Processing machine, processing system and method of manufacturing a workpiece

Abstract

In the processing machine (1), the X-axis control unit (33X) performs feedback control of the position in the X-direction of the X-axis table (9X) every control cycle Tc. The Z-axis control unit (33Z) acquires the most recent detected value of the position in the Z-direction of the Z-axis table (9Z) every control cycle Tc, calculates a second deviation based on the difference between the acquired detected value and the target position, and controls the Z-axis drive source (23Z) to reduce the second deviation. The Z-axis control unit (33Z) acquires the most recent detected value of the first error, which is the displacement in the Z-direction of the X-axis table (9), every control cycle Tc, and increases or decreases the second deviation based on the detected value of the first error so that at least a portion of the error in the relative position of the work (103) and the tool (101) in the Z-direction caused by the first error is eliminated by the movement of the Z-direction of the Z-axis table (9Z).

Description

Technology Field

[0001] The present disclosure relates to a processing machine, a processing system, and a method for manufacturing a workpiece. Background Technology

[0002] A machining machine that processes a workpiece using a tool is known (e.g., Patent Documents 1 to 3). The machining machine has a movable part (e.g., a table or head) that holds and supports the tool or workpiece and is driven in a predetermined direction to move the tool and the workpiece relative to each other. The movable part is guided, for example, by a guide and ideally moves along a straight line. However, in reality, due to manufacturing errors of the guide, etc., it moves while generating a wave pattern. That is, the straightness or perpendicularity does not become zero. This wave pattern reduces machining precision.

[0003] Patent Document 1 discloses a technique for reducing perpendicularity by pre-registering perpendicularity regarding the movement of a table in a numerical control (NC) device and moving the table to a target position corrected by the perpendicularity.

[0004] Patent Document 2 discloses a technology for detecting the movement trajectory when a machining machine is operated according to an NC program, and correcting the NC program based on the detected movement trajectory and the ideal movement trajectory.

[0005] Patent Document 3 discloses a machining machine having a first table that holds and supports a workpiece, a second table that moves in a direction orthogonal to the direction of movement of the first table, and a fine adjustment stage provided on the second table that holds and supports a tool. This machining machine detects the straightness of the first table in real time and drives the fine adjustment table so that the influence of the detected straightness on the machining error is reduced. Prior art literature

[0006] Japanese Patent Publication No. Sho 62-55706, Japanese Patent Publication No. Hei 4-111003, Japanese Patent Publication No. Hei 9-76141 The problem to be solved

[0007] The technology of Patent Documents 1 and 2, in that it is a method of measuring straightness in advance, cannot handle, for example, straightness that lacks reproducibility or straightness where reproducibility is limited to a short period of time. As a result, it is not suitable for, for example, ultra-precision machining requiring precision of tens of nanometers or less. The technology of Patent Document 3, for example, requires a fine adjustment table to reduce straightness, which leads to the enlargement and / or complexity of the machining equipment.

[0008] A machining machine, a machining system, and a method for manufacturing a workpiece capable of reducing machining errors caused by straightness are expected. means of solving the problem

[0009] A machining device according to one embodiment of the present disclosure has a first movable part, a first guide, a first driving source, a first sensor, a second movable part, a second guide, a second driving source, a second sensor, and a control device. The first movable part supports a workpiece or a tool. The first guide guides the first movable part in a first direction. The first driving source drives the first movable part in the first direction. The first sensor outputs a signal corresponding to a first displacement, which is a displacement of the first movable part in the first direction, and a first error, which is a displacement of the first movable part in a second direction orthogonal to the first direction. The second movable part supports the workpiece or the tool. The second guide guides the second movable part in the second direction. The second driving source drives the second movable part in the second direction. The second sensor outputs a signal corresponding to a second displacement, which is a displacement of the second movable part in the second direction. The control device controls the first driving source and the second driving source according to a program containing information on commands regarding the movement of the first movable part and the second movable part. The control device has an interpolation unit, a first control unit, and a second control unit. Based on the information of the program, the interpolation unit calculates a first target position for every predetermined control cycle in the first direction of the first movable part and a second target position for every control cycle in the second direction of the second movable part. The first control unit acquires a recent detection value of the first displacement based on a signal from the first sensor for every control cycle, calculates a first deviation based on the difference between the acquired detection value and the first target position, and controls the first driving source to reduce the first deviation.The second control unit acquires a recent detection value of the second displacement based on a signal from the second sensor at each control cycle, calculates a second deviation based on the difference between the acquired detection value and the second target position, and controls the second driving source to reduce the second deviation. Additionally, the second control unit acquires a recent detection value of the first error based on a signal from the first sensor at each control cycle, and increases or decreases the second deviation based on the detection value of the first error so that at least a portion of the error in the relative position of the workpiece and the tool in the second direction caused by the first error is eliminated by the movement of the second movable part in the second direction.

[0010] A processing system according to one embodiment of the present disclosure has the processing machine and a diagnostic device that acquires information of the detection value of the first error from the processing machine and displays an image according to the acquired information.

[0011] A method for manufacturing a workpiece according to one aspect of the present disclosure has a step of using the processing machine to bring the workpiece and the tool into contact to process the workpiece into a workpiece. Effects of the invention

[0012] According to the above configuration or procedure, processing errors caused by straightness can be reduced. Brief explanation of the drawing

[0013] FIG. 1 is a schematic perspective view illustrating the configuration of a processing machine according to an embodiment. FIG. 2(a) is a perspective view illustrating an example of a configuration for linearly moving the X-axis table of the processing machine of FIG. 1, and FIG. 2(b) is a cross-sectional view along line II-II of FIG. 2(a). FIGS. 3(a) and FIGS. 3(b) are drawings illustrating the configuration and operation of the X-axis sensor of the processing machine of FIG. 1. FIG. 4 is a block diagram illustrating the configuration of a control system in the processing machine of FIG. 1. FIG. 5 is a drawing showing details of a part of the block diagram of FIG. 4. FIGS. 6(a) and FIGS. 6(b) are conceptual diagrams for explaining detection values ​​regarding straightness used for control. FIG. 7 is a block diagram of the control system of a processing machine for a modified example. FIG. 8 is a drawing illustrating a configuration different from the configuration example of FIG. 3 (a) with respect to a two-dimensional scale. FIG. 9 is a drawing illustrating a configuration example different from the configuration example described with reference to FIG. 2(b) regarding the guide. FIG. 10 is a cross-sectional view illustrating an example of the configuration of the bearing of the main spindle of the machining machine of FIG. 1. Specific details for implementing the invention

[0014] (Overall configuration of the processing machine)

[0015] FIG. 1 is a schematic perspective view illustrating the configuration of a processing machine (1) according to an embodiment. For convenience, the orthogonal coordinate system XYZ is attached to the drawing. The +Y direction is, for example, vertically upward.

[0016] The technology described in this disclosure is applicable to various processing machines, and the processing machine (1) illustrated is merely an example thereof. However, for convenience, the following description may be based on the configuration of the processing machine (1).

[0017] The processing machine (1) performs grinding and / or polishing of a workpiece (103) by, for example, a tool (101). More specifically, in the illustrated example, the workpiece (103) is rotated around an axis parallel to the Z direction. Additionally, the tool (101) is composed of a grinding wheel and is rotated around an axis parallel to the Y direction. Then, the grinding and / or polishing of the workpiece (103) is performed by the tool (101) coming into contact with the workpiece (103). Such a processing machine can be used as an aspherical processing machine for, for example, manufacturing aspherical lenses.

[0018] The processing machine (1) has, for example, a machine body (3) that holds and supports a tool (101) and a workpiece (103), and a control device (5) that controls the machine body (3).

[0019] The machine body (3) rotates, for example, the work (103) and the tool (101) as described above, and moves the tool (101) and the work (103) relative to each other to bring them close together and separate them. The relative direction of the rotation axis of the work (103) and the rotation axis of the tool (101), the direction of each rotation axis in the absolute coordinate system, the direction of the relative movement of the tool (101) and the work (103), the presence or absence of movement in the absolute coordinate system of the tool (101) and the work (103), and the direction of said movement may be appropriately set.

[0020] In the example of the city, prior to cutting, the tool (101) is moved in the Y direction to determine its position. During cutting, as previously described, the workpiece (103) is rotated around an axis parallel to the Z direction, and the tool (101) is rotated around an axis parallel to the Y axis. Additionally, the tool (101) and the workpiece (103) move relative to each other in the Z direction and the X direction. More specifically, the tool (101) moves in the X direction in the absolute coordinate system, and the workpiece (103) moves in the Z direction in the absolute coordinate system. Through these movements, the surface of the workpiece (103) on the +Z side and / or the outer surface around an axis parallel to the Z axis is ground or / or polished.

[0021] The configuration for realizing rotation and translation as described above may be, for example, similar to various known configurations or be an application of known configurations. Examples of the illustration are as follows.

[0022] The machine body (3) has a base (7), an X-axis table (9X) supported by the base (7), a column (11) fixed to the X-axis table (9X), a saddle (13) supported by the column (11), and a tool spindle (15T) supported by the saddle (13). The tool spindle (15T) holds and supports a tool (101) and can rotate the tool (101) around an axis parallel to the Y direction. The X-axis table (9X) can move linearly in the X direction on the base (7), thereby driving the tool (101) in the X direction. The saddle (13) can move linearly in the Y direction relative to the column (11), thereby driving the tool (101) in the Y direction.

[0023] Additionally, the machine body (3) has a Z-axis table (9Z) supported on a base (7) and a work main axis (15W) supported on the Z-axis table (9Z). The work main axis (15W) holds and supports the work (103) and can rotate the work (103) around an axis parallel to the Z direction. The Z-axis table (9Z) can move linearly in the Z direction on the base (7), thereby driving the work (103) in the Z direction.

[0024] Additionally, in the following description, the X-axis table (9X) and the Z-axis table (9Z) are not distinguished and are referred to as Table (9). Also, the tool spindle (15T) and the work spindle (15W) are not distinguished and are referred to as Spindle (15).

[0025] The configuration of the mechanism for realizing the movement of the table (9), the movement of the saddle (13), and the rotation of the main shaft (15) may be a known configuration or an application of a known configuration. For example, the driving source may be an electric motor, a hydraulic device, or a pneumatic device. Additionally, the electric motor may be a rotary motor or a linear motor. The linear guide that guides the table (9) or the saddle (13) (or, from another perspective, restricts movement in directions other than the driving direction) may be a sliding guide in which a movable part and a fixed part slide, a rolling guide in which a rolling body rolls between a movable part and a fixed part, a hydrostatic guide in which air or oil is interposed between a movable part and a fixed part, or a combination of two or more of these. Likewise, the bearing of the main shaft (15) may be a sliding bearing, a rolling bearing, a hydrostatic bearing, or a combination of two or more of these.

[0026] The control unit (5) is configured to include, for example, an NC device and a driver (e.g., a servo driver), although not specifically illustrated. The NC device is configured to include, for example, a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an external storage device, although not specifically illustrated. In other words, the NC device is configured to include a computer. Various functional units that perform control, etc., are constructed by the CPU executing a program stored in the ROM and / or external storage device. Additionally, the NC device may include a logic circuit that performs only a specific operation.

[0027] The control device (5) controls the rotational speed of, for example, the main shaft (15) (or, in another view, the main shaft motor not shown), and the speed and position of the table (9) and saddle (13). Position control may be a so-called closed-loop control. That is, the detected position of the table (9) and saddle (13) may be fed back. Speed ​​control of the table (9) and saddle (13) may be a closed-loop control, just like position control. However, speed control may be an open-loop control in which no feedback is provided, or a semi-closed-loop control in which the detected value of the rotational speed of the motor is fed back.

[0028] The machining precision of the machining machine (1) may be appropriately set. For example, the machining machine (1) may be capable of machining with a precision of the sub-micron meter order (error of less than 1 μm) or a precision of the nanometer order (error of less than 10 nm). Such machine tools have already been commercialized by the applicant of the present invention (e.g., UVM series, ULG series and ULC series). More specifically, for example, the positioning precision in the X direction of the X-axis table (9X), the positioning precision in the Z direction of the Z-axis table (9Z), and / or the positioning precision in the Y direction of the saddle (13) may be 1 μm or less, 0.1 μm or less, 10 nm or less, or 1 nm or less.

[0029] (An example of a mobility device)

[0030] As previously explained, the configuration for moving the table (9) along a straight line may be of a suitable configuration. An example is shown below.

[0031] FIG. 2(a) is a perspective view illustrating an example of a configuration for moving an X-axis table (9X) in a straight line. FIG. 2(b) is a cross-sectional view along line II-II of FIG. 2(a).

[0032] In the example of the city, the X-axis guide (17X) that guides the X-axis table (9X) is configured by a VV rolling guide. For example, the X-axis guide (17X) has two V-shaped grooves (19a) formed on the upper surface of the X-axis bed (19X) that supports the X-axis table (9X), two triangular-shaped protrusions (9a) formed on the lower surface of the X-axis table (9X), and a plurality of rollers (21) (rolling moving bodies) interposed between the grooves (19a) and the protrusions (9a). The grooves (19a) and the protrusions (9a) extend in a straight line shape in the X direction, and the protrusions (9a) are fitted into the grooves (19a) through the rollers (21). By this, the movement of the X-axis table (9X) in the Z direction is restricted. Additionally, the roller (21) rolls against the inner surface of the groove (19a) and the outer surface of the protrusion (9a), allowing relative movement of both in the X direction. As a result, the X-axis table (9X) moves in the X direction with relatively small resistance. Movement of the X-axis table (9X) toward the +Y side is restricted, for example, by its own weight. Movement of the X-axis table (9X) toward the -Y side is restricted, for example, by a reaction force from the X-axis bed (19X).

[0033] In addition, in the example of the city, the X-axis driving source (21X) that drives the X-axis table (9X) is configured by a linear motor. For example, the X-axis driving source (21X) has a magnet row (21a) consisting of a plurality of magnets (21c) arranged in the X direction on the upper surface of the X-axis bed (19X), and a coil (21b) fixed to the lower surface of the X-axis table (9X) and facing the magnet row (21a). Then, by supplying alternating current power to the coil (21b), the magnet row (21a) and the coil (21b) generate a driving force in the X direction. Furthermore, the X-axis table (9X) moves in the X direction.

[0034] Although a configuration for linearly moving the X-axis table (9X) has been described, as can be understood from FIG. 1, the above description may be applied to a configuration for linearly moving the Z-axis table (9Z) by substituting X with Z. That is, the Z-axis guide (17Z) may be a VV rolling guide having a groove (19a) of the Z-axis bed (19Z), a projection (9a) of the Z-axis table (9Z), and a roller (21) interposed between them. The Z-axis driving source (23Z) (Fig. 4) of the Z-axis guide (17Z) may be configured by a linear motor.

[0035] (Method for reducing machining errors caused by straightness)

[0036] Ideally, the X-axis table (9X) moves in a straight line in the X direction. However, in reality, due to various factors, it moves in the X direction while generating a wave (displacement in a direction orthogonal to the X direction). That is, the tool (101) generates a positioning error in a direction orthogonal to the X direction. Even if a guide (17) with high straightness is used, this error occurs with a size of, for example, 10 nm or more and 1 μm or less. Therefore, in a machining machine (1) that requires high machining precision (for example, an error of 1 μm or less or 0.1 μm or less), such as an ultra-precision machining machine, the influence of the above-mentioned positioning error increases.

[0037] Therefore, in this embodiment, the displacement (error) in the Z direction of the X-axis table (9X) is detected in real time. For example, during movement in the X direction of the X-axis table (9X) (in another perspective, for example, during machining), the error in the Z direction of the X-axis table (9X) (in another perspective, tool (101)) is detected at a predetermined period. Then, the Z-axis table (9Z) (in another perspective, work (103)) is moved in the Z direction to eliminate the error in the relative position of the tool (101) and the work (103) caused by the error (part or all thereof). For example, in the illustrated example, if the X-axis table (9X) generates an error in the +Z direction, the Z-axis table (9Z) is moved in the +Z direction by an amount of movement equal to that error. More specifically, the amount of movement corresponding to the above error is added to the original amount of movement in the Z direction of the Z-axis table (9Z) (a amount of movement defined by the NC program). By doing so, the effect of straightness regarding the movement of the X-axis table (9X) on the machining error can be reduced.

[0038] Although the error in the Z direction of the X-axis table (9X) was explained as an example, the above-described method for reducing machining errors is applicable to the error in the Y direction of the X-axis table (9X), and is also applicable to the Z-axis table (9Z) and the saddle (13). However, in the description of this embodiment, the error in the Z direction of the X-axis table (9X) and the error in the X direction of the Z-axis table (9Z) are mainly used as examples.

[0039] Below, an example configuration for realizing the above-mentioned method for reducing processing errors is described.

[0040] (Sensor)

[0041] As illustrated in FIG. 2(a), the processing machine (1) has an X-axis sensor (25X) that detects the position in the X direction and the position in the Z direction of the X-axis table (9X). As can be understood from the description so far, the position in the X direction detected by the X-axis sensor (25X) is used for closed-loop control regarding the position in the X direction of the X-axis table (9X). In addition, the position in the Z direction detected by the X-axis sensor (25X) is used for control regarding the position in the Z direction of the Z-axis table (9Z).

[0042] In FIG. 2(a), a two-dimensional scale (in other words, a two-dimensional encoder) is exemplified as an X-axis sensor (25X). The two-dimensional scale has, for example, a scale portion (27) that extends in the X direction and a detection portion (29) that faces the scale portion (27). In the scale portion (27), a plurality of patterns formed, for example optically or magnetically, are arranged at a constant pitch in the X direction (in addition to the X direction, the Z direction is formed by the configuration of the X-axis sensor (25X)). The detection portion (29) generates a signal based on the relative position with respect to each pattern. Thus, displacement (position) can be detected by the coefficient of the signal (i.e., the coefficient of the pattern) generated in conjunction with the relative movement of the scale portion (27) and the detection portion (29).

[0043] One of the scale section (27) and the detection section (29) (in the illustrated example, the scale section (27)) is fixed to the X-axis table (9X). The other of the scale section (27) and the detection section (29) (in the illustrated example, the detection section (29)) is fixed directly or indirectly to the X-axis bed (19X). Therefore, when the X-axis table (9X) moves, the scale section (27) and the detection section (29) move relative to each other. By this, the displacement (position) of the X-axis table (9X) is detected.

[0044] The specific installation locations of the scale section (27) and the detection section (29) may be appropriately set. Additionally, the X-axis sensor (25X) may be an absolute type capable of determining the position (absolute position) of the detection section (29) relative to the scale section (27) based on the pattern of the scale section (27), or an incremental type that cannot determine such position. As is known, even with an incremental scale, the absolute position can be determined by moving the detection section (29) to a predetermined position (e.g., a moving position) relative to the scale section (27) and performing calibration.

[0045] The error (displacement in the Z direction) regarding the movement of the X-axis table (9X) is, of course, small compared to the movable length of the X-axis table (9X) in the X direction. Therefore, in the X-axis sensor (25X), the length of the range in which the position in the Z direction can be detected may be shorter than the length of the range in which the position in the X direction can be detected. For example, the latter may be 10 times or more or 100 times or more than the former. In addition, the length of the range in which the position in the Z direction can be detected may be, for example, 1 cm or less, 1 mm or less, 10 μm or less, or 1 μm or less. In addition, the range in which the position in the X direction can be detected may be, for example, 1 cm or more, 5 cm or more, 10 cm or more, or 30 cm or more, provided that it is longer than the length of the range in which the position in the Z direction can be detected. Additionally, in the above description, the length of the range in which the position in the X direction can be detected and the length of the range in which the position in the Z direction can be detected may be substituted with the length in the X direction and the length in the Z direction of the X-axis sensor (25X) (more specifically, for example, the scale part (27)).

[0046] In the X-axis sensor (25X), the detection precision of the X-direction position and the detection precision of the Z-direction position may be equal to each other or different from each other. In either case, in the X-axis sensor (25X), the detection precision of the X-direction position and the detection precision of the Z-direction position may each be relatively high, for example, 1 μm or less, 0.1 μm or less, 10 nm or less, or 1 nm or less.

[0047] Although the X-axis sensor (25X) for detecting the position of the X-axis table (9X) has been described, the above description may be applied to the Z-axis sensor (25Z) (Fig. 4) for detecting the Z-axis table (9Z) by substituting X and Z for each other.

[0048] (An example of a 2D scale)

[0049] The configuration of the two-dimensional scale may be various configurations including known configurations. An example thereof is shown below. For convenience, the X-axis sensor (25X) is used as an example in the following description.

[0050] FIG. 3(a) is an enlarged view of a part of the X-axis sensor (25X). Also, for convenience of explanation, FIG. 3(a) and other drawings have different orientations of the scale part (27) and the detection part (29) with respect to the orthogonal coordinate system XYZ, but this is not an essential difference.

[0051] The scale section (27) has, for example, an A-phase scale section (27a) and a B-phase scale section (27b) that extend in the X direction parallel to each other. The A-phase scale section (27a) and the B-phase scale section (27b) have a plurality of patterns (27c) formed optically or magnetically. The plurality of patterns (27c) are straight lines inclined with respect to the X direction. In the A-phase scale section (27a) and the B-phase scale section (27b), the magnitude of the inclination angles of the plurality of patterns (27c) are equal to each other, and the inclination directions are opposite to each other. The detection section (29) has, for example, an A-phase detector (29a) that detects the pattern (27c) of the A-phase scale section (27a) and a B-phase detector (29b) that detects the pattern (27c) of the B-phase scale section (27b).

[0052] Figure 3(b) is a schematic diagram showing an enlarged view of a portion of the A-phase scale section (27a).

[0053] A displacement dA in a direction orthogonal to the pattern (27c) of the A-phase scale unit (27a) is detected by the coefficient of the pattern (27c) detected by the A-phase detector unit (29a). Let θ be the angle of inclination with respect to the X-axis in the direction orthogonal to the pattern (27c), let x1 be the X-direction component of the displacement dA, and let z1 be the Z-direction component of the displacement dA. At this time, the following equation holds true.

[0054]

[0055] Meanwhile, by the coefficient of the pattern (27c) detected by the B-phase detector (29b), a displacement dB (Fig. 3(a)) in a direction orthogonal to the pattern (27c) of the B-phase scale section (27b) is detected. At this time, since the inclination angle of the pattern (27c) in the A-phase scale section (27a) and the B-phase scale section (27b) is the same, the inclination angle (absolute value) with respect to the X-axis in a direction orthogonal to the pattern (27c) in the B-phase scale section (27b) is also θ. Furthermore, assuming that the detector (29) does not rotate around the Y-axis, the X-direction component and Z-direction component of the displacement dB are identical to the X-direction component and Z-direction component (x1 and z1) of the displacement dA. Therefore, the following equation holds true.

[0056]

[0057] From the above-mentioned equations (1) and (2), the following equation is derived.

[0058]

[0059] Based on this principle, the two-dimensional scale of the city example can detect displacement in two directions.

[0060] Although the X-axis sensor (25X) has been described, the above description of the two-dimensional scale may be applied to the Z-axis sensor (25Z) (Fig. 4) by substituting X and Z. Furthermore, the configuration of the two-dimensional scale described with reference to Fig. 3(a) and Fig. 3(b) is merely an example of the configuration of the X-axis sensor (25X) or the Z-axis sensor (25Z). However, for convenience, the following description may be based on the configuration of the above-described two-dimensional scale.

[0061] (Configuration of the control system in a processing machine)

[0062] FIG. 4 is a block diagram illustrating the configuration of a control system in a processing machine (1). More specifically, among the configurations of the control system in the processing machine (1), the configuration regarding the control of the position of the X-axis table (9X) and the position of the Z-axis table (9Z) is extracted.

[0063] The X-axis sensor (25X) inputs, for example, a detection signal SX to the X-axis output unit (31X). The detection signal SX is, for example, a pulse signal in which one pattern (27c) passing directly below the detection unit (29) corresponds to one waveform (pulse wave). The pulse wave is, for example, a sine wave, a square wave, a triangular wave, or a sawtooth wave. The detection signal SX includes a pulse signal generated by the A-phase detection unit (29a) and a pulse signal generated by the B-phase detection unit (29b).

[0064] The X-axis calculation unit (31X) counts the detected pattern (27c) based on the input detection signal SX, and then performs operations such as equation (3) and equation (4). By doing so, the position in the X direction of the X-axis table (9X) and the position in the Z direction of the X-axis table (9X) are determined. Then, the X-axis calculation unit (31X) outputs a signal SXx containing information on the former position and a signal SXz containing information on the latter position.

[0065] A signal SXx containing information on the position of the X-axis table (9X) in the X direction is input to the X-axis control unit (33X) of the control device (5) via the integrated control unit (35) of the control device (5). The X-axis control unit (33X) drives the X-axis driving source (23X) based on the information contained in the signal SXx to provide feedback control of the position of the X-axis table (9X).

[0066] In this manner, control similar to general feedback control regarding the position in the X direction of the X-axis table (9X) is performed. This control similar to general feedback control is also performed in the same way for the Z-axis table (9Z). The above description may be applied to control regarding the position in the Z direction of the Z-axis table (9Z) by substituting X and Z (and x and z) with one another.

[0067] A signal SXz containing information on the position in the Z direction of the X-axis table (9X) generated in the X-axis calculation unit (31X) is input to the Z-axis control unit (33Z) together with a signal SZz containing information on the position in the Z direction of the Z-axis table (9Z) generated in the Z-axis calculation unit (31Z). Then, the Z-axis control unit (33Z) performs control that incorporates the information contained in the signal SXz in the feedback control based on the information contained in the signal SZz. That is, as previously explained, in order to eliminate the effect of the position error in the Z direction of the X-axis table (9X) on the machining precision, the amount of movement of the Z-axis table (9Z) is increased or decreased according to the magnitude of the error.

[0068] Similarly to the above, the effect of positional error in the X-direction of the Z-axis table (9Z) on machining precision may be reduced. Specifically, a signal SZx containing information on the position in the X-direction of the Z-axis table (9Z) generated by the Z-axis calculation unit (31Z) is input to the X-axis control unit (33X) together with a signal SXx containing information on the position in the X-direction of the X-axis table (9X) generated by the X-axis calculation unit (31X). Then, the X-axis control unit (33X) performs control that incorporates the information contained in the signal SZx in the feedback control based on the information contained in the signal SXx.

[0069] In the X-axis control unit (33X), the acquisition of a position based on signals SXx and SZx, and the control of the X-axis drive source (23X) based on the acquired signals are performed repeatedly at a predetermined control cycle. Likewise, in the Z-axis control unit (33Z), the acquisition of a position based on signals SZz and SXz, and the control of the Z-axis drive source (23Z) based on the acquired signals are performed repeatedly at a predetermined control cycle. The control cycle in the X-axis control unit (33X) and the control cycle in the Z-axis control unit (33Z) are, for example, the same (it is not impossible to make them different), and are also synchronized by the integrated control unit (35).

[0070] The integrated control unit (35) acquires a signal SXx from the X-axis calculation unit (31X) at a predetermined sampling period, for example. Likewise, the integrated control unit (35) acquires a signal SZz from the Z-axis calculation unit (31Z) at a predetermined sampling period, for example. The integrated control unit (35) acquires a signal SXz from the X-axis calculation unit (31X) at a predetermined sampling period, for example. The integrated control unit (35) acquires a signal SZx from the Z-axis calculation unit (31Z) at a predetermined sampling period, for example. The signals SXx, SZz, SXz, and SZx contain information on the amount of movement or position for each sampling period.

[0071] The sampling period of the signal SXx, which contains information on the position in the X direction of the X-axis table (9X), and the signal SZz, which contains information on the position in the Z direction of the Z-axis table (9Z), is, for example, equal to or shorter than the control period in the X-axis control unit (33X) and the Z-axis control unit (33Z). Accordingly, the most recent detected value of the position used for feedback control is updated every control period.

[0072] The sampling period of signal SXz, which contains information on the position in the Z direction of the X-axis table (9X), and SZx, which contains information on the position in the X direction of the Z-axis table (9Z), may be shorter than, equal to, or longer than the control period described above. This is because, as can be understood from the description of FIG. 6(a) and FIG. 6(b) described later, the most recent detected value of the error regarding straightness does not necessarily need to be updated every control period. However, for convenience, in the following description, there are cases where the sampling period of signals SXz and SZx is less than or equal to the control period.

[0073] The sampling periods of signals SXx and SZz are, for example, the same (or different). The sampling period of signal SXz may be the same or different with respect to the sampling period of signal SXx or SZz. Likewise, the sampling period of signal SZx may be the same or different with respect to the sampling period of signal SZz or SXx. However, for convenience, in the following description, there are cases where the four signals SXx, SXz, SZz, and SZx are described under the premise that their sampling periods are the same.

[0074] Additionally, the integrated control unit (35), the X-axis control unit (33X), and the Z-axis control unit (33Z) are functional or conceptual distinctions. Therefore, from a hardware perspective, these control units may be configured as a single unit, or they may be configured in a distributed manner, such as in the illustration or in a manner different from the illustration. Furthermore, the X-axis control unit (33X) and the Z-axis control unit (33Z) may be conceptually conceived to include a driver.

[0075] Generally, the term "sensor" may refer only to a converter that converts a physical quantity into a signal, or it may refer to a device including a converter and a functional unit connected thereto. Examples of functional units include a driver that supplies power to the converter and a computational unit that processes signals from the converter. In this embodiment as well, the combination of the X-axis sensor (25X) and the X-axis calculation unit (31X) may be conceived as the X-axis sensor (37X). Likewise, the combination of the Z-axis sensor (25Z) and the Z-axis calculation unit (31Z) may be conceived as the Z-axis sensor (37Z). From a hardware perspective, the X-axis sensor (25X) and the X-axis calculation unit (31X) may or may not be adjacent. The same applies to the Z-axis sensor (25Z) and the Z-axis calculation unit (31Z).

[0076] (An example of the configuration of the control system for each axis)

[0077] FIG. 5 is a block diagram illustrating an example of the configuration of a control system for each axis. Here, the configuration regarding the control of the position of the Z-axis table (9Z) is given as an example.

[0078] The NC program (107) includes information on commands regarding the driving of each axis. For example, the NC program (107) includes information on commands regarding the movement of the X-axis table (9X), the Z-axis table (9Z), and the saddle (13). The information on commands regarding movement includes, for example, information on multiple positions on the movement trajectory and the speed between the multiple positions.

[0079] The interpretation unit (39) of the control device (5) reads and interprets the NC program (107). By doing so, information regarding a plurality of positions that pass sequentially and the speed between the plurality of positions is obtained, for example, for each of the table (9) and the saddle (13).

[0080] The interpolation unit (41) of the control device (5) calculates the target position, etc. for each predetermined control cycle based on the information acquired by the analysis unit (39). For example, based on two positions that are passed sequentially and the speed between those two positions, multiple target positions to be reached sequentially for each control cycle are set between the two positions. The interpolation unit (41) calculates and outputs the target position, etc. for each axis and each control cycle. In FIG. 5, the target position for each control cycle of the Z-axis table (9Z) is output to the addition unit (43) of the control device (5).

[0081] In the addition unit (43), the deviation between the target position for each control cycle described above and the position (signal SZz) in the Z-direction of the Z-axis table (9Z) detected by the Z-axis sensor (25Z) is calculated. Additionally, to eliminate the effect of the error in the Z-direction of the X-axis table (9X) on the processing error, the error in the Z-direction of the X-axis table (9X) detected by the X-axis sensor (25X) is added to or subtracted from this deviation. In the example of FIG. 1, the error is added to the deviation by moving the Z-axis table (9Z) to the same side as the side where the error of the X-axis table (9X) occurred (e.g., the +Z side).

[0082] The subsequent steps are similar to the configuration of a general control system. For example, the deviation (target movement amount per control cycle) calculated in the adder (43) is input to the position control unit (45) of the control device (5). The position control unit (45) calculates the target speed per control cycle by multiplying the input deviation by a predetermined gain and outputs it to the adder (47) of the control device (5). The adder (47) calculates the deviation between the input target speed per control cycle and the detection speed obtained by differentiating the detection position of the Z-axis sensor (25Z) by the derivative unit (55) of the control device (5), and outputs it to the speed control unit (49) of the control device (5). The speed control unit (49) calculates the target current (target torque) per control cycle by multiplying the input deviation by a predetermined gain and outputs it to the adder (51) of the control device (5). The adder (51) calculates the deviation between the target current for each input control cycle and the detected current from the current detection unit (not shown) and outputs it to the current control unit (53) of the control device (5). The current control unit (53) supplies power according to the input deviation to the Z-axis driving source (23Z).

[0083] The above is merely an example and may be appropriately modified. For instance, although not specifically illustrated, feedforward control may be added. An acceleration loop may be inserted instead of a current loop. In cases where the driving source is a rotary electric motor and a rotation sensor (e.g., an encoder or resolver) for detecting rotation is provided, speed control may be performed based on the detected value of the rotation sensor.

[0084] In the example of the city, the error detected by the X-axis sensor (25X) (detection error based on signal SXz) is input to the adder (43). Instead of inputting to the adder (43), it may be input to the interpolation unit (41) and used to calculate the target position for each control cycle. In any case, the deviation input to the position control unit (45) is increased or decreased by comparing it to the case where the target position based only on the NC program (107) and the detection position based only on the signal SZz are calculated.

[0085] The configuration shown in FIG. 5 may be appropriately correlated with the configuration of FIG. 4. For example, the analysis unit (39), the interpolation unit (41), and the addition unit (43) may be identified as part of the integrated control unit (35). The path from the position control unit (45) to the current control unit (53) may be identified as part of the Z-axis control unit (33Z).

[0086] Although the control regarding the movement of the Z-axis table (9Z) has been described, the above description may be applied to the control regarding the movement of the X-axis table (9X) by substituting X and Z.

[0087] (Detection value used for control)

[0088] The most recent detected value of the error regarding straightness used for control (the detected value of the error input to the adder (43)) may be the same as the detected value (unprocessed detected value) that the signal SXz or SZx maintains as information, or it may be a value that has undergone some processing on the said unprocessed detected value. An example is given below. In the following description, a configuration in which the effect of the error regarding straightness of the X-axis table (9X) on machining precision is reduced by the movement of the Z-axis table (9Z) is given as an example, but the same applies to a configuration in which the effect of the error regarding straightness of the Z-axis table (9Z) on machining precision is reduced by the movement of the X-axis table (9X).

[0089] FIG. 6(a) is a schematic diagram illustrating the change in detection position over time. In these figures, the horizontal axis t represents elapsed time. In the upper graph of FIG. 6(a), the vertical axis represents the position in the Z direction of the Z-axis table (9Z), and in another view, represents the unprocessed detection value maintained in signal SZz. In the lower graph of FIG. 6(a), the vertical axis represents the position (error) in the Z direction of the X-axis table (9X), and in another view, represents the unprocessed detection value maintained in signal SXz.

[0090] The black dots plotted in the drawing represent unprocessed detection values ​​acquired by the integrated control unit (35) from the Z-axis calculation unit (31Z) or the X-axis calculation unit (31X) at each sampling period Ts. In the example of FIG. 6 (a), the sampling period Ts is the same as the control period Tc in which feedback control is repeated by the Z-axis control unit (33Z). In other words, the integrated control unit (35) acquires signals SZz and SXz from the Z-axis calculation unit (31Z) and the X-axis calculation unit (31X) at each control period Tc.

[0091] Furthermore, the unprocessed detection value referred to here is the detection value for each sampling period Ts. Therefore, even if a value has been corrected for the detection value maintained by, for example, the signal SZz or SXz (unprocessed detection value in the narrow sense), as long as the format for each sampling period Ts is maintained, it is acceptable to identify it as an unprocessed detection value.

[0092] In the control loop described with reference to FIGS. 4 and 5, as the detection value of the position in the Z direction of the Z-axis table (9Z), for example, the most recent unprocessed detection value among the multiple unprocessed detection values ​​obtained as a result of control for each control cycle Tc up to the previous time may be used. For example, as shown in the upper graph of FIG. 6 (a), if the current time point is time point t1, the detection value P1 immediately prior to that is input to the Z-axis control unit (33Z) (add unit (43)). By doing this, for example, the delay in control regarding the actual position in the Z direction of the Z-axis table (9Z) can be reduced, and position determination can be performed with high precision.

[0093] Meanwhile, as the detection value of the position (error) in the Z direction of the X-axis table (9X), for example, the average value (moving average) of a predetermined number of unprocessed detection values ​​obtained as a result of control for each control cycle Tc up to the previous time may be used. For example, as shown in the lower graph of FIG. 6 (a), if the current time point is time point t1, the average value of a predetermined number (three in the example shown) of detection values ​​P2 immediately prior to that time point is input to the Z-axis control unit (33Z) (add unit (43)). By doing this, the probability of moving the Z-axis table (9Z) according to, for example, specific unprocessed detection values ​​can be reduced. Furthermore, the probability of increasing the processing error can be reduced. However, just like the position in the Z direction of the Z-axis table (9Z), it is acceptable to use only the most recent unprocessed detection value of the error.

[0094] In the case where the average value of a predetermined number of unprocessed detection values ​​is used as described above, the predetermined number may be appropriately set. For example, the predetermined number may be 2, 5 or more, or 10 or more.

[0095] The predetermined number of unprocessed detection values ​​used for calculating the average value may include, for example, the most recent (latest) unprocessed detection values. Furthermore, the term "recent" as used herein may be interpreted as, for example, within the range that can be embedded in the control loop. For example, in a case where the acquisition of unprocessed detection values, the calculation of the average value, and the repetition of the control loop are executed in parallel by multitasking, even if a new unprocessed detection value is detected during the period until the average value is calculated and input into the control loop, the unprocessed detection value in question is not the most recent detection value; rather, the most recent unprocessed detection value is the latest among the unprocessed detection values ​​included in the average value. The same may apply to "recent" in other descriptions, such as detection values ​​related to normal feedback control (detection values ​​maintained by signals SXx and SZz).

[0096] The predetermined number of unprocessed detection values ​​used to calculate the average value are, for example, unprocessed detection values ​​that are continuous at intervals of a sampling period Ts. That is, the predetermined number of unprocessed detection values ​​used to calculate the average value is not selectively chosen. However, selective selection may be performed. For example, specific detection values ​​may be removed by filtering, and the average value may be calculated based on the remaining unprocessed detection values. In this case, the number of remaining unprocessed detection values ​​may be adjusted to a predetermined number, or such adjustment may not be performed.

[0097] Unless otherwise specified, the average value includes not only the average of the commercial units but also other averages such as the weighted average. For example, a weighted average may be calculated such that the weight increases as the unprocessed detection value is closer to the current point in time, and this weighted average may be used as the detection value input to the adder (43).

[0098] Figure 6(b) is a drawing similar to Figure 6(a), illustrating an example different from the example in Figure 6(a).

[0099] In the example of Fig. 6(b), the sampling period Ts is less than half of the control period Tc during which feedback control is repeated. Therefore, within the control period Tc, multiple (six in the illustrated example) unprocessed detection values ​​are obtained for positions in the Z direction.

[0100] As for the detection value of the position in the Z direction of the Z-axis table (9Z), for example, the most recent unprocessed detection value among a plurality of unprocessed detection values ​​within the control cycle Tc may be used. For example, as shown in the upper graph of FIG. 6 (b), if the current time point is time point t1, the detection value P1 immediately prior to that may be input to the Z-axis control unit (33Z) (add unit (43)). By doing this, for example, as in the example of FIG. 6 (a), the delay in control regarding the actual position in the Z direction of the Z-axis table (9Z) can be reduced, and position determination can be performed with high precision.

[0101] Meanwhile, as the detection value of the position (error) in the Z direction of the X-axis table (9X), for example, the average value of multiple unprocessed detection values ​​within the control cycle Tc immediately preceding the current point in time is used. For example, as shown in the lower graph of FIG. 6 (b), if the current point in time is time t1, the average value of multiple detection values ​​P2 immediately preceding it is input to the Z-axis control unit (33Z) (add unit (43)). By doing this, the probability of moving the Z-axis table (9Z) according to specific unprocessed detection values, for example, as in the example of FIG. 6 (a), can be reduced. Of course, just like the position in the Z direction of the Z-axis table (9Z), it is acceptable to use only the most recent unprocessed detection value of the error.

[0102] In the example of FIG. 6(b), the average value is calculated based on only some (4 in the illustrated example) of the multiple (6 in the illustrated example) unprocessed detection values ​​included in the recent control cycle Tc. However, the average value may be calculated based on all unprocessed detection values ​​included in the recent control cycle Tc. In addition, as can be understood from the example of FIG. 6(a), the average value may be calculated based on unprocessed detection values ​​in the past control cycle Tc in addition to the recent control cycle Tc.

[0103] (Sampling period)

[0104] As mentioned in the description of FIG. 4, the sampling period for acquiring the position (error) in the Z direction of the X-axis table (9X) and the position (error) in the X direction of the Z-axis table (9Z) may be appropriately set. This sampling period may be set in terms of compatibility with the control period, or it may be set based on the size of the target wave, etc. Below, an example is shown of a case where the sampling period is set based on the size of the wave, processing conditions, and the number of unprocessed detection values ​​when calculating the average value described above. In the following description, the sampling period of the error of the X-axis table (9X) is given as an example, but the same applies to the sampling period of the error of the Z-axis table (9Z).

[0105] For example, it is assumed that the length (half-wavelength) of one peak of the wave (error in the Z direction) of the X-axis table (9X) in the X direction is 0.03 mm or more and 3 mm or less. Also, it is assumed that the speed of the X-axis table (9X) in the X direction is 0.12 mm / min or more and 12 mm / min or less. At this time, the minimum time to pass through one peak of the wave is as follows.

[0106] 0.03 / 12=0.0025min=0.15sec

[0107] It is assumed that, in order to reliably detect the height of one peak of a wave (error in the Z direction), the average of 10 unprocessed detection values ​​(10-point average) is required for one peak. Furthermore, the sampling period is set so that 10 unprocessed detection values ​​are obtained per peak, even in the minimum time to pass through the aforementioned peak. In this case, the sampling period is as follows.

[0108] 0.15 / 10 = 0.015 sec

[0109] In this manner, the sampling period may be set. In addition, from another perspective, the processing machine (1) may be configured to enable real-time processing with a sampling period less than or equal to the time length set as above.

[0110] Here, specific examples of the sampling period and the control period are shown. The sampling period and / or the control period may be, for example, 0.02 sec or less, 0.01 sec or less, or 0.005 sec or less.

[0111] (Processing System)

[0112] Returning to FIG. 1, the processing machine (1) may be connected to a diagnostic device (93) using technology such as Open CNC (computerized numerical control). Alternatively, a processing system (91) may be constructed by the processing machine (1) and the diagnostic device (93).

[0113] The diagnostic device (93) may be configured to include, for example, a computer (not shown). The computer is configured to include, although not specifically shown, a CPU, ROM, RAM and external storage, and various functional parts are established by the CPU executing a program stored in the ROM and / or external storage.

[0114] The diagnostic device (93) (functional unit) obtains information regarding processing, for example, from the control device (5) of the processing machine (1). The information may include, for example, information on the position (error) in the Z direction of the X-axis table (9X) detected by the X-axis sensor (25X), and / or information on the position (error) in the X direction of the Z-axis table (9Z) detected by the Z-axis sensor (25Z). The error information may be the unprocessed information described above, or information on which some processing (for example, the processing for control described above) has been performed. Then, the diagnostic device (93) performs processing based on the acquired information.

[0115] Processing based on the above-mentioned acquired information may include, for example, the display of an image based on the acquired information. For example, the diagnostic device (93) has a display device (93a). The display device (93a) is capable of displaying any image, for example, and is composed of a liquid crystal display or an organic EL display. And, the diagnostic device (93) changes the image displayed on the display device (93a) according to the acquired information.

[0116] Examples of images displayed by the diagnostic device (93) include, for instance, a graph in which the X-direction position of the X-axis table (9X) is the horizontal axis and the Z-direction position (error) of the X-axis table (9X) is the vertical axis, thereby showing the error itself. A similar image may be displayed for the Z-axis table (9Z). Additionally, the image may be a predetermined warning image displayed when the acquired error (straightness) is large.

[0117] In addition to the above, the processing performed by the diagnostic device (93) may include, for example, transmitting a control command to the control device (5) according to the error (straightness). For example, the diagnostic device (93) may transmit a signal to the control device (5) to stop the processing cycle when the error is large.

[0118] The diagnostic device (93) may be connected by a cable adjacent to the control device (5), or it may be spaced apart from the control device (5) (processor (1)) and wireless communication and / or wired communication may be performed between it and the control device (5). In the latter case, an internet and / or telephone network may be interposed between the control device (5) and the diagnostic device (93). Furthermore, when the diagnostic device (93) is adjacent to the control device (5), the diagnostic device (93) may be considered as part of the processor (1). Additionally, the diagnostic device (93) may be included in the control device (5).

[0119] As described above, in the present embodiment, the processing machine (1) has a first movable part (X-axis table (9X)), a first guide (X-axis guide (17X)), a first driving source (X-axis driving source (23X)), a first sensor (X-axis sensor (25X)), a second movable part (Z-axis table (9Z)), a second guide (Z-axis guide (17Z)), a second driving source (Z-axis driving source (23Z)), a second sensor (Z-axis sensor (25Z)), and a control device (5). The X-axis table (9X) supports a workpiece (103) or a tool (101) (in the present embodiment, a tool (101)). The X-axis guide (17X) guides the X-axis table (9X) in a first direction (X direction). The X-axis driving source (23X) drives the X-axis table (9X) in the X direction. The X-axis sensor (25X) outputs a signal SX corresponding to a first displacement, which is a displacement in the X direction of the X-axis table (9X), and a first error, which is a displacement in a second direction (Z direction) orthogonal to the X direction of the X-axis table (9X). The Z-axis table (9Z) supports a workpiece (103) or a tool (101) (in this embodiment, the workpiece (103)). The Z-axis guide (17Z) guides the Z-axis table (9Z) in the Z direction. The Z-axis driving source (23Z) drives the Z-axis table (9Z) in the Z direction. The Z-axis sensor (25Z) outputs a signal SZ corresponding to a second displacement, which is a displacement in the Z direction of the Z-axis table (9Z). The control device (5) controls the X-axis drive source (23X) and the Z-axis drive source (23Z) according to a program (NC program (107)) that includes information on commands regarding the movement of the X-axis table (9X) and the Z-axis table (9Z). The control device (5) has an interpolation unit (41), a first control unit (X-axis control unit (33X)), and a second control unit (Z-axis control unit (33Z)). The interpolation unit (41) calculates a first target position for every predetermined control period Tc in the X-direction of the X-axis table (9X) and a second target position for every control period Tc in the Z-direction of the Z-axis table (9Z), based on the NC program (107).The X-axis control unit (33X) acquires a recent detection value of the first displacement based on a signal SX from the X-axis sensor (25X) at every control cycle Tc, calculates a first deviation based on the difference between the acquired detection value and the first target position, and controls the X-axis drive source (23X) to reduce the first deviation. The Z-axis control unit (33Z) acquires a recent detection value of the second displacement based on a signal SZ from the Z-axis sensor (25Z) at every control cycle Tc, calculates a second deviation based on the difference between the acquired detection value and the second target position, and controls the Z-axis drive source (23Z) to reduce the second deviation. Additionally, the Z-axis control unit (33Z) acquires a recent detection value of the first error based on a signal SX from the X-axis sensor (25X) at each control cycle Tc, and increases or decreases the second deviation based on the detection value of the first error so that at least a portion of the error in the relative position of the work (103) and the tool (101) in the Z-direction caused by the first error is eliminated by moving the Z-axis table (9Z) in the Z-direction.

[0120] Therefore, for example, machining errors caused by straightness can be reduced. In addition, since errors regarding straightness are acquired in real time, for example, it is possible to handle straightness that lacks reproducibility or straightness where reproducibility is limited to a short period of time. As a result, high machining precision can be realized. For example, in a demonstration experiment conducted by the inventor, regarding the relative movement of the tool (101) and the workpiece (103), a wave with a wave height of 25 nm or more could be reduced to a wave with a wave height of 5 nm or less. Furthermore, the movement to reduce the influence of straightness on machining errors is realized by the movement of the Z-axis table (9Z) to move the workpiece (103) in the Z direction according to the NC program (107). Therefore, there is no need to provide a table that is unrelated to the NC program (107) (a dedicated table for reducing the influence of straightness). As a result, the configuration of the machining machine (1) can be simplified. In another perspective, the effect of straightness on machining error can be reduced by applying the technology according to the present disclosure to an existing machining machine (1). In addition, the machining machine (1) is innovative in that it utilizes the detection values ​​for two axes by the X-axis sensor (25X) and the Z-axis sensor (25Z) to drive the Z-axis table (9Z) for one axis. In another perspective, the detection values ​​of the X-axis sensor (25X) provided for the X-axis table (9X) for one axis are utilized to drive the X-axis table (9X) and the Z-axis table (9Z) for two axes.

[0121] The second sensor (Z-axis sensor (25Z)) may output a signal corresponding to the second error, which is the displacement in the first direction (X-direction) of the second movable part (Z-axis table (9Z)). The first control unit (X-axis control unit (33X)) may acquire the most recent detected value of the second error based on the signal SZ from the Z-axis sensor (25Z) at each control cycle Tc, and increase or decrease the first deviation based on the detected value of the second error so that at least a portion of the error in the relative position of the work (103) and the tool (101) in the X-direction caused by the second error is eliminated by the movement of the first movable part (X-axis table (9X)) in the X-direction.

[0122] In this case, for example, the above-mentioned effect can be obtained not only for the straightness regarding the movement of the X-axis table (9X), but also for the straightness regarding the movement of the Z-axis table (9Z). As a result, the machining precision is improved for any direction in the XZ plane.

[0123] The first movable part (X-axis table (9X)) may support one of the work (103) and the tool (101) (in this embodiment, the tool (101)). The second movable part (Z-axis table (9Z)) may support the other of the work (103) and the tool (101) (in this embodiment, the work (103)).

[0124] In this case, compared to an embodiment in which, for example, one of the X-axis table (9X) and the Z-axis table (9Z) supports the other, and both tables support one of the work (103) and the tool (101) (such an embodiment may also be included in the technology of the present disclosure), it is easy to reduce the effect of straightness on machining precision. For example, in an embodiment in which the X-axis table (9X) also serves as the Z-axis bed (19Z) to support the Z-axis table (9Z) (such an embodiment may also be included in the technology of the present disclosure), if the X-axis table (9X) is inclined with respect to the X direction (rotated around the Y-axis) while causing an error in the Z direction, the direction in which the Z-axis table (9Z) is guided by the Z-axis bed (19Z) is inclined with respect to the Z direction. As a result, even if the Z-axis table (9Z) is moved with a displacement equal in magnitude to the error in the Z direction of the X-axis table (9X), the error cannot be completely eliminated because the Z direction in which the error is detected and the direction in which the Z-axis table (9Z) moves are inclined toward each other. However, in the configuration where the X-axis table (9X) holds and supports the tool (101) and the Z-axis table (9Z) holds and supports the work (103), the two tables can move independently of each other, so the above-mentioned problem does not occur.

[0125] The first sensor (X-axis sensor (25X)) may be a two-dimensional scale.

[0126] In this case, the configuration is simplified compared to an embodiment in which, for example, a sensor detecting displacement in the X direction of the X-axis sensor (25X) and a sensor detecting displacement (error) in the Z direction of the X-axis sensor (25X) are installed separately and the entire assembly is used as the X-axis sensor (25X) (such embodiment may also be included in the technology related to the present disclosure).

[0127] The two-dimensional scale (X-axis sensor (25X)) may have a range length capable of detecting a position in the first direction (X-direction) that is 10 times or more the range length capable of detecting a position in the second direction (Z-direction).

[0128] In this case, for example, the X-axis sensor (25X) can be miniaturized while detecting both the movement of the X-axis table (9X) in the X-direction according to the NC program (107) and the error regarding minute straightness compared to the distance of this movement without excess or deficiency. By miniaturizing the X-axis sensor (25X), the degree of freedom of the installation position of the X-axis sensor (25X) within the processing machine (1), for example, is improved. As a result, it becomes easier to improve detection precision by arranging the X-axis sensor (25X) by considering, for example, the Abbe principle.

[0129] The control device (5) may have an integrated control unit (35). The integrated control unit (35) may acquire an unprocessed detection value of a first error (position in the Z direction) based on a signal SX from a first sensor (X-axis sensor (25X)) at a predetermined sampling period Ts, and may calculate an average value of a plurality of unprocessed detection values ​​of the first error. The second control unit (Z-axis control unit (33Z)) may use the average value as the detection value of the first error (recent detection value).

[0130] In this case, for example, as previously explained, the likelihood of moving the Z-axis table (9Z) for a specific unprocessed detection value among a plurality of unprocessed detection values ​​regarding the position (error) in the Z direction of the X-axis table (9X) is reduced. Furthermore, the likelihood of lowering the machining precision is reduced.

[0131] The first guide (X-axis guide (17X)) may be a VV rolling guide.

[0132] In this case, for example, it is easy to reduce the straightness of the X-axis guide (17X). Additionally, since the frictional resistance when moving the X-axis table (9X) in the X direction is small, positioning in the X direction can be performed with high precision. With such a configuration, high machining precision can be realized. As a result, the usefulness of the effect of reducing the influence of the straightness of the X-axis table (9X) on machining precision by moving the Z-axis table (9Z) is increased.

[0133] The first driving source (X-axis driving source (23X)) and the second driving source (Z-axis driving source (23Z)) may each be a linear motor.

[0134] In this case, compared to an embodiment in which, for example, the rotation of a rotary drive source is converted into translational motion and transmitted to the table (9) (such embodiment may also be included in the technology related to the present disclosure), mechanical errors caused by backlash, etc., are reduced, and high machining precision can be realized. As a result, the usefulness of the effect of reducing the influence of the straightness of the X-axis table (9X) on machining precision by moving the Z-axis table (9Z) is increased. Furthermore, it is easier to move the Z-axis table (9Z) by an amount equivalent to the magnitude of the error regarding the minute straightness of the X-axis table (9X), thereby enhancing the effect of reducing the influence of the straightness of the X-axis table (9X) on machining precision.

[0135] The processing system (91) according to the present disclosure may have a processing machine (1) as described above and a diagnostic device (93). The diagnostic device (93) may acquire information on the detection value of the first error (position in the Z direction of the X-axis table (9X)) from the processing machine (1) and display an image according to the acquired information.

[0136] In this case, for example, the condition of the guide surface of the X-axis guide (17X) can be managed by using information for controlling the processing machine (1). In other words, there is no need to add a special measuring system to measure the condition of the guide surface of the X-axis guide (17X). In addition, the condition of the guide surface can be managed in real time during processing. As a result, the probability of continuing processing (manufacturing of defective products) in a state where the guide surface has aged deterioration or broken down is reduced at a low cost.

[0137] In addition, the method for manufacturing a workpiece according to the present disclosure has a step of processing the workpiece (103) into a workpiece by bringing the workpiece (103) and the tool (101) into contact using the processing machine (1) as described above.

[0138] In this case, for example, a workpiece with high shape precision can be obtained due to the effect of reducing the influence of the aforementioned straightness on machining precision.

[0139] (Variation Example)

[0140] Variations of the embodiments are described below. In the following description, basically only the parts that differ from the embodiments are described. Matters not specifically mentioned may be the same as the embodiments or inferred from the embodiments. In the following description, for convenience, the reference numerals of the embodiments may be assigned to configurations corresponding to the configurations of the embodiments even if they differ from the embodiments.

[0141] (Example of a variation regarding the target axis)

[0142] FIG. 7 is a block diagram of a control system of a processing machine (201) regarding a modified example. This diagram corresponds to a more simplified diagram of FIG. 4.

[0143] As described in the description of the embodiments, the method for reducing the influence of straightness on machining error may be applied to the straightness of any direction of any axis among the multiple axes related to parallel translation. FIG. 7 illustrates an embodiment in which the method for reducing machining error is applied to the straightness of all directions of all axes. Specifically, it is as follows.

[0144] An X-axis sensor (37X) that detects the position of an X-axis table (9X) (including an X-axis sensor (25X) and an X-axis calculation unit (31X)) outputs a signal SXy that includes information on the detected position value in the Y direction of the X-axis table (9X), in addition to the signals SXx and SXz described so far. That is, the X-axis sensor (37X) is capable of detecting the position of all three axes.

[0145] The X-axis sensor (37X) that detects the three-axis position as described above may be appropriately implemented. For example, in addition to the X-axis sensor (25X) already described, a two-dimensional scale having the same configuration as the X-axis sensor (25X) may be provided to detect the position in the X direction and the position in the Y direction. Also, for example, in addition to the X-axis sensor (25X), a sensor that detects only the position in the Y direction may be provided. Furthermore, instead of the X-axis sensor (25X) (two-dimensional scale), a three-dimensional scale may be provided. The three-dimensional scale may, for example, have the same or similar configuration as the two-dimensional scale, determine the distance between the scale portion (27) and the detection portion (29) based on the intensity of the signal SX generated according to the pattern (27c).

[0146] In addition, in addition to controlling the position of the Z-axis table (9Z) in the Z-direction based on the detection position (detection error) of the X-axis table (9X) maintained in signal SXz, control of the position of the saddle (13) in the Y-direction based on the detection position (detection error) of the X-axis table (9X) maintained in signal SXy may be performed in the same manner as said control. Specifically, information of signal SXy is input to the Y-axis control unit (33Y). The Y-axis control unit (33Y) controls the Y-axis driving source (23Y) that drives the saddle (13) based on the detection error in the Y-direction so that at least a portion of the error in the relative position of the work (103) and the tool (101) caused by the error in the Y-direction is eliminated by the movement of the saddle (13) in the Y-direction.

[0147] Additionally, when removing the influence of the error in the Z direction of the X-axis table (9X), the error in the Z direction is added to the deviation of the position control loop of the Z-axis table (9Z). Meanwhile, the saddle (13) is supported on the X-axis table (9X), unlike the Z-axis table (9Z). Therefore, when removing the influence of the error in the Y direction of the X-axis table (9X), the error in the Y direction is subtracted from the deviation of the position control loop of the saddle (13), contrary to the above. However, this description is conceptual when the orthogonal coordinate system XYZ shown in FIG. 1 is applied directly to the control. Therefore, for example, in the actual calculation within the control unit, the addition and subtraction may be the opposite of the above description.

[0148] In the same way as the control regarding the straightness of the X-axis table (9X) described above, control regarding the straightness of the Z-axis table (9Z) and control regarding the straightness of the saddle (13) may be performed.

[0149] Specifically, the Y-axis sensor (37Y) outputs a signal SYx containing information on the detection position (detection error) in the X direction of the saddle (13), a signal SYy containing information on the detection position in the Y direction of the saddle (13), and a signal SYz containing information on the detection position (detection error) in the Z direction of the saddle (13). The signal SYy is used for position control in the Y direction of the saddle (13) according to the NC program (107). The signal SYx is used for position control in the X direction of the X-axis table (9X) to reduce the effect of the error in the X direction of the saddle (13) on the machining precision. The signal SYz is used for position control in the Z direction of the Z-axis table (9Z) to reduce the effect of the error in the Z direction of the saddle (13) on the machining precision.

[0150] The Z-axis sensor (37Z) outputs a signal SZy containing information on the detection position (detection error) in the Y direction of the Z-axis table (9Z), in addition to the previously described signals SZx and SZz. The signal SZy is used for position control of the saddle (13) in the Y direction to reduce the effect of the error in the Y direction of the Z-axis table (9Z) on the machining precision.

[0151] In addition, although not specifically described, a method for reducing the effect of straightness on machining precision may be applied, for example, only to the straightness of one direction of one axis (e.g., error in the Z direction of the X-axis table (9X)). Furthermore, for example, the method may be applied only to the straightness of two directions of one axis (e.g., error in the Z direction and Y direction of the X-axis table (9X)). Furthermore, for example, the method may be applied only to the straightness of one direction of one axis and the straightness of another axis in the same direction as the said one direction regarding parallel movement in a direction different from the said one direction (e.g., error in the Y direction of the X-axis table (9X) and error in the Y direction of the Z-axis table (9Z)).

[0152] (Another example of a 2D scale composition)

[0153] FIG. 8 is a drawing illustrating a configuration different from the configuration example described with reference to FIG. 3(a) regarding a two-dimensional scale. Here, for convenience of explanation, an X-axis sensor (25X) is used as an example.

[0154] The X-axis sensor (25X) has a scale section (27) and a detection section (29), similar to the configuration example of FIG. 3 (a). The scale section (27) has an A-phase scale section (27a) and a B-phase scale section (27b) that extend in the X direction parallel to each other. The detection section (29) has an A-phase detection section (29a) that detects a pattern (27c) of the A-phase scale section (27a) and a B-phase detection section (29b) that detects a pattern (27c) of the B-phase scale section (27b).

[0155] However, unlike the configuration example of FIG. 3(a), in the A-phase scale section (27a), a plurality of patterns (27c) extending parallel to the X-direction are arranged in the Z-direction. Accordingly, the A-phase detector (29a) detects the position in the Z-direction. In addition, in the B-phase scale section (27b), a plurality of patterns (27c) extending parallel to the Z-direction are arranged in the X-direction. Accordingly, the B-phase detector (29b) detects the position in the X-direction. As described above, the illustrated two-dimensional scale detects displacement in two directions.

[0156] In addition, although not specifically described, for example, the two-dimensional scale may detect a bit pattern arranged in two dimensions. Also, the two-dimensional scale may capture the scale portion at a predetermined period to acquire an image, and calculate a two-directional movement amount based on a comparison of the previous image and the current image.

[0157] (Another example of guide composition)

[0158] FIG. 9 is a drawing illustrating a configuration different from the configuration described with reference to FIG. 2(b) regarding a guide that guides a table (9) or a saddle (13). This drawing is a cross-sectional view corresponding to FIG. 2(b). For convenience of explanation, a table (9) is used as an example of a member guided by the guide.

[0159] The guide (17A) illustrated in FIG. 9 is configured by a so-called static pressure guide. Specifically, a gap is formed between the guide surface of the table (9) and the guide surface of the bed (19). Fluid is supplied into the gap at a predetermined pressure by a pump (57), etc. The fluid may be a gas (e.g., air) or a liquid (e.g., oil).

[0160] In this case, when the guide (17A) is configured by a static pressure guide, the frictional resistance is small when moving the table (9) in the direction of movement according to, for example, the NC program (107), so the position of the direction of movement can be determined with high precision. With such a configuration, high machining precision can be realized. As a result, the usefulness of the effect of reducing the influence of straightness on machining precision is increased.

[0161] (Other examples of driving mechanisms)

[0162] FIG. 9, described above, is also a drawing illustrating an example of a configuration other than a linear motor as a configuration of a driving mechanism. Specifically, FIG. 9 illustrates a screw shaft (59) and a nut (61) that is screw-coupled to the screw shaft (59). That is, a screw mechanism (e.g., a ball screw mechanism or a sliding screw mechanism) is illustrated. With the rotation of one of the screw shaft (59) and the nut (61) (in the illustrated example, the nut (61)) restricted, the other of the screw shaft (59) and the nut (61) (in the illustrated example, the screw shaft (59)) rotates, causing both to move relative to each other in the axial direction. One of the screw shaft (59) and the nut (61) (in the illustrated example, the screw shaft (59)) is supported on the bed (19), and the other of the screw shaft (59) and the nut (61) (in the illustrated example, the nut (61)) is supported on the table (9). The driving force for rotating the screw shaft (59) (or nut (61)) is generated, for example, by a rotary electric motor (not shown).

[0163] (Example of main shaft bearing configuration)

[0164] FIG. 10 is a cross-sectional view illustrating an example of the configuration of a bearing of a main shaft (15).

[0165] As described in the description of the embodiment, the bearing of the main shaft (15) may be a sliding bearing, a rolling bearing, a hydrostatic bearing, or a combination of two or more of these. In FIG. 10, a hydrostatic bearing is exemplified. Specifically, a gap is formed between the outer surface of a main shaft body (15a) (this main shaft body (15a) may be referred to as the main shaft) that holds and supports a tool (101) or a workpiece (103) and rotates around the shaft, and the inner surface of a bearing member (15b) (hydrostatic bearing) that surrounds the main shaft body (15a) around the shaft. Fluid is supplied to the gap at a predetermined pressure by a pump (57), etc. The fluid may be a gas (e.g., air) or a liquid (e.g., oil).

[0166] In this case, when the spindle body (15a) is supported by a hydrostatic bearing, for example, the frictional resistance is small when the spindle body (15a) is rotated around the axis according to an NC program (107), so the rotational speed of the spindle body (15a) can be controlled with high precision, and furthermore, high machining precision can be realized. As a result, the usefulness of the effect of reducing the influence of straightness on machining precision is increased.

[0167] In addition, in the above embodiments and variations, the X direction is an example of the first direction. The X-axis table (9X) is an example of the first movable part. The X-axis guide (17X) is an example of the first guide. The X-axis driving source (23X) is an example of the first driving source. The X-axis sensor (25X) is an example of the first sensor. The X-axis control unit (33X) is an example of the first control unit. The Z direction is an example of the second direction. The Z-axis table (9Z) is an example of the second movable part. The Z-axis guide (17Z) is an example of the second guide. The Z-axis driving source (23Z) is an example of the second driving source. The Z-axis sensor (25Z) is an example of the second sensor. The Z-axis control unit (33Z) is an example of the second control unit.

[0168] The technology related to the present disclosure is not limited to the above embodiments and variations, and may be implemented in various forms.

[0169] As described in the description of the embodiments, the processing machine is not limited to the configuration exemplified in FIG. 1. For example, the processing machine is not limited to special machine tools such as ultra-precision aspherical processing machines, but may be a general machine tool. Furthermore, the processing machine is not limited to machine tools and may be, for example, a robot. In another aspect, the program containing information on commands regarding movement is not limited to an NC program and may be one generated by teaching.

[0170] In addition, the processing machine is not limited to performing grinding and / or polishing, but may perform, for example, cutting or electrical discharge machining, or may be capable of performing two or more of the various processing operations described above. The processing may involve contacting a non-rotating tool with a rotating workpiece (e.g., turning), contacting a rotating tool with a non-rotating workpiece (e.g., milling), or both the workpiece and the tool may not be rotating.

[0171] A machining machine has at least two mutually orthogonal axes as axes for translating the workpiece and / or tool. Thus, for example, a machining machine does not have to have three axes for translation, but conversely, it may have four or more axes. Explanation of the symbols

[0172] 1: Machining machine 5: Control unit 9X: X-axis table (first movable part) 9Z: Z-axis table (second movable part) 17X: X-axis guide (1st guide) 17Z: Z-axis guide (second guide) 23X: X-axis drive source (1st drive source) 23Z: Z-axis drive source (second drive source) 25X: X-axis sensor (1st sensor) 25Z: Z-axis sensor (second sensor) 33X: X-axis control unit (first control unit) 33Z: Z-axis control unit (second control unit) 41: Cadre 101: Tools 103: Work 107: NC Program (Program)

Claims

Claim 1 The apparatus comprises a first movable part supporting one of a workpiece and a tool, a first guide guiding the first movable part in a first direction, a first driving source driving the first movable part in the first direction, a first sensor outputting a signal according to a first error which is a displacement of the first movable part in the first direction and a displacement of the first movable part in a second direction orthogonal to the first direction, a second movable part supporting the other of the workpiece and the tool, a second guide guiding the second movable part in the second direction, a second driving source driving the second movable part in the second direction, a second sensor outputting a signal according to a second displacement which is a displacement of the second movable part in the second direction, and a control device controlling the first driving source and the second driving source according to a program containing information on commands regarding the movement of the first movable part and the second movable part, wherein the control device, based on the information of the program, [has] a first target at every predetermined control cycle in the first direction of the first movable part The apparatus has an interpolation unit that calculates a position and a second target position for each control cycle in the second direction of the second movable part, a first control unit that acquires a recent detection value of the first displacement based on a signal during processing from the first sensor during each control cycle in processing, calculates a first deviation based on the difference between the acquired detection value and the first target position, and controls the first driving source to reduce the first deviation, and a second control unit that acquires a recent detection value of the second displacement based on a signal during processing from the second sensor during each control cycle in processing, calculates a second deviation based on the difference between the acquired detection value and the second target position, and controls the second driving source to reduce the second deviation, wherein the second control unit, during each control cycle in processing,A machining machine that acquires a recent detection value of the first error based on a signal from the first sensor during the machining process, and increases or decreases the second deviation based on the detection value of the first error such that at least a portion of the error in the relative position of the workpiece and the tool in the second direction caused by the first error is eliminated by the movement of the second movable part in the second direction. Claim 2 A machining machine according to claim 1, wherein the second sensor outputs a signal corresponding to a second error, which is a displacement of the second movable part in the first direction, and the first control unit acquires a recent detection value of the second error based on the signal from the second sensor at each control cycle, and increases or decreases the first deviation based on the detection value of the second error so that at least a portion of the error in the relative position of the workpiece and the tool in the first direction caused by the second error is eliminated by the movement of the first movable part in the first direction. Claim 3 delete Claim 4 A processing machine according to claim 1 or 2, wherein the first sensor is a two-dimensional scale. Claim 5 A processing machine according to claim 4, wherein, in the above two-dimensional scale, the length of the range in which the position of the first direction can be detected is at least 10 times the length of the range in which the position of the second direction can be detected. Claim 6 A first movable part supporting one of a workpiece and a tool, a first guide guiding the first movable part in a first direction, a first driving source driving the first movable part in the first direction, a first sensor which is a two-dimensional scale and outputs a signal according to a first error which is a displacement of the first movable part in the first direction and a displacement of the first movable part in a second direction orthogonal to the first direction, a second movable part supporting the other of the workpiece and the tool, a second guide guiding the second movable part in the second direction, a second driving source driving the second movable part in the second direction, a second sensor which outputs a signal according to a second displacement which is a displacement of the second movable part in the second direction, and a control device that controls the first driving source and the second driving source according to a program including information on commands regarding the movement of the first movable part and the second movable part, and the control device, based on the information of the program, a predetermined control in the first direction of the first movable part The apparatus comprises an interpolation unit that calculates a first target position for each period and a second target position for each control period in the second direction of the second movable part; a first control unit that, for each control period, acquires a recent unprocessed detection value of the first displacement based on a signal from the first sensor, calculates a first deviation based on the difference between the acquired unprocessed detection value and the first target position, and controls the first driving source to reduce the first deviation; and a second control unit that, for each control period, acquires a recent unprocessed detection value of the second displacement based on a signal from the second sensor, calculates a second deviation based on the difference between the acquired unprocessed detection value and the second target position, and controls the second driving source to reduce the second deviation, wherein the second control unit acquires a recent detection value of the first error based on a signal from the first sensor for each control period,A processing machine that increases or decreases the second deviation based on the detection value of the first error so that at least a portion of the error in the relative position of the workpiece and the tool in the second direction caused by the first error is eliminated by the movement of the second movable part in the second direction, and the control device has an integrated control unit that acquires an unprocessed detection value of the first error based on a signal from the first sensor at a predetermined sampling period and calculates an average value of a plurality of unprocessed detection values ​​of the first error, and the second control unit uses the average value as the detection value of the first error to increase or decrease the second deviation. Claim 7 A processing machine according to claim 1 or 2, wherein the first guide is a static pressure guide or a VV rolling guide. Claim 8 A machining machine according to claim 1 or 2, wherein the machining machine has a main shaft that holds and supports the workpiece or the tool, and a hydrostatic bearing that supports the main shaft so as to be rotatable around the shaft. Claim 9 A processing machine according to claim 1 or 2, wherein each of the first driving source and the second driving source is a linear motor. Claim 10 A processing system having a processing machine described in claim 1 or 2, and a diagnostic device that acquires information on the detection value of the first error from the processing machine and displays an image according to the acquired information. Claim 11 A method for manufacturing a workpiece, comprising the step of using a processing machine described in claim 1 or 2 to bring the workpiece and the tool into contact to process the workpiece into a workpiece. Claim 12 In claim 1, the apparatus further comprises a support, a third movable part supported by the first movable part and supporting one of a workpiece and a tool, a third guide that guides the third movable part with respect to the first movable part in a third direction orthogonal to both the first direction and the second direction, and a third driving source that drives the third movable part with respect to the first movable part in the third direction, wherein the first guide guides the first movable part with respect to the support in the first direction, and the first driving source drives the first movable part with respect to the support in the first direction, the first displacement is the displacement of the first movable part with respect to the support in the first direction, and the first error is the displacement of the first movable part with respect to the support in the second direction, and the second guide guides the second movable part with respect to the support in the second direction, and the second driving source drives the second movable part with respect to the support in the second direction, and the second displacement is the displacement of the second movable part with respect to the support A processing machine having a displacement in the second direction, wherein the interpolation unit calculates a third target position in the third direction of the third movable part for each control cycle based on information from the program, and the control device has a third control unit that controls the third driving source based on the detection position of the third movable part and the third target position for each control cycle, and does not increase or decrease the second deviation based on the recent detection value of the third error, which is the displacement of the third movable part in the second direction relative to the first movable part for each control cycle.

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