阅读说明：本技术 机床的对象物的位置测量方法及位置测量系统、计算机可读记录介质 (Method and system for measuring position of object of machine tool, and computer-readable recording medium ) 是由 神户礼士 于 2020-11-05 设计创作，主要内容包括：提供机床的对象物的位置测量方法及位置测量系统、计算机可读记录介质,能够自动地实施包含校正在内的全部的测量工序。机床的数值控制装置能够执行如下步骤：步骤(S1),使用接触式传感器取得接触位置(Z1’)(基准刀具位置)；步骤(S2),使用接触探头测量基准块的接触位置(Z2’)(基准块的位置)；步骤(S3),根据接触位置(Z1’)、接触位置(Z2’)、距离(dZb)以及基准刀具的长度(Td),计算接触探头的长度方向校正值(Tp’)；以及步骤(S4),通过接触探头来测量对象物,并且使用接触探头的长度方向校正值(Tp’)来校正对象物的测量位置。(Provided are a method and a system for measuring the position of an object of a machine tool, and a computer-readable recording medium, which can automatically perform all measurement steps including calibration. The numerical controller of the machine tool can execute the following steps: a step (S1) of acquiring a contact position (Z1') (reference tool position) using a touch sensor; a step (S2) of measuring a contact position (Z2') of the reference block (position of the reference block) using a contact probe; a step (S3) of calculating a longitudinal correction value (Tp ') of the contact probe from the contact position (Z1 '), the contact position (Z2 '), the distance (dZb) and the length (Td) of the reference tool; and a step (S4) of measuring the object by the contact probe and correcting the measurement position of the object by using the longitudinal correction value (Tp') of the contact probe.)

1. A method for measuring the position of an object to be machined by a machine tool having a translation axis with 3 or more axes, a main axis to which a tool can be attached and which can rotate, and a table, wherein the position of the object fixed to the table is measured by a position measuring sensor attachable to the main axis,

the method for measuring the position of an object of a machine tool comprises the following steps:

a tool sensor position acquisition step of attaching a reference tool, which is a length reference of the tool, to the spindle and acquiring a detection position of a tip of the reference tool using a tool sensor;

a tool length correction value acquisition step of mounting the tool on the spindle and obtaining a longitudinal correction value of the tool by using the tool sensor;

a machining surface position acquisition step of rotating the tool to cut into a machining block provided on the table side to machine a surface, and measuring and acquiring a position of the machining surface by using the position measurement sensor;

a position measurement sensor length calculation step of calculating a length of the position measurement sensor based on the longitudinal direction correction value of the tool acquired in the tool length correction value acquisition step and the position of the machining surface acquired in the machining surface position acquisition step;

a relative position calculation step of measuring a position of a reference block provided on the tool sensor side by using the position measurement sensor, and calculating a relative position of the reference block with respect to the detection position based on the detection position acquired in the tool sensor position acquisition step, the position of the reference block, the length of the position measurement sensor calculated in the position measurement sensor length calculation step, and the length of the reference tool;

a reference tool position acquisition step of attaching the reference tool to the spindle and acquiring a reference tool position as a tip end position of the reference tool using the tool sensor;

a reference block position measuring step of mounting the position measuring sensor on the main shaft and measuring the position of the reference block using the position measuring sensor;

a length correction value calculation step of calculating a length direction correction value of the position measurement sensor based on the reference tool position acquired in the reference tool position acquisition step, the position of the reference block measured in the reference block position measurement step, the relative position calculated in the relative position calculation step, and the length of the reference tool; and

a position measurement step of measuring the object by the position measurement sensor attached to the spindle, and correcting a measurement position of the object by using the longitudinal correction value of the position measurement sensor calculated in the longitudinal correction value calculation step.

2. The method of measuring a position of an object of a machine tool according to claim 1,

is executed 1 time from the tool sensor position acquisition stage to the relative position calculation stage,

the reference tool position acquisition stage is executed a plurality of times until the position measurement stage.

3. The method of measuring a position of an object of a machine tool according to claim 1,

the positions measured by the position measuring sensor in the reference block position measuring phase and the position measuring phase are the positions of the translation axis when the position measuring sensor detects contact with the object.

4. The method of measuring a position of an object of a machine tool according to claim 1 or 2,

the reference block is a reference ball having a ball diameter, the position measuring sensor is a contact sensor for the object,

before the position measurement phase is performed, a radial correction value acquisition phase of acquiring a radial correction value of the position measurement sensor using the reference ball is also performed,

in the position measurement stage, the measurement position of the object is corrected using the radial correction value acquired in the radial correction value acquisition stage.

5. A system for measuring the position of an object fixed to a table in a machine tool having a translation axis with 3 or more axes, a main axis to which a tool can be attached and which can rotate, a table, a position measuring sensor attachable to the main axis, and a control device for controlling the translation axis and the main axis, wherein the position of the object fixed to the table is measured by the position measuring sensor,

the system for measuring the position of an object of a machine tool includes:

a reference tool serving as a length reference of the tool;

a tool sensor that detects a distal end position of the reference tool attached to the spindle;

a reference block provided on the tool sensor side;

a processing block disposed on the table side;

a tool sensor position acquisition unit that moves the reference tool attached to the main spindle via the translation axis, and acquires and stores a detection position of a tip of the reference tool using the tool sensor;

a tool length correction value acquisition unit that moves the tool attached to the main spindle via the translation shaft and acquires a longitudinal correction value of the tool using the tool sensor;

a machining surface position acquisition unit that rotates the tool at an arbitrary position of the machining block to cut into the machining block to machine a surface, moves the position measurement sensor attached to the main shaft via the translation shaft to contact a machining surface, and measures and acquires a position of the machining surface;

a position measurement sensor length calculation unit that calculates a length of the position measurement sensor based on the longitudinal direction correction value of the tool acquired by the tool length correction value acquisition unit and the position of the machining surface acquired by the machining surface position acquisition unit;

a relative position calculating unit that measures and stores a position of the reference block using the position measuring sensor attached to the spindle, and calculates and stores a relative position of the reference block with respect to the detected position based on the detected position acquired by the tool sensor position acquiring unit, the position of the reference block, the length of the position measuring sensor acquired by the position measuring sensor length calculating unit, and the length of the reference tool;

a reference tool position acquisition unit that moves the reference tool attached to the main spindle via the translation axis, and acquires and stores a reference tool position as a tip end position of the reference tool using the tool sensor;

a reference block position measuring unit that measures and stores a position of the reference block using the position measuring sensor attached to the spindle;

a length correction value calculation unit that calculates and stores a length direction correction value of the position measurement sensor based on the reference tool position acquired by the reference tool position acquisition unit, the position of the reference block acquired by the reference block position measurement unit, the relative position calculated by the relative position calculation unit, and the length of the reference tool; and

and a position measuring unit that measures the object by the position measuring sensor attached to the spindle and corrects a measurement position of the object by using the longitudinal correction value of the position measuring sensor calculated by the longitudinal correction value calculating unit.

6. The system for measuring a position of an object of a machine tool according to claim 5,

the processing block is arranged on the cutter sensor fixed on the workbench.

7. The system for measuring a position of an object of a machine tool according to claim 5 or 6,

the position measurement sensor measures a position of the translation axis or a position in consideration of signal delay when the position measurement sensor detects the object.

8. The system for measuring a position of an object of a machine tool according to any one of claims 5 to 7,

the position measuring system for the object of the machine tool further includes a radial correction value acquiring unit that acquires and stores a radial correction value of the position measuring sensor by using the reference block as a reference sphere having a spherical diameter and the position measuring sensor as a contact sensor for the object,

the position measuring means corrects the measurement position using the length correction value acquired by the length correction value calculating means and the radial correction value acquired by the radial correction value acquiring means.

9. A computer-readable recording medium, which is a non-transitory recording medium, wherein,

the computer-readable recording medium is used for causing a control device of a machine tool having a translation axis of 3 or more axes, a main axis capable of mounting a tool and rotating, and a table to execute the method of measuring a position of an object of the machine tool according to any one of claims 1 to 4.

Technical Field

The present invention relates to a position measuring method, a position measuring system, and a computer-readable recording medium for measuring a position of an object such as a tool or a workpiece in a machine body of a machine tool.

Background

In a machine tool that machines a workpiece attached to a table by a tool attached to a spindle and rotating, a method of automatically measuring the length of the tool or the position of the workpiece and correcting the tool or the position of the workpiece is used to perform high-precision machining.

As the automatic measurement method of the workpiece position, for example, the following methods are used: the coordinates at the time when the stylus of the probe contacts the workpiece 31 or the time when the delay is taken into consideration are obtained by using the contact probe 30 shown in fig. 2. In this case, in order to acquire the coordinates of the workpiece 31 in the Z-axis direction, the length of the contact probe 30 at the time of contact is required.

As a method for measuring the length of the contact probe 30 at the time of contact, the following method is generally used: a reference tool is attached to the main spindle 2a, the Z axis is manually operated so that the reference tool is brought into contact with a reference surface such as the table 3 via a gauge block, and a position where a gap between the gauge block and the reference tool is substantially 0 is found and a Z axis coordinate at this time is recorded. Then, the coordinates of the Z-axis position when the contact probe 30 is brought into contact with the reference surface are measured, and the length of the contact probe 30 at the time of contact is determined by subtracting the coordinates recorded by the reference tool and the thickness of the gauge block from the coordinates measured by the contact probe 30. However, manual work is required, and there is a problem that the length of the contact probe 30 at the time of contact cannot be automatically measured.

Therefore, as a method for automatically measuring the length of the contact probe, the applicant of the present application discloses, in patent document 1, a method of: the length of the position measurement sensor is measured by attaching a reference block to the tool sensor such as a touch sensor or a laser sensor, recording coordinates of a Z-axis position where the reference tool and the reference block are in contact with each other in advance, acquiring coordinates of a Z-axis position where the reference tool and the tool sensor are in contact with each other, acquiring a contact position of the tool sensor by the reference tool by making a relative position between the contact position of the tool sensor and the reference block known from the coordinates of the reference tool and the tool sensor, and measuring the position of the reference block by the position measurement sensor.

Patent document 1: japanese patent laid-open publication No. 2017-193043

In the method of patent document 1, when the coordinates of the reference block are acquired at the 1 st time, manual work is required, and there is a problem that all the measurement steps cannot be automatically performed.

Disclosure of Invention

Therefore, an object of the present invention is to provide a method, a system, and a program for measuring a position of an object of a machine tool, which can automatically perform all measurement steps including calibration.

In order to achieve the above object, the invention according to claim 1 is a method for measuring a position of an object in a machine tool, the method using a machine tool having a translation axis with 3 or more axes, a main spindle to which a tool is attachable and which is rotatable, and a table, the method being characterized in that a position of the object fixed to the table is measured by a position measuring sensor attachable to the main spindle,

the method for measuring the position of an object of a machine tool comprises the following steps:

a tool sensor position acquisition step of attaching a reference tool, which is a length reference of the tool, to the spindle and acquiring a detection position of a tip of the reference tool using a tool sensor;

a tool length correction value acquisition step of mounting the tool on the spindle and obtaining a longitudinal correction value of the tool by using the tool sensor;

a machining surface position obtaining step of rotating the tool, cutting into a machining block provided on the table side to machine a surface, and obtaining a position of the machining surface by measuring with the position measuring sensor;

a position measurement sensor length calculation step of calculating a length of the position measurement sensor based on the longitudinal direction correction value of the tool acquired in the tool length correction value acquisition step and the position of the machining surface acquired in the machining surface position acquisition step;

a relative position calculation step of measuring a position of a reference block provided on the tool sensor side by using the position measurement sensor, and calculating a relative position of the reference block with respect to the detection position based on the detection position acquired in the tool sensor position acquisition step, the position of the reference block, the length of the position measurement sensor calculated in the position measurement sensor length calculation step, and the length of the reference tool;

a reference tool position acquisition step of attaching the reference tool to the spindle and acquiring a reference tool position as a tip end position of the reference tool using the tool sensor;

a reference block position measuring stage of mounting the position measuring sensor on the main shaft and measuring the position of the reference block by using the position measuring sensor;

a length correction value calculation step of calculating a length direction correction value of the position measurement sensor based on the reference tool position acquired in the reference tool position acquisition step, the position of the reference block measured in the reference block position measurement step, the relative position calculated in the relative position calculation step, and the length of the reference tool; and

a position measurement step of measuring the object by the position measurement sensor attached to the spindle, and correcting a measurement position of the object by using the longitudinal correction value of the position measurement sensor calculated in the longitudinal correction value calculation step.

Here, the "table side" includes a case where the machining block is directly provided on the table, but includes a case where the machining block is provided via a tool sensor or the like on the table.

The "tool sensor side" naturally includes a case where the reference block is directly provided on the tool sensor, but also includes a case where the reference block is separately provided in the vicinity of the tool sensor.

The invention according to claim 2 is characterized in that, in the above configuration, the tool sensor position acquisition stage to the relative position calculation stage are executed 1 time,

the reference tool position acquisition phase to the position measurement phase are performed a plurality of times.

The invention according to claim 3 is characterized in that, in the above configuration, the position measured by the position measuring sensor in the reference block position measuring stage and the position measuring stage is the position of the translation axis when the position measuring sensor detects contact with the object.

The invention according to claim 4 is characterized in that, in the above configuration, the reference block is a reference ball having a ball diameter, the position measuring sensor is a contact sensor for the object,

before the position measurement phase is performed, a radial correction value acquisition phase of acquiring a radial correction value of the position measurement sensor using the reference ball is also performed,

in the position measurement stage, the measurement position of the object is corrected using the radial correction value acquired in the radial correction value acquisition stage.

In order to achieve the above object, the invention according to claim 5 is a system for measuring a position of an object in a machine tool having a translation axis with 3 or more axes, a main axis capable of being rotatably attached with a tool, a table, a position measuring sensor capable of being attached to the main axis, and a control device for controlling the translation axis and the main axis, wherein the position of the object fixed to the table is measured by the position measuring sensor,

the system for measuring the position of an object of a machine tool includes:

a reference tool serving as a length reference of the tool;

a tool sensor that detects a distal end position of the reference tool attached to the spindle;

a reference block provided on the tool sensor side;

a processing block disposed on the table side;

a tool sensor position acquisition unit that moves the reference tool attached to the main spindle via the translation axis, and acquires and stores a detection position of a tip of the reference tool using the tool sensor;

a tool length correction value acquisition unit that moves the tool attached to the main spindle via the translation shaft and acquires a longitudinal correction value of the tool using the tool sensor;

a machining surface position acquisition unit that rotates the tool at an arbitrary position of the machining block to cut into the machining block to machine a surface, moves the position measurement sensor attached to the main shaft via the translation shaft to contact a machining surface, and measures and acquires a position of the machining surface;

a position measurement sensor length calculation unit that calculates a length of the position measurement sensor based on the longitudinal direction correction value of the tool acquired by the tool length correction value acquisition unit and the position of the machining surface acquired by the machining surface position acquisition unit;

a relative position calculating unit that measures and stores a position of the reference block using the position measuring sensor attached to the spindle, and calculates and stores a relative position of the reference block with respect to the detected position based on the detected position acquired by the tool sensor position acquiring unit, the position of the reference block, the length of the position measuring sensor acquired by the position measuring sensor length calculating unit, and the length of the reference tool;

a reference tool position acquisition unit that moves the reference tool attached to the main spindle via the translation axis, and acquires and stores a reference tool position as a tip end position of the reference tool using the tool sensor;

a reference block position measuring unit that measures and stores a position of the reference block using the position measuring sensor attached to the spindle;

a length correction value calculation unit that calculates and stores a length direction correction value of the position measurement sensor based on the reference tool position acquired by the reference tool position acquisition unit, the position of the reference block acquired by the reference block position measurement unit, the relative position calculated by the relative position calculation unit, and the length of the reference tool; and

a position measuring unit that measures the object by the position measuring sensor attached to the spindle, and corrects a measurement position of the object using the longitudinal direction correction value of the position measuring sensor calculated by the longitudinal correction value calculating unit.

The invention according to claim 6 is characterized in that, in the above configuration, the processing block is provided to the tool sensor fixed to the table.

The invention according to claim 7 is characterized in that, in the above configuration, the position measurement sensor measures a position of the translation axis or a position in consideration of signal delay when the position measurement sensor detects the object.

The invention according to claim 8 is characterized in that, in the above configuration, the position measurement system for the object of the machine tool further includes a radial correction value acquisition unit that acquires and stores a radial correction value of the position measurement sensor by using the reference block as a reference sphere having a spherical diameter and the position measurement sensor as a contact sensor for the object,

in the position measuring unit, the measurement position is corrected using the length correction value acquired by the length correction value calculating unit and the radial correction value acquired by the radial correction value acquiring unit.

In order to achieve the above object, the invention according to claim 9 is a program for measuring a position of an object of a machine tool, wherein a control device of the machine tool, which has a translation axis having 3 or more axes, a main axis capable of mounting a tool and rotating, and a table, is caused to execute the method for measuring a position of an object of a machine tool according to any one of claims 1 to 4.

According to the present invention, the length of the position measuring sensor that needs to be known can be automatically measured by measuring the position of the machining surface of the machining block after machining by the tool of which the length is known by the tool sensor, in advance by the position measuring sensor.

Therefore, the positional relationship between the detection position of the tool sensor and the reference block is known in advance from the length of the position measurement sensor and the position of the reference block measured by the position measurement sensor, and thus, the length of the position measurement sensor, that is, the longitudinal correction value can be automatically measured by automatically measuring the reference tool by the tool sensor and the reference block by the position measurement sensor thereafter.

Further, if the position measuring sensor is in contact with the object, if the correction value in the radial direction is also obtained, the position of the object can be measured with higher accuracy.

Thus, even if the length of the position measuring sensor changes due to thermal displacement or the like, all the measurement steps including correction can be automatically performed.

Drawings

Fig. 1 is a schematic view of a machining center.

Fig. 2 is a schematic view of a contact probe.

Fig. 3 is a schematic diagram of a laser sensor as an example of the tool sensor of the present invention.

Fig. 4 is a schematic diagram of a laser sensor as an example of the tool sensor of the present invention.

Fig. 5 is a schematic view of a touch sensor as an example of the tool sensor of the present invention.

Fig. 6 is a schematic view of a touch sensor as an example of the tool sensor of the present invention.

Fig. 7 (a) and (b) are schematic diagrams of a process of measuring the length of the position measurement sensor.

Fig. 8 is a flowchart of the measurement preparation operation of the present invention.

FIG. 9 is a flow chart of a contact probe measurement method of the present invention.

Fig. 10 is an explanatory diagram of step SR1 of the measurement preparation operation of the present invention.

Fig. 11 is an explanatory diagram of step SR2 of the measurement preparation operation of the present invention.

Fig. 12 is an explanatory diagram of step SR3 of the measurement method of the present invention.

Fig. 13 is an explanatory diagram of step SR5 of the measurement method of the present invention.

Fig. 14 is a schematic diagram of a laser sensor as an example of the tool sensor of the present invention.

Fig. 15 is a schematic view of a laser sensor as an example of the tool sensor of the present invention.

Fig. 16 is a schematic view of a touch sensor as an example of the tool sensor of the present invention.

Fig. 17 is a schematic view of a touch sensor as an example of the tool sensor of the present invention.

FIG. 18 is a flow chart of a contact probe measurement method of the present invention.

Description of the reference symbols

1: a bed body; 2: a main spindle box; 2 a: a main shaft; 3: a work table; 8: a reference tool; 9: a cutting tool; 11: a laser light emitting section; 12: a laser light receiving unit; 30: contacting the probe; 31: a workpiece; 40: a laser sensor; 42. 52: a reference block; 45. 55: processing the blocks; 50: a touch sensor; 51: a touch sensor section; 56: a reference ball.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 is a schematic view of a machining center having 3 translation axes perpendicular to each other, which is one mode of a machine tool.

The headstock 2 is capable of 2-degree-of-translational-freedom movement relative to the bed 1 via the column 4 and the saddle 5 through X and Z axes as translation axes and perpendicular to each other. The table 3 is capable of movement with 1 translational degree of freedom with respect to the bed 1 through the Y axis which is a translation axis and is perpendicular to the X axis and the Z axis. Therefore, the headstock 2 can move with 3 translational degrees of freedom with respect to the table 3. Each feed shaft is driven by a servo motor controlled by a numerical controller, not shown, and the workpiece is fixed to the table 3, a tool is attached to the spindle 2a of the headstock 2 and rotated, and the relative position and relative posture of the workpiece and the tool are controlled, whereby the workpiece can be machined.

As the control device of the present invention, the numerical controller functions as a tool sensor position acquisition means, a tool length correction value acquisition means, a machined surface position acquisition means, a position measurement sensor length calculation means, a relative position calculation means, a reference tool position acquisition means, a reference block position measurement means, a length correction value calculation means, a radial correction value acquisition means, and a position measurement means, according to a program stored in advance in the storage unit. The attachment and detachment of the cutting tool to and from the spindle 2a and the attachment and detachment of a reference tool and a contact probe, which will be described later, which are accompanied by the measurement of the object, are manually performed by an operator, or automatically performed by a numerical controller via a tool changer.

The machine of the present invention is not limited to a machining center, and may be a machine tool such as a lathe, a compound machine, or a grinding machine. The number of axes is not limited to 3, and only 3, 4, and 6 axes of the translation axis may be used. Further, the table 3 or the headstock 2 may have 1 degree of freedom of rotation or more by the rotation axis.

Fig. 3 is a schematic diagram of a laser sensor 40 as an example of the tool sensor of the present invention. The laser sensor 40 includes a laser light emitting unit 11 that emits laser light 14, a laser light receiving unit 12 that receives the laser light 14, a base unit 13, a reference block 42, and a processing block 45. The laser light emitting unit 11, the laser light receiving unit 12, the reference block 42, and the processing block 45 are fixed to the base unit 13. The laser sensor 40 is attached to the upper surface of the table 3 of the machining center of fig. 1. As shown in fig. 4, the reference block 42 and the processing block 45 may be provided near the base portion 13.

Fig. 5 is a schematic view of a touch sensor 50 as an example of the tool sensor of the present invention. The touch sensor 50 includes a touch sensor unit 51, a reference block 52, a processing block 55, and a base unit 53. The touch sensor unit 51, the reference block 52, and the processing block 55 are fixed to the base unit 53. Similarly to the laser sensor 40, the touch sensor 50 is attached to the upper surface of the table 3 of the machining center in fig. 1. As shown in fig. 6, the reference block 52 and the processing block 55 may be separately disposed near the base portion 53.

Fig. 7 is a schematic diagram of an example of a unit for measuring the length of the position measuring sensor of the present invention. The machining block 55, the cutting tool 9 (fig. 7 (a)), and the contact probe 30 (fig. 7 (b)) as a position measurement sensor are used. The processing block 55 is attached to the base portion 53 of the touch sensor 50 as shown in fig. 5, or is separately disposed near the base portion 53 as shown in fig. 6.

Next, a case where the touch sensor 50 is used as a tool sensor will be described. The touch sensor 50 and the laser sensor 40 are different only in detection method and are substantially the same.

The procedure of the measurement preparation job is explained based on the flowchart of fig. 8. The measurement preparation operation is an operation performed in advance before measurement by a contact probe described later.

In step SR1, the reference tool 8 is attached to the spindle 2a, and measurement is performed by the touch sensor 50 (tool sensor position acquisition stage). Here, as shown in fig. 10, the Z axis is moved so that the reference tool 8 comes into contact with the touch sensor unit 51, and a contact position Z1 in the Z axis direction is obtained at the time when the tip of the reference tool 8 presses the touch sensor unit 51 or at the time when the signal delay is taken into consideration. The acquired contact position Z1 is stored in a storage unit in the numerical controller. The length Td of the reference tool 8 is also stored in the storage unit in advance.

In step SR2, as a preparation for measuring the length of the contact probe, the cutting tool 9 is attached to the spindle 2a, and the contact sensor 50 measures the length Tc of the cutting tool 9 (tool length correction value acquisition step). In the same manner as in step SR1, the Z-axis is moved so that the cutting tool 9 comes into contact with the touch sensor unit 51, and the contact position ZZ in the Z-axis direction is obtained at the time when the tip of the cutting tool 9 presses the touch sensor unit 51 or at the time when the signal delay is taken into consideration. Based on the acquired contact position ZZ, the contact position Z1 acquired in step SR1, and the length Td of the reference tool 8, the length of the cutting tool 9 is calculated as Tc ═ Td + (ZZ-Z1) and stored in the storage unit.

Then, as shown in fig. 11, the cutting tool 9 is cut in the longitudinal direction of the machining block 55 to machine the surface to the Zc' position, and the Z-axis position Zc at this time is acquired. Based on the acquired Z-axis position Zc and the length of the cutting tool 9, a machining surface Zc' is calculated as Zc-Tc and stored in a storage unit.

In step SR3, the contact probe 30 is attached to the spindle 2a, and the machining surface Zc' of the machining block 55 similar to that in step SR2 is measured (machining surface position acquisition stage). Here, as shown in fig. 12, the Z-axis is moved so that the contact probe 30 approaches the measurement position at the Zc' position of the processing block 55 similar to step SR2, and the contact position Zp in the Z-axis direction is obtained at the time when the stylus 30a of the contact probe 30 touches and transmits the trigger signal or the time when the signal delay is taken into consideration. The acquired contact position Zp is stored in the storage unit.

In step SR4, the length direction correction value of the contact probe 30, that is, the length of the contact probe 30 at the time of contact is calculated (position measurement sensor length calculation step). Here, the length-direction correction value Tp (═ Zp-Zc ') that is the length of the contact probe 30 is obtained from the position Zc' of the machining surface stored in step SR2 and the contact position Zp stored in step SR3, and stored in the storage unit.

In step SR5, the contact probe 30 is attached to the main shaft 2a, and the contact position Z2 (position of the reference block) of the reference block 52 in the Z-axis direction is measured. Here, as shown in fig. 13, the Z-axis is moved so that the contact probe 30 approaches the reference block 52, and the contact position Z2 in the Z-axis direction is obtained at the time when the stylus 30a of the contact probe 30 makes contact and transmits the trigger signal or the time when the signal delay is taken into consideration.

In step SR6, the distance (relative position) dZb in the Z-axis direction between the detection position of the touch sensor 50 and the detection position of the reference block 52 by the touch probe 30 is calculated (steps SR5, SR 6: relative position calculation step). Here, the Z-axis direction distance dZb (═ Z2+ Tp- (Z1+ Td)) between the contact position Z1 with the touch sensor 50 and the contact position Z2 with the reference block 52 is determined from the contact position Z1 of the reference tool 8 with the touch sensor 50 determined in step SR1, the contact position Z2 of the touch probe 30 with the reference block 52 determined in step SR5, and the length correction value Tp and the reference tool length Td of the touch probe 30, and is stored in the storage unit.

Next, a flow of measurement by the contact probe 30 of the present invention will be described based on the flowchart of fig. 9.

In step S1, as in step SR1, the reference tool 8 is attached to the spindle 2a, the contact position Z1' is measured by the touch sensor 50, and the contact position Z is stored in the storage unit (reference tool position acquisition stage).

In step S2, similarly to step SR5, the contact probe 30 is attached to the spindle 2a, the reference block 52 is measured by the contact probe 30, and the contact position Z2' (the position of the reference block) is stored in the storage unit (reference block position measurement stage).

In step S3, the longitudinal correction value of the contact probe 30, that is, the length of the contact probe 30 at the time of contact is calculated (length correction value calculation step). The length direction correction value Tp ' (-Z1 ' -Z2 ' + dZb + Td) is found from the contact position Z1 ' stored in step S1, the contact position Z2 ' stored in step S2, the distance dZb between the contact position of the touch sensor 50 and the contact position of the reference block 52 stored in the storage unit, and the reference tool length Td, and stored in the storage unit.

In step S4, the object is measured using the contact probe 30 (position measurement stage). At this time, the measurement position is corrected using the longitudinal correction value Tp' of the contact probe 30 calculated in step S3.

In this way, in the object position measuring method and the object position measuring system of the above-described aspect, the numerical controller executes the steps of: a step SR1 of acquiring a detection position (contact position Z1) of the end of the reference tool 8 using the touch sensor 50 (tool sensor); and a step SR2 of obtaining the length Tc of the cutting tool 9 (tool) (tool longitudinal direction correction value) by the touch sensor 50. And, the following steps are performed: a step SR3 of cutting the cutting tool 9 into the machining block 55 to machine the machining surface Zc', and measuring and acquiring a contact position Zp (position of the machining surface) using the contact probe 30 (position measuring sensor); and a step SR4 of calculating a length Tp (longitudinal correction value) of the contact probe 30 from the contact position Zc' and the contact position Zp based on the length Tc of the cutting tool 9. And the following steps SR5, SR6 are performed: the contact position Z2 of the reference block 52 (the position of the reference block) is measured using the contact probe 30, and the distance dZb (relative position) of the reference block 52 with respect to the contact position Z1 is calculated from the contact position Z1, the contact position Z2, the length Tp of the contact probe 30, and the length of the reference tool 8.

Then, the numerical control apparatus executes the steps of: step S1, acquiring a contact position Z1' (reference tool position) using the touch sensor 50; and a step S2 of measuring the contact position Z2' (the position of the reference block) of the reference block 52 using the contact probe 30. And further performing the steps of: a step S3 of calculating a length-direction correction value Tp ' of the contact probe 30 from the contact position Z1 ', the contact position Z2 ', the distance dZb, and the length Td of the reference tool 8; and a step S4 of measuring the object by the contact probe 30 and correcting the measurement position of the object using the longitudinal correction value Tp' of the contact probe 30.

Thus, by measuring the contact position Zp in contact with the processing surface Zc' processed by the cutting tool 9 of which the length is known by the contact sensor 50, the length of the contact probe 30 that needs to be known can be automatically measured.

Therefore, by previously knowing the positional relationship between the detection position of the touch sensor 50 and the reference block 52 based on the length of the touch probe 30 and the position of the reference block 52 measured by the touch probe 30, the length of the touch probe 30, that is, the longitudinal correction value can be automatically measured by automatically measuring the reference tool 8 by the touch sensor 50 and automatically measuring the reference block 52 by the touch sensor 50.

Thus, even if the length of the contact probe 30 changes due to thermal displacement or the like, the numerical controller can automatically perform all measurement steps including calibration.

Other embodiments of the present invention will be described with reference to the drawings.

Fig. 14 is a schematic view of another embodiment of the laser sensor 40 of the present invention. The laser sensor 40 includes a laser light emitting unit 11, a laser light receiving unit 12, a base unit 13, a reference ball 56, and a processing block 45, and the reference ball 56 and the processing block 45 are fixed to the base unit 13. As shown in fig. 15, the reference ball 56 and the processing block 45 may be separately disposed near the base portion 13.

Fig. 16 is a schematic view of another embodiment of the touch sensor 50 as an example of the tool sensor of the present invention. The touch sensor 50 includes a touch sensor portion 51, a reference ball 56, a base portion 53, and a processing block 55, and the touch sensor portion 51, the reference ball 56, and the processing block 55 are fixed to the base portion 53. As shown in fig. 17, the reference ball 56 and the processing block 55 may be separately disposed near the base portion 53.

Next, a flow of measurement by the contact probe 30 using the laser sensor 40 as the tool sensor will be described based on the flowchart of fig. 18. Unlike the touch sensor 50 only in the detection method, it is essentially the same.

The parts from step S1 to step S3 are the same as those in fig. 9 except that the laser sensor 40 is used, and therefore, the description thereof is omitted.

In step S5, a radial correction value of the contact probe 30 is acquired (radial correction value acquisition stage). Here, on the same plane in the horizontal direction of the reference sphere 56 (the radial direction of the contact probe 30), a total of 4 vertexes of the X-axis positive/negative direction and the Y-axis positive/negative direction are measured by the contact probe 30. At this time, the spindle 2a is calculated in such a manner that the contact point of the contact probe 30 is the same. The obtained average value of the X-axis position and the average value of the Y-axis position are X, Y coordinate values of the center of the reference sphere 56, respectively. Again, 4 vertex measurements are made for this center position X, Y. The X-axis positive direction correction value Rxp, the X-axis negative direction correction value Rxm, the Y-axis positive direction correction value Ryp, and the Y-axis negative direction correction value Rym of the contact probe 30 are calculated from the obtained differences between the 4 positions and the center position.

In step S6, the contact probe 30 is used to measure the object. At this time, the measurement position is corrected using the longitudinal correction value Tp of the contact probe 30 calculated in step S3, and the radial correction values Rxp, Rxm, Ryp, Rym of the contact probe 30 calculated in step S5.

In this way, when the contact probe 30 of the contact type is used, if the correction values in the radial direction are collectively obtained, the position of the object can be measured with higher accuracy.

In addition, in the above-described manner, the steps SR1 to SR5 as the measurement preparation job may be executed 1 time, but the steps S1 to S4 may be executed a plurality of times.

The position measuring sensor is not limited to a contact probe, and a non-contact sensor such as a laser displacement sensor may be used. In this case, the apparent distance between the object to be measured and the non-contact sensor at the time of measurement is the target, and the length at the time of contact is not the target.

When the contact probe length is set to a length corresponding to the reference tool length, the contact position Z1 between the cutting tool and the touch sensor may be obtained by using the cutting tool 9 instead of the reference tool 8.