Compensation value calculation method for a position measuring sensor and compensation value calculation system for a position measuring sensor in a machine tool

Abstract

A compensation value calculation method for a position measuring sensor (30) in a machine tool (M) comprises a tool sensor detection position measuring step (S1), a position measuring sensor length calculation step (S2), a relative position determination step (S3), a reference tool distal end position measuring step (S11), a tool sensor position measuring step (S12) and a position measuring sensor longitudinal direction compensation value calculation step (S13).

Description

AREA OF INVENTION

[0001] The disclosure relates to a compensation value calculation method for a position measuring sensor and a compensation value calculation system for the position measuring sensor in a machine tool, wherein the method and the system serve to calculate a compensation value for the position measuring sensor, which is used to measure a position of a workpiece in the machine tool in which a table holding the workpiece and a main spindle holding a tool move relative to each other along translational axes. BACKGROUND OF THE INVENTION

[0002] In a numerically controlled machine tool M with three translation axes, as in Fig. As shown in Figure 1, when a workpiece located on a table 3 is machined with a tool mounted on a main spindle 2, a reference position for machining the workpiece must be registered in advance in a control unit. The reference position for machining is determined, for example, by measuring the position of the workpiece.

[0003] A well-known method for measuring the position of a workpiece uses a tactile probe, which is a position measuring sensor mounted on a main spindle. A signal is transmitted the moment a probe attached to the tactile probe makes contact with the workpiece. An NC control device installed in a machine tool receives this signal via a connected receiver. Upon receiving the signal, the NC control device calculates the workpiece position using a compensation value in the longitudinal direction of the tactile probe, in addition to the positions of the respective axes at that time.

[0004] However, the tactile probe is subject to changes over time, such as thermal deformation due to fluctuations in room temperature. Therefore, to accurately measure the workpiece position, it is necessary to recalculate the longitudinal compensation value of the tactile probe accordingly.

[0005] As a method for calculating the compensation value in the longitudinal direction of the tactile measuring probe, the applicant discloses a method as described in JP 7266511 B.

[0006] The method described in JP 7266511 B uses a tool sensor, such as a laser sensor and a touch sensor, a reference block mounted on the base of the tool sensor, and a reference tool of known length. First, the detection position of the tool sensor, the relative position of the reference block with respect to the detection position, and a longitudinal compensation value of a tactile probe are determined. Then, by measuring the detection position of the reference tool with the tool sensor and the position of the reference block with the tactile probe, the longitudinal compensation value of the tactile probe can be calculated.

[0007] However, if the previously determined relative position of the reference block changes with respect to the detection position of the tool sensor, an error in the longitudinal compensation value of the tactile probe can occur in some cases. Therefore, in JP 7266511 B, the reference block is installed on the same base as the tool sensor, thus reducing the change in relative position. However, if, for example, the coefficient of linear expansion differs between the tool sensor and the reference block, the relative positions will change according to changes in ambient temperature, even if the tool sensor and the reference block are installed on the same base. Consequently, the generation of an error in the longitudinal compensation value of the tactile probe remains a problem.

[0008] As described in JP 7266511 B, the tool sensor and the reference block are often provided separately and are each installed at an arbitrary position on a table. Therefore, there was a desire to solve the problem of a limited table area on which the workpiece is placed.

[0009] Therefore, it is a task of the disclosure to provide a compensation value calculation method for a position measuring sensor and a compensation value calculation system for the position measuring sensor in a machine tool, which are able to minimize an error generated in a compensation value in the longitudinal direction of a position measuring sensor regardless of a change in ambient temperature and to increase a table area on which a workpiece is placed. SUMMARY OF THE INVENTION

[0010] To solve the problems described above, a first configuration of the disclosure is a compensation value calculation method for a position sensor in a machine tool for calculating a compensation value in a longitudinal direction of the position sensor. The machine tool comprises a table configured to hold a workpiece, a rotatable main spindle to which a tool is attached, a translational axis configured to perform a relative movement of the main spindle and the table with two or more translational degrees of freedom, and a tool sensor configured to measure a position of the tool attached to the main spindle. The machine tool is configured to measure a position of the workpiece held by the table using the position sensor attachable to the main spindle.The tool sensor comprises a detection section that detects a detection object, and a reference section that is integrally provided with the tool sensor in the vicinity of the detection section and serves as a position reference for the tool sensor.

[0011] The method comprises: a tool sensor detection position measurement step in which a reference tool of known length is attached to the main spindle, whereby the detection section of the tool sensor detects a distal end of the reference tool in order to determine a distal end position of the reference tool, and measuring a position of the detection section of the tool sensor based on the determined distal end position of the reference tool and a length of the reference tool; a position measuring sensor length calculation step in which a reference position is determined using the reference tool attached to the main spindle, then the position measuring sensor is attached to the main spindle, the reference position is measured using the position measuring sensor to determine a position measuring sensor reference position, and a length of the position measuring sensor is calculated from the determined position measuring sensor reference position, the length of the reference tool and the reference position; a relative position determination step in which the position measuring sensor is attached to the main spindle, a position of the reference section is measured, and a relative position of the position of the reference section with respect to the position of the detection section is determined from the measured position of the reference section, the position of the detection section measured in the tool sensor detection position measurement step, and the length of the position measuring sensor calculated in the position measuring sensor length calculation step; a reference tool distal end position measurement step in which the reference tool is attached to the main spindle, the distal end of the reference tool is brought into contact with the detection section and a position of the distal end of the reference tool is measured; a tool sensor position measuring step of measuring a position of the tool sensor by attaching the position measuring sensor to the main spindle and measuring the position of the reference section; and a position measuring sensor length direction compensation value calculation step of calculating the compensation value in the longitudinal direction of the position measuring sensor from the length of the reference tool, the relative position determined in the relative position determination step, the position of the distal end of the reference tool measured in the reference tool distal end position measurement step and the position of the tool sensor measured in the tool sensor position measurement step.

[0012] In another aspect of the first configuration of the disclosure, which is present in the configuration above, the steps from the tool sensor detection position step to the relative position determination step are executed once, and the steps from the reference tool distal end position measurement step to the position measurement sensor length direction compensation value calculation step are executed multiple times.

[0013] In another aspect of the first configuration of the disclosure, which is present in the configuration above, the sensing section and the reference section are formed from a material that does not cause any change in the relative position between the sensing section and the reference section in an ambient temperature range present during machining by the machine tool.

[0014] To solve the problems described above, a second configuration of the disclosure is a compensation value calculation system for a position sensor in a machine tool for calculating a compensation value in a longitudinal direction of the position sensor. The machine tool comprises a table configured to hold a workpiece, a rotatable main spindle to which a tool is attached, a translational axis configured to perform relative movement of the main spindle and the table with two or more translational degrees of freedom, a control device controlling the table, the translational axis, and the main spindle, and a tool sensor configured to measure a position of the tool attached to the main spindle. The machine tool is configured to measure a position of the workpiece held by the table using the position sensor attachable to the main spindle.The tool sensor comprises a detection section that detects a detection object, and a reference section that is integrally provided with the tool sensor in the vicinity of the detection section and serves as a position reference for the tool sensor.

[0015] The system includes a reference tool with a known length; a tool sensor sensing position measuring unit, via which the reference tool is attached to the main spindle, which actuates the translation axis, which causes the sensing section of the tool sensor to sensing a distal end of the reference tool in order to determine a distal end position of the reference tool, and which measures a position of the sensing section of the tool sensor based on the determined distal end position of the reference tool and a length of the reference tool; a position measuring sensor length calculation unit, via which the reference tool is attached to the main spindle and actuates the translation axis to determine a reference position, via which the position measuring sensor is then attached to the main spindle, which actuates the translation axis to measure the reference position using the position measuring sensor, in order to determine a position measuring sensor reference position, and calculates a length of the position measuring sensor from the length of the reference tool, the reference position and the position measuring sensor reference position; a relative position determination unit, via which the position measuring sensor is attached to the main spindle, which actuates the translation axis to measure a position of the reference section, and determines a relative position of the position of the reference section with respect to the position of the detection section from the measured position of the reference section, the position of the detection section measured by the tool sensor detection position measuring unit, and the length of the position measuring sensor calculated by the position measuring sensor length calculation unit; a reference tool distal end position measuring unit, via which the reference tool is attached to the main spindle, which actuates the translation axis to bring the distal end of the reference tool into contact with the sensing section, and which measures a position of the distal end of the reference tool; a tool sensor position measuring unit that measures the position of the tool sensor by mounting the position measuring sensor on the main spindle and actuating the translation axis to measure the position of the reference section; and a position measuring sensor length direction compensation value calculation unit that calculates the compensation value in the longitudinal direction of the position measuring sensor from the length of the reference tool, the relative position determined by the relative position determination unit, the position of the distal end of the reference tool measured by the reference tool distal end position measurement unit, and the position of the tool sensor measured by the tool sensor position measurement unit.

[0016] In another aspect of the second configuration of the disclosure, which is present in the configuration above, the sensing section and the reference section are formed from a material that does not cause any change in the relative position between the sensing section and the reference section in an ambient temperature range present during machining by the machine tool.

[0017] According to the disclosure, by providing the reference section, which is integrated with the tool sensor near the sensing section, the change in relative position can be reduced even with changes in ambient temperature. Accordingly, when calculating the compensation value in the longitudinal direction of the position sensor, using the relative position between the position of the sensing section and the position of the reference section on the tool sensor, the error arising in the compensation value in the longitudinal direction of the position sensor can be minimized. Furthermore, since no separate reference block is required from the tool sensor, the table area on which the workpiece is placed can be increased.

[0018] Since the detection section and the reference section are made of a material that does not cause a change in the relative position between the detection section and the reference section in an ambient temperature range present during machining by the machine tool, the change in relative position caused by the temperature change can be further reduced. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is an explanatory representation illustrating a compensation value calculation system for a position measurement sensor according to the disclosure. Fig. Figure 2 is a block diagram illustrating a configuration of an NC control device. Fig. Figure 3 is an explanatory illustration that depicts a laser sensor according to the disclosure. Fig. Figure 4 is an explanatory illustration depicting a touch sensor according to the revelation. Fig. Figure 5 is an explanatory illustration of the measurement of a reference position of a table surface using a tactile measuring probe. Fig. Figure 6 is a flowchart of a preset for calculating a compensation value in a longitudinal direction of the tactile measuring probe according to the disclosure. Fig. Figure 7 is an explanatory illustration of how to determine the reference position of the table surface using a reference tool. Fig. Figure 8 is an explanatory view of the measurement of the position of a reference section of the laser sensor. Fig. Figure 9 is an explanatory view of the measurement of the position of a reference section of the touch sensor. Fig. Figure 10 is a flowchart of a calculation method for the compensation value in the longitudinal direction of the tactile measuring probe according to the disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0019] The following describes embodiments of the disclosure with reference to the drawings.

[0020] In the embodiment as described in Fig. Figure 1 shows a numerically controlled machine tool M based on a machining center with three translation axes consisting of an X-axis, a Y-axis, and a Z-axis as an example of a machine tool. However, a different machine can also be used as a machine tool, for example, a multi-axis machine tool with a rotary axis in addition to the translation axes, or a lathe-based numerically controlled machine tool.

[0021] The numerically controlled machine tool M in the disclosure is, as in the Fig. 1 and Fig. Figure 2 shows a machining center-based machine tool with three translation axes consisting of an X-axis, a Y-axis, and a Z-axis. The numerically controlled machine tool M comprises a bed 1, a main spindle 2 on which a tool (not shown) can be mounted, a table 3 that can hold a workpiece (not shown), and an NC control device 21. Furthermore, the numerically controlled machine tool M includes a tool sensor and a position measuring sensor.

[0022] The numerically controlled machine tool M preferably comprises a magazine in which several tools are stored and a tool changer that can automatically exchange a tool attached to the main spindle 2 for a tool stored in the magazine. If a reference tool 10 and a position measuring sensor, as described later, are stored in the magazine, they can be automatically attached to and removed from the main spindle 2, thus improving practicality. The tool can also be manually attached to and removed from the main spindle 2 by an operator.

[0023] The numerically controlled machine tool M is a so-called portal machine. Therefore, a saddle 6 is movably mounted on rails 5, which are formed on a column 4 and extend in the X-axis direction. The saddle 6 is equipped with a main spindle head 7 that is movable in the Z-axis direction. The main spindle head 7 has a lower end at which the main spindle 2 is mounted. Accordingly, the main spindle 2 can move along the Z-axis and the X-axis, which are two mutually orthogonal translational axes. In particular, the main spindle 2 can perform a translational movement with two degrees of freedom with respect to the bed 1. A feed axis is driven by an X-axis translational servomotor 11a to move the saddle 6 so that the main spindle 2 moves in the X-axis direction.A feed axis is driven by a Z-axis translation servomotor 11c to move the main spindle stock 7 so that the main spindle 2 moves in the Z-axis direction. An X-axis position detector 8a is provided on a surface on the side of the saddle 6 facing the column 4. A Z-axis position detector 8c is provided on a surface on the side of the main spindle stock 7 facing the saddle 6.

[0024] The table 3 is formed on the bed 1 and is movably arranged on rails 9 extending along the Y-axis, which is a translational axis orthogonal to the Z-axis and the X-axis. In particular, the table 3 can perform a translational movement with one degree of freedom with respect to the bed 1. A feed axis is driven by a Y-axis translation servomotor 11b, so that the table 3 moves in the Y-axis direction. Furthermore, a Y-axis position detector 8b is provided on a surface on the side of the table 3 facing the bed 1.

[0025] As in Fig. As shown in Figure 2, the NC control device 21 has functions as a recording unit 22, a display unit 23, and a servo command value generation unit 24. The NC control device 21 includes a CPU and memory connected to the CPU and uses these to execute various types of processes.

[0026] The recording unit 22 is configured to record information such as a machining program entered by an input unit 26 described later, a length of the reference tool 10, a detection position of the tool sensor, a relative position of a reference section with respect to the detection position, and a compensation value in a longitudinal direction of the position measuring sensor.

[0027] The recording unit 22 stores programs to allow the NC control device 21 to function as a tool sensor detection position measuring unit, a position measuring sensor length calculation unit, a relative position determination unit, the reference tool distal end position measuring unit, a tool sensor position measuring unit and a position measuring sensor length direction compensation value calculation unit.

[0028] Display unit 23, for example, is a monitor. Display unit 23 shows information such as an editing program and the respective positions of the translation axes.

[0029] The NC control device 21 is connected to the X-axis position detector 8a, the Y-axis position detector 8b, the Z-axis position detector 8c, an X-axis translation servo amplifier 12a, a Y-axis translation servo amplifier 12b, and a Z-axis translation servo amplifier 12c. The servo amplifiers 12a to 12c are further connected to the X-axis translation servo motor 11a, the Y-axis translation servo motor 11b, and the Z-axis translation servo motor 11c. Accordingly, the NC control device 21 controls the servomotors 11a to 11c in a suitable manner on the basis of the position information of the respective axes obtained from the position detectors 8a to 8c, whereby the machining of the workpiece held by the table 3 is carried out with the tool held by the main spindle 2.

[0030] Here, an exemplary procedure for generating a servo command value of the translation axis, which is executed by the servo command value generation unit 24, and an exemplary procedure for relative position control between the table 3 and the main spindle 2 based on the servo command value are described.

[0031] When the machining program is entered into the NC control device 21, the servo command value generation unit 24 generates command values ​​for the respective translation axes based on the position information from the position detectors 8a to 8c of the respective axes and the previously obtained position information of the workpiece.

[0032] The generated command values ​​of the respective translation axes are transmitted to a servo command conversion unit 25 and converted into servo command values. Subsequently, the servo command values ​​corresponding to the X-axis, Y-axis, and Z-axis are transmitted to the servo amplifiers 12a to 12c. The servo amplifiers 12a to 12c drive the servo motors 11a to 11c based on the received servo command values ​​corresponding to the X-axis, Y-axis, and Z-axis, respectively. The relative position of the main spindle 2 with respect to the table 3 is therefore controlled by driving the servo motors 11a to 11c.

[0033] The NC control device 21 is further connected to the tool sensor and the position sensor. For the connection to the tool sensor and the position sensor, a receiver can be connected to the NC control device 21 to receive information from a sensor via a wireless connection, or the NC control device 21 can be connected to the tool sensor and the position sensor via cables. In this embodiment, it is assumed that the NC control device 21 is connected to the tool sensor via cables. At the same time, it is assumed that the NC control device 21 is also wirelessly connected to the position sensor. Therefore, a receiver 33 is connected to the NC control device 21 to receive the signal from the position sensor.

[0034] The NC control device 21 is also connected to the input unit 26, such as a keyboard and a touch panel, to allow the operator to perform various types of inputs, including the machining program.

[0035] A laser sensor 40 as a tool sensor includes, as in Fig. Figure 3 shows a laser emission unit 41, which emits a laser 43, as a detection section, a laser receiving unit 42, which receives the laser 43, and a base section 44. Furthermore, the laser sensor 40 integrally includes a reference section 45 on a top surface of the laser emission unit 41. The reference section 45 is made of the same material as the laser emission unit 41 and the laser receiving unit 42, or of a material with a similar coefficient of linear expansion to the laser emission unit 41 and the laser receiving unit 42. The laser sensor 40 is mounted at any position on the table 3.

[0036] A touch sensor 50 as a tool sensor includes, as in Fig. Figure 4 shows a touch sensor main body 51, a sensing section 52 that detects the position of the distal end of the tool, and a base section 53. The touch sensor 50 also integrally includes a reference section 54 on a top surface of the touch sensor main body 51. The reference section 54 is made of the same material as the sensor section 52 and the touch sensor main body 51, or of a material with a similar coefficient of linear expansion to the sensing section 52 and the touch sensor main body 51. The touch sensor 50 is mounted at any position on the table 3.

[0037] Here, in the disclosure, the similar linear expansion coefficient means a linear expansion coefficient that exhibits a similarity such that no change in the relative position between the sensing section and the reference section occurs within an ambient temperature range observed during machining of the workpiece by the numerically controlled machine tool M. Alternatively, the similar linear expansion coefficient means a linear expansion coefficient that exhibits a similarity such that a machined product falls within an acceptable quality range even if the relative position changes, within an ambient temperature range observed during machining of the workpiece by the numerically controlled machine tool M.

[0038] Based on various factors, such as the structure and installation environment of the numerically controlled machine tool M, any laser sensor 40 or touch sensor 50 is selected and installed in the numerically controlled machine tool M.

[0039] Thus, in the compensation value calculation system for the position measuring sensor according to the disclosure, the laser sensor 40 includes the reference section 45 on the laser emission unit 41. The reference section 45 is made of the same material as the laser emission unit 41 and the laser receiving unit 42, or of a material with a similar coefficient of linear expansion as the laser emission unit 41 and the laser receiving unit 42. Therefore, even if the laser emission unit 41 is thermally deformed due to the temperature change around the laser sensor 40, it is less likely that the relative position between the laser 43 and the reference section 45 will change.Similarly, the touch sensor 50 includes the reference section 54, which is made of the same material as the sensing section 52 and the touch sensor main body 51, or of a material with a similar coefficient of linear expansion to that of the sensing section 52 and the touch sensor main body 51. Therefore, even if the touch sensor main body 51 is thermally deformed due to temperature changes around the touch sensor 50, the relative position between the sensing section 52 and the reference section 54 is less likely to change. Accordingly, the error that arises when calculating the compensation value in the longitudinal direction of the position measuring sensor described later can be minimized.

[0040] Reference section 45 is integrally formed with the laser sensor 40. Likewise, reference section 54 is integrally formed with the touch sensor 50. Accordingly, the table area on which the workpiece is placed can be enlarged.

[0041] A tactile measuring probe 30 as a position measuring sensor comprises, as in Fig. Figure 5 shows a tactile probe main body 31, a probe head 32 attached to the distal end and the receiver 33 connected to the NC control device 21.

[0042] As already described, in order to measure the position of a measuring object, for example a workpiece, with the tactile measuring probe 30 it is necessary to determine the compensation value in the longitudinal direction of the tactile measuring probe 30 beforehand and to store it in the recording unit 22 of the NC control device 21.

[0043] The following describes a calculation method for the compensation value in the longitudinal direction of the tactile measuring probe 30 according to the disclosure. First, a flowchart is used to illustrate this. Fig. 6 describes the determination of the relative position between the detection section and the reference section of the tool sensor, which represents a preliminary setting for the calculation of the compensation value in the longitudinal direction of the tactile measuring probe 30 according to the disclosure.

[0044] To perform a tool measurement with the tool sensor, the detection position of the tool sensor must first be determined and stored in the recording unit 22 of the NC control device 21. Therefore, in step S1, a detection position of the laser sensor 40 or the touch sensor 50 as a tool sensor is measured, which is a position at which the position of the distal end of the tool is detected. Step S1 is a tool sensor detection position measurement step in the disclosure. Here, the measurement of the detection position in the Z-axis direction of the distal end of the tool is described as an example.

[0045] First, the reference tool 10 of known length is attached to the main spindle 2. Then, the main spindle 2 is positioned so that the distal end of the reference tool 10 is directly above the laser 43. Subsequently, as described in Fig. As shown in Figure 3, the Z-axis (feed axis) is operated in the negative direction. When the laser 43 is interrupted by the distal end of the reference tool 10, this is detected, and the laser receiver 42 sends a signal to the NC control unit 21. When the signal is received by the laser sensor 40, the NC control unit 21 stops the Z-axis translation servo motor 11c. In the NC control unit 21, a detection position Zrt' is measured using a Z-axis position Zrt at the time of signal reception, and a length Lr of the reference tool 10 is measured by calculation using formula (1). The measured detection position Zrt' is the detection position in the Z-axis direction to detect the position of the distal end of the tool and is determined in advance. The detection position Zrt' is stored in the recording unit 22. Zrt'=Zrt−Lr

[0046] A method for tool measurement using the touch sensor 50 is essentially similar to the method described above for tool measurement using the laser sensor 40, with the exception of the detection method. In the case of the touch sensor 50, as described in Fig. 4 shows that when the distal end of the tool comes into contact with the detection area 52 of the touch sensor 50, it is detected that it has been detected, and the touch sensor main body 51 sends a signal to the NC control device 21.

[0047] After measuring the detection position Zrt' of the tool sensor, a length of the tactile probe 30 is calculated in S2. S2 is a position measuring sensor length calculation step in the disclosure. Similar to S1, the reference tool 10 is attached to the main spindle 2, and the main spindle 2 is positioned such that the distal end of the reference tool 10 is near the top of the table 3. Then, as in Fig. Figure 7 shows the distal end of the reference tool 10 being brought into contact with a reference block 13, which is arranged on the table 3 and has a known thickness. Using the Z-axis position detector 8c, the contact position between the reference tool 10 and the reference block 13 is determined as position Z1 of the top of the table over a known thickness t of the reference block 13. Thus, a reference position Z1' is determined from the determined position Z1, the thickness t of the reference block 13, and a length Lr of the reference tool 10 by calculation using formula (2). Z1'=Z1−Lr−t

[0048] The tactile probe 30 is then attached to the main spindle 2, and the main spindle 2 is positioned so that a distal end of the probe head 32 is positioned near the position at which the reference position Z1' was determined. Then, as described in Fig. Figure 5 shows the Z-axis (feed axis) operating in the negative direction. When the probe head 32 comes into contact with the reference position Z1', the tactile probe body 31 transmits a signal to the receiver 33 connected to the NC control device 21. A contact position Z2 at this time is a position sensor reference position as described in the disclosure. The length Lp of the tactile probe is calculated from the contact position Z2 (the position sensor reference position) and the reference position Z1' using formula (3) and stored in the recording unit 22. Lp=Z2−Z1'

[0049] After calculating the length Lp of the tactile measuring probe 30, the relative position of the reference section 45 with respect to the laser 43 as the detection section of the laser sensor 40, or the relative position of the reference section 54 with respect to the detection section 52 of the touch sensor 50, is determined in S3. S3 is a relative position determination step in the disclosure.

[0050] As in the Fig. 8 and Fig. As shown in Figure 9, the main spindle 2 is positioned such that the distal end of the probe head 32 of the tactile measuring probe 30 attached to the main spindle 2 is positioned near the reference section 45 of the laser sensor 40 or the reference section 54 of the touch sensor 50. Then the Z-axis (feed axis) is operated in the negative direction. When the probe head 32 comes into contact with the reference section 45 of the laser sensor 40 or the reference section 54 of the touch sensor 50, the tactile probe main body 31 transmits a signal to the receiver 33 connected to the NC control device 21. A relative position dZ3 is determined from the contact position Z3 at that time, the detection position Zrt' and the length Lp of the tactile probe 30 by calculation using a formula (4), and the determined relative position dZ3 is stored in the recording unit 22. dZ3=Z3−Lp−Zrt'

[0051] As described above, by executing S1 to S3 to save the relative position dZ3 of the reference sections 45, 54 with respect to the detection sections 43, 52 of the laser sensor 40 or the touch sensor 50, the presetting of the calculation of the compensation value in the longitudinal direction of the tactile measuring probe 30 is completed.

[0052] Next, a flowchart will be used to illustrate the process. Fig. 10 a calculation method for the compensation value in the longitudinal direction of the tactile measuring probe 30 is described, which is executed after completion of the presetting.

[0053] In S11, the detection position of the tool sensor is measured again. Using the procedure described above, which is similar to S1, as in the Fig. 3 and Fig. Figure 4 shows a measured acquisition position Zrt''. S11 is a reference tool distal end position measurement step in the disclosure.

[0054] In S12, the tactile probe 30 is attached to the main spindle 2, and the main spindle 2 is positioned such that the distal end of the probe head 32 is near the position of the reference section 45 of the laser sensor 40 or the reference section 54 of the touch sensor 50 measured in S3. Then, as in the Fig. 8 and Fig. Figure 9 shows the Z-axis (feed axis) operating in the negative direction. When the probe head 32 is brought into contact with the reference section 45 of the laser sensor 40 or the reference section 54 of the touch sensor 50, a contact position Z3' is measured. The contact position Z3' is a sensor position in the disclosure, and S12 is a tool sensor position measurement step.

[0055] Then, in S13, a compensation value Lp' in the longitudinal direction of the tactile measuring probe 30 is calculated from the detection position Zrt'' measured in S11, the contact position Z3' determined in S12, and the relative position dZ3 determined in S3 and stored in the recording unit 22 by calculation using formula (5), and the compensation value Lp' is stored in the recording unit 22. S13 is a position measuring sensor longitudinal direction compensation value calculation step in the disclosure.

[0056] In the compensation value calculation method for the position measuring sensor according to the disclosure, if S1 to S3 are executed once as a preset for the calculation of the compensation value in the longitudinal direction of the tactile measuring probe 30, S11 to S13 can be executed multiple times. Lp'=Z1=3'−Zrt''−dZ3

[0057] The compensation value Lp' calculated as described above in the longitudinal direction of the tactile measuring probe 30 is used to compensate for the measuring position when measuring the workpiece position.

[0058] In the compensation value calculation method for the position measuring sensor according to the disclosure, the laser sensor 40 is used as the tool sensor. The laser sensor 40 comprises the reference section 45, which is made of the same material as the laser emission unit 41 and the laser receiver unit 42, or of a material with a similar coefficient of linear expansion to that of the laser emission unit 41 and the laser receiver unit 42. Therefore, even if the laser emission unit 41 is thermally deformed due to temperature changes around the laser sensor 40, the relative position between the laser 43 and the reference section 45 is less likely to change.When the touch sensor 50 is used as a tool sensor, it similarly includes the reference section 54, which is made of the same material as the sensing section 52 and the touch sensor main body 51, or of a material with a similar coefficient of linear expansion to that of the sensing section 52 and the touch sensor main body 51. Therefore, even if the touch sensor main body 51 is thermally deformed due to temperature changes around the touch sensor 50, the relative position between the sensing section 52 and the reference section 54 is less likely to change. Consequently, the error that arises when calculating the compensation value in the longitudinal direction of the position measuring sensor can be minimized.

[0059] The configurations of the method and the system for calculating the compensation value for the position measuring sensor in the machine tool according to the disclosure are not limited to the aspects of the embodiment described above and can be modified as necessary without deviating from the essence of the disclosure.

[0060] For example, the reference section need not be located on the top side of the tool sensor, as long as the reference section is integral with the tool sensor and located near the sensing section. While the reference section is highlighted in the embodiment described above and shown in the drawings, a predetermined section that excludes the sensing section in the tool sensor can be used as the reference section.

[0061] While the laser sensor, the touch sensor and the tactile probe are described as examples of the tool sensor and the position measuring sensor, other sensors can also be used.

[0062] It is expressly stated that all features disclosed in the description and / or the claims are disclosed separately and independently of one another for the purposes of the original disclosure and for the purpose of limiting the claimed invention, irrespective of the composition of the features in the embodiments and / or the claims. It is expressly stated that all ranges of values ​​or specifications of groups of entities disclose all possible intermediate values ​​or entities for the purposes of the original disclosure and for the purpose of limiting the claimed invention, in particular as limits of value ranges. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 7266511 B [0005, 0006, 0007, 0008]

Claims

[1] A compensation value calculation method for a position measuring sensor (30) in a machine tool (M) for calculating a compensation value in a longitudinal direction of the position measuring sensor (30), wherein The machine tool (M) includes: a table (3) configured to hold a workpiece; a rotatable main spindle (2) to which a tool is attached; a translation axis (X, Y, Z) configured to perform a relative movement of the main spindle (2) and the table (3) with two or more translational degrees of freedom; and a tool sensor (40, 50) configured to measure the position of the tool attached to the main spindle (2), wherein the machine tool (M) is configured to measure the position of the workpiece held by the table (3) using the position measuring sensor (30) which can be attached to the main spindle (2), and the tool sensor (40, 50) comprises a detection section (43, 52) which detects a detection object, and a reference section (45, 54) which is integrally provided with the tool sensor (40, 50) in the vicinity of the detection section (43, 52) and serves as a position reference of the tool sensor (40, 50), wherein The procedure includes: a tool sensor detection position measurement step (S1) in which a reference tool (10) of a known length is attached to the main spindle (2), whereby the detection section (43, 52) of the tool sensor (40, 50) detects a distal end of the reference tool (10) in order to determine a distal end position of the reference tool (10), and measuring a position of the detection section (43, 52) of the tool sensor (40, 50) based on the determined distal end position of the reference tool (10) and a length of the reference tool (10); a position measuring sensor length calculation step (S2) to determine a reference position using the reference tool (10) mounted on the main spindle (2), subsequent attachment of the position measuring sensor (30) to the main spindle (2), measuring the reference position using the position measuring sensor (30) to determine a position measuring sensor reference position, and calculating a length of the position measuring sensor (30) from the determined position measuring sensor reference position, the length of the reference tool (10) and the reference position; a relative position determination step (S3) in which the position measuring sensor (30) is attached to the main spindle (2), a position of the reference section (45, 54) is measured and a relative position of the position of the reference section (45, 54) with respect to the position of the detection section (43, 52) is determined from the measured position of the reference section (45, 54), the position of the detection section (43, 52) measured in the tool sensor detection position measurement step (S1) and the length of the position measuring sensor (30) calculated in the position measuring sensor length calculation step (S2); a reference tool distal end position measurement step (S11) in which the reference tool (10) is attached to the main spindle (2), the distal end of the reference tool (10) is brought into contact with the detection section (43, 52) and a position of the distal end of the reference tool (10) is measured; a tool sensor position measuring step (S12) of measuring a position of the tool sensor (40, 50) by attaching the position measuring sensor (30) to the main spindle (2) and measuring the position of the reference section (45, 54); and a position measuring sensor length direction compensation value calculation step (S13) of calculating the compensation value in the longitudinal direction of the position measuring sensor (30) from the length of the reference tool (10), the relative position determined in the relative position determination step (S3), the position of the distal end of the reference tool (10) measured in the reference tool distal end position measurement step (S11) and the position of the tool sensor (40, 50) measured in the tool sensor position measurement step (S12). [2] The compensation value calculation method for a position measuring sensor (30) in a machine tool (M) according to claim 1, wherein the steps from the tool sensor detection position measurement step (S1) to the relative position determination step (S3) are executed once and The steps from the reference tool distal end position measurement step (S11) to the position measuring sensor length direction compensation value calculation step (S13) are executed multiple times. [3] The compensation value calculation method for a position measuring sensor (30) in a machine tool (M) according to claim 1 or 2, wherein the sensing section (43, 52) and the reference section (45, 54) are formed from a material which does not cause any change in the relative position between the sensing section (43, 52) and the reference section (45, 54) in an ambient temperature range that is present during machining by the machine tool (M). [4] A compensation value calculation system for a position measuring sensor (30) in a machine tool (M) for calculating a compensation value in the longitudinal direction of the position measuring sensor (30), wherein The machine tool (M) includes: a table (3) configured to hold a workpiece; a rotatable main spindle (2) to which a tool is attached; a translation axis (X, Y, Z) configured to perform a relative movement of the main spindle (2) and the table (3) with two or more translational degrees of freedom; a control device that controls the table (3), the translation axis (X, Y, Z) and the main spindle (2); and a tool sensor (40, 50) configured to measure the position of the tool that can be attached to the main spindle (2), wherein the machine tool (M) is configured to measure the position of the workpiece held by the table (3) using the position measuring sensor (30) attached to the main spindle (2), and the tool sensor (40, 50) comprises a detection section (43, 52) which detects a detection object, and a reference section (45, 54) which is integrally provided with the tool sensor (40, 50) in the vicinity of the detection section (43, 52) and serves as a position reference of the tool sensor (40, 50), wherein The system includes: a reference tool (10) with a known length; a tool sensor sensing position measuring unit, via which the reference tool (10) is attached to the main spindle (2), which actuates the translation axis (X, Y, Z), causes the sensing section (43, 52) of the tool sensor (40, 50) to sensing a distal end of the reference tool (10) in order to determine a distal end position of the reference tool (10), and measures a position of the sensing section (43, 52) of the tool sensor (40, 50) based on the determined distal end position of the reference tool (10) and a length of the reference tool (10); a position measuring sensor length calculation unit, via which the reference tool (10) is attached to the main spindle (2) and which actuates the translation axis (X, Y, Z) to determine a reference position, via which the position measuring sensor (30) is subsequently attached to the main spindle (2), which actuates the translation axis (X, Y, Z) to measure the reference position using the position measuring sensor (30) in order to determine a position measuring sensor reference position, and calculates a length of the position measuring sensor (30) from the length of the reference tool (10), the reference position and the position measuring sensor reference position; a relative position determination unit, via which the position measuring sensor (30) is attached to the main spindle (2), which actuates the translation axis (X, Y, Z) to measure a position of the reference section (45, 54), and determines a relative position of the position of the reference section (45, 54) with respect to the position of the detection section (43, 52) from the measured position of the reference section (45, 54), the position of the detection section (43, 52) measured by the tool sensor detection position measuring unit, and the length of the position measuring sensor (30) calculated by the position measuring sensor length calculation unit; a reference tool distal end position measuring unit, via which the reference tool (10) is attached to the main spindle (2), which actuates the translation axis (X, Y, Z) to bring the distal end of the reference tool (10) into contact with the sensing section (43, 52), and which measures a position of the distal end of the reference tool (10); a tool sensor position measuring unit that measures the position of the tool sensor (40, 50) by attaching the position measuring sensor (30) to the main spindle (2) and actuating the translation axis (X, Y, Z) to measure the position of the reference section (45, 54); and a position measuring sensor length direction compensation value calculation unit that calculates the compensation value in the longitudinal direction of the position measuring sensor (30) from the length of the reference tool (10), the relative position determined by the relative position determination unit, the position of the distal end of the reference tool (10) measured by the reference tool distal end position measuring unit and the position of the tool sensor (40, 50) measured by the tool sensor position measuring unit. [5] The compensation value calculation system for a position measuring sensor (30) in a machine tool (M) according to claim 4, wherein the sensing section (43, 52) and the reference section (45, 54) are formed from a material that does not cause any change in the relative position between the sensing section (43, 52) and the reference section (45, 54) in an ambient temperature range that is present during machining by the machine tool (M).

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