Machine tool control device and control method

Abstract

Relative to time (t), the tool (T) and the workpiece (W) are vibrated in a straight line distance of l+al(1‑cos(Mωt)), or in a vertical direction at alsin(Mωt), or a combination thereof. (ω) is the angular velocity of the workpiece, (M) is the number of faces of the polygon, and (a) is the adjustment parameter. In this way, the unevenness of the machined surface can be adjusted by vibrating.

Description

Technical Field

[0001] The present invention relates to a control device and a control method for a machine tool for polygon processing. Background Art

[0002] In the past, there was polygonal machining in which a workpiece was machined into a polygonal shape by rotating the tool and the workpiece at a constant ratio. In polygonal machining, the tool tip describes an elliptical orbit relative to the workpiece. When the rotation ratio between the workpiece and the tool and the number of tools are changed, the phase and number of the ellipse change, and the workpiece can be machined into a polygon such as a quadrilateral or hexagon.

[0003] Fig.13A Indicates the movement path of the tool relative to the workpiece when the center of the workpiece is the origin. In this example, the rotation ratio of the workpiece to the tool is 1:2, and the number of tools is 2. The movement path of tool T1 relative to the workpiece is track 1, and the movement path of tool T2 relative to the workpiece is track 2. During one rotation of the workpiece, the two tools T1 and T2 draw elliptical tracks 1 and track 2 around the workpiece, forming a quadrilateral on the workpiece surface. Fig. 13B This is a case where the rotation ratio is 1:2 and there are three cutters. In this case, when the three cutters draw an elliptical orbit around the workpiece and the cutters cut the workpiece along the orbit, a hexagon is formed on the workpiece surface.

[0004] Polygon machining creates polygons by combining ellipses, so the cutting surface becomes a gentle curve, which is not suitable for high-precision machining that requires high flatness. Compared with polygon machining using a milling machine, polygon machining has the advantage of shortening the machining time. Polygon machining is used for machining parts that do not require high precision in actual use (such as the head of a bolt, the blade of a screwdriver, etc.).

[0005] As a method for improving the flatness of polygon processing, there is a method of increasing the diameter of the tool. However, there is a limit to the size of the tool mechanism. In the past, as a technology for reducing the diameter of the tool body, the following technology is known: a storage part for the cutting blade is provided on the cutter body, the cutting blade is stored in the storage part, and the position of the cutting blade is adjusted using a fixing bolt and a positioning bolt. For example, refer to Patent Document 1.

[0006] In addition, there is a technology for freely processing a workpiece by moving a rotating axis. For example, in Patent Document 2, a first spindle and a second spindle are rotated at different speeds, and the first spindle and the second spindle are offset in the direction of a virtual straight line based on a phase difference in each first cycle, so that the surface of the workpiece is freely processed.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2018-140482

[0010] Patent Document 2: Japanese Patent Application Publication No. 2015-79348 Summary of the invention

[0011] Problems to be solved by the invention

[0012] In Patent Document 1, although the size of the cutter body can be reduced, the cutter diameter does not become smaller because the cutter protrudes from the cutter body.

[0013] In Patent Document 2, in order to process the workpiece into a free shape, complex control is required such as movement of the spindle in accordance with the phase difference between the first spindle and the second spindle.

[0014] In the field of polygon machining, a technology for reshaping a machined surface without changing the mechanism of a machine tool is desired.

[0015] Means for solving problems

[0016] One embodiment of the present invention is a control device that controls polygonal processing to form a polygon on the surface of a workpiece, and comprises: a workpiece instruction generating unit that generates an instruction for the angular velocity of the workpiece; a tool instruction generating unit that generates an instruction for the angular velocity of the tool; and a vibration generating unit that generates a vibration component that causes the relative position of the workpiece and the tool to vibrate.

[0017] Another embodiment of the present invention is a control method for controlling polygonal processing in which a workpiece and a tool are rotated simultaneously to form a polygon on the workpiece surface, and the control is performed in the following manner: an instruction for the angular velocity of the workpiece is generated; an instruction for the angular velocity of the tool is generated; a vibration component is generated that causes the relative position of the workpiece and the tool to vibrate; the workpiece and the tool are rotated at the generated angular velocity, and the relative position of the workpiece and the tool is vibrated.

[0018] Effects of the Invention

[0019] According to one aspect of the present invention, it is possible to shape a machined surface without changing the mechanism of a machine tool. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a hardware structure diagram of the control device in the present disclosure.

[0021] Figure 2 This is a block diagram of a control device that causes the tool to vibrate in the X-axis direction.

[0022] Figure 3 This is a diagram for explaining conventional polygon processing.

[0023] Figure 4It is a diagram showing the vibration of the tool in the X-axis direction in the present disclosure.

[0024] Figure 5A This is a diagram showing the flatness of a processed surface by conventional polygon processing.

[0025] Figure 5B This is a diagram showing changes in the flatness of a machined surface due to vibration in the X-axis direction.

[0026] Figure 6 This is a block diagram of a control device that causes the tool to vibrate in the Y-axis direction.

[0027] Figure 7 It is a diagram showing the vibration of the tool in the Y-axis direction in the present disclosure.

[0028] Figure 8 This is a diagram for explaining the position of the tool tip when the tool is vibrated in the Y-axis direction.

[0029] Fig.9A This is a diagram showing the flatness of a processed surface by conventional polygon processing.

[0030] Fig. 9B This is a diagram showing changes in the flatness of a machined surface due to vibration in the Y-axis direction.

[0031] Fig. 10A This is a diagram showing the shape of a machined surface when the adjustment parameter a is set to 0.06 in the vibration in the X-axis direction.

[0032] Fig. 10B This is a diagram showing the shape of a machined surface when the adjustment parameter a is set to 0.15 during vibration in the X-axis direction.

[0033] Fig.11A This is a diagram showing the shape of a machined surface when the adjustment parameter a is set to 0.12 during vibration in the Y-axis direction.

[0034] Fig. 11B This is a diagram showing the shape of a machined surface when the adjustment parameter a is set to 0.18 during vibration in the Y-axis direction.

[0035] Fig.12 Detailed description of the invention is given in the following figure.

[0036] Fig.13A This is a diagram for explaining the trajectory of a tool when a quadrilateral is formed on a workpiece surface in conventional polygon machining.

[0037] Fig. 13B This is a diagram for explaining the trajectory of a tool when a hexagon is formed on a workpiece surface in conventional polygon machining. DETAILED DESCRIPTION

[0038] An example of the control device 100 of the present disclosure is shown below. Figure 1 As shown, the control device 100 includes a CPU 111 for controlling the control device 100 as a whole, a ROM 112 for recording programs and data, and a RAM 113 for temporarily expanding data. The CPU 111 reads the system program recorded in the ROM 112 via the bus 120 and controls the control device 100 as a whole according to the system program.

[0039] The nonvolatile memory 114 is backed up by, for example, a battery (not shown), and maintains the storage state even when the power supply of the control device 100 is turned off. The nonvolatile memory 114 stores programs read from the external device 72 via the interfaces 115, 118, and 119, user operations input via the input unit 30, and various data (e.g., setting parameters, sensor information, etc.) acquired from various components of the control device 100, the machine tool 200, and the like.

[0040] The interface 115 is an interface for connecting the control device 100 and an external device 72 such as an adapter. Programs, various parameters, etc. are read from the external device 72. In addition, programs, various parameters, etc. edited in the control device 100 can be stored in an external storage unit via the external device 72. The PMC 116 (Programmable Machine Controller) performs signal input and output and control with the machine tool 200, the robot, the sensor installed in the machine tool 200 or the robot, etc. through the sequence and program built into the control device 100 via the I / O unit 117.

[0041] Display unit 70 displays an operation screen of machine tool 200 , a display screen showing the operating state of machine tool 200 , and the like. Input unit 30 is composed of an MDI, an operation panel, a touch panel, and the like, and transmits an operator's operation input to CPU 111 .

[0042] The servo amplifier 140 controls each axis of the machine tool 200. The servo amplifier 140 receives the axis movement instruction amount from the CPU 111 and drives the servo motor. The machine tool 200 includes at least a servo motor 151 for tool rotation, a servo motor 152 for the Z axis, and a servo motor 153 for the X axis (or a servo motor 154 for the Y axis). The servo motor 151 for tool rotation, the servo motor 152 for the Z axis, and the servo motor 153 for the X axis (or the servo motor 154 for the Y axis) have a built-in position / speed detector, and the position / speed feedback signal from the position / speed detector is fed back to the servo amplifier 140 to perform position / speed feedback control.

[0043] The control device 100 sets a virtual coordinate system in the machine tool 200. In the following description, the central axis of the workpiece W is the Z axis, the axis connecting the workpiece center and the tool center is the X axis, and the axis orthogonal to the X axis is the Y axis.

[0044] The machine tool 200 disclosed in the present invention includes at least a tool rotating servo motor 151 for rotating a tool T (tool axis), a Z-axis servo motor 152 for moving a tool holder (hereinafter referred to as a tool T) in the Z-axis direction, and an X-axis servo motor 153 for moving the tool T in the X-axis direction.

[0045] The spindle amplifier 161 receives a spindle rotation instruction for the spindle 164 of the machine tool 200 and drives the spindle motor 162. The power of the spindle motor 162 is transmitted to the spindle 164 via the gears, and the spindle 164 rotates at the instructed rotation speed. The spindle 164 is coupled to a position encoder 163, which outputs feedback pulses in synchronization with the rotation of the spindle 164, and the feedback pulses are read by the CPU 111.

[0046] A workpiece W is mounted on the spindle 164. The spindle 164 is parallel to the axial direction of the tool axis, and the spindle 164 and the tool axis rotate at a predetermined rotation ratio. When the spindle 164 and the tool axis rotate simultaneously, the tool T mounted on the tool axis cuts the workpiece surface to form a polygon on the workpiece surface.

[0047] Figure 2 This is a block diagram of the control device 100 having a polygon processing adjustment function. The functions in the block diagram are implemented by the CPU 111 executing a program recorded in a storage device such as the ROM 112 .

[0048] The control device 100 includes a polygon machining control unit 10. The polygon machining control unit 10 includes a workpiece command generating unit 11 that generates a rotation command for a workpiece axis, a tool command generating unit 12 that generates a rotation command for a tool axis, and a movement command generating unit 13 that generates a movement command for a tool T.

[0049] The workpiece command generation unit 11 generates a rotation command for the spindle 164. The workpiece command generation unit 11 generates a command for rotating the spindle 164 at a constant angular velocity ω, and outputs the command to the spindle amplifier 161. The spindle amplifier 161 controls the spindle motor 162 according to the command from the workpiece command generation unit 11. The spindle motor 162 rotates the spindle 164 at a constant angular velocity ω. As a result, the workpiece W mounted on the spindle 164 rotates at a constant angular velocity ω.

[0050] The tool command generation unit 12 generates a rotation command for the tool T. The tool command generation unit 12 generates a command for rotating the tool T at a constant angular velocity, and outputs the command to the servo amplifier 140. The servo amplifier 140 controls the tool rotation servo motor 151 according to the command from the tool command generation unit 12. The tool rotation servo motor 151 rotates the tool T at a constant angular velocity according to the control of the servo amplifier 140. The angular velocity of the tool T is determined by the rotation ratio of the workpiece W and the tool T. In the example described later, the angular velocity of the tool T is 2ω.

[0051] The movement command generation unit 13 generates a movement command for the tool T. The movement command synchronously controls the movement of the tool T in the Z-axis direction and the X-axis direction. The command in the Z-axis direction is a feed command. The Z-axis servo motor 152 moves the tool T at the feed speed instructed by the movement command generation unit 13.

[0052] The vibration component generating unit 14 generates a vibration component in the X-axis direction of the tool T. The X-axis servo motor 153 vibrates the tool T in the X-axis direction according to the vibration command generated by the vibration component generating unit 14. The control device 100 of the present disclosure changes the relative distance between the workpiece W and the tool T in the X-axis direction by vibrating the tool T in the X-axis direction, thereby adjusting the flatness of the machined surface.

[0053] Hereinafter, the polygon processing of the present disclosure will be described in comparison with conventional polygon processing.

[0054] [Conventional polygon processing]

[0055] First, conventional polygon processing will be described.

[0056] In the previous polygon processing, the angular velocity of the tool axis and the workpiece axis is constant. In the following description, the rotation ratio of the workpiece axis to the tool axis is set to 1:2. That is, when the angular velocity of the workpiece axis is set to ω, the angular velocity of the tool axis is 2ω, which is twice that. When two tools t1 and t2 are installed with a rotation ratio of 1:2, the two tools t1 and t2 cut the workpiece surface twice during one rotation of the workpiece W, forming a quadrilateral on the workpiece surface. In addition, when the number of tools T is increased to three, the three tools cut the workpiece surface twice during one rotation of the workpiece W, forming a hexagon on the workpiece surface.

[0057] Reference Figure 3, the trajectory of the tool tip fixed on the XY orthogonal coordinate system of the workpiece W is described. The origin O is the center of the workpiece. The distance between the center of the workpiece W and the tool T is set to l, and the radius of the workpiece is set to r. When the workpiece W rotates clockwise at an angular velocity ω, the center P of the tool T moves at an angular velocity ω on a circle of radius l with point O as the center. Since the tool T rotates counterclockwise at an angular velocity ω (tool angular velocity 2ω-workpiece angular velocity ω), the position Q(x, y) of the tool tip relative to the center of the workpiece changes with respect to time t as follows.

[0058] [Number 1]

[0059] x=l cos(-ωt)+r cos(ωt)

[0060] y=l sin(-ωt)+r sin(ωt)

[0061] Furthermore, when the tool number is set to n (=1, ..., N; N is the number of tools), the phases of the respective tools are shifted by 2π / n, so the trajectory of each tool is as follows.

[0062] [Number 2]

[0063]

[0064]

[0065] There are two tools T, so the trajectories (x1, y1) and (x2, y2) of tool t1 and tool t2 are as follows, respectively.

[0066] [Number 3]

[0067] x1=l cos(ωt)+r cos(ωt)

[0068] y1=-l sin(ωt)+r sin(ωt)

[0069] x2=l cos(ωt)+r cos(ωt+π)

[0070] y2=-l sin(ωt)+r sin(ωt+π)

[0071] [First disclosure: Vibration in the X-axis direction]

[0072] In the present disclosure, both or either one of the tool axis and the workpiece axis is vibrated along the Z axis. As a result, the relative distance between the tool and the workpiece (the distance between the centers of the tool and the workpiece) increases or decreases, and the flatness of the workpiece surface (machined surface) can be adjusted. If the vibration component in the Z-axis direction is expressed by a mathematical formula, it is al(1-cos(Mωt)). M is the number of faces of the polygon, and the vibration component vibrates at a frequency that is several times the number of faces of the workpiece W. a is an adjustment parameter. When the adjustment parameter a is increased or decreased, the convexity and concavity of the machined surface changes as described later. When the machined surface is to be made flat, select an adjustment parameter a such that there is no concavity and convexity.

[0073] Reference Figure 4 , showing the relationship between the vibration component and the movement of the tool T in the X-axis direction. In this figure, three tools t1, t2, and t3 are installed on the tool body. In addition, the workpiece W and the tool T rotate at a rotation ratio of 1:2. During one rotation of the workpiece W, the three tools t1, t2, and t3 cut the surface of the workpiece W twice to form a hexagon. Figure 4 As shown, the center distance between the tools t1, t2, t3 and the workpiece W is 1 as the minimum and vibrates in the range of 1 to 1+2al. The vibration frequency of the vibration component is several times the rotation frequency of the workpiece W, and the vibration component vibrates 6 times during one rotation of the workpiece W. The phase of the vibration component is adjusted to be the minimum when the tools t1, t2, t3 reach the center of the processing surface. That is, at the moment when the tools t1, t2, t3 reach the center of the processing surface, the center distance between the workpiece W and the tools t1, t2, t3 is 1.

[0074] Generally, since the rotation ratio of the workpiece W to the tool is 1:2, when the number of tools T is N, the number of faces of the workpiece W is M=2N. When the tool axis is vibrated with an amplitude of a×1, the center-to-center distance changes by 1(1+a(1-cos(2Nωt))). If the workpiece center is set as the origin O of the XY orthogonal coordinate system and the position of the tool tip is expressed by a mathematical formula, it is as follows.

[0075] [Number 4]

[0076]

[0077]

[0078] When there are two tools T, the trajectories (x1, y1) and (x2, y2) of the tool t1 and the tool t2 are respectively as follows.

[0079] [Number 5]

[0080] x1=l(1+a(1-cos(2Nωt)))cos(ωt)+r cos(ωt)

[0081] y1=-l(1+a(1-cos(2Nωt)))sin(ωt)+r sin(ωt)

[0082] x2=l(1+a(1-cos(2Nωt)))cos(ωt)+r cos(ωt+π)

[0083] y2=-l(1+a(1-cos(2Nωt)))sin(ωt)+r sin(ωt+π)

[0084] The graph shown in Figure 5 is the result of calculating the above formula with N = 2, l = 10, r = 5, a = 0.03, ω = 20π / 3 (= 200rpm). Figure 5A ) compared to the polygon processing ( Figure 5B ) improves the flatness of the quadrilateral machined surface. The flatness of the machined surface can be changed by adjusting the value of the adjustment parameter a. The adjustment parameter a can be set manually by the engineer, or the maximum value at which the machined surface will not sag can be derived through numerical analysis.

[0085] [Second disclosure: Vibration in the Y-axis direction]

[0086] Next, the vibration in the Y-axis direction will be described.

[0087] The tool axis can also be vibrated along the Y-axis to increase or decrease the relative distance between the tool and the workpiece, thereby adjusting the flatness of the workpiece surface (processing surface). Figure 6 The control device 100 includes a Y-axis servo motor 154 to vibrate the tool T (specifically, the tool holder to which the tool T is mounted) in the Y-axis direction.

[0088] In addition, Figure 6 In the control device 100, a workpiece command generating unit 11, a tool command generating unit 12, a spindle amplifier 161, a spindle motor 162, a servo amplifier 140, a tool rotation servo motor 151, a Z-axis servo motor 152 and Figure 2 The control device 100 is the same as that of FIG. 1 , and therefore the description thereof is omitted.

[0089] The movement command generation unit 13 includes a vibration component generation unit 14. The vibration component generation unit 14 generates a component for vibrating the tool T in the Y-axis direction. The Y-axis servo motor 154 vibrates the tool T in the Y-axis direction according to the vibration command generated by the vibration component generation unit 14. The control device 100 of the present disclosure changes the relative distance between the workpiece W and the tool T in the Y-axis direction by vibrating the tool T in the Y-axis direction, thereby adjusting the flatness of the machined surface.

[0090] The vibration component is alsin(Mωt). M is the number of faces of the polygon, and the vibration component vibrates at a frequency that is multiple of the number of faces of the workpiece W. a is an adjustment parameter. When the adjustment parameter a is increased or decreased, the convexity and concavity of the machined surface change as described later. If you want to make the machined surface flat, select an adjustment parameter a that does not have concavity and convexity.

[0091] Reference Figure 7 , showing the relationship between the vibration component and the movement of the tool T in the Y-axis direction. In this figure, three tools t1, t2, and t3 are installed on the tool body. And the workpiece W and the tool T rotate at a rotation ratio of 1:2. The Y-axis component of the tool T vibrates with an amplitude of l×a around the Y-axis component of the workpiece center O. And when the tool t1 reaches the center of the processing surface, the displacement in the Y-axis direction becomes 0. Similarly, when the tools t2 and t3 reach the processing surface, the displacement in the Y-axis direction becomes 0.

[0092] The locus of the tool edge Q (x, y) when the center of the workpiece W is set as the origin O of the XY rectangular coordinate system can be calculated as follows.

[0093] like Figure 8 As shown, the center position P of the tool T before vibration is (lcos(ωt), -lsin(ωt)). When the tool T is vibrated in the Y-axis direction, the center P of the tool T vibrates at alsin(2Nωt) in the tangent direction of the workpiece W. If the vibration component is taken into account, the center position Q of the tool T is as follows.

[0094] [Number 6]

[0095]

[0096] Since the tool tip rotates at an angular velocity ω (tool angular velocity 2ω-workpiece angular velocity ω) about the tool center Q, the trajectory of the tool tip is as follows.

[0097] [Number 7]

[0098]

[0099]

[0100] When there are two tools T, the trajectories (x1, y1) and (x2, y2) of the tool t1 and the tool t2 are respectively as follows.

[0101] [Number 8]

[0102] x1=l(cos(ωt)+a sin(2Nωt)sin(ωt))+r cos(ωt+2π)

[0103] y1=-l(sin(ωt)-a sin(2Nωt)cos(ωt))+r sin(ωt+2π)

[0104] x2=l(cos(ωt)+a sin(2Nωt)sin(ωt))+r cos(ωt+π)

[0105] y2=-l(sin(ωt)-a sin(2Nωt)cos(ωt))+r sin(ωt+π)

[0106] The graph shown in Figure 9 is the result of calculating the above formula with N = 2, l = 10, r = 5, a = 0.06, ω = 20π / 3 (= 200rpm). Fig.9A ) compared to the polygon processing ( Fig. 9B ) improves the flatness of the quadrilateral machined surface. The flatness of the machined surface can be changed by adjusting the value of the adjustment parameter a. The adjustment parameter a can be set manually by the engineer, or the maximum value at which the machined surface will not sag can be derived through numerical analysis.

[0107] [Deformation of machined surface]

[0108] The graph shown in FIG10 shows how the machined surface changes according to the change of the adjustment parameter a when the tool T is vibrated in the X-axis direction. When the tool T is vibrated in the X-axis direction under the conditions of N=2, l=10, r=5, ω=20π / 3 (=200rpm), if the adjustment parameter a is set to 0.06, the machined surface is concave ( Fig. 10A ), if the adjustment parameter a is set to 0.15, the machined surface is further sunken ( Fig. 10B ).

[0109] The graph shown in FIG11 shows how the machined surface changes according to the change of the adjustment parameter a when the tool T is vibrated in the Y-axis direction. If the adjustment parameter a is set to 0.12, the machined surface is concave in a wavy manner ( Fig.11A ), if the adjustment parameter a is set to 0.18, it will further sink ( Fig. 11B ). The machined shape of the workpiece W changes according to the value of the adjustment parameter a.

[0110] [Adjustment method of processing surface]

[0111] Reference Fig.12The adjustment method of polygonal machining of the present disclosure is described with reference to the flowchart. First, the workpiece W and the tool T are mounted on the machine tool 200, and the distance l between the rotation center of the workpiece W and the rotation center of the tool, the tool radius r, the rotation speed ω of the workpiece W, and the number of blades N of the tool T are input to the control device 100 (step S1). So far, the operation is the same as that of ordinary polygonal machining.

[0112] Next, the adjustment parameter a is set (step S2). The engineer of the machine tool 200 sets an appropriate adjustment parameter a in the control device while observing the graph of the above mathematical formula and confirming the flatness of the machined surface. The adjustment parameter a can be set manually by the engineer, or the maximum value at which the machined surface will not be concave can be derived through numerical analysis.

[0113] When the operator of the machine tool 200 instructs to start polygonal machining (step S3), the workpiece instruction generation unit 11 outputs a rotation instruction of the workpiece W to the spindle amplifier 161 (step S4). The spindle motor 162 rotates the workpiece W at a constant angular velocity ω according to the control of the spindle amplifier 161 (step S5). At the same time, the tool instruction generation unit 12 outputs a rotation instruction of the tool axis to the servo amplifier 140 (step S6). The tool rotation servo motor 151 rotates the tool axis at a constant angular velocity 2ω according to the control of the servo amplifier 140 (step S7).

[0114] The vibration component generation unit 14 generates a vibration component when the tool T is vibrated in the X-axis (or Y-axis direction) (step S8 ). The movement command generation unit 13 outputs a vibration command of the tool T to the servo amplifier 140 (step S9 ).

[0115] The X-axis servo motor 153 (or the Y-axis servo motor 154) vibrates the tool post (tool T) in the X-axis direction (or the Y-axis direction) according to the control of the servo amplifier 140 (step S10). While vibrating the tool T along the X-axis (or the Y-axis), polygon processing is performed, thereby forming a polygon with adjusted flatness on the workpiece surface (step S11).

[0116] In the first disclosure, the tool axis of polygon machining is vibrated in the X-axis direction, and the phase of the vibration is matched so that the vibration range is from 1 to 1+2a1 and is minimized when the tool tip reaches the center of the machining surface.

[0117] In this way, by vibrating the tool T in the X-axis direction, the unevenness of the machined surface can be adjusted by adjusting the adjustment parameter a, which is a coefficient of the vibration range.

[0118] In the second disclosure, the tool axis of polygon processing is vibrated in the Y-axis direction. The vibration phase is matched so that the vibration range is from -al to al and the Y-axis component of the tool tip is zero when the tool tip reaches the center of the processing surface. In this way, by vibrating in the Y-axis direction, the adjustment parameter a, which is a coefficient of the vibration range, can be adjusted to adjust the unevenness of the processing surface.

[0119] In the first and second disclosures, a sine wave is used as the vibration component, but it does not need to be a sine wave. In addition, in the first and second disclosures, the rotation ratio between the workpiece W and the tool T is set to 1:2, but the shape of the machined surface can be adjusted regardless of the rotation ratio.

[0120] One embodiment has been described above, but the present invention is not limited to the above disclosure and can be implemented in various ways by applying appropriate changes. For example, in the present disclosure, a structure in which the workpiece axis is set as the main axis and the tool axis is set as the servo axis is adopted, but it can also be a main axis polygon processing in which both axes are main axes.

[0121] In addition, in the present disclosure, the tool axis is vibrated in the X-axis direction (or the Y-axis direction), but the workpiece axis may also be vibrated in the X-axis direction (or the Y-axis direction). As long as the relative distance between the tool axis and the workpiece axis changes, both the workpiece axis and the tool axis may be vibrated. In addition, the tool axis and the workpiece axis may be vibrated simultaneously in the X-axis direction and the Y-axis direction.

[0122] In the present disclosure, a regular quadrilateral and a regular hexagon are described, but even if the shape formed is not a regular polygon, it is also included in the present disclosure. For example, in a polygonal cutter with two cutters, when the phase difference between the cutters is not 180 degrees but 90 degrees, the shape of the workpiece is not a regular quadrilateral but a rhombus. In this way, by adjusting the phase difference between the cutters, the present disclosure can also be applied to other polygons such as rhombuses. In such a shape, it is not necessary to set the position where the vibration component is minimum or zero as the center of the processing surface. In order to improve the flatness, the vibration component is appropriately adjusted.

[0123] Explanation of symbols

[0124] 100 Control device

[0125] 200 Machine Tools

[0126] 10 Polygon processing control unit

[0127] 11 Workpiece instruction generation unit

[0128] 13. Movement instruction generation unit

[0129] 14. Vibration component generation unit

[0130] 111 CPU

[0131] 112 ROM

[0132] 113 RAM

[0133] 140 Servo amplifier

[0134] 151 Servo motor for tool rotation

[0135] 152 Z-axis servo motor

[0136] 153 X-axis servo motor

[0137] 154 Y-axis servo motor

[0138] 161 Spindle amplifier

[0139] 162 Spindle motor

[0140] 164 Spindle.

Claims

1. A control device for controlling polygonal machining in which a workpiece and a tool are rotated simultaneously to form a polygon on a surface of the workpiece, characterized in that: The control device comprises: a workpiece instruction generating unit that generates an angular velocity instruction of the workpiece; and a tool command generating unit, which generates a command for the angular velocity of the tool, The control device increases or decreases the relative distance between the workpiece and the tool along a second axis orthogonal to a first axis connecting a rotation center of the workpiece and a rotation center of the tool so as to adjust the shape of the processed surface. The control device also has: a vibration component generating unit that generates a vibration component in which the relative distance is minimized when the tool tip passes near the center of the polygonal processing surface; and A movement instruction generating unit is configured to instruct an increase or decrease in the relative distance using the vibration component.

2. The control device according to claim 1, characterized in that: The vibration component includes an adjustment parameter, and the shape of the machined surface of the workpiece is changed by the adjustment parameter.

3. The control device according to claim 1, characterized in that: The vibration component vibrates at a frequency that is a multiple of the face of the polygon relative to the angular velocity of the workpiece.

4. The control device according to claim 1, characterized in that: The shape adjustment of the processed surface improves the flatness.

5. A method for controlling polygonal machining, which controls polygonal machining by rotating a workpiece and a tool simultaneously to form a polygon on a surface of the workpiece, characterized in that: The control method is controlled in the following manner: generating an instruction for an angular velocity of the workpiece; generating an instruction for the angular velocity of the tool; generating a vibration component that increases and decreases the relative distance between the workpiece and the tool along a second axis that is orthogonal to the first axis that connects the rotation center of the workpiece and the rotation center of the tool, and the relative distance is minimum when the tool tip passes near the center of the polygonal processing surface; as well as The workpiece and the tool are rotated at the generated angular velocity, and the relative position of the workpiece and the tool is vibrated using the vibration component to indicate an increase or decrease in the relative distance.

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