JP2001239440A - Machining center - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect an actual main spindle position in at least directions of two axes close to a workpiece machining position receiving no influence of thermal deformation and compensate a workpiece machining position of a main spindle based on the main spindle position to machine a workpiece with high precision. SOLUTION: X-axis and Y-axis magnetic sensors 24, 25 are provided at positions apart from machine zero point O by respective reference distances Lx, Ly in the directions of X-axis and Y-axis on a jig 18 on a bed. Position detection tools provided with magnets for detecting X-axis and Y-axis directions are mounted on the main spindle of machining center. Deviation amounts, Δx, Δy are obtained from actual travel distances L1x, L1y of the main spindle when the sensors 24, 25 corresponding to each magnet detect each magnet and the reference distances Lx, Ly to compensate a workpiece coordinate zero point O1 to use it as a new workpiece coordinate zero point O2. The workpiece W is machined based on the new workpiece coordinate zero point O2 to improve machining precision.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a machining center capable of detecting a relative distance between a spindle and a workpiece, and more particularly, to a machining center capable of correcting a workpiece machining position of the spindle during workpiece processing based on the detected relative distance. .

[0002]

2. Description of the Related Art Generally, a machine tool such as a machining center uses a moving amount measuring means such as a pulse coder provided on a motor for moving a column or a spindle head, or a linear scale provided in parallel with a moving direction. The position of the spindle equipped with a tool is detected by measuring the amount of movement of the column or the spindle head. However, the moving amount measuring means is provided at a position distant from the processing portion of the work, and when the inclination of the jig or the column falls due to thermal deformation, the spindle measured by the moving amount measuring means due to the influence thereof. Between the position (tool position) and the actual position of the spindle.
For this reason, there is a problem that the measurement accuracy of the relative distance between the main shaft and the jig (workpiece processing portion) is reduced.

[0003] In order to solve such a problem, there is an apparatus in which the position of a tool is detected near a work and the position of the tool can be measured without being affected by thermal deformation or the like. Such a device is disclosed in JP-A-60-123255. In this method, a magnetic sensor, which is a detecting means, is fixed to a jig to which a workpiece to be processed is fixed, and a magnet fixed to a tool holder is detected by the magnetic sensor to detect a position of a cutting tool (tool) provided on a main shaft. It is supposed to. The tool is advanced in the Z-axis direction (toward the spindle axis direction) toward the workpiece, and the position where the magnetic sensor detects the magnet is set as the machining origin, and the feed amount of the cutter in the Z-axis direction is measured from this machining origin. Is used to accurately detect the tool position.

In the apparatus disclosed in JP-A-1-193115, a detecting means is provided on a jig on which a work is placed, and the tip of the tool is brought into contact with the detecting means so that the tip of the tool and the jig of the jig can be connected. The distance from the top surface is used as the machining origin when machining the workpiece. This machining origin is calculated from the distance between the upper surface of the jig and the upper surface of the detecting means and the amount of tool movement when the tool tip comes into contact with the detecting means, and the distance between the tool tip and the upper surface of the jig is calculated as the machining origin. Is set, and the accurate tool position of the tool moving toward the workpiece is detected.

[0005]

In the prior art, only the position in the Z-axis direction, which is the tool advancing direction when the tool is sent toward the workpiece, is detected, so that the specific one-axis direction is used. In the case of only processing, for example, processing such as drilling a hole, when it is desired to perform processing with an accurate processing depth, the processing can be performed with high accuracy. However, in a machine tool such as a machining center that sends the spindle in three orthogonal directions of X, Y, and Z axes, the spindle is moved from the origin set at a predetermined position at the time of workpiece machining to the work processing position in the X and Y axes. It is also necessary to accurately detect the position of the spindle in the X and Y axis directions, and detecting the position in the Z axis direction alone will result in thermal deformation of the workpiece processing position in the X and Y axes directions. And the like, and it is difficult to position the main spindle at an accurate work processing position. Therefore, there is a limit in processing a workpiece with higher accuracy. An object of the present invention is to detect the position of a spindle near a workpiece processing position that is not easily affected by thermal deformation and the like, and to position the spindle at an accurate workpiece processing position based on the detection of the spindle position, thereby achieving high accuracy. An object of the present invention is to provide a machining center capable of performing high workpiece machining.

[0006]

According to the present invention, in a machining center capable of detecting the position of a spindle having a tool at a tip thereof near a workpiece, the position of the spindle can be detected in at least two orthogonal directions orthogonal to each other. (Claim 1). According to this, the relative work processing position between the work and the spindle can be accurately detected.

[0007] Either a means to be detected or a means for detecting the means to be detected is provided on the jig side of the spindle head, and the jig is separated from the machine origin by a predetermined reference distance in each of the axial directions. The other means is provided at each axial reference position. According to this, at the time of detecting the spindle position, the tip of the spindle provided with one of the means and the tip of the spindle head are located near the jig, so that the position of the spindle at a position away from the spindle ( As compared with the case of measuring the amount of movement, accurate detection that is not affected by thermal deformation or the like can be performed.

Preferably, when the main shaft is moved from the mechanical origin toward at least two axial reference positions, the actual movement distance of the main shaft in each axial direction is detected, and the actual movement distance and the actual movement distance of each main shaft are detected. The spindle position at the time of workpiece machining is corrected based on the amount of deviation from the reference distance (claim 3). Since the detection means detects the detection means in the state of relative movement of the main spindle with respect to the work, the detection accuracy is high, and the displacement can be corrected with high accuracy.

The detected means includes an X-axis direction detecting magnet and a Y-axis direction detecting magnet, which are detection bodies for detecting at least the X-axis direction movement and the Y-axis direction movement of the main shaft,
The detecting means includes an X-axis magnetic sensor for detecting the X-axis direction detecting magnet and a Y-axis magnetic sensor for detecting the Y-axis direction detecting magnet, which correspond to the X-axis direction detecting magnet and the Y-axis direction detecting magnet, respectively. It is a sensor (claim 4).

Further, the detected means is a position detecting tool, the position detecting tool is replaceably provided on the main shaft, and the jig is provided with a detecting means. Providing the main spindle with the position detecting tool is preferable because the position can be detected in substantially the same state as in normal machining with the normal spindle provided on the main spindle.

More specifically, in a machining center capable of detecting the position of a spindle provided with a tool at a tip thereof near a workpiece, the spindle is provided with a replaceable position detection tool, and the tip of the position detection tool is provided with a spindle. An X-axis direction detecting magnet for detecting the X-axis direction movement and a Y-axis direction detecting magnet for detecting the Y-axis direction movement are provided, and the jig is provided with a predetermined X-axis direction reference distance from the machine origin. An X-axis magnetic sensor for detecting an X-axis direction detecting magnet at an X-axis reference position, and detecting a Y-axis direction detecting magnet at a Y-axis reference position at a predetermined Y-axis direction reference distance from a machine origin. , And when the main axis is moved from the machine origin to each reference position, the deviation amount between the actual movement distance of the main axis in the X and Y axis directions and each reference distance is obtained, and the deviation amount in each X and Y axis direction is obtained. Is set to a predetermined position from the machine origin based on It was was configured to correct the work coordinate origin as the origin of the workpiece machining position during workpiece machining (claim 6). According to this, the work coordinate origin at the time of work machining is set separately from the machine origin which is the absolute reference of the spindle position, and the spindle is moved to the machining position set based on the work coordinate origin to machine the work. Therefore, if the work coordinate origin is corrected, the processing position is also corrected, which is preferable. In addition, since the processing position is set based on the work coordinate origin, the dimension values described on the drawing correspond directly to the dimension values input to the machining center. No calculations are required, and the dimensions can be easily confirmed.

The position detecting tool is provided with a detecting body at a tip portion thereof, and the detecting body is located on the center axis of the position detecting tool. According to this, when the tool is mounted on the main spindle, even if a slight rotation is allowed between the tool holder having the tool and the main spindle, the mounting position of the detection body is always on the center axis, so that accurate detection is possible. Detection can be performed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. The machining center (machine tool) 1 is substantially the same as that disclosed, for example, in Japanese Patent No. 2980028, and is mounted on a bed 2 of the machining center 1 by a motor M1 in the Z-axis (front-back) direction (FIG. 1).
A slider (Z-axis movable base) 3 is provided so as to be movable in the left-right direction in FIG. The slider 3 has a motor M2
A column 4 is provided which is movable in the X-axis (left-right) direction (in the direction perpendicular to the plane of FIG. 1). Column 4
A spindle head 7 on which a spindle 6 on which a tool 5 is mounted is rotatably supported is provided so as to be movable in a Y-axis (vertical) direction (vertical direction in FIG. 1) by a motor M3.

A column 8 is erected on the upper surface of the bed 2, and a magazine support base 9 is provided on an upper end of the column 8, and is located above the column 4. The magazine support base 9 is provided with a tool changing device (ATC device) 10. The tool changing device 10 includes an arm device 11, a tool magazine 12, and a transfer device 13, and exchanges a tool holder 14 provided with each tool 5 between the tool magazine 12 and the main shaft 6. The arm device 11 is integrally mounted on the lower surface of the magazine support base 9 with a slight gap between the lower surface of the column 4 and the tool support arm 1.
5 is rotatably provided. The tool magazine 12 includes a magazine base 1 provided on an upper surface of the magazine support base 9.
6 is equipped. The tool magazine 12 includes a magazine plate 17 which is turned and indexed, and the magazine plate 17 is provided with a large number of tool holders 14 holding the tools 5. The transfer device 13 is disposed inside the magazine base 16 between the arm device 11 and the tool magazine 12. The transfer device 13 transfers the tool holder 14 indexed by the tool magazine 12 to a position where the tool change arm 15 can be replaced with the tool holder 14 of the main spindle 6, and returns the replaced tool holder 14 to the tool magazine 12. It has become.

A jig 18 is provided on the bed 2. The jig 18 is provided with a processing hole 19 at the center as shown in FIGS. At the four corners of the jig 18, clamp cylinders 20 are provided, respectively, and the pallet 21 is held on one side of the jig 18 by the clamp cylinders 20 as shown in FIG. 3. A work (workpiece) W is fixed to the pallet 21 so as to be exchangeable.
A processing through hole (not shown) is formed corresponding to the processing location of the workpiece W.

On the other side of the jig 18, an X sensor mounting member 22 and a Y sensor mounting member 23 are protruded as shown in FIG. The X sensor mounting member 22 and the Y sensor mounting member 23 are connected to the X-axis magnetic sensor 2
4 and the Y-axis magnetic sensor 25 are attached, X
An axial magnetic sensor 24 is provided at an X-axis reference position separated by a reference distance Lx from the mechanical origin O in a predetermined X-axis direction, and a Y-axis magnetic sensor 25 is disposed at a reference distance L from the mechanical origin O in a predetermined Y-axis direction.
In FIG. 2, the X sensor mounting member 22 is provided on the left portion of the upper frame 26 and the Y sensor mounting member 23 is provided on the upper portion of the left frame 27 so as to be provided at the Y-axis reference position separated by y. . In the embodiment of the present application, the tool 5 of the spindle 6 is used.
A tool replacement position where the spindle 6 is located, at which the tool 5 of the tool magazine 12 can be replaced with the tool 5, is defined as a machine origin O.

As shown in FIG. 4, a position detecting tool 28 provided on the main shaft 6 is provided with an X-axis direction detecting magnet 29 and a Y-axis direction detecting magnet 29 on the tip side of the tool holder 14. A cylindrical detector mounting member 31 provided with a magnet 30 is mounted. Attachment portion 31 of X-axis direction detection magnet 29 at tip end of detector attachment member 31
a has an X-axis direction detecting magnet detected by the X-axis magnetic sensor 24 on the ZX plane 32 of the semicircle portion, the cross section of which does not include the center axis C of the tool holder 14. 2
9 are attached. The surface 33 of the X-axis direction detecting magnet 29 facing the X-axis magnetic sensor 24 is located at a position including the center axis C of the tool holder 14.

A ZX plane 32 having a substantially semicircular cross section is integrally formed at the tip of the mounting portion 31a of the X-axis direction detecting magnet 29.
Is a mounting portion 31b of the Y-axis direction detecting magnet 30 on which a YZ plane 34 orthogonal to the YZ plane 34 is formed.
4, a Y-axis direction detecting magnet 30 detected by the Y-axis magnetic sensor 25 is attached, and a surface 35 of the Y-axis direction detecting magnet 30 facing the Y-axis magnetic sensor 25 is aligned with the center axis C of the tool holder 14. It is in the position including. Opposite surfaces 33, 3 of these X, Y axis direction detecting magnets 29, 30 with sensors 24, 25.
When the tool 5 includes the central axis C, even if the tool holder 14 and the spindle 6 can be slightly rotated relative to each other when the tool is exchanged, they are detected by the sensors 24 and 25 of the magnets 29 and 30. The position is not affected by the rotation and the sensor 24,
25 allows the same location of the magnets 29 and 30 to be always detected, and accurate detection can be performed.

Numerical control unit 36 of machining center 1
Is provided with a spindle position detecting unit 37, a comparing and calculating unit 38, a work coordinate origin correcting unit 39, a storage unit 40, and a numerical control unit 41. The storage unit 40 stores the X of the X-axis magnetic sensor 24.
The reference distance Lx in the axial direction, the reference distance Ly in the Y-axis direction of the Y-axis magnetic sensor 25, the work coordinate origin O1 at a predetermined position from the mechanical origin O which is the origin of the work processing position during work processing, and the work coordinate origin. The coordinates and the like of the processing position of the work W are set and stored based on O1. Number position control unit 41
Performs the machining of the work W by controlling the movement of the spindle 6 and the drive of the tool changing device 10 and the like.

An X-axis magnetic sensor 24 and a Y-axis magnetic sensor 25 provided on the X sensor mounting member 22 and the Y sensor mounting member 23, respectively, are connected to the main shaft position detecting means 37. The main shaft position detecting means 37 is connected to respective pulse coders 42 and 43 for generating pulses corresponding to the rotations of the motors M2 and M3. The main shaft position detecting means 37 detects the main shaft position, that is, the mechanical position based on the number of pulses from each of the pulse coders 42 and 43 when the X and Y axis direction detecting magnets 29 and 30 are detected by the X and Y axis magnetic sensors 24 and 25, respectively. X, Y axis magnetic sensor 24 from origin O,
25, the actual movement distances L1x, L of the main shaft 6 in the X and Y axes directions.
Measure 1y. Actual measured distance L1 in each axis direction
x and L1y are output to the comparison calculation means 38. Note that X,
Instead of the pulse coders 42 and 43, the actual movement distances L1x and L1y in the Y-axis direction may be measured in combination with linear scales provided in the X and Y-axis directions.

The comparison calculating means 38 compares the reference distance Lx in the X-axis direction and the reference distance Ly in the Y-axis direction with the actual movement distances L1x and L1y of the main shaft 6 in the X- and Y-axis directions. The reference distances Lx and Ly and the actual movement distances L1x in the X and Y axis directions,
The shift amounts Δx and Δy from L1y are calculated, and the shift amounts Δ
x and Δy are output to the storage unit 40 and stored in the storage unit 40, and the deviation amounts Δx and Δy are output to the work coordinate origin correction unit 39 as correction amounts.

The work coordinate origin correction means 39 corrects the work coordinate origin O1 based on the deviation amounts Δx and Δy calculated by the comparison calculation means 38, and sets and stores the new work coordinate origin O2 in the storage section 40 as a new work coordinate origin O2.

Next, the operation will be described. FIG. 6 is a flowchart showing a machining program for one workpiece,
The machining center 1 performs one cycle of processing of the work W in accordance with this flowchart. When the machining center 1 is started and the processing of the work W is started, it is determined whether or not the work coordinate origin O1 is corrected by the correction determining means in step S1. In this step S1, the storage unit 40
, The elapsed time from the start of machining of the appropriate work W, for example, for each machining cycle of one work W in the machining center 1, or for a plurality of cycle times in which an appropriate number of works W are machined. Or or work W
The relative displacement Δx between the main shaft 6 and the jig 18 (work W) depends on whether the next processing is high-precision processing in the processing step, or after the appropriate number of tool changes. , Δy are to be corrected.

Hereinafter, in the embodiment of the present application, step S1
It is assumed that it is determined whether the correction is made based on the elapsed time from the start of the processing of the work W. First, immediately after the start of the machining center 1, it is determined in step S1 to be Yes (the work coordinate origin O1 is corrected).
In step 2, the spindle 6 moves to the machine origin O, which is a tool change position, and the cutting tool 5 mounted on the spindle 6 is replaced by the tool changing device 10 with the position detecting tool 28. At this time, the spindle 6 is stopped at a fixed position.

Next, in step S3, the spindle 6 is moved to the position X1 near the X-axis magnetic sensor 24 shown in FIG.
Sent from at high speed. Then, it is sent at a low speed from the position X1 to the X-axis magnetic sensor 24, and stopped at the position X2.
At this time, the movement of the spindle 6 causes the X of the position detecting
An axial direction detecting magnet 29 faces the X-axis magnetic sensor 24,
At this time, the X-axis magnetic sensor 24 is set to the X-axis direction detecting magnet 29.
Is detected. When the X-axis direction detecting magnet 29 is detected, X
The detection signal from the shaft magnetic sensor 24 is used as the main shaft position detecting means 3
7, and the pulse from the pulse coder 42 corresponding to the motor M2 at this time is counted, and the number of pulses in the X-axis direction from the mechanical origin O of the main shaft 6 to the X-axis magnetic sensor 24 displaced from this pulse number is counted. The actual moving distance L1x is measured.

Next, in step S4, the main shaft 6 is sent from the position X2 to the position Y1 near the Y-axis magnetic sensor 25 by rapid traverse. Then, the position detection tool 28 is sent to the Y-axis magnetic sensor 25 to the position Y2 in substantially the same manner as in step S5. When the Y-axis direction detecting magnet 30 is detected by the Y-axis magnetic sensor 25, the main shaft position detecting means 37 detects the main shaft 6 from the detection signal from the Y-axis magnetic sensor 25 and the number of pulses of the motor M3 at that time. Y displaced from mechanical origin O
The actual movement distance L1y in the Y-axis direction up to the axial magnetic sensor 25 is measured.

Next, in step S5, the actual movement distances L1x, measured in steps S3 and S4 by the comparison calculation means 38,
The shift amounts Δx and Δy are calculated from L1y and stored in the storage unit 40. In step S6, the work coordinate origin correcting means 39
As a result, the X coordinate and the Y coordinate of the work coordinate origin O1 with respect to the machine origin O are corrected based on the shift amounts Δx and Δy in the X and Y axis directions calculated in step S5, and the coordinate value of the work coordinate origin O1 is newly set. The coordinate value of the work coordinate origin O2 is stored in the storage unit 40. The correction amount of the coordinate value from the mechanical origin O to the work coordinate origin corrected at this time is calculated in proportion to the deviation amounts Δx and Δy. Next, step S
At 7, the spindle 6 moves to the tool change position O, and the position detecting tool 28 mounted on the spindle 6 is replaced by the tool changing device 10 with the normal cutting tool 5. Next, step S8
Then, the processing of the work W is performed based on the new work coordinate origin O2, and the processing ends.

When the processing of the work W is completed, a new work W is fixed to the jig 18 of the machining center 1 and
Processing is started again by the processing program. In the process of machining several works W at the beginning of the work, relative displacement Δx between the spindle 6 and the jig 18 (working position of the work W),
Δy is easy to change. For this reason, for several works W at the beginning of work processing, it is determined Yes in step S1 every time one cycle is completed, and steps S1 to S8 are repeated in the same manner as described above, and the work coordinate origin O1 is determined in this processing step. New work coordinate origin O2 and the work W
To process.

After several workpieces W have been machined from the start of machining, the shift amounts Δx and Δy are not calculated every time a new workpiece W is machined, but are calculated a plurality of times (for example, two times). Deviation amount Δx for each processing cycle)
Δy is calculated. At this time, first, in step S1, Ye
s, and steps S1 to S
8 is repeated, and the work W is processed. When the next new workpiece W is to be machined, No is determined in step S1 and the process proceeds to step S9, in which the shift amount Δ calculated at the start of the first machining cycle in a plurality of machining cycles.
x, Δy, that is, the previously calculated deviation amounts Δx, Δyt are called from the storage unit 40, and the process proceeds to step S6. In step S6, the work coordinate origin is corrected from O1 to O2 based on the shift amounts Δx and Δy calculated last time. Next, the process proceeds from step S7 to step S8, and the processing ends. Thereafter, Step S1, Steps S6 to S9 are repeated until a plurality of set machining cycles are completed. When a plurality of machining cycles are completed, the deviation amounts Δx and Δy are newly calculated in steps S1 to S5 again, and the work coordinate origin is corrected based on the deviation amounts Δx and Δy in step S6. The work W is processed, and in the processing of the next work W, step S
1. Steps S6 to S9 are repeated.

As described above, the workpiece can be machined while eliminating the influence of the displacement of the spindle 6, so that the workpiece can be machined with high accuracy. Further, by correcting the work coordinate origin O1, which is the processing origin with respect to the work processing position during work processing, the work W is processed even if the processing position is shifted due to the influence of the column 4 falling or the feed screw elongating. Since the position coordinates are input with reference to the work coordinate origin O1, the coordinate values are used as they are in the machining without being corrected, and there is no need to recalculate the machining position coordinates of the work W. There is no need to create a program for calculating the workpiece processing position coordinates based on Δy, and the processing position coordinates are displayed on the numerical control device as the dimension values at the time of input, and can be easily confirmed. In addition, the displacement of the spindle 6 with respect to the workpiece processing position is corrected each time the workpiece is replaced in the first few cycles of the workpiece processing in which the shift amount is liable to change. Can be shortened, which is preferable.

Although the position detecting tool 28 is used for detecting the amount of displacement, a magnet may be provided integrally with the tip of the spindle head 7 to detect the amount of displacement. Further, a magnet for detecting the Z-axis direction and a Z-axis magnetic sensor may be provided so that the detection including the shift amount in the Z-axis direction may be performed. Further, the means to be detected and the detecting means are not limited to the magnet and the magnetic sensor, and other means may be used.

[0032]

As described above, in the present invention, the position of the main spindle is detected in at least two directions perpendicular to each other near the workpiece. In addition to being able to perform accurate detection that is not affected by the influence, unlike the conventional one that detects only one axis direction, the amount of deviation is calculated from the detected main axis position in two axis directions and corrected, and the main spindle is positioned at the correct work processing position. An excellent effect of being able to be obtained. Thereby, high-precision work processing can be performed.

Also, by providing a tool for position detection on the spindle and detecting it by the detecting means provided on the jig, the position can be detected in substantially the same state as during normal machining with the ordinary tool on the spindle. It is possible and suitable.

In addition, the work coordinate origin at the time of work machining is set separately from the mechanical origin which is an absolute reference of the spindle position,
If the work coordinate origin is corrected at the time of work processing, it is not necessary to correct the input dimension value for work processing based on the work coordinate origin, so that the calculation for correcting the processing position becomes unnecessary and It is easy to confirm the input machining position.

Further, since the detection body provided on the position detecting tool is located on the axis of rotation of the spindle, the tool holder and the spindle can be slightly rotated relative to each other when the tool is changed. Can be performed.

[Brief description of the drawings]

FIG. 1 is a side view of a machining center of the present application.

FIG. 2 is a II view of FIG.

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is an explanatory view showing a position detection tool.

FIG. 5 is an explanatory diagram showing a main configuration of the machining center.

FIG. 6 is a flowchart showing a work machining program.

[Explanation of symbols]

 Reference Signs List 1 machining center 5 tool 6 spindle 7 spindle head 18 jig 24 X-axis magnetic sensor 25 Y-axis magnetic sensor 28 position detecting tool 29 X-axis direction detecting magnet 30 Y-axis direction detecting magnet C Center axis Lx X-axis direction reference distance Ly Y-axis direction reference distance L1x X-axis actual movement distance L1y Y-axis actual movement distance Δx X-axis deviation amount Δy Y-axis deviation amount O Mechanical origin O1 Work coordinate origin W Work

Claims (7)

[Claims] 1. A machining center capable of detecting the position of a spindle having a tool at a tip thereof near a workpiece, wherein the position of the spindle can be detected in at least two orthogonal directions. 2. A jig side of the spindle head is provided with either a means to be detected or a detecting means to detect the means to be detected, and the jig is provided with a predetermined reference from the mechanical origin in each axial direction. 2. The machining center according to claim 1, wherein the other means is provided at each axial reference position at a distance. 3. An actual movement distance of the spindle in each axis direction when the spindle is moved from the machine origin to at least two axial reference positions, and the actual movement distance and each reference distance are detected. 3. The machining center according to claim 2, wherein the spindle position at the time of machining the workpiece is corrected based on the amount of deviation from the machining center. 4. The detection means includes an X-axis direction detecting magnet and a Y-axis direction detecting magnet, which are detection bodies for detecting at least the X-axis direction movement and the Y-axis direction movement of the main shaft. Means are an X-axis magnetic sensor for detecting the X-axis direction detecting magnet and a Y-axis magnetic sensor for detecting the Y-axis direction detecting magnet, respectively corresponding to the X-axis direction detecting magnet and the Y-axis direction detecting magnet. The machining center according to claim 2, wherein: 5. The apparatus according to claim 2, wherein the detected means is a position detecting tool, the position detecting tool is exchangeably provided on the main shaft, and the jig is provided with a detecting means. The machining center described. 6. A machining center capable of detecting a position of a spindle having a tool at a tip thereof near a workpiece, wherein a position detection tool is exchangeably provided on a spindle, and the spindle is moved in the X-axis direction at a tip portion of the position detection tool. And a Y-axis direction detecting magnet for detecting the movement in the Y-axis direction are provided on the jig, and an X-axis reference position at a predetermined X-axis direction reference distance from the machine origin is provided on the jig. An X-axis magnetic sensor for detecting the X-axis direction detecting magnet is provided, and a Y-axis magnetic sensor for detecting the Y-axis direction detecting magnet is provided at a Y-axis reference position at a predetermined Y-axis direction reference distance from the machine origin. Of the actual movement of the spindle in the X and Y axis directions and the reference distances when X is moved from the machine origin to the respective reference positions.
A machining center configured to correct a work coordinate origin, which is set at a predetermined position from a machine origin and is an origin of a work processing position at the time of work processing, based on an axial deviation amount. 7. The position detecting tool according to claim 5, wherein a detecting body is provided at a tip portion of the tool, and the detecting body is located on a central axis of the position detecting tool. Machining center.