JP2014087883A - Method for measuring tool length, and machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for measuring tool length and a machine tool by which a workpiece can be processed in high accuracy even when a fixed state of the workpiece to a table is changed.SOLUTION: The method for measuring tool length includes: a step for setting a workpiece W on a predesignated position of a table 12; a step for setting a touch sensor on a predesignated position on the top surface of the workpiece by relatively displacing a spindle 18 and the table after taking out a tool holder 1B holding the touch sensor 6 from the inside of a tool storage device to be held to the spindle; and a step for measuring the tool length of a tool by relatively displacing the table and the spindle to make the tip end of the tool get in touch with the touch sensor after taking the tool holder having the tool from the inside of the tool storage device to be held on the spindle.

Description

  The present invention relates to a tool length measuring method and a machine tool. Specifically, the present invention relates to a tool length measuring method and a machine tool that can measure the tool length of a tool based on a workpiece.

2. Description of the Related Art Conventionally, a machine tool for cutting a workpiece by attaching a tool having a cutter to a main shaft and rotating the tool has been used.
In such machine tools, the rigidity of the support structure is improved in order to improve the machining accuracy, and the operation accuracy of the X, Y, and Z axis moving mechanisms that move the main shaft is improved. .

In the machine tool described above, the operation accuracy of each axis moving mechanism affects the position accuracy of the spindle in the coordinate system of the machine tool.
However, it is the cutting edge of the tool tip that is the machining part that directly affects the machining accuracy of the workpiece. For example, if the mounting condition of the tool with respect to the spindle is unstable, or the distance to the tool tip (tool length) changes due to wear of the cutting edge, etc., these become error factors and improve the position accuracy of the spindle. However, the positional accuracy at the tool tip is not sufficiently improved.

As a method to eliminate such errors due to tool length fluctuations, the tool length of the tool mounted on the spindle is measured prior to machining, and the difference between the actual measured value at the tool tip and the reference value is obtained to determine the machining operation. Sometimes, the above-described difference is corrected.
As a method for measuring such a tool length, for example, a technique described in Patent Document 1 is known.

  In Patent Document 1, when a workpiece is placed on a table and cutting is performed with a tool attached to the spindle, a measurement touch sensor is placed at a location different from the workpiece on the table prior to the machining. Then, the spindle on which the tool used for machining is mounted is moved, and the tip of the tool is brought into contact with the touch sensor. When the touch of the tool is detected by the touch sensor, the current tool length of the spindle can be acquired from the spindle coordinates of the machine tool at that time.

Japanese Patent Laid-Open No. 2001-300836

By the way, in the above-described tool length measurement of Patent Document 1, the tool is brought into contact with a touch sensor placed at a position different from the work on the table, and the coordinate position of the acquired tool tip is based on the table surface. It is a thing.
However, when cutting a workpiece, the depth of cut is specified based on the workpiece upper surface (machined surface) directed to the main axis among the workpiece surfaces to be machined. Therefore, whether the reference is the table surface or the workpiece upper surface. An error may occur depending on whether or not.
In particular, when placing a workpiece on the table surface, the distance from the table surface to the workpiece upper surface may vary depending on the structure and setting conditions for fixing the workpiece to the table. May not be obtained.

  An object of the present invention is to provide a tool length measuring method and a machine tool capable of machining a workpiece with high accuracy even if the fixed state of the workpiece with respect to the table fluctuates.

In the present invention, a tool length measuring instrument (touch sensor) is installed not on the table surface but on the workpiece upper surface. If the touch sensor is installed at an arbitrary position on the workpiece upper surface, the control device of the machine tool is in a state where the position of the touch sensor (coordinate position along the workpiece upper surface) is unknown.
Therefore, in the present invention, the operator does not install the touch sensor on the workpiece upper surface, but holds the touch sensor on the spindle and moves the spindle to the predetermined position on the workpiece upper surface by relative movement between the spindle and the table. It is intended to be installed.

  Specifically, it is a tool length measuring method for measuring a tool length of a tool that is mounted on a spindle of a machine tool and processes a work placed on a table of the machine tool, and the tool is stored in a tool storage device. A preparatory step of storing a tool holder and a touch sensor capable of contacting the tip of the tool and capable of detecting the tip contact of the tool; and a workpiece setting step of setting a workpiece at a predetermined position of the table; After the touch sensor is taken out from the tool storage device and held on the spindle, the touch sensor is installed at a predetermined position on the upper surface of the workpiece by moving the spindle and the table relative to each other. After the installation step and the tool holder having the tool out of the tool storage device are taken out and held on the spindle, the touch sensor is placed at the installation position. A tool length measuring step of measuring the tool length of the tool by moving the table and the spindle relative to each other so that the writing tool is positioned and bringing the tip of the tool into contact with the touch sensor. And

According to such a structure, the tool holder and tool which have a tool are accommodated in a tool storage device (preparation process).
Then, the work is set at a predetermined position on the table (work setting process), and after the touch sensor is taken out from the tool storage device and held on the spindle, the spindle and the table are relatively moved to move the touch sensor. Is installed at a predetermined position on the upper surface of the workpiece (touch sensor installation step).
After that, the tool holder having the tool is taken out of the tool storage device and held on the spindle, and then the table and the spindle are moved relative to each other so that the tool is positioned at the installation position of the touch sensor, and the tip of the tool is moved. The tool length of the tool is measured by contacting the touch sensor (tool length measuring step).
Therefore, the tool length of the tool can be measured with reference to the upper surface of the workpiece, that is, the workpiece machining surface. Therefore, the tool length is measured with reference to the workpiece machining surface even if the fixed state of the workpiece table changes. Therefore, the workpiece can be machined with high accuracy.
In particular, in the present invention, the touch sensor is automatically installed at a designated position on the workpiece upper surface by the relative movement of the spindle and the table, rather than the operator installing the touch sensor on the workpiece upper surface. The burden on the operator can be reduced and the tool length measurement can be performed efficiently.

  In the tool length measuring method of the present invention, the touch sensor is housed in the tool storage device in a state of being held by a tool holder, and the tool holder is detachably attached to the spindle, A touch sensor holding unit that detachably holds the touch sensor, and in the touch sensor installation step, after taking out the tool holder holding the touch sensor from the tool storage device and holding it on the spindle The spindle and the table are moved relative to each other so that the touch sensor is positioned at a predetermined position on the upper surface of the work, and the touch sensor holding portion is released to move the touch sensor to the specified upper surface of the work. It is preferable to install at a position.

According to such a configuration, in the touch sensor installation process, after the tool holder holding the touch sensor is taken out of the tool storage device and held on the spindle, the spindle and the table are moved relative to each other to move the touch sensor to the workpiece. When the touch sensor holding unit is released in this state, the touch sensor is placed at the designated position on the workpiece upper surface.
Therefore, using the touch sensor holding function of the tool holder, the touch sensor can be automatically installed from the tool storage device at a designated position on the workpiece upper surface.

  In the tool length measurement method of the present invention, the touch sensor is provided integrally with a tool holder, and the tool holder is attached to the spindle detachably attached to the spindle mounting portion, and the spindle mounting portion is provided inside the upper surface of the spindle mounting portion. A touch sensor storage unit in which a touch sensor is disposed; and a base unit installed on an upper surface of the workpiece. In the touch sensor installation step, a tool holder having the touch sensor is taken out of the tool storage device. After the spindle is held, the spindle and the table are relatively moved so that the spindle is positioned at a predetermined position on the upper surface of the workpiece, the tool holder is released from the spindle, and the touch sensor is It is preferable to install at a designated position on the upper surface of the workpiece.

According to such a configuration, in the touch sensor installation process, after the tool holder having the touch sensor is taken out from the tool storage device and held on the spindle, the spindle and the table are relatively moved to move the spindle on the upper surface of the workpiece. When the tool holder is released from the spindle after being positioned at a previously designated position, the touch sensor is installed at the designated position on the workpiece upper surface.
Therefore, a tool holder having a touch sensor can be automatically installed at a specified position on the upper surface of the workpiece from the tool storage device using a normal automatic tool changer.

In the tool length measurement method of the present invention, the touch sensor is installed on the upper surface of the work until the work is finished, and the tool length measurement step is performed at any time before and during the work of the work. It is preferable to execute.
According to such a configuration, the touch sensor is installed on the upper surface of the work until the work is finished. Therefore, the tool length measurement process is executed at any time before and during the work of the work. be able to. Therefore, highly accurate machining can be performed by executing the tool length measurement process at a plurality of times during machining, for example, according to machining conditions such as heavy machining.

The machine tool of the present invention is a machine tool comprising a table for placing a workpiece, a spindle on which a tool for machining the workpiece is mounted, and a relative movement mechanism for relatively moving the table and the spindle. A tool holder having a tool and a tool storage device storing a touch sensor capable of contacting the tip of the tool and detecting the tip contact of the tool, and the tool holder or the touch sensor between the tool storage device and the spindle An automatic tool changer for exchanging the tool, and a control device. The control device takes out the touch sensor from the tool storage device and holds it on the spindle by driving the automatic tool changer. Touch sensor installation means for installing the touch sensor at a predetermined position on the upper surface of the workpiece by relatively moving the spindle and the table And taking out the tool holder having the tool from the tool storage device and holding it on the spindle, and then relatively moving the table and the spindle so that the tool is positioned at the installation position of the touch sensor. And a relative movement command means for bringing the tip of the tool into contact with the touch sensor, and a tool length measuring means for measuring the tool length of the tool based on a contact detection signal from the touch sensor. It is characterized by that.
According to such a configuration, the same effect as the above-described tool length measuring method can be expected.

The front view of the machine tool which shows one Embodiment of this invention. The figure which shows the tool holder holding the tool in embodiment same as the above. The figure which shows the tool holder holding the touch sensor in embodiment same as the above. The block diagram which shows the control system of embodiment same as the above. The figure which shows operation | movement of a touch sensor installation process in embodiment same as the above. The figure which shows operation | movement of a tool length measurement process in embodiment same as the above. The figure which shows the tool holder which has a touch sensor used in other embodiment of this invention.

Embodiments of the present invention will be described with reference to the drawings.
<Description of machine tool body>
FIG. 1 is a front view showing an embodiment of a machine tool of the present invention.
The machine tool includes a machine tool main body 10 and an NC device 30 as a control device that drives and controls the machine tool main body 10 according to a machining program, a tool length measurement program, and the like.

  The machine tool main body 10 includes a base 11, a table 12 provided on the base 11 so as to be movable in the front-rear direction (X-axis direction), and a work 12 placed on the upper surface thereof, and a pair standing upright on both sides of the base 11. Columns 13A, 13B, a cross rail 14 spanned between the upper portions of both columns 13A, 13B, and a saddle 16 provided so as to be movable in the left-right direction (Y-axis direction) along the cross rail 14. A ram 17 provided on the saddle 16 so as to be movable up and down (Z-axis direction), a main shaft 18 rotatably accommodated in the ram 17, and a drive motor 19 for rotating the main shaft 18. Prepare. The X axis, the Y axis, and the Z axis are orthogonal to each other.

  The base 11 is provided with an X-axis moving mechanism 21 that moves the table 12 in the X-axis direction, and the cross rail 14 is provided with a Y-axis moving mechanism 22 that moves the saddle 16 in the Y-axis direction. Is provided with a Z-axis moving mechanism 23 for moving the ram 17 in the Z-axis direction. The X-axis moving mechanism 21, the Y-axis moving mechanism 22, and the Z-axis moving mechanism 23 constitute a control axis. From these three control axes, the table 12 (work W) and the main shaft 18 are moved in a three-dimensional direction. A three-dimensional relative movement mechanism is provided for relative movement.

A tool storage device 25 and an ATC (automatic tool changer) 26 are provided on one column 13A side of the pair of columns 13A and 13B.
The tool storage device 25 stores a plurality of different types of tool holders, for example, a tool holder 1A (see FIG. 2) on which the tool T is mounted and a tool holder 1B (see FIG. 3) holding the touch sensor 6.
The ATC 26 performs tool exchange between the tool storage device 25 and the main shaft 18. For example, when the main shaft 18 is moved closer to the left end in FIG. 1 by driving the Y-axis moving mechanism 22, the tool holder in use attached to the main shaft 18 and the tool holder in the tool storage device 25 are automatically moved. Exchange.

As shown in FIG. 2, the tool holder 1 </ b> A is formed with a taper shank portion 2 as a main shaft mounting portion that is detachably mounted on the main shaft 18, and an intermediate flange portion 3 with respect to the taper shank portion 2. Tool holder 4A.
The taper shank portion 2 is provided with a pull stud 5 that is pulled up by a clamp claw (not shown) provided in the main shaft 18 when the tool holder 1A is mounted on the main shaft 18.
A tool T such as a drill is attached to the tool holding portion 4A. Here, before or during machining, the tool length of the tool T, that is, the length from the tip of the tool holding portion 4A to the tip of the tool T is registered as the tool length TL.

As shown in FIG. 3, the tool holder 1 </ b> B is formed via a taper shank portion 2 as a main shaft mounting portion that is detachably mounted on the main shaft 18, and an intermediate flange portion 3 with respect to the taper shank portion 2. Touch sensor holding portion 4B.
The taper shank portion 2 is provided with a pull stud 5 similarly to the tool holder 1A.
The touch sensor holding unit 4B includes a pair of clamp claws 7 that detachably hold the touch sensor 6 and an opening / closing mechanism 8 that opens and closes the pair of clamp claws 7.

The touch sensor 6 detects the contact of the main body 6C, the contact portion 6A provided on the upper surface of the main body 6C, which contacts the tip of the tool T, and the contact of the tip of the tool T on the contact portion 6A. It is the structure which has the contact detection part 6B emitted by radio | wireless.
When the contact detection unit 6B detects the contact of the tool T, a contact detection signal is wirelessly transmitted to the NC device 30 from the contact detection unit 6B.

<Description of NC device and its peripheral devices>
As shown in FIG. 4, the NC device 30 includes an X-axis moving mechanism 21, a Y-axis moving mechanism 22, a Z-axis moving mechanism 23, an X-axis displacement detector 27, a Y-axis displacement detector 28, and a Z-axis displacement detector. 29, a drive motor 19, an ATC 26, a touch sensor 6, an opening / closing mechanism 8 of the tool holder 1B attached to the spindle 18 in place of the tool holder 1A, an input device 31, a display 32, a printer 33, a memory 34, and the like are connected. ing.

  In the memory 34, in addition to a machining program for driving the X-axis moving mechanism 21, the Y-axis moving mechanism 22, the Z-axis moving mechanism 23, the drive motor 19, the ATC 26, and the like in a predetermined order, a tool length measurement program and various calculations Storage areas are provided. In the tool length measurement program, coordinate position information of the workpiece W installed on the table 12 and coordinate position information for installing the touch sensor 6 on the upper surface of the workpiece W are registered in advance. As for the coordinate position information where the touch sensor 6 is installed, a position where no machining is performed is registered in advance on the upper surface of the workpiece W.

  In addition to the function of driving the X-axis moving mechanism 21, the Y-axis moving mechanism 22, the Z-axis moving mechanism 23, the drive motor 19, the ATC 26, and the like according to the machining program, the NC device 30 drives the tool storage device 25 by driving the ATC 26. After the tool holder 1B holding the touch sensor 6 is taken out from and held on the spindle 18, the spindle 18 and the table 12 are moved relative to each other to install the touch sensor 6 at a predetermined position on the upper surface of the workpiece W. After removing the tool holder 1A having the tool T from the touch sensor installation means and the tool storage device 25 and holding it on the spindle 18, the table 12 and the spindle are arranged so that the tool T is positioned at the installation position of the touch sensor 6. 18 and a relative movement command means for bringing the tip of the tool T into contact with the touch sensor 6 and a contact detection signal from the touch sensor 6. It is configured to include a tool length measuring means for measuring a tool length of the tool T in the group.

<Tool length measurement>
First, before machining the workpiece W, the tool length TL of the tool T to be used is measured, and this tool length TL is registered.
For this purpose, an operator installs a workpiece W in advance at a designated position on the upper surface of the table 12 (work installation step). Thereafter, when the tool length measurement program is executed, the tool length measurement is executed as follows.

First, by driving the ATC 26, the tool holder 1 </ b> B (the tool holder 1 </ b> B in FIG. 3) holding the touch sensor 6 is taken out from the tool storage device 25 and mounted on the spindle 18.
Subsequently, the table 12 and the spindle 18 are relatively moved by driving the relative movement mechanism, and the touch sensor 6 is positioned at a predetermined position on the upper surface of the workpiece W (see FIG. 5A). In other words, the table 12 and the main shaft 18 are moved relative to each other by driving the X-axis moving mechanism 21, the Y-axis moving mechanism 22, and the Z-axis moving mechanism 23, and the touch sensor 6 is positioned in advance on the upper surface of the workpiece W (preliminarily specified). It is located at the registered touch sensor coordinate position).
After that, when the opening / closing mechanism 8 of the tool holder 1B is opened, the pair of clamp claws 7 are opened as shown in FIG. (Touch sensor installation process).

Next, by driving the ATC 26, the tool holder 1 </ b> A (the tool holder 1 </ b> A in FIG. 2) holding the tool T is taken out from the tool storage device 25 and mounted on the spindle 18.
Subsequently, the table 12 and the spindle 18 are relatively moved by driving the relative movement mechanism, the tool T is moved to the touch sensor installation coordinate position, and the tip of the tool T is brought into contact with the touch sensor 6 (see FIG. 6). That is, by driving the X-axis moving mechanism 21, the Y-axis moving mechanism 22, and the Z-axis moving mechanism 23, the table 12 and the main shaft 18 are relatively moved, and the tip of the tool T is brought into contact with the touch sensor 6.

  When the tip of the tool T comes into contact with the touch sensor 6, a contact detection signal is given from the touch sensor 6 to the NC device 30. Then, the NC device 30 takes in the detection value of the Z-axis displacement detector 29 and obtains the tool length TL of the tool T from this detection value (tool length measurement step). That is, the tool length TL with respect to the upper surface of the workpiece W is measured. After that, the tool length TL is registered in a predetermined area of the memory 34 and used during machining.

<Workpiece processing>
In machining the workpiece W, the X-axis movement mechanism 21, the Y-axis movement mechanism 22, and the Z-axis movement mechanism 23 are driven according to the machining program. Thereby, the workpiece W is machined by the tool T while the table 12 and the spindle 18 are relatively moved.
At this time, as a result of controlling the movement of the main shaft 18 in the Z-axis direction based on the registered tool length TL, the depth of the hole can be machined with high accuracy. That is, since the tool length TL is measured and registered with respect to the upper surface of the workpiece W, it is possible to control with high accuracy when the tip of the tool T is positioned on the upper surface of the workpiece W. Can be processed.

<Effect of embodiment>
According to the present embodiment, the workpiece W is set at a specified position on the upper surface of the table 12, the touch sensor 6 is set on the upper surface of the workpiece W, and then the tip of the tool T is brought into contact with the touch sensor 6 to set the tool length. Since TL is measured, the tool length TL of the tool T can be measured based on the upper surface of the workpiece W, that is, the machining surface of the workpiece W. Therefore, even if the fixed state of the workpiece W with respect to the table 12 varies, the workpiece W can be processed with high accuracy.

  Further, when the touch sensor 6 is installed on the upper surface of the workpiece W, the tool holder 1B holding the touch sensor 6 is stored in the tool storage device 25 together with the tool holder 1A having the tool T, and the tool storage is performed when measuring the tool length. After the tool holder 1B holding the touch sensor 6 is taken out from the device 25 and held on the spindle 18, the spindle 18 and the table 12 are moved relative to each other, and the touch sensor 6 is designated in advance on the upper surface of the workpiece W. Since the touch sensor 6 is not installed on the upper surface of the work W, the touch sensor 6 is designated on the upper surface of the work W by relative movement between the spindle 18 and the table 12. Therefore, the tool length measurement can be efficiently performed while reducing the burden on the operator.

Further, the tool holder 1B holding the touch sensor 6 is attached to the main shaft 18 in a detachable manner with a tapered shank portion 2 having a pull stud 5 at the tip, and an intermediate flange portion 3 with respect to the tapered shank portion. Since the structure includes the formed touch sensor holding portion 4B, the tool can be changed in the same manner as the tool holder 1A having the normal tool T.
In addition, the touch sensor holding portion 4B includes a pair of clamp claws 7 that detachably hold the touch sensor 6 and an opening / closing mechanism 8 that opens and closes the pair of clamp claws 7. The touch sensor 6 can be easily held and released simply by operating.

Further, since the touch sensor 6 is installed on the upper surface of the workpiece W until the machining of the workpiece W is completed, the tool length measurement process can be executed at any time before and during the machining of the workpiece W. it can.
Therefore, highly accurate machining can be performed by executing the tool length measurement process at a plurality of times during machining, for example, according to machining conditions such as heavy machining.

<Modification>
The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.

In the above-described embodiment, the touch sensor 6 is held by the tool holder 1B having the pair of clamp claws 7 and the opening / closing mechanism 8, and the opening / closing mechanism 8 is opened at the upper surface designated position of the workpiece W so that the touch sensor 6 is moved to the workpiece W. However, the present invention is not limited to this.
For example, the touch sensor 6 may be configured to be detachably held on the tool holder using vacuum, magnetism, or the like. Alternatively, the touch sensor 6 may be integrated with the tool holder. Also good.

For example, as a structure in which the touch sensor 6 is provided integrally with the tool holder, a structure as shown in FIG. 7 may be used.
That is, the taper shank part 2 which is detachably attached to the main shaft 18 and has the pull stud 5 at the tip, the intermediate flange part 3, the base part 4C, the taper shank part 2 and the upper surface of the pull stud 5 are provided. It has a structure having a touch sensor housing portion 9 for housing the touch sensor 6. A contact portion 6 A of the touch sensor 6 is provided on the upper surface of the pull stud 5, and a contact detection portion 6 B of the touch sensor 6 is provided inside the tapered shank portion 2. The base portion 4C is formed on a flat surface so that the posture is stabilized when the bottom surface is installed on the top surface of the workpiece W.

  In the case of this tool holder 1C, after the tool holder 1C having the touch sensor 6 is taken out from the tool storage device 25 and held on the spindle 18 in the touch sensor installation process, the spindle 18 and the table 12 are moved relative to each other. If the main shaft 18 is positioned at a predetermined position on the upper surface of the workpiece W and the tool holder 1C is released from the main shaft 18, the touch sensor 6 can be installed at the specified position on the upper surface of the workpiece W.

  In the above embodiment, the table 12 is described as an example of a machine tool that can move in the X-axis direction and the main shaft 18 can move in the Y-axis direction and the Z-axis direction. Any machine tool may be used as long as the machine tool is structured to move relative to each other.

  INDUSTRIAL APPLICABILITY The present invention can be used for a machine tool that performs cutting of a workpiece by mounting and rotating a tool having a cutter on a main shaft.

1A, 1B, 1C ... Tool holder,
2… Taper shank (main shaft mounting part),
4A ... Tool holder,
4B ... Touch sensor holding part,
4C ... pedestal,
6 ... Touch sensor,
6A ... contact part,
6B ... contact detection unit,
9: Touch sensor housing,
12 ... table,
18 ... Spindle,
21 ... X-axis movement mechanism (relative movement mechanism),
22 ... Y-axis movement mechanism (relative movement mechanism),
23 ... Z-axis movement mechanism (relative movement mechanism),
26 ... ATC (automatic tool changer),
30 ... NC device (control device, touch sensor installation means, relative movement command means, tool length measurement means),
T ... Tool,
TL ... Tool length,
W ... Work.

Claims (5)

A tool length measuring method for measuring a tool length of a tool that is mounted on a spindle of a machine tool and processes a workpiece placed on a table of the machine tool,
A preparatory step of storing a tool holder having the tool in the tool storage device and a touch sensor capable of contacting the tip of the tool and detecting the tip contact of the tool;
A workpiece installation step of installing a workpiece at a predetermined position of the table;
After the touch sensor is taken out from the tool storage device and held on the spindle, the touch sensor is installed at a predetermined position on the upper surface of the workpiece by moving the spindle and the table relative to each other. Installation process;
After taking out the tool holder having the tool from the tool storage device and holding the tool holder on the spindle, the table and the spindle are relatively moved so that the tool is positioned at the installation position of the touch sensor, A tool length measuring step of measuring the tool length of the tool by bringing the tip of the tool into contact with the touch sensor;
A tool length measuring method comprising: In the tool length measuring method according to claim 1,
The touch sensor is stored in the tool storage device while being held by a tool holder,
The tool holder has a spindle mounting part that is detachably mounted on the spindle, and a touch sensor holding part that detachably holds the touch sensor,
In the touch sensor installation step, the tool holder holding the touch sensor is taken out from the tool storage device and held on the spindle, and then the spindle and the table are moved relative to each other to move the touch sensor to the workpiece. It is located at a predesignated position on the upper surface, and the touch sensor holding part is released to install the touch sensor at a designated position on the upper surface of the workpiece.
The tool length measuring method characterized by the above-mentioned. In the tool length measuring method according to claim 1,
The touch sensor is provided integrally with the tool holder,
The tool holder includes a spindle mounting section that is detachably mounted on the spindle, a touch sensor storage section in which the touch sensor is disposed inside an upper surface of the spindle mounting section, and a base section that is installed on the upper surface of the workpiece. Have
In the touch sensor installation step, after the tool holder having the touch sensor is taken out from the tool storage device and held on the spindle, the spindle and the table are moved relative to each other to move the spindle on the upper surface of the workpiece. Positioned at a predesignated position, releasing the tool holder from the spindle and installing the touch sensor at a designated position on the workpiece upper surface;
The tool length measuring method characterized by the above-mentioned. In the tool length measuring method in any one of Claims 1-3,
The touch sensor is installed on the upper surface of the workpiece until the processing of the workpiece is completed,
Performing the tool length measuring step at any time before and during machining of the workpiece;
The tool length measuring method characterized by the above-mentioned. In a machine tool comprising a table for placing a workpiece, a spindle on which a tool for machining the workpiece is mounted, and a relative movement mechanism for relatively moving the table and the spindle,
A tool storage device storing a tool holder having the tool and a touch sensor capable of contacting the tip of the tool and detecting the tip contact of the tool;
An automatic tool changer for exchanging the tool holder or touch sensor between the tool storage device and the spindle;
A control device,
The control device drives the automatic tool changer to take out the touch sensor from the tool storage device and hold it on the spindle, and then relatively moves the spindle and the table to move the touch sensor. Touch sensor installation means installed at a predetermined position on the upper surface of the workpiece, and after taking out a tool holder having the tool from the tool storage device and holding the tool holder on the spindle, the touch sensor is installed at the installation position of the touch sensor. Relative movement command means for moving the table and the spindle relative to each other so that the tool is positioned, and bringing the tip of the tool into contact with the touch sensor, and the tool of the tool based on a contact detection signal from the touch sensor A tool length measuring means for measuring the length,
A machine tool characterized by that.

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