origin check, the type of tool used, and the like. Further, the outline shape 130 of the test workpiece 1 can also be displayed.

[0075] After the input is completed, the tool information input screen 200 shown in Figure 14 is displayed by clicking the advance button 110. The tool information input screen 200 has regions for inputting tool parameters such as the tool diameter, and regions 202, 204, 206, 208 for inputting the periodic feed amount, spindle rotation speed, and feed speed as machining conditions. The input tool parameters and machining conditions are stored in the storage section 77. In addition, the input screen 100 can include a region 220 for displaying the machining process of the test workpiece 1 such as the workpiece origin check, the type of tool used, and the like. Further, the outline shape 230 of the tool used for machining the test workpiece 1 can also be displayed.

[0076] After the input is completed, the tool information input screen 200 shown in Figure 14 is displayed by clicking the advance button 110. The tool information input screen 200 has regions for inputting tool parameters such as the tool diameter, and regions 202, 204, 206, 208 for inputting the periodic feed amount, spindle rotation speed, and feed speed as machining conditions. The input tool parameters and machining conditions are stored in the storage section 77. In addition, the input screen 100 can include a region 220 for displaying the machining process of the test workpiece 1 such as the workpiece origin check, the type of tool used, and the like. Further, the outline shape 230 of the tool used for machining the test workpiece 1 can also be displayed.Figure 15 The correction amount is displayed on the correction amount display screen 300. The operator confirms the correction amount, and by clicking the apply button 310, performs the processing with the correction amount applied at the time of actual processing.

[0077] Explanation of symbols

[0078] 1: workpiece for test; 1-1: surface portion; 1-10: surface portion; 1-2: surface portion; 1-3: surface portion; 1-4: surface portion; 1-5: surface portion; 1-6: surface portion; 1-7: surface portion; 1-8: surface portion; 1-9: surface portion; 2: rotary tool; 11: machine tool; 13: bed; 15: column; 17: saddle; 19a: X-axis rail; 19b: X-axis rail; 21: headstock; 23a: Z-axis rail; 23b: Z-axis rail; 25: spindle; 27: moving body; 28: tilt rotary table; 29a: Y-axis rail; 29b: Y-axis rail; 35: rotary table; 35a: workpiece mounting surface; 40: measuring device; 40a: measuring probe; 52: axis; 53: axis; 70: control device; 71: input program; 72: read and interpretation section; 73: interpolation operation section; 74: servo motor control section; 75: axis servo motor; 76: operation section; 77: storage section; 100: input screen; 200: tool information input screen; 300: correction amount display screen; C3: center; C5: center; CV: correction amount; Dx: difference; Dy: difference; Hz: target value; Lx: target value; Ly: target value; T: rotary tool; W: workpiece; α: deviation; β: deviation; γ: difference; γ3: distance; γ5: distance; δ: difference; δ3: distance; δ5: distance; ε: difference; ζ: difference; η: average value; λ: average value.

Claims

1. A processing method which is performed by a machine tool moving a rotary tool mounted on a main shaft and a workpiece fixed on a rotary table relative to each other, the machine tool having orthogonal 3-axis linear feed shafts, a rotary feed shaft around an axis parallel to one of the orthogonal 3-axis linear feed shafts, and a rotary feed shaft around an axis different from the axis of the rotary feed shaft, characterized by, before actual processing of the workpiece, fixing a test workpiece on the rotary table, the test workpiece being a cuboid having one surface and four side surfaces connected to the one surface, the one surface having two surface portions, each of the four side surfaces including two surface portions, positioning the test workpiece in a posture in which the one surface is perpendicular to the axis of the main shaft, processing one of the two surface portions of the one surface by a leading end of the rotary tool used at the time of actual processing of the workpiece, processing one of the two surface portions of each of the four side surfaces of the test workpiece by a side surface of the rotary tool, positioning the test workpiece in a posture in which one of the four side surfaces is perpendicular to the axis of the main shaft, processing the other of the two surface portions of the one surface by the side surface of the rotary tool, processing the other of the two surface portions of the side surface by the leading end of the rotary tool, next positioning the test workpiece in a posture in which each of the remaining side surfaces of the four side surfaces of the test workpiece is perpendicular to the axis of the main shaft, processing the other of the two surface portions by the leading end of the rotary tool, measuring each of the surface portions of the test workpiece on which processing has been performed, correcting a tool length of the rotary tool based on the results of the measurement, calculating an X-direction deviation (α) and a Y-direction deviation (β) of the four side surfaces processed by the leading end of the rotary tool from the four side surfaces processed by the side surface of the rotary tool from coordinate values measured for the four side surfaces processed by the leading end of the rotary tool and coordinate values measured for the four side surfaces processed by the side surface of the rotary tool, setting the X-direction deviation (α) as an X-direction correction amount (CV1) of a rotation center of the rotary table and setting the Y-direction deviation (β) as a Y-direction correction amount (CV2) of the rotation center of the rotary table, and correcting an error of the rotary feed shaft in accordance with position information of the rotation center of the rotary table with respect to a machine coordinate system, and performing actual processing of the workpiece by the rotary tool. The rotary tool is a ball end mill. The rotary tool is a ball end mill. ​ ​ ​ ​ ​ ​ 2. The processing method of claim 1, wherein, ​

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