Machine tool and method for smoothing a workpiece

Abstract

Machine tool, comprising: a machine table (20) having a workpiece support surface (18) to which a workpiece (16) is attached; a spindle (26) equipped with a tool (28) configured to perform a smoothing operation on the workpiece (16) fixed to the machine table (20); a unit (30) for controlling the smoothing of a workpiece, which is configured to perform smoothing on the workpiece (16) using the tool (28) such that the machining areas of the tool (28) partially overlap on a surface of the workpiece (16); at least one contact element arranged on the spindle (26) in a position opposite the machine table (20); a contact element position storing unit (36) configured to store a plurality of measurement values ​​obtained by performing a measurement of a position of the contact element at least twice in a state where the spindle (26) is set to at least one phase and the contact element is positioned at an identical point; a spindle inclination angle calculation unit (40) configured to calculate an inclination angle of the spindle (26) relative to an XY plane (31) for machining based on the plurality of measured values ​​stored in the contact element position storage unit (36); and a coordinate system rotating unit (42) configured to rotate the XY plane (31) about at least one of the X-axis and the Y-axis based on the inclination angle of the spindle (26) calculated by the spindle inclination angle calculating unit (40), wherein the workpiece smoothing control unit (30) machines a flat surface of the workpiece (16) so as to be parallel to the XY plane (31) rotated by the coordinate system rotating unit (42).

Description

BACKGROUND OF THE INVENTIONField of the invention

[0001] The present invention relates to a machine tool having a smoothing unit and a method for smoothing a workpiece. General state of the art

[0002] Recently, when machining a flat surface on a workpiece using a machining center, a milling tool having a diameter larger than one of the dimension in the X direction and the dimension in the Y direction when viewed from the top of the workpiece is attached to the spindle of the machine tool, and then the tool is moved on a single straight path, whereby it is possible to machine a flat surface with good smoothness.

[0003] However, if the workpiece to be machined is large, the diameter of the milling tool needs to be increased, and thus the machine tool tends to become large, which leads to a cost problem.

[0004] To solve this problem, there is a method of smoothing with a small-diameter milling cutter using a small machine tool. However, since the entire area of ​​the workpiece's top surface cannot be covered with a single straight-line machining pass, machining must be performed on at least two or more passes. In this case, if the spindle attached to the machine tool is not mounted so that it is exactly orthogonal to the feed axes to perform drive in the X and Y axes, tiny steps will form on the machined surface between two or more passes.

[0005] It is virtually impossible to assemble the machine during manufacturing so that the spindle is precisely orthogonal to the feed axes for driving in the X and Y axes without any assembly errors. Furthermore, even if the spindle is mounted with static precision as close to zero as possible, there is a risk that the spindle mounting angle will be tilted relative to the feed axes due to thermal displacement in order to drive in the X and Y axes. Therefore, when forming a flat surface with a milling tool with a diameter smaller than the size of a workpiece, a height difference will inevitably occur on the machined surface.

[0006] According to Japanese Patent Laid-Open No. 2008-264883, the following method is disclosed. That is, before machining begins, the spindle is rotated at the machining speed, and the tool center position and the thermal displacement of the spindle are determined, thereby determining the ratio of the tool center position to the thermal displacement as a compensation coefficient. After machining begins, machining is performed using the obtained compensation coefficient while correcting the control amount of the cutting and moving device. SUMMARY OF THE INVENTION

[0007] However, the method described in Japanese Patent Laid-Open No. 2008-264883 is not intended to make a correction taking into account the inclination of the spindle, but to correct the position on the Z-axis relative to the program command value, and therefore it is difficult to eliminate the height difference when machining a flat surface.

[0008] It now takes place with reference to Fig. 27A to 28 a description of the factors causing the height difference when machining a flat surface is carried out using a small diameter milling tool.

[0009] The description concerns a case where the smoothing is performed on a workpiece 1006 by means of a milling tool 1004 gripped by a spindle 1002 of a machine tool 10C0 configured as shown in Fig. 27A. As shown in Fig. 27B and Fig. 27C, when the diameter D of the milling tool 1004 is smaller than a narrow side dimension Ls of the workpiece 1006, at least two machining paths or machining paths in which the contact areas of the milling tool 1004 overlap are required.

[0010] In the ideal case of the machine tool 10C0, which has a Fig. 27A, the spindle 1002 must be mounted so that it is exactly orthogonal to both the Y-axis for driving a carriage 1008 and the X-axis for driving a machine table 1010. However, during the manufacturing phase, it is very difficult or even nearly impossible to assemble these components without static error, so most machine tools ultimately have minor errors.

[0011] As in Fig. 27A, if the spindle 1002 is inclined relative to the Y-axis when the workpiece 1006 is milled on a straight line in the X-direction, a step 1012 is formed in the workpiece 1006, as in Fig. 28. The Fig. The example shown in Figure 28 is purely illustrative. Even when using a milling tool 1004 that has a larger format than the narrow side dimension Ls of the workpiece 1006, if machining is performed on two or more machining paths or on machining paths in which the contact areas of the milling tool 1004 overlap on the paths, steps are created as described above.

[0012] As a means to avoid the emergence of levels 1012, as in Fig. As shown in Figure 28, the spindle 1002 must be assembled orthogonally to the Y-axis feed direction with high precision during the manufacturing stage. However, if thermal displacement occurs in a column 1014 or a spindle head 106 of the machine tool 10C0 due to the influence of the ambient temperature or the like at the mass production site, a problem arises that a slight skew relative to the feed axis movement is generated even if the spindle 1002 is assembled with high precision.

[0013] The present invention has been conceived in view of the above problem, and it is therefore an object of the present invention to provide a machine tool and a method for smoothing a workpiece, which are capable of eliminating the generation of height differences on the workpiece surface as much as possible by smoothing a large workpiece using, for example, a general-purpose small-sized machine tool.

[0014] [1] A machine tool according to a first aspect of the present invention comprises: a machine table having a workpiece support surface and to which a workpiece is fixed; a spindle equipped with a tool configured to perform smoothing on the workpiece, which is fixed to the machine table; a workpiece smoothing control unit configured to perform smoothing on the workpiece using the workpiece such that machining areas of the tool partially overlap on a surface of the workpiece; at least one contact member arranged on the spindle in a position facing the machine table;a contact element position storing unit configured to store a plurality of measurement values ​​obtained by measuring a position of the contact element at least twice in a state where the spindle is set to at least one phase and the contact element is positioned at an identical point; a spindle inclination angle calculating unit configured to calculate an inclination angle of the spindle relative to an XY plane for smoothing based on the plurality of measurement values ​​stored in the contact element position storing unit;and a coordinate system rotating unit configured to rotate the XY plane about at least one of the X-axis and the Y-axis based on the spindle inclination angle calculated by the spindle inclination angle calculating unit, and the workpiece flattening control unit machines a flat surface of the workpiece to be parallel to the XY plane rotated by the coordinate system rotating unit.;

[0015] With this configuration, it is possible to eliminate as much as possible the occurrence of height differences on the workpiece surface by smoothing a large workpiece, for example, using a universal small-format machine tool.

[0016] [2] In the first aspect, the contact element position storing unit may be configured to store a plurality of measurement values ​​obtained by performing a measurement on one of the contact elements in a state where the spindle is set to two or more different phases and the one contact element is positioned at an identical point.

[0017] For example, in the above configuration, if a single contact element is positioned at an identical point with the spindle set to two different phases, it is possible to create an orthogonal relationship between one direction (e.g., the Y direction) of the XY plane and the spindle. This makes it possible to create a good, flat surface on a workpiece with almost no height differences, even when milling multiple times on multiple paths in the other direction (e.g., the X direction).

[0018] Furthermore, if a single contact element is positioned at an identical point with the spindle set to three different phases, it is possible to create an orthogonal relationship between one direction (e.g., the Y direction) of the XY plane and the spindle, and between the other direction (X direction) of the XY plane and the spindle. This makes it possible to create a sufficiently flat surface on a workpiece with almost no height differences.

[0019] The reason for using a single contact element is as follows: If multiple contact elements are used, the process of measuring the positions of contact elements can sometimes be affected by the assembly errors of the multiple contact elements. To address this, using a single contact element for measurement prevents the measurement from being affected by the assembly error of the contact element, thus making it possible to establish a high-precision orthogonal relationship between a direction of the XY plane and the spindle.

[0020] [3] In the first aspect, the plurality of contact elements may be arranged on the spindle, the contact element position storing unit may be configured to store the obtained plurality of measurement values ​​obtained by measuring the position of each of the plurality of contact elements in a state where the spindle is adjusted to a phase and each of the plurality of contact elements is positioned at an identical point, and the spindle inclination angle calculating unit may determine an inclination angle of the spindle relative to at least one direction of the XY plane based on the plurality of measurement values.

[0021] This configuration makes it possible to create an orthogonal relationship between one direction (e.g. the Y direction) of the XY plane and the spindle, thus creating a good flat surface on a workpiece with almost no height differences on the workpiece.

[0022] In particular, the spindle's inclination angle with respect to the aforementioned one direction can be determined by positioning and measuring the spindle only in the first phase. This makes it possible to reduce the number of steps and the working time to make one direction of the XY plane and the spindle orthogonal to each other.

[0023] [4] The first aspect may be configured such that the contact element is a tip disposed on the tool at a position facing the machine table, and the contact element position storing unit is configured to store a plurality of measurement values ​​obtained by measuring the position of a cutting edge of the tip at least twice using a cutting edge position measuring unit fixed to the machine table in a state where the cutting edge of the tip is positioned.

[0024] Using the tip as a contact element can eliminate the need for a dedicated measuring device, resulting in cost reduction. Furthermore, since a tool that is actually used for machining the workpiece can be used, it is possible to perform position measurement while taking the dimensional tolerance of the tool into account. When using a measuring device, it is usually necessary to finely correct the measurements taking the tolerance of the tool into account. However, according to the present invention, such fine correction is not necessary, and thus the measuring work can be simplified.

[0025] [5] In the first aspect, it is preferable that a tool length measuring device configured to measure the length of the tool is used as the cutting edge position measuring unit. This makes it possible to measure the distance between the tip attached to the tool and the touch sensor surface of the tool length measuring device with high precision. The tool length measuring device may be of either a contact type or a non-contact type.

[0026] [6] In the first aspect, it is preferable that the contact element is a probe element of a touch probe mounted on the spindle in a position facing the machine table, and that the probe element is deflected from the center axis of the spindle toward the X-direction or Y-direction of the machine table. This makes it possible to secure an installation space on the table top without having to mount a special measuring device on the machine table side.

[0027] [7] In the first aspect, the machine tool may further include rotary axes configured to rotate the workpiece support surface so that the XY plane rotated by the coordinate system rotating unit and the workpiece support surface are parallel.

[0028] Typically, the tabletop forms a workpiece support surface when a workpiece is placed on the machine table. In this case, the XY plane and the workpiece support surface of the machine table are not necessarily parallel to each other, which may result in a slight error. This slight error may adversely affect the workpiece after machining a flat surface on the workpiece. In other words, the side surface of the workpiece may not be able to be machined in a rectangular shape.

[0029] However, since this configuration of the present invention includes rotation axes that rotate the workpiece support surface such that the XY plane rotated by the coordinate system rotating unit and the workpiece support surface are parallel to each other, it is possible to make the XY plane and the workpiece support surface parallel to each other. Therefore, when performing smoothing on the workpiece based on the XY plane after rotating the coordinate system, it is possible to machine the side surface of the workpiece in a rectangular shape, thereby achieving an improvement in machining quality.

[0030] [8] In the first aspect, the machine tool may further include a dedicated jig configured to position the workpiece support surface such that the XY plane rotated by the coordinate system rotating unit and the workpiece support surface are made parallel to each other. This configuration makes it possible to make the XY plane and the workpiece support surface parallel. Therefore, when planar machining is performed on the workpiece based on the XY plane after rotation of the coordinate system, it is possible to perform machining while maintaining the lateral surface of the workpiece in a rectangular shape, thereby achieving an improvement in machining quality.

[0031] [9] In the first aspect, the diameter of the tool may be smaller than a narrow side dimension of the workpiece.

[0032] When milling is performed multiple times on multiple machining paths in this configuration, steps are minimal on the workpiece, even when the tool machining paths overlap, and a well-flat surface can be formed on the workpiece. The tool machining paths can be not only straight but also curved.

[0033]

[10] A method for smoothing a workpiece according to a second aspect of the present invention is a method for smoothing a workpiece to smooth a workpiece using: a machine table having a workpiece support surface and to which the workpiece is fixed; a spindle equipped with a tool configured to perform smoothing on the workpiece fixed to the machine table;and the tool that performs machining such that the machining areas of the tool partially overlap on a surface of the workpiece, comprising: a step of storing measured values, which consists in storing a plurality of measured values ​​obtained by measuring a position of at least one contact element arranged on the spindle in a position facing the machine table in a state in which the spindle is adjusted to at least one phase and the contact element is positioned at an identical point, at least twice; a step of calculating an inclination angle of a spindle, which consists in calculating an inclination angle of the spindle relative to an XY plane for smoothing based on the plurality of stored measured values;and a coordinate system rotating step of rotating the XY plane about at least one of the X-axis and the Y-axis based on the calculated inclination angle of the spindle, wherein a flat surface of the workpiece is machined to be parallel to the XY plane rotated by the coordinate system rotating step;

[0034]

[11] In the second aspect, in the step of storing measured values, a plurality of measured values ​​obtained by measuring one of the contact elements in a state in which the spindle is set to two or more different phases and the one contact element is positioned at an identical point may be stored.

[0035]

[12] The second aspect may be configured such that the plurality of contact elements are arranged on the spindle; in the step of storing measured values, a plurality of measured values ​​obtained by measuring the position of each of the plurality of contact elements in a state where the spindle is adjusted to a phase and each of the plurality of contact elements is positioned at an identical point are stored; and in the step of calculating an inclination angle of a spindle, an inclination angle of the spindle relative to at least one direction of the XY plane is determined based on the plurality of measured values.

[0036]

[13] The second aspect may be constructed such that the contact element is a tip disposed on the tool at a position facing the machine table; and in the step of storing measured values, a plurality of measured values ​​obtained by measuring the position of a cutting edge of the tip by using a cutting edge position measuring unit fixed to the machine table in a state where the cutting edge of the tip is positioned are stored.

[0037]

[14] The second aspect may be constructed such that the contact element is a probe element of a touch probe fixed to the spindle at a position facing the machine table; and the probe element is deflected from the center axis of the spindle to the X-direction or Y-direction of the machine table.

[0038]

[15] In the second aspect, the diameter of the tool may be smaller than a narrow side dimension of the workpiece.

[0039] According to the machine tools and the method for smoothing a workpiece of the present invention, it is possible to eliminate as much as possible the generation of height differences on the workpiece surface by smoothing a large workpiece using, for example, a general-purpose small-sized machine tool.

[0040] The above and other objects, features and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present invention is shown by way of illustrative example. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] They show: Fig. 1 is a configuration diagram showing a machine tool (first machine tool) according to a first embodiment of the present invention; Fig. 2A is an explanatory view showing an example of a tip of a milling tool positioned on a workpiece support surface; Fig. 2B is an outline drawing showing a milling tool seen from above; Fig. 2C is an outline drawing of a workpiece seen from above, with a portion thereof omitted; Fig. 3A is a view showing a state in which a specific tip is positioned on a touch sensor surface of a tool length measuring device placed on a workpiece placement surface, as viewed from the X direction; Fig. 3B a view showing the Fig. 3A shows the state seen from the Z direction with a part thereof omitted; Fig. 4 is a flowchart showing the processing operation of the first machine tool; Fig. 5A is a view showing a state in which the spindle is rotated by 180° after the spindle is rotated from the state of Fig. 3A was moved upwards, seen from the X direction; Fig. 5B is a plan view showing the state shown in Fig. 5A, viewed from the Z direction with a part thereof omitted; Fig. 6A is a view showing a state in which a specific tip on the touch sensor surface of the device for measuring a tool length is removed from the state of Fig. 5A is positioned, seen from the X direction; Fig. 6B is a view showing the state that Fig. 6A, viewed from the Z direction with a part thereof omitted; Fig. 7 is an explanatory view showing smoothing by the first machine tool; Fig. 8 is a configuration diagram showing a machine tool (second machine tool) according to a second embodiment of the present invention; Fig. 9 is a flow chart (part 1) showing a processing operation of the second machine tool; Fig. 10 is a flowchart (part 2) showing the processing operation of the second machine tool; Fig. 11A is an explanatory view showing a state in which a specific tip is positioned on a touch sensor surface of a tool length measuring device with the spindle set to a first phase; Fig. 11B is an explanatory view showing a state in which the spindle is adjusted from the first phase to a second phase and positioned on the tool length measuring device; Fig. 11C is an explanatory view showing a state in which the spindle is set from the second phase to a third phase and is positioned on the tool length measuring device; Fig. 12 is an explanatory view showing the characteristics of a machine tool (third machine tool) according to the third embodiment; Fig. 13 is a flowchart showing a processing operation of a third machine tool of the present invention; Fig. 14A is a view showing a state in which a first specific tip is positioned on a touch sensor surface of a tool length measuring device with the spindle set to a first phase, as viewed from the X direction; Fig. 14B is a view showing the state shown in Fig. 14A, viewed from the Z direction with a part thereof omitted; Fig. 15A is a view showing a state in which a second specific tip is positioned on the touch sensor surface of the tool length measuring device without changing the phase of the spindle, as viewed from the X direction; Fig. 15B a view showing the state of Fig. 15A, viewed from the Z direction with a part thereof omitted; Fig. 16 is a configuration diagram showing a machine tool (fourth machine tool) according to a fourth embodiment of the present invention; Fig. 17 is a flow chart (part 1) showing a processing operation of the fourth machine tool; Fig. 18 is a flow chart (part 2) showing the processing operation of the fourth machine tool; Fig. 19 is a configuration diagram showing a machine tool (fifth machine tool) according to a fifth embodiment of the present invention; Fig. 20A is a view showing a state in which a probe element of a touch probe is positioned at a specific position on the workpiece support surface, as viewed from the X direction; Fig. 20B a view showing the state that is in Fig. 20A, viewed from the Z direction with a part thereof omitted; Fig. 21 is a flowchart showing a processing operation of the fifth machine tool; Fig. 22A is a view showing a state in which the spindle is rotated by 180 degrees after the spindle is returned from the state of Fig. 20A was moved upwards, seen from the X direction; Fig. 22B is a plan view showing the state shown in Fig. 22A, viewed from the Z direction with a part thereof omitted; Fig. 23A is a view showing a state in which the probe element of the touch probe is positioned at a specific position on the workpiece support surface, from the state of Fig. 22A, seen from the X direction; Fig. 23B is a view showing the state shown in Fig. 23A, viewed from the Z direction with a part thereof omitted; Fig. 24 is a view showing a change example of the touch probe as seen from the X direction; Fig. 25 is a configuration diagram showing a machine tool (sixth machine tool) according to a sixth embodiment of the present invention; Fig. 26 is a configuration diagram showing a machine tool (seventh machine tool) according to a seventh embodiment of the present invention; Fig. 27A is a schematic configuration diagram showing a machine tool according to a conventional example; Fig. 27B is an outline drawing showing a milling tool viewed from above; Fig. 27C is an outline drawing of a workpiece seen from above, with a portion thereof omitted; and Fig. 28 is an explanatory view showing a conventional problem (a step formed on the surface of a workpiece). DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] Preferred embodiments of machine tools and methods for smoothing a workpiece according to the present invention will now be described with reference to Fig. 1 to 28. In this description, a numerical range that includes "to" is used to indicate a range that includes the numerical values ​​before and after "to" as lower and upper limits. First machine tool

[0043] First, a machine tool (hereinafter referred to as a first machine tool 10A) according to a first embodiment includes: a bed 12 as a base; a machine table 20 movably mounted on the bed 12 by a slide 14 and including a workpiece support surface 18 with a workpiece 16 mounted thereon; a column 24 fixed to the bed 12 and configured to vertically movably support a spindle head 22; a spindle 26 of the spindle head 22 disposed at a position opposing the workpiece support surface 18 of the machine table 20; a milling tool 28 mounted on the spindle 26 and configured to smooth the workpiece 16; and a workpiece smoothing control unit 30 that controls smoothing of the workpiece 16 using the milling tool 28 such that the milling areas (machining areas) of the milling tool 28 partially overlap on the plane of the workpiece 16.

[0044] The machine table 20 moves over the carriage 14 in the X direction along a feed axis (X axis) not shown, while the carriage 14 moves over the bed 12 in the Y direction along another feed axis (Y axis) not shown. The movements of the machine table 20 and the carriage 14 are carried out automatically or manually by the unit 30 for controlling the smoothing of a workpiece. That is, the machine table 20 moves in the X direction and the Y direction along the XY plane 31, which is defined by the X axis and the Y axis, along which the machine table 20 is driven.

[0045] The milling tool 28 is mounted on the spindle 26 in a position opposite the workpiece support surface 18 of the machine table 20 and has a plurality of tips 32 projecting toward the workpiece support surface 18, as shown in Fig. 2A. In Fig. 2A, two centers 32 mounted 180° opposite each other are shown as a typical example, but in reality, three or more centers 32 are arranged along the circumference of the milling tool 28, for example, at the same angle. As shown in Fig. 2B and Fig. As shown in Figure 2C, the diameter D of the milling tool 28 is smaller than the short dimension Ls (narrow side dimension) of the workpiece 16.

[0046] Furthermore, as in Fig. 1, the first machine tool 10A includes a unit 34 for measuring a cutting edge position, a unit 38 for storing a cutting edge position, a unit 36 ​​for storing a position of a contact element, a unit 40 for calculating an inclination angle of a spindle, and a unit 42 for rotating a coordinate system.

[0047] The cutting edge position measuring unit 34 includes a spindle displacement measuring unit 44 for measuring the displacement of the spindle 26 and a tool length measuring device 46 mounted and fixed to the workpiece support surface 18.

[0048] As in Fig. 3A and Fig. 3B, the tool length measuring device 46 is placed on the workpiece support surface 18 of the machine table 20 with a touch sensor surface 46a facing upward. As will be described later, when the spindle 26 is moved toward the tool length measuring device 46 so that the cutting edge of a specific tip 32 (hereinafter referred to as specific tip 32a) as a contact element comes into contact with the touch sensor surface 46a, or the cutting edge of the specific tip 32a is positioned on the tool length measuring device 46, the tool length measuring device 46 outputs a detection signal Sa to the spindle displacement measuring unit 44.

[0049] The spindle displacement measuring unit 44 measures the movement amount of the specific tip 32a from the position where the movement of the specific tip 32a is started, and stores the measurement values ​​including the movement amount of the specific tips 32a in the cutting edge position storing unit 38 based on the input of the detection signal Sa from the tool length measuring device 46.

[0050] Specifically, the cutting edge position storing unit 38 stores a plurality of measurement values ​​(a first measurement value M1 and a second measurement value M2) obtained by twice executing the process for positioning the cutting edge of the specific tip 32a using the cutting edge position measuring unit 34. At this time, the storage of the measurement values ​​including the movement amount of the specific tip 32a in the cutting edge position storing unit 38 can be performed by an operator operating an input button arranged on the control panel of the first machine tool 10A when the cutting edge of the specific tip 32a is positioned on the tool length measuring device 46.

[0051] The spindle inclination angle calculating unit 40 determines the inclination angle of the spindle 26 relative to the XY plane 31, specifically an inclination angle αy relative to the Y direction, based on the plurality of measured values ​​stored in the cutting edge position storing unit 38.

[0052] The coordinate system rotating unit 42 rotates the XY plane 31 around the X-axis by the inclination angle ay of the spindle 26, which is calculated by the spindle inclination angle calculating unit 40. Specifically, the coordinate system rotating unit 42 generates the rotated XY plane 31 by driving the Z-axis simultaneously with driving the Y-axis, so that the Y-axis is driven in a direction to cancel the calculated inclination angle αy. As a result, the Y direction of the generated XY plane 31 and the spindle 26 become orthogonal to each other.

[0053] Next, the processing operation of the first machine tool 10A will be described with reference to Fig. 3A to 7. It is assumed that spindle 26 is in its initial state at the machine zero point.

[0054] First, in step S1, Fig. 4, as described in the previously Fig. 3A, the device 46 for measuring a tool length is placed on the workpiece support surface 18 of the machine table 20 with the touch sensor surface 46a facing upwards.

[0055] In step S2, as in Fig. 3B, the spindle 26 is set to a first phase in which one tip (hereinafter referred to as a specific tip 32a) of the plurality of tips provided on the end side of the milling tool 28 is directed in the Y direction.

[0056] In step S3, as in Fig. 3B, the machine table 20 and the carriage 14 are moved such that the central portion of the touch sensor surface 46a of the tool length measuring device 46 is positioned below the specific tip 32a.

[0057] In step S4, as in Fig. 3A, the spindle 26 is moved downward to the position of the specific tip 32a in the central portion of the touch sensor surface 46a of the tool length measuring device 46.

[0058] In step S5, the spindle displacement measuring unit 44 stores the displacement of the specific tip 32a, that is, the movement amount of the specific tip 32a, as the first measured value M1 in the cutting edge position storing unit 38. Now, the cutting edge position storing unit 38 can store the three-dimensional coordinates (X1, Y1, Z1) therein. In this case, if the mounted position of the tool length measuring device 46 is defined as the starting point, X1 = 0 and Y1 = 0 because no displacement occurs at the X coordinate or the Y coordinate. Z1 corresponds to the movement amount of the specific tip 32a in the Z direction.

[0059] In step S6, the spindle 26 is moved upwards and returned to the machine zero point.

[0060] In step S7, as in Fig. 5A and Fig. As shown in Figure 5B, the spindle 26 is rotated by 180° compared to the first phase.

[0061] In step S8, in order to allow the specific tip 32a to be measured again by the tool length measuring device 46, that is, in order to position the central portion of the touch sensor surface 46a of the tool length measuring device 46 below the specific tip 32a, the machine table 20 and the carriage 14 are moved in the Y direction as shown in Fig. 6A and Fig. 6B shown.

[0062] In step S9, the spindle 26 is moved downward to position the specific tip 32a in the central portion of the touch sensor surface 46a of the tool length measuring device 46.

[0063] In step S10, the spindle displacement measuring unit 44 stores the displacement of the specific tip 32a, that is, the movement amount of the specific tip 32a, in the cutting edge position storing unit 38 as the second measured value M2. Now, the cutting edge position storing unit 38 can store the three-dimensional coordinates (X2, Y2, Z2) therein. In this case, if the mounted position of the tool length measuring device 46 is defined as the starting point, since no displacement occurs at the X coordinate, X2 = 0. Y2 corresponds to the displacement in the Y direction on the XY plane 31, and Z2 corresponds to the displacement of the spindle 26 in the Z direction.

[0064] In step S11, the spindle inclination angle calculation unit 40 calculates the inclination angle of the spindle 26 relative to the XY plane 31 based on the first measured value M1 and the second measured value M2 stored in the cutting edge position storage unit 38. Since the X coordinates are the same in the above example, trigonometric functions are used to calculate the inclination angle αy of the spindle 26 relative to the Y axis from the stored Y coordinates and Z coordinates of the first and second measured values ​​M1 and M2.

[0065] In step S12, the coordinate system rotating unit 42 rotates the XY plane 31 around the X-axis by the inclination angle αy of the spindle 26 calculated by the spindle inclination angle calculating unit 40. Specifically, the coordinate system rotating unit 42 drives the Z-axis simultaneously with driving the Y-axis, so that the Y-axis is driven in a direction to cancel the calculated inclination angle αy. As a result, the Y direction of the XY plane 31 and the spindle 26 become orthogonal to each other. The coordinate information Dxy of the rotated XY plane 31 is stored in an XY-plane information table TB.

[0066] In step S13, the workpiece smoothing control unit 30 reads the coordinate information Dxy of the XY plane 31 from the XY plane information table TB and performs smoothing processing on the workpiece 16 mounted on the workpiece support surface 18 in parallel with the XY plane 31 generated by coordinate system rotation by the coordinate system rotation unit 42. Hereinafter, this also applies to the following embodiments.

[0067] Since the diameter D of the milling tool 28 is smaller than the short dimension Ls of the workpiece 16, when the workpiece is smoothed, it is necessary to perform milling on multiple paths multiple times. In the present embodiment, since the Y-direction of the XY plane 31 and the spindle 26 are arranged orthogonally to each other, even if milling in the X-axis direction is performed multiple times on the multiple machining paths of the milling tool 28 that overlap, there is hardly any difference in the height of the workpiece 16, as shown in FIG. Fig. 7, so that a good flat surface can be formed on the workpiece 16. That is, the flatness of the machined surface of the workpiece 16 can be improved. The above effects can be achieved not only in the case of straight machining paths of the milling tool 28, but also in the case of arcuate machining paths thereof.

[0068] The reason why the phase of the spindle 26 is rotated by 180° in the first machine tool 10A is as follows. If multiple tips 32a are used as the specific tips, the multiple tips may not be located at positions 180° apart due to mounting errors of the tips 32a. To address this, using a single specific tip 32a for measurement prevents the measurement from being affected by the mounting errors of the multiple tips 32a, and thus makes it possible to establish an orthogonal relationship between the Y direction of the XY plane 31 and the spindle 26 with high precision. Here, in the above example, the contact tool length measuring device 46 is used, but a non-contact tool length measuring device, a sensor, etc., may be used if there is no interference.This also applies to the various embodiments described below. Second machine tool

[0069] Next, a machine tool according to a second embodiment (hereinafter referred to as second machine tool 10B) will be described with reference to Fig. 8 to 11C.

[0070] The second machine tool 10B has substantially the same configuration as that of the previously described first machine tool 10A, except that the X direction of the XY plane 31 is made orthogonal to the spindle 26 and the Y direction of the XY plane 31 is also made orthogonal to the spindle 26.

[0071] That is, as in Fig. 8, the second machine tool 10B stores a plurality of measurement values ​​(first to third measurement values ​​M1 to M3) obtained by positioning the specific tip 32a on the same tool length measuring device 46 at three different phases of the spindle 26 in the cutting edge position storage unit 38. The spindle inclination angle calculation unit 40 calculates the inclination angle of the spindle 26 relative to the XY plane 31, specifically, an inclination angle ay relative to the Y direction and an inclination angle αx in the X direction, based on the plurality of measurement values ​​stored in the cutting edge position storage unit 38.

[0072] The coordinate system rotation unit 42 generates the XY plane 31 by driving the Z-axis simultaneously with the Y-axis and X-axis, so that the Y-axis and X-axis are driven in directions that cancel the calculated inclination angles αy and αx, respectively. As a result, the Y-direction and X-direction of the generated XY plane 31 become orthogonal to the spindle 26.

[0073] Next, the processing operation of the second machine tool 10B will be described with reference to Fig. 9 to Fig. 11C. Note that a repeated description of similar steps as those in the first machine tool 10A is omitted.

[0074] First, in steps S101 to S105, Fig. 9 Work sequences similar to the previously described processing (steps S1 to S5) in the first machine tool 10A as shown in Fig. 11A, and the movement amount of the specific tip 32a is stored as the first measured value M1 in the cutting edge position storage unit 38. When the three-dimensional coordinates (X1, Y1, Z1) are stored in the cutting edge position storage unit 38, X1 = 0 and Y1 = 0, and Z1 corresponds to the movement amount of the specific tip 32a in the Z direction. In this case, the movement amount of the spindle 26 in the first phase is stored in the cutting edge position storage unit 38 as the first measured value MI. The first phase may be, for example, 0° or may be another phase (e.g., 37°, etc.).

[0075] Subsequently, in step S106, the spindle 26 is moved upwards and returned, for example, to the machine zero point.

[0076] In step S107, the spindle 26 is rotated from the first phase to another phase (a second phase). The second phase may be, for example, 241°, etc.

[0077] In step S108, in order to allow the specific tip 32a to be measured by the tool length measuring device 46, that is, to position the central portion of the touch sensor surface 46a of the tool length measuring device 46 below the specific tip 32a, the machine table 20 and the carriage 14 are positioned as shown in Fig. 11B shown moves.

[0078] In step S109, the spindle 26 is moved downward to position the specific tip 32a at the central portion of the touch sensor surface 46a of the tool length measuring device 46.

[0079] In step S110, the spindle displacement measuring unit 44 stores the displacement of the specific tip 32a, that is, the movement amount of the specific tip 32a, in the cutting edge position storing unit 38 as the second measured value M2. Now, the three-dimensional coordinates (X2, Y2, Z2) can be stored in the cutting edge position storing unit 38. In this case, X2 corresponds to the displacement amount in the X direction on the XY plane 31, Y2 corresponds to the displacement amount in the Y direction on the XY plane 31, and Z2 corresponds to the displacement amount of the spindle 26 in the Z direction.

[0080] In step S111 in Fig. 10 the spindle 26 is moved upwards and returned to the machine zero point.

[0081] In step S112, the spindle 26 is rotated from the second phase to another phase (a third phase). For example, the third phase can be 309°, etc.

[0082] In step S113, in order to allow the specific tip 32a to be measured by the tool length measuring device 46, that is, to position the central portion of the touch sensor surface 46a of the tool length measuring device 46 below the specific tip 32a, the machine table 20 and the carriage 14 are positioned as shown in Fig. 11C shown moves.

[0083] In step S114, the spindle 26 is moved downward to position the specific tip 32a at the central portion of the touch sensor surface 46a of the tool length measuring device 46.

[0084] In step S115, the cutting edge position measuring unit 34 stores the displacement of the specific tip 32a, that is, the movement amount of the specific tip 32a, in the cutting edge position storing unit 38 as the third measured value M3. Now, the cutting edge position storing unit 38 may store the three-dimensional coordinates (X3, Y3, Z3) therein. In this case, if the mounted position of the tool length measuring device 46 is defined as the starting point, X3 corresponds to the displacement in the X direction on the XY plane 31, Y3 corresponds to the displacement in the Y direction on the XY plane 31, and Z3 corresponds to the displacement of the spindle 26 in the Z direction.

[0085] In step S116, the spindle inclination angle calculation unit 40 calculates the inclination angle of the spindle 26 relative to the XY plane 31 based on the plurality of measured values ​​stored in the cutting edge position storage unit 38. That is, based on the stored X-coordinates, Y-coordinates, and Z-coordinates, the first, second, and third measured values ​​M1, M2, and M3, the inclination angle ax of the spindle 26 relative to the X-direction, and the inclination angle ay thereof relative to the Y-direction are calculated using trigonometric functions.

[0086] In step S117, the coordinate system rotating unit 42 rotates the XY plane 31 around the Y axis by the inclination angle αx of the spindle 26 calculated by the spindle inclination angle calculating unit 40, and rotates the XY plane 31 around the X axis by the calculated inclination angle αy of the spindle 26.

[0087] Specifically, the coordinate system rotating unit 42 generates the rotated XY plane 31 by driving the Z-axis while simultaneously driving the Y-axis and the X-axis such that the Y-axis and the X-axis are driven in directions that cancel the calculated inclination angles αy and αx, respectively. As a result, the Y-direction and the X-direction of the generated XY plane 31 become orthogonal to the spindle 26.

[0088] In step S118, the workpiece smoothing control unit 30 performs smoothing on the workpiece 16 fixed to the workpiece support surface 18, parallel to the XY plane 31 generated by the coordinate system rotation by the coordinate system rotating unit 42.

[0089] Since the Y-direction of the XY plane 31 and the spindle 26 are orthogonal to each other, even if the milling is carried out several times on several paths in the X-direction, there is hardly any difference in height on the workpiece 16, as in Fig. 7, so that a good flat surface can be formed on the workpiece 16. That is, the flatness of the machined surface of the workpiece 16 can be improved.

[0090] Since in the second machine tool 10B both the X-direction and the Y-direction of the XY plane 31 are made orthogonal to the spindle 26, it is possible to further improve the machining accuracy compared to the first machine tool 10A. In particular, sometimes the flatness of the machined surface may be of primary importance, while it is not so important that the shape of the lateral surface of the workpiece becomes more or less trapezoidal depending on the tolerance of the machined product. In such a case, this configuration can exhibit considerable effectiveness. Third machine tool

[0091] Next, a machine tool according to a third embodiment (hereinafter referred to as third machine tool 10C) will be described with reference to Fig. 12 to 15B. The overall configuration of the third machine tool is essentially the same as that of the Fig. 1 shown first machine tool 10A.

[0092] As in Fig. 12, the third machine tool 10C has substantially the same configuration as that of the previously described first machine tool 10A, except that two specific tips (a first specific tip 32a and a second specific tip 32b) are mounted on the spindle 26 opposite each other by 180°.

[0093] Now, the processing operation of the third machine tool 10C is described with reference to Fig. 13 to 15B. Note that a repeated description of steps similar to those in the first machine tool 10A is omitted.

[0094] First, in steps S201 to S205, Fig. 13 Work processes similar to the previously described processing (steps S1 to S5) in the first machine tool 10A as shown in Fig. 14A and Fig. 14B, and the movement amount of a first specific tip 32a is stored as the first measured value M1 (X1, Y1, Z1) in the cutting edge position storage unit 38. In this case, X1 = 0, Y1 = 0, and Z1 corresponds to the movement amount of the first specific tip 32a in the Z direction.

[0095] In step S206, the spindle 26 is moved upwards and returned to the machine zero point, for example.

[0096] In step S207, in order to allow the second specific peak 32b to be measured by the tool length measuring device 46 without changing the phase of the spindle 26, that is, in order to position the central portion of the touch sensor surface 46a of the tool length measuring device 46 below the second specific peak 32b, the machine table 20 and the carriage 14 are positioned as shown in Fig. 15A and Fig. 15B shown moves.

[0097] Subsequently, in step S208, the spindle 26 is moved downward to position the second specific tip 32b at the central portion of the touch sensor surface 46a of the tool length measuring device 46.

[0098] In step S209, the cutting edge position measuring unit 34 stores the displacement of the second specific tip 32b, that is, the movement amount of the second specific tip 32b, in the cutting edge position storing unit 38 as the second measured value M2 (X2, Y2, Z2). Since no displacement occurs at the X coordinate in this case, X2 = 0. Y2 corresponds to the displacement in the Y direction of the XY plane 31, and Z2 corresponds to the displacement of the spindle 26. In step S210, the spindle inclination angle calculating unit 40 calculates the inclination angle of the spindle 26 relative to the XY plane 31 based on the first and second measured values ​​M1 and M2 stored in the cutting edge position storing unit 38.As in the case of the first machine tool 10A, trigonometric functions are used to calculate the inclination angle αy of the spindle 26 relative to the Y-axis from the stored Y-coordinates and Z-coordinates of the first and second measured values ​​M1 and M2.

[0099] In step S211, the coordinate system rotating unit 42 rotates the XY plane 31 around the X-axis by the inclination angle αy of the spindle 26 calculated by the spindle inclination angle calculating unit 40.

[0100] In step S212, the workpiece smoothing control unit 30 performs smoothing on the workpiece 16 fixed to the workpiece support surface 18, parallel to the XY plane 31 generated by coordinate system rotation by the coordinate system rotation unit 42.

[0101] Since the Y-direction of the XY plane 31 and the spindle 26 are orthogonal to each other, even if milling is carried out several times on multiple paths in the X-axis direction, there is hardly any difference in height on the workpiece 16, as in Fig. 7, so that a good flat surface can be formed on the workpiece 16. That is, the flatness of the machined surface of the workpiece 16 can be improved.

[0102] The third machine tool 10C can be preferably implemented as long as the first specific tip 32a and the second specific tip 32b are 180° opposite each other, and the assembly errors of these tips do not affect the machining accuracy. According to the third machine tool 10C, the inclination angle αy of the spindle 26 can be determined by positioning and measuring the spindle 26 only in the first stage, thus reducing the number of steps and the working time required to make the Y direction of the XY plane and the spindle 26 orthogonal to each other. Fourth machine tool

[0103] Next, with reference to Fig. 16 and Fig. 17, a machine tool according to a fourth embodiment (hereinafter referred to as fourth machine tool 10D) is described.

[0104] The fourth machine tool 10D has substantially the same configuration as the previously described third machine tool 10C, except that both the X-direction and the Y-direction of the XY plane 31 are made orthogonal to the spindle 26.

[0105] That is, as in Fig. 16, the fourth machine tool 10D stores a plurality of measurement values ​​(first to fourth measurement values ​​M1 to M4) obtained by the first and second specific peaks 32a and 32b (see Fig. 12) on the same device 46 for measuring a tool length in two different phases of the spindle 26, in the unit 38 for storing a cutting edge position.

[0106] The spindle inclination angle calculating unit 40 calculates, based on the plurality of measured values ​​stored in the cutting edge position storing unit 38, the inclination angle of the spindle 26 relative to the XY plane 31, specifically the inclination angle αy relative to the Y direction and the inclination angle αx in the X direction.

[0107] Similar to the second machine tool 10B, the coordinate system rotating unit 42 generates the rotated XY plane 31 by driving the Z-axis simultaneously with driving the Y-axis and the X-axis, such that the Y-axis and the X-axis are driven in directions that cancel the calculated inclination angle αy and the inclination angle αx, respectively. As a result, the Y-direction and the X-direction of the generated XY plane 31 become orthogonal to the spindle 26.

[0108] Now, the processing operation of the fourth machine tool 10D is described with reference to Fig. 17. It should be noted that a repeated description of steps similar to those in the third machine tool 10C is omitted.

[0109] First, in steps S301 to S309, Fig. 17 Operations similar to the above-described processing (steps S201 to S209) are performed in the third machine tool 10C, and the movement amount of the first specific tip 32a is stored as the first measured value M1 (X1, Y1, Z1) in the cutting edge position storage unit 38. Then, the movement amount of the second specific tip 32b is stored as the second measured value M2 (X2, Y2, Z2) in the cutting edge position storage unit 38.

[0110] Subsequently, in step S310, Fig. 18, the spindle 26 is moved upwards and returned, for example, to the machine zero point.

[0111] In step S311, the spindle 26 is rotated from the first phase to another phase (a second phase).

[0112] In step S312, in order to allow the first specific tip 32a to be measured again by the tool length measuring device 46, that is, to position the central portion of the touch sensor surface 46a of the tool length measuring device 46 below the first specific tip 32a, the machine table 20 and the carriage 14 are moved.

[0113] In step S313, the spindle 26 is moved downward to position the first specific tip 32a at the central portion of the touch sensor surface 46a of the tool length measuring device 46.

[0114] In step S314, the cutting edge position measuring unit 34 stores the displacement of the first specific tip 32a, that is, the movement amount of the first specific tip 32a, in the cutting edge position storing unit 38 as the third measured value M3 (X3, Y3, Z3).

[0115] In step S315, the spindle 26 is moved upwards and returned to the machine zero point, for example.

[0116] In step S316, in order to allow the second specific tip 32b to be measured by the tool length measuring device 46 while the spindle 26 is held in the second phase, that is, to position the central portion of the touch sensor surface 46a of the tool length measuring device 46 below the second specific tip 32b, the machine table 20 and the carriage 14 are moved.

[0117] In step S317, the spindle 26 is moved downward to position the second specific tip 32b at the central portion of the touch sensor surface 46a of the tool length measuring device 46.

[0118] In step S318, the cutting edge position measuring unit 34 stores the displacement of the second specific tip 32b, that is, the movement amount of the second specific tip 32b, as the fourth measured value M4 (X4, Y4, Z4) in the cutting edge position storing unit 38.

[0119] In step S319, the spindle inclination angle calculating unit 40 determines the inclination angles αx and αy of the spindle 26 relative to the XY plane 31 based on the first to fourth measured values ​​M1 to M4 stored in the cutting edge position storing unit 38.

[0120] In step S320, the coordinate system rotation unit 42 generates the XY plane 31 by driving the Z-axis simultaneously with driving the Y-axis and the X-axis, such that the Y-axis and the X-axis are respectively driven in directions to cancel the calculated inclination angle αy and the inclination angle αx. As a result, the Y-direction and the X-direction of the XY plane 31 become orthogonal to the spindle 26.

[0121] In step S321, the workpiece smoothing control unit 30 performs smoothing on the workpiece 16 fixed to the workpiece support surface 18, parallel to the XY plane 31 formed by coordinate system rotation by the coordinate system rotating unit 42.

[0122] In this fourth machine tool, since both the X-direction and Y-direction of the XY plane 31 are set orthogonally to the spindle 26, there is hardly any difference in the height of the workpiece 16, so that a good flat surface can be formed on the workpiece 16. Furthermore, the machining accuracy can be further improved compared to the third machine tool 10C. Furthermore, flatness may sometimes be a priority, and it is not important that the shape of the side surfaces of the workpiece become more or less trapezoidal depending on the tolerance of the machined product. In this case, this configuration can exhibit considerable effectiveness.

[0123] The fourth machine tool 10D can be preferably implemented as long as the first specific tip 32a and the second specific tip 32b are 180° opposite each other, and the assembly errors of these tips do not affect the machining accuracy. According to the fourth machine tool 10D, the inclination angles αx and ay of the spindle 26 can be determined only by positioning and measuring the spindle 26 in the first stage and positioning and measuring the spindle 26 in the second stage, so it is possible to reduce the number of steps and the working time for making the X direction of the XY plane 31 orthogonal to the spindle 26 and making the Y direction of the XY plane 31 orthogonal to the spindle 26. Fifth machine tool

[0124] Next, a machine tool according to a fifth embodiment (hereinafter referred to as fifth machine tool 10E) will be described with reference to Fig. 19 to 23B.

[0125] As in Fig. 19, the fifth machine tool 10E has substantially the same configuration as that of the previously described first machine tool 10A, except that the fifth machine tool includes a probe position measuring unit 101 using a contact probe 100 instead of the tool length measuring device 46, and a probe position storing unit 102 as a contact element position storing unit 36 ​​for performing the same processing as the cutting edge position storing unit 38 instead of the same.

[0126] As in Fig. 20A, the contact probe 100 includes a sensor unit 104 mounted on a portion of the spindle 26 opposite the workpiece support surface 18, and a shaft assembly 108 extending downward from the bottom of the sensor unit 104 and then bent or curved in the middle, and having a spherical probe element 106 as a contact element attached to its distal end. The shaft assembly 108 includes a first shaft portion 108a extending from the bottom of the sensor unit 104, a second shaft portion 108b extending laterally from the bottom of the first shaft portion 108a, and a third shaft portion 108c extending downward from the distal end of the second shaft portion 108b. The probe element 106 is attached to the distal end of the third shaft portion 108c.

[0127] Then, as will be described later, the spindle 26 is moved toward the workpiece support surface 18, and when the probe element 106 contacts the workpiece support surface 18, that is, when the probe element 106 of the contact probe 100 is positioned, the sensor unit 104 outputs a detection signal Sa to the spindle displacement measuring unit 44.

[0128] The spindle displacement measuring unit 44 measures the movement amount of the spindle 26 from the time the downward movement of the spindle 26 is started, and stores the measured value including the movement amount of the probe element 106 in the probe position storing unit 102 based on the input of the detection signal Sa from the sensor unit 104 of the touch probe 100.

[0129] That is, the probe position storing unit 102 stores therein a plurality of measurement values ​​(the first measurement value M1 and the second measurement value M2) obtained by performing the positioning process of the probe element 106 using the touch probe 100 twice.

[0130] Now the processing operation of the fifth machine tool 10E is also carried out with reference to Fig. 21 to 23B. It is assumed that spindle 26 is in its initial state at the machine zero point.

[0131] First, in step S401, Fig. 21, as in Fig. 20A and Fig. 20B, the spindle 26 is set to a first phase in which the probe element 106 of the touch probe 100 provided at the lower end of the spindle 26 is oriented in the Y direction.

[0132] In step S402, the spindle 26 is moved downward, and then the probe element 106 of the contact probe 100 is brought into contact with a specific position on the workpiece support surface 18 (the position shown in Fig. 20B and others indicated by X) to thereby position the probe element 106.

[0133] In step S403, the spindle displacement measuring unit 44 stores the displacement of the spindle 26, that is, the movement amount of the probe element 106, as the first measured value M1 (X1, Y1, Z1) in the probe position storing unit 102. Since the X coordinate and the Y coordinate are not changed, X1 = 0, Y1 = 0, and Z1 corresponds to the movement amount of the probe element 106 in the Z direction.

[0134] In step S404, the spindle 26 is moved upwards and returned to the machine zero point.

[0135] In step S405, as in Fig. 22A and Fig. 22B, the spindle 26 is rotated by 180° compared to the first phase.

[0136] In step S406, the machine table 20 and the carriage 14 are moved such that the probe element 106 can be positioned again in the previously mentioned specific position on the workpiece support surface 18.

[0137] In step S407, as in Fig. 23A and Fig. 23B, the spindle 26 is moved downward to position the probe element 106 of the touch probe 100.

[0138] In step S408, the spindle displacement measuring unit 44 stores the displacement of the spindle 26, i.e., the movement amount of the probe element 106, as the second measured value M2 (X2, Y2, Z2) in the probe position storing unit 102. Regarding the X coordinate, since no movement occurs in the X direction, X2 = 0. Y2 corresponds to the displacement in the Y direction of the XY plane 31, and Z2 corresponds to the displacement of the spindle 26.

[0139] In step S409, the spindle inclination angle calculation unit 40 determines the inclination angle αy of the spindle 26 relative to the XY plane 31 based on the first and second measured values ​​M1 and M2 stored in the probe position storage unit 102. Since the X-axis coordinates are the same in the above example, the inclination angle αy of the spindle 26 is calculated from the stored Y-axis coordinates and Z-axis coordinates of the first measured value M1 and the second measured value M2 using trigonometric functions.

[0140] In step S410, the coordinate system rotating unit 42 rotates the XY plane 31 around the X-axis by the inclination angle αy of the spindle 26 calculated by the spindle inclination angle calculating unit 40. Specifically, the coordinate system rotating unit 42 drives the Z-axis simultaneously with driving the Y-axis, so that the Y-axis is driven in a direction to cancel the calculated inclination angle αy. This makes the Y-direction of the XY plane 31 orthogonal to the spindle 26.

[0141] In step S411, the workpiece smoothing control unit 30 performs flat surface processing on the workpiece 16 fixed to the workpiece support surface 18, parallel to the XY plane 31 generated by coordinate system rotation performed by the coordinate system rotation unit 42.

[0142] Now, similar to the first machine tool 10A, even if milling is performed multiple times on multiple paths in the X direction, there is hardly any difference in the height of the workpiece 16, so that a good flat surface can be formed on the workpiece 16. Particularly, in the fifth machine tool 10E, since the contact probe 100 mounted on the spindle 26 is used, it is not necessary to install a special measuring device on the side of the machine table 20, and thus it is possible to secure an installation space on the top of the machine table 20.

[0143] In the fifth machine tool 10E, the reason why the phase of the spindle 26 is rotated by 180° is as follows. If a plurality of probe elements 106 are provided, the plurality of probe elements 106 may not be located at positions 180° apart from each other due to assembly errors of the plurality of probe elements 106. To address this, by using a single probe element 106 for measurement, the measurement is not affected by the assembly errors of the plurality of probe elements 106. Thus, it is possible to establish an orthogonal relationship between the Y direction of the XY plane 31 and the spindle 26 with high precision.

[0144] Of course, similar to the second machine tool 10B described above, based on the multiple measurement values ​​(first to third measurement values ​​M1 to M3) obtained by positioning the probe element 106 at specific positions in three different phases of the spindle 26, the inclination angle αy of the spindle 26 in the Y direction and the inclination angle αx in the X direction relative to the XY plane 31 can be obtained. Then, the coordinate system rotating unit 42 generates an XY plane 31 by driving the Z axis while simultaneously driving the Y axis and the X axis such that the Y axis and the X axis are driven in directions to cancel the calculated inclination angles αy and inclination angle αx, respectively, thereby making it possible to make the Y axis direction and the X direction of the generated XY plane 31 orthogonal to the spindle 26.

[0145] Further, similar to the first and second specific tips 32a and 32b used in the third machine tool 10C, a contact probe 100 having two probe elements (first and second probe elements 106a and 106b) arranged 180° opposite to each other may be used, as shown in Fig. 24 shown.

[0146] This configuration can be preferably implemented as long as the first probe element 106a and the second probe element 106b are 180° apart, and assembly errors of these probe elements do not affect the machining accuracy. Furthermore, the inclination angle ay of the spindle 26 can be determined by positioning and measuring the spindle 26 only in the first phase, making it possible to reduce the number of steps and the working time required to make the Y direction of the XY plane 31 and the spindle 26 orthogonal to each other. Sixth machine tool

[0147] Next, a machine tool according to a sixth embodiment (hereinafter referred to as sixth machine tool 10F) will be described with reference to Fig. 25 described.

[0148] In the second machine tool 10B, the fourth machine tool 10D, and the like described above, the positional relationship between the XY plane 31 and the spindle 26 is corrected (coordinate system rotation) to be placed in an orthogonal relationship based on the inclination angle of the spindle 26 with respect to the XY plane 31 before the correction.

[0149] Incidentally, when the workpiece 16 is placed on the top surface of the machine table 20, the top surface of the machine table 20 forms the workpiece support surface 18. In this case, since the XY plane 31 and the workpiece support surface 18 of the machine table 20 are not necessarily parallel to each other, it may sometimes be that the shape of the side surface of the workpiece 16 cannot be machined in a rectangular shape.

[0150] Therefore, the sixth machine tool 10F has a means for making the XY plane 31 and the workpiece support surface 18 parallel to each other. That is, instead of placing the workpiece support surface 18 on top of the machine table 20, a workpiece support surface 18 is reset parallel to the XY plane 31. Incidentally, as the means for making the XY plane 31 and the spindle 26 orthogonal to each other, the second machine tool 10B, the fourth machine tool 10D, and the like described above can be adopted.

[0151] The sixth machine tool 10F has a two-axis machine table 112 that can freely change its position through two rotation axes (a first rotation axis 110a and a second rotation axis 110b) on the top of the machine table 20.

[0152] The two-axis machine table 112 includes a support 114 for supporting the workpiece 16 so that it faces the spindle 26, a second rotation axis 110b for rotationally driving the support 114 about a horizontal axis, and a first rotation axis 110a for rotationally driving the support 114 and the second rotation axis 110b about a vertical axis. In this case, the top surface of the support 114 forms a new workpiece support surface 18.

[0153] Based on the inclination angle αy of the spindle 26 relative to the Y direction and the inclination angle αx of the spindle 26 relative to the X direction, the first rotation axis 110a and the second rotation axis 110b are rotated such that the two-axis machine table 112 is orthogonal to the spindle 26. Thus, the spindle 26 becomes orthogonal to the workpiece support surface 18 of the two-axis machine table 112.

[0154] As a result, the XY plane 31 becomes parallel to the workpiece support surface 18, and when the workpiece 16 is subjected to a smoothing process based on the XY plane 31 after rotation of the coordinate system, a satisfactory flat surface can be formed on the workpiece 16. Furthermore, since the shape of the side surface of the workpiece 16 can be machined in a rectangular shape, the machined surface of the workpiece 16 can also become parallel to the workpiece support surface 18, and thus the machining quality can be improved. Seventh machine tool

[0155] Next, a machine tool according to a seventh embodiment (hereinafter referred to as seventh machine tool 10G) will be described with reference to Fig. 26 described.

[0156] The seventh machine tool 10G also has a means for making the XY plane 31 and the workpiece support surface 18 parallel to each other. In this case, too, the workpiece support surface 18 is reset to be parallel to the XY plane 31 instead of setting the workpiece support surface 18 on the top surface of the machine table 20. Incidentally, as the means for bringing the XY plane 31 and the spindle 26 into an orthogonal positional relationship, the second machine tool 10B, the fourth machine tool 10D, etc., described above, can be adopted.

[0157] The seventh machine tool 10G includes a dedicated fixture 120 disposed on the top surface of the machine table 20 and including a plurality of dedicated bars (for example, the first to third dedicated bars 122A to 122C) slidably forward and backward, and a reference tool 124 mounted on the spindle 26 for positioning the plurality of dedicated bars.

[0158] The dedicated fixture 120 includes a base 126 and first to third dedicated rods 122A to 122C mounted to extend from and retract into the base 126. These first to third dedicated rods 122A to 122C are arranged at arbitrary positions on the base 126 to define a single plane (workpiece support surface 18) with their tips.

[0159] The dedicated fixture 120 may be a generic type having the following configuration.

[0160] That is, the first to third dedicated rods 122A to 122C are each supported by a spring and continuously pushed upward. When the reference tool 124 gradually moves downward and then the protrusion amount of each of the rods becomes equal to a predetermined protrusion amount, each of the first to third dedicated rods 122A to 122C is positioned and is clamped by the hydraulic pressure resulting from the pressure increase accompanying the positioning.

[0161] Alternatively, the first to third dedicated rods 122A to 122C are positioned inside the base 126 in the initial state. When the reference tool 124 reaches the height corresponding to the protrusion amount of each rod, the first to third dedicated rods 122A to 122C are each moved and positioned by a piston or the like when the protrusion amount becomes equal to a predetermined protrusion amount, and each rod is clamped by the hydraulic pressure resulting from the pressure increase accompanying the positioning.

[0162] Then, based on the Y-direction inclination angle αy of the spindle 26 and the X-direction inclination angle αx of the spindle 26, the protrusion amount of each of the first to third dedicated rods 122A to 122C is determined and positioned so that the workpiece support surface 18 and the spindle 26 are orthogonal to each other. Thus, the workpiece support surface 18 and the spindle 26 are orthogonal to each other.

[0163] That is, in the seventh machine tool 10G, the XY plane 31 and the workpiece support surface 18 are also set parallel to each other, and when the workpiece 16 is smoothed based on the XY plane 31 after the coordinate system rotation, it is possible to create a machined surface with satisfactory flatness in the workpiece 16. In addition, since the shape of the side surface of the workpiece 16 can be machined into a rectangular shape, it is possible to make the machined surface of the workpiece 16 parallel to the workpiece support surface 18 and therefore improve the machining quality.

Claims

[1] Machine tool, comprising: a machine table (20) having a workpiece support surface (18) to which a workpiece (16) is attached; a spindle (26) equipped with a tool (28) configured to perform a smoothing operation on the workpiece (16) fixed to the machine table (20); a unit (30) for controlling the smoothing of a workpiece, which is configured to perform smoothing on the workpiece (16) using the tool (28) such that the machining areas of the tool (28) partially overlap on a surface of the workpiece (16); at least one contact element arranged on the spindle (26) in a position opposite the machine table (20); a contact element position storing unit (36) configured to store a plurality of measurement values ​​obtained by performing a measurement of a position of the contact element at least twice in a state where the spindle (26) is set to at least one phase and the contact element is positioned at an identical point; a spindle inclination angle calculation unit (40) configured to calculate an inclination angle of the spindle (26) relative to an XY plane (31) for machining based on the plurality of measured values ​​stored in the contact element position storage unit (36); and a coordinate system rotating unit (42) configured to rotate the XY plane (31) about at least one of the X-axis and the Y-axis based on the inclination angle of the spindle (26) calculated by the spindle inclination angle calculating unit (40), wherein the workpiece smoothing control unit (30) machines a flat surface of the workpiece (16) so as to be parallel to the XY plane (31) rotated by the coordinate system rotating unit (42). [2] A machine tool according to claim 1, wherein the contact element position storing unit (36) is configured to store a plurality of measurement values ​​obtained by performing a measurement on one of the contact elements in a state where the spindle (26) is set to two or more different phases and the one contact element is positioned at an identical point. [3] Machine tool according to claim 1, wherein: several contact elements are arranged on the spindle (26); the contact element position storing unit (36) is configured to store a plurality of measurement values ​​obtained by measuring the position of each of the plurality of contact elements in a state in which the spindle (26) is adjusted to a phase and each of the plurality of contact elements is positioned at an identical point; and the spindle inclination angle calculation unit (40) determines an inclination angle of the spindle (26) relative to at least one direction of the XY plane (31) based on the plurality of measured values. [4] Machine tool according to one of claims 1 to 3, wherein: the contact element is a tip (32) arranged on the tool (28) in a position facing the machine table (20); and the contact element position storing unit (36) is configured to store a plurality of measurement values ​​obtained by measuring a position of a cutting edge of the tip (32) at least twice using a cutting edge position measuring unit (34) attached to the machine table (20) in a state where the cutting edge of the tip (32) is positioned. [5] The machine tool according to claim 4, wherein a tool length measuring device (46) configured to measure a length of the tool is used as the cutting edge position measuring unit (34). [6] Machine tool according to one of claims 1 to 3, wherein: the contact element is a probe element (106) of a touch probe (100) mounted on the spindle (26) in a position facing the machine table (20); and the probe element (106) is deflected from a central axis of the spindle (26) to the X-direction or Y-direction of the machine table (20). [7] A machine tool according to any one of claims 1 to 6, further comprising rotation axes (110a, 110b) configured to rotate the workpiece support surface (18) such that the XY plane (31) rotated by the coordinate system rotating unit (42) and the workpiece support surface (18) are made parallel to each other. [8] A machine tool according to any one of claims 1 to 6, further comprising a dedicated clamping device (120) configured to position the workpiece support surface (18) such that the XY plane (31) rotated by the coordinate system rotating unit (42) and the workpiece support surface (18) are made parallel to each other. [9] Machine tool according to one of claims 1 to 8, wherein a diameter of the tool (28) is smaller than a narrow side dimension of the workpiece (16). [10] A method for smoothing a workpiece, for smoothing a workpiece (16) using: a machine table (20) having a workpiece support surface (18) and to which the workpiece (16) is mounted; a spindle (26) equipped with a tool (28) configured to perform smoothing on the workpiece (16) mounted on the machine table (20); and the tool (28) performing machining such that the machining areas of the tool (28) partially overlap on a surface of the workpiece (16), comprising: a step of storing measured values, which consists in storing a plurality of measured values ​​obtained by measuring a position of at least one contact element arranged on the spindle (26) in a position facing the machine table (20) at least twice in a state in which the spindle (26) is set to at least one phase and the contact element is positioned at an identical point; a step of calculating an inclination angle of a spindle, which consists in calculating an inclination angle of the spindle (26) relative to an XY plane (31) for machining based on the plurality of stored measured values; and a coordinate system rotating step of rotating the XY plane (31) about at least one of the X-axis and the Y-axis based on the calculated inclination angle of the spindle (26), wherein a flat surface of the workpiece (16) is machined to be parallel to the XY plane (31) rotated by the coordinate system rotating step. [11] A method for smoothing a workpiece according to claim 10, wherein in the step of storing measured values, a plurality of measured values ​​obtained by performing a measurement on one of the contact elements in a state in which the spindle (26) is set to two or more different phases and the one contact element is positioned at an identical point are stored. [12] A method for smoothing a workpiece according to claim 10, wherein: several contact elements are arranged on the spindle (26); in the step of storing measured values, a plurality of measured values ​​obtained by measuring the position of each of the plurality of contact elements in a state in which the spindle (26) is adjusted to a phase and each of the plurality of contact elements is positioned at an identical point are stored; and in the step of calculating an inclination angle of a spindle, an inclination angle of the spindle (26) relative to at least one direction of the XY plane (31) is determined based on the plurality of measured values. [13] A method for smoothing a workpiece according to any one of claims 10 to 12, wherein: the contact element is a tip (32) arranged on the tool (28) in a position facing the machine table (20); and in the step of storing measured values, a plurality of measured values ​​obtained by measuring a position of a cutting edge of the tip (32) using a cutting edge position measuring unit (34) attached to the machine table (20) in a state in which the cutting edge of the tip (32) is positioned is stored at least twice. [14] A method for smoothing a workpiece according to any one of claims 10 to 12, wherein: the contact element is a probe element (106) of a touch probe (100) mounted on the spindle (26) in a position facing the machine table (20); and the probe element (106) is deflected from a central axis of the spindle (26) to the X-direction or Y-direction of the machine table (20). [15] A method for smoothing a workpiece according to any one of claims 10 to 14, wherein a diameter of the tool (28) is smaller than a narrow side dimension of the workpiece (16).

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