JP2008105134A - Machine tool and machining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a machine tool which accurately and practically performs fine and precise machining work using a tool for fine machining, and further to provide a machining method. <P>SOLUTION: The machining method comprises steps of: mounting a tool 6 on the main spindle 5 of the machine tool 1 (S4); turning the main spindle 5 under the same condition as that in actual machining (S5); stabilizing the position of the main spindle 5 (S6); sensing the electric discharge phenomenon between the tool 6 and a workpiece 7 by making the tool 6 approach the vicinity of the workpiece 7 (S7); calculating a machining origin of the workpiece 7 from the positional data of the discharge (S8); and starting the machining operation by moving the main spindle 6 to the machining position based on the calculated machining origin of the workpiece 7 (S9). When the machining condition has changed, the steps from the step (S5) of turning the main spindle to the step (S9) of starting the machining operation are carried out again. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a machine tool and a machining method, and in particular, a tool rotating at a rotation speed at the time of machining is brought close to the workpiece as a non-contact type measurement probe, and the workpiece and the rotating tool are The present invention relates to a machine tool and a machining method for starting machining by calculating a machining origin from a tool position at this time when a minute electric discharge phenomenon occurs.

Conventionally, a machine tool such as a machining center that uses a machining tool such as an end mill (appropriately abbreviated as a tool) has been required to improve machining accuracy. In order to improve the machining accuracy, for example, in each element of the machine tool including the tool, the operation method, and the like, it is necessary to accurately measure the tool dimension and accurately position the machining origin.
For this reason, various techniques have been developed.

For example, in Patent Document 1, a potential difference is given between the spindle of a machine tool and a table, the relative position between a tool attached to the spindle and a probe fixed to the table is detected by electrical conduction, Techniques for measuring tool dimensions for measuring dimensions are disclosed.
With this technology, the spindle that detects a discharge phenomenon in a non-contact state between the tool and the probe by rotating the tool attached to the spindle from the reference position where the tool does not interfere with the probe and rotating it in the direction of the probe. The tool length and the tool diameter are measured based on the position in the direction and the position in the radial direction of the spindle.
According to the above technique, the tool length and the tool diameter, which are tool dimensions, can be accurately measured by a practical non-contact method without contacting the tool in the same state as the machining state.

In Patent Document 2, a potential difference is given between the spindle of the machine tool and the table, the tool attached to the spindle is brought close to the probe fixed to the table, and the tool and the probe are placed between each other. A technique of a tool dimension measuring method is disclosed in which a discharge phenomenon that occurs in a non-contact state in a formed fine gap is detected, and a tool dimension is measured from a relative position between the tool and a probe at this position.
In this technique, a measuring element has a measurement surface arranged along a vertical direction and a horizontal direction, and a tool and a measurement surface are relatively approached from a direction perpendicular to the measurement surface to cause a discharge phenomenon. It is characterized in that the dimensions of the tool are obtained by calculation based on the relative position between the tool and the probe at the time of detection.
According to the above technique, it is possible to accurately measure the tool dimensions in a short time by employing a simple process.

Patent Document 3 discloses a technique of a grinding apparatus having a grinding tool that is rotationally driven, a workpiece fixing device, and a controllable moving device that changes a relative position between the grinding tool and the workpiece. .
This technique includes a discharge generator that can be connected to a grinding tool and a workpiece or a reference element, and the moving device is controlled by a control circuit that uses a discharge current as a control parameter upon contact to perform the grinding tool and electric discharge machining. Tools are arranged to be usable with the same set of workpieces. Also, the grinding tool is made of a conductive material, and the electric discharge generator and its control circuit are connected to the tool for electric discharge machining, and the control circuit moves the moving device based on the program storage device and / or during the mechanical grinding operation. Or it is characterized by controlling regarding the distance between a grinding tool and a workpiece based on the discharge current utilized only as a control current.
According to the above technology, when two completely different machining methods (grinding and electrical discharge machining) are performed, the workpiece can be carried out in the same fixed (set) state, which not only shortens the process but also improves accuracy. Can also be realized.

Further, Patent Document 3 discloses a technique of a grinding method for grinding a workpiece by determining a contact position with a grinding tool.
In this technique, a grinding tool is brought into contact with a workpiece or a reference element, and a discharge voltage is applied between them to perform a predetermined positioning motion and / or feed motion for mechanical grinding with reference to the contact position. It is as. Also, using a conductive grinding tool as the grinding tool, in the same set state, the workpiece is processed by electric discharge machining or electric discharge grinding with the first tool as the first stage, and then the grinding tool is discharged as the second stage. A mechanical grinding process is performed by bringing the workpiece into a contact position suitable for mechanical ablation based on the electric current, and the discharge current for the contact is determined by a corresponding control circuit used during the electric discharge machining or electric discharge grinding of the workpiece. For forming and then for the second stage mechanical grinding, the discharge voltage is turned off or essentially adjusted to a numerical value for mechanical material ablation.
According to this technique, the discharge current controlled automatically in the second stage of mechanical grinding using the second tool following the first stage of electric discharge machining using the first tool is automatically and quickly performed. In addition, accurate positioning and feeding of the second tool with respect to the workpiece can be realized, and the second tool can be continuously adjusted during the second stage of mechanical grinding as required.

Further, in Patent Document 4, in a machine tool, a cutting tool and a contacted object are relatively moved by a moving device capable of detecting a moving position to bring them into contact with each other, and based on the moving position of the moving device at the time of contact. The technique of the blade tool position control method which controls the relative movement of the subsequent blade tool and a workpiece is disclosed.
This technology includes a normal confirmation process for confirming that the contact detection device that detects contact between the blade and the contacted object can detect the contact between the blade and the contacted object, and the normal confirmation thereof. It includes a contact detection step of detecting that the blade has come into contact with the contacted object by moving the blade and the contacted object closer to each other by a moving device while performing the normality confirmation process after the process.
According to the above technique, when the contact position is detected by bringing the cutting tool into contact with the contacted object and the relative position between the cutting tool and the workpiece is controlled based on the contact position, The reliability of detection of contact can be improved.

In Patent Document 5, a tool or a workpiece is attached to a main shaft, and the main shaft is rotationally driven, and contact between the tool and the workpiece is detected in a machine tool that is processed by bringing the tool into contact with the workpiece. Techniques for contact detection methods for machine tools are disclosed.
In this technique, the counter electrode is disposed so as to be capacitively coupled to the main shaft, and connected to the machine tool body via the coil for the annular circuit, and the main shaft, the counter electrode, the coil for the ring circuit, the machine tool body, the workpiece, and The exciter coil and the detection coil are configured so that the ring circuit is closed when the tool and the work piece are in contact with each other and opened when the tool and the work piece are not in contact with each other. And an alternating current is passed through the excitation coil to generate an induced electromotive force in the annular circuit, and the voltage generated in the detection coil is detected by the alternating current flowing through the annular circuit.
According to the above technique, even in a machine tool having an insulated main shaft, it is possible to detect contact between a tool and a workpiece, even when the main shaft is rotating or in a stationary state. Can be detected.
Japanese Patent Laid-Open No. 11-207573 (FIGS. 2, 6 and pages 2, 3, 5) Japanese Patent Application Laid-Open No. 2004-243426 (FIGS. 2, 5, and 6 and pages 2, 4, and 13) Japanese Patent No. 2849387 (Attached figure and pages 1 to 5) JP 2002-120130 (FIGS. 2, 7, 9, 10 and 2, 3, 11, 12) JP 2002-233933 A (FIG. 1 and pages 2, 3 and 7)

By the way, in the precision processing field such as watch parts, in order to further reduce the size and weight, for example, by using a micro processing tool such as an end mill having a tool diameter of several tens to several μm, Is required to perform.
In such a case, in order to perform machining with accuracy using the techniques described in Patent Documents 1 and 2, it is necessary to eliminate a movement error or the like when moving the fine machining tool to the machining position.

Further, the technique of the grinding method described in Patent Document 3 needs to perform post-processing dimension measurement and correction processing as necessary in order to perform fine precision processing efficiently. There was a problem that it could not be carried out well and efficiently.
Furthermore, in the technique of the blade tool position control method described in Patent Document 4, in order to perform fine precision processing efficiently, it is necessary to perform dimension measurement after processing and correction processing as necessary. There is a problem that it is not possible to perform the process accurately and efficiently.

Moreover, since the technique of patent document 5 needs to contact a workpiece, for example, when using a tool for fine processing such as an end mill having a tool diameter of a dozen μm or more, contact with the workpiece. There was a problem that the risk of damage increased.
Furthermore, for example, in order to perform fine precision processing with high precision using a tool for fine processing such as an end mill having a tool diameter of several tens of μm, even if the techniques of each of the above patent documents are simply gathered, practical processing can be performed. There was a problem that it could not be done.

  The present invention has been proposed in order to solve the above-described problems of the prior art, and a machine tool capable of performing fine precision machining with high accuracy and practical use using a tool for fine machining. And to provide a processing method.

In order to achieve the above object, a machine tool of the present invention includes a main shaft to which a tool is attached, a driving unit for rotating the main shaft, a table on which a workpiece is placed, a moving unit for moving the main shaft and / or the table, And a machine tool provided with a control means for controlling the driving means and the moving means for detecting a discharge phenomenon between the workpiece or the reference member and the tool in an actual machining state, and a discharge detection signal. When the discharge detection means outputs the discharge detection signal, the control means calculates the machining origin from the tool position when the discharge phenomenon occurs, and the calculated machining origin Based on this, the processing is started.
In this way, the tool rotating at the machining speed is used as a measurement probe, the vibration error due to vibration of the spindle and tool, the expansion error due to the temperature of each part of the machine due to rotation, etc., or the displacement and rotation balance when changing the tool. Since it is possible to accurately determine the machining origin by eliminating adverse effects such as fluctuations, extremely precise machining can be performed.

In order to achieve the above object, the machining method of the present invention includes a first tool used for machining in a machining method of a workpiece by a machine tool that machines the workpiece using a tool such as an end mill. A tool attaching step for attaching to a spindle of a machine tool, a spindle rotating step for rotating the spindle under the same conditions as actual machining, and bringing the tool and the workpiece or reference member close to each other so that the tool and the workpiece or A discharge detection step of detecting a discharge phenomenon between the reference member and outputting a discharge detection signal; an origin calculation step of calculating a processing origin of the workpiece from position data when the discharge is detected; and a calculation Based on the processing origin of the processed workpiece, the processing step from which the main shaft is arranged at the processing position to start the first processing, and the processing from the main shaft rotation step to the processing step in accordance with the change in processing conditions. There as a way to run again.
As described above, the present invention is also effective as a machining method, using a tool rotating at a machining rotation speed as a measurement probe, and expanding due to vibration errors due to vibrations of the spindle and the tool, temperature of each part of the machine due to rotation, etc. Since it is possible to accurately determine the machining origin by eliminating adverse effects such as errors or displacement at the time of tool change and fluctuations in rotation balance, it is possible to perform extremely precise machining. In addition, precise machining can be performed without being affected by changes in machining conditions.

Further, the change in the machining condition is a change in the rotational speed of the main shaft.
In this way, it is possible to eliminate adverse effects such as vibration errors due to vibrations of the spindle and tool, expansion errors due to the temperature of each part of the machine due to rotation, etc., or displacements and fluctuations in rotation balance during tool replacement.

Further, the change in the machining condition is a change in environmental conditions such as a temperature at a place where the machine tool is installed.
In this way, adverse effects such as expansion errors due to changes in room temperature and the like can be eliminated.

In order to achieve the above object, the machining method of the present invention includes a first tool used for machining in a machining method of a workpiece by a machine tool that machines the workpiece using a tool such as an end mill. A tool attaching step for attaching to a spindle of a machine tool, a spindle rotating step for rotating the spindle under the same conditions as actual machining, and bringing the tool and the workpiece or reference member close to each other so that the tool and the workpiece or A discharge detection step of detecting a discharge phenomenon between the reference member and outputting a discharge detection signal; an origin calculation step of calculating a processing origin of the workpiece from position data when the discharge is detected; and a calculation A machining step of starting the first machining by arranging the spindle at a machining position based on the machining origin of the workpiece to be processed, and the first tool and the second tool after the first machining is completed. Tool to replace And conversion process, with respect to the second tool is a method of performing second processing to perform the steps from the spindle rotation process to the processing step again.
According to the present invention, precise machining can be performed even when the tool is replaced.

Preferably, the machining method includes an origin measurement step of measuring the origin of the workpiece in advance using a measuring instrument when the spindle of the machine tool is stopped.
Thus, the positional relationship between the machine origin of the machine tool and the workpiece can be obtained by measuring the origin of the workpiece.

Preferably, in the machining method, the spindle position is measured every predetermined time with the spindle rotating step and the spindle rotated, and a deviation amount between the current measurement value and the previous measurement value is determined. And a stabilization step of repeatedly measuring until the dimension is within the range.
In this way, the thermal displacement and balance fluctuation of the spindle are stabilized, and the reliability of the machining accuracy can be improved by confirming that the spindle is stabilized.

Preferably, the machining method includes a tool diameter measuring step of measuring a tool diameter of the tool in an actual machining state using the discharge phenomenon and a predetermined reference device.
In this way, the machining accuracy can be further improved by using the measured tool diameter of the tool rotating at the machining rotational speed.

Preferably, after the processing is completed, the control unit measures a processing dimension using the tool as a measurement probe, and when the measurement result deviates from a predetermined processing dimension standard, the control unit performs reprocessing based on the measurement result. It is good to start.
If it does in this way, the processing dimension after the end of processing can be measured efficiently. Moreover, it is possible to measure by using a tool as a measurement probe for a place where the measurement probe does not enter by utilizing the micro discharge phenomenon. Furthermore, since the automatic follow-up process is performed on the measurement result, the productivity can be greatly improved.

Preferably, the conduction detecting means provided in the machine tool detects a conduction state between the workpiece and the tool during machining, and outputs a non-conduction detection signal when non-conduction is detected. And when the said control means inputs the said non-conduction detection signal, it is good to recognize that the said tool was damaged and to issue an automatic stop and / or an alarm.
In this way, tool breakage is automatically detected during machining, and if it breaks, it is automatically stopped and notified by an alarm, for example, so that loss time can be reduced.

  According to the machine tool and the machining method of the present invention, a tool rotating at a machining rotational speed is used as a measurement probe, and vibration errors due to vibrations of the spindle and the tool, expansion errors due to the temperature of each part of the machine due to rotation, etc. Since it is possible to accurately determine the machining origin by eliminating adverse effects such as displacement at the time of replacement and fluctuations in rotation balance, extremely precise machining can be performed. Moreover, fine precision machining can be performed using a tool for fine machining.

[One Embodiment of Machine Tool]
Hereinafter, an embodiment of a machine tool of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram for explaining the structure of an embodiment of the machine tool of the present invention, (a) showing a perspective view, (b) showing a front view, c) shows a side view.
In FIG. 1, a machine tool 1 is a machining center including a bed 2, a Y table 3, an X table 4, a spindle 5, and the like.
The machine tool according to the present invention is not limited to a machining center, and may be any machine tool that has a numerical control device and performs machining using an electrically conductive tool. For example, a turning center, NC (Numerical control) A jig borer, NC drilling machine, etc. can be mentioned.

A column 20 is erected on the rear end of the bed 2. An arm 21 protrudes from the top of the column 20 in the front direction.
A spindle holder 51 is provided at the tip of the arm 21 in the vertical direction. The spindle holder 51 has a spindle 5 to which the tool 6 is attached, a motor (not shown) for rotating the spindle 5, and the spindle 5. And a moving means (not shown) for raising and lowering the motor is provided.

A Y table 3 is attached to the bed 2 so as to be movable in the Y axis direction, and an X table 4 is attached to the bed 2 so as to be movable in the X axis direction.
The X table 4 is a table on which the workpiece 7 is placed, and the workpiece 7 is detachably fixed on the table. For this reason, although not shown, the X table 4 is an electromagnetic chuck for fixing the workpiece 7 with a magnetic attraction force, a vacuum chuck for fixing the workpiece 7 with a vacuum suction force, or from above. A fixing member or the like for pressing down and fixing the workpiece 7 is provided.

The control means (not shown) includes an NC device (numerical control device) 11 and the like, and controls the moving means for the Y table 3, the moving means for the X table 4, and the moving means for the spindle 5. Control the number of rotations of the motor. Although not shown, each moving means is usually composed of a linear bearing, a ball screw, a stepping motor, and the like.
The control means controls an ATC (automatic tool changer) 10 provided on the side surface of the tip of the arm 21.

The tool 6 is a rotary tool such as an end mill or a drill. Here, the tool 6 of this embodiment is an end mill for performing fine processing, and is a tool for fine processing having a tool diameter of about 10 to 5 μm. In such a micromachining tool, when attached to the spindle 5, the tool tip position (Z-axis direction position) and the tool axis position (X-axis direction position and Y-axis direction position) in the XY plane are contacted. It cannot be measured by the measurement method of the method and the laser method. The reason is that, in the contact method, when the tool tip is brought into contact with the measurement member, the tool is broken or damaged. Further, in the laser method, since the diameter of the laser beam is about 30 μm, it cannot be accurately determined whether or not the laser beam is blocked.
The machine tool 1 of the present invention is provided with a discharge detecting means 8 so that the above-described micromachining tool can be used.
Next, the discharge detection means 8 will be described with reference to the drawings.

FIG. 2: has shown the schematic enlarged view of the principal part for demonstrating the discharge detection means in a Z-axis direction of one Embodiment concerning the machine tool of this invention.
FIG. 3 is a schematic enlarged view of a main part for explaining the discharge detection means in the X-axis direction of one embodiment according to the machine tool of the present invention.
2 and 3, the machine tool 1 has a tool 6 attached to the lower end of a main shaft 5. The tool 6 is selected from the ATC (automatic tool changer) 10 according to the machining content by a command from the NC unit (numerical control unit) 11. In the machine tool 1, the tool 6 mounted on the spindle 5 is rotated, and the NC device 11 controls the Y table 3 in the Y axis direction, the X table 4 in the X axis direction, and the spindle 5 in the Z axis direction. The required processing is performed on the workpiece 7 by moving.

  The discharge detection unit 8 includes an excitation coil 81, a detection coil 82, and a potential difference application unit 83. The potential difference applying unit 83 applies a potential difference V between the main shaft 5 and the X table 4 with the main shaft 5 as a positive electrode and the X table 4 as a negative electrode. When discharge occurs in a non-contact state having a very close minute gap immediately before contact between the tool 6 and the workpiece 7, the discharge detection means 8 forms a closed loop circuit 84 and instantaneously A spike current flows through the and discharges. The back electromotive force due to the instantaneously flowing high frequency current is detected by the discharge detecting means 8 and transmitted to the control amplifier 12, amplified by the control amplifier 12, and transmitted to the NC device 11 as a discharge detection signal. And NC device 11 inputs this discharge detection signal, reads the coordinate position of tool 6 at the time of discharge, and memorizes it in a storage device.

Next, a processing method of the machine tool having the above configuration will be described with reference to the drawings.
FIG. 4: has shown the schematic flowchart figure for demonstrating the processing method of one Embodiment concerning the machine tool of this invention.
In the figure, in the machine tool 1, first, the Y table 3, the X table 4 and the spindle 5 return to the origin (step S1).
In the present embodiment, the origin (appropriately referred to as the machine origin) is a position moved to the front side for the Y table 3, a position moved to the left side for the X table 4, and a position moved upward for the spindle 5. It is as. The NC device 11 resets (0, 0, 0) as the machine origin coordinates. The coordinate system is an orthogonal coordinate system.

Next, the workpiece 7 is fixed to the X table 4 (step S2).
In the present embodiment, the workpiece 7 is fixed approximately at the center of the X table 4 by an electromagnetic chuck.

Next, the origin of the workpiece 7 (referred to as a workpiece reference point as appropriate) is measured (step S3). That is, the absolute value from the machine origin to the workpiece reference point is measured using a dial gauge, a position microscope, a touch rope, etc., and this absolute value is input to the workpiece coordinates of the machine tool 1.
In the present embodiment, the workpiece 7 is a plate-shaped rectangular parallelepiped, and the workpiece reference point is the center of the upper surface of the workpiece 7.
The workpiece reference point is usually measured in a state where the spindle 5 is stopped.

Next, the tool 6 used for processing is attached to the spindle 5 (step S4).
The machine tool 1 includes an ATC 10, and a first tool 6 is attached to the spindle 5 using the ATC 10 from a magazine in which a plurality of tools are mounted. Subsequently, the length of the tool 6 is measured using a laser beam, a position detection sensor, or the like, and the workpiece origin is incremented by this measured value.

Next, the main shaft 5 is rotated under the same conditions as in actual machining (step S5).
Here, the same condition as the actual machining means that the spindle on which the tool is attached is rotated at a predetermined machining rotation speed when machining. For example, when the main shaft 5 rotates at several hundreds of revolutions per minute and when it rotates at several tens of thousands of revolutions per minute, the amount of heat generated by the motor is greatly different. The mode is different. That is, even if the tool 6 is positioned in the low-speed rotation state, if the tool 6 is rotated at a high speed, the position of the tool 6 is shifted. By rotating the main shaft 5 under the same conditions as actual machining against such an expansion error due to heat, the expansion error can be reduced and the machining accuracy can be improved.

Next, the position of the rotating spindle 5 is measured every predetermined time while the spindle 5 is rotated under the same conditions as the actual machining. Then, measurement is repeated until the displacement between the current measurement value and the previous measurement value falls within the determined dimension and the displacement is stabilized, and the position of the spindle 5 is stabilized (step S6).
As described above, by confirming that the temperature of each component of the machine tool 1 is stable with respect to the amount of heat generated by the motor, it is possible to stabilize the thermal displacement and balance fluctuation of the spindle 5 and the tool 6. And processing accuracy can be improved.

Next, while the main shaft 5 is rotated under the same conditions as the actual machining, the discharge phenomenon between the tool 6 and the workpiece 7 is detected by approaching to the vicinity of the workpiece 7 (step S7). .
At this stage, the workpiece reference point, the machine origin, the shape of the workpiece 7, the shape of the tool 6, the tool length and diameter of the tool 6 in a stationary state, the thermal displacement at the end of the spindle 5, etc. Therefore, the machine tool 1 can make the tool 6 approach the vicinity of the workpiece 7. The processing origin of the workpiece 7 is the center point on the upper surface of the plate-shaped rectangular parallelepiped.
Next, this discharge detection step (step S7) will be described with reference to the drawings.

FIG. 5 is a schematic view of a tool and a workpiece for explaining an electric discharge detection process of an embodiment according to the machine tool of the present invention, (a) is a perspective view, and (b) is a perspective view. The top view is shown and (c) has shown the side view.
In the figure, the machine tool 1 moves the rotating tool 6 to a position away from the upper surface of the workpiece 7 by a predetermined distance, and then, for example, a micro feed or super approach approaching by 0.5 μm. Perform low-speed feed. If a discharge occurs between the tool 6 and the workpiece 7 immediately before the tool 6 gradually approaches and contacts the workpiece 7, the discharge detection means 8 detects this discharge and discharges to the NC device 11. A detection signal is output. NC device 11 inputs the discharge detection signal, the proximity of the tool 6 is stopped, stores the working origin position z ₅ of the Z-coordinate of the end center of the tool 6 at this time.
As described above, when the tool feed is set to a minute distance (for example, about 0.01 mm to 0.005 mm) and the non-contact method using the discharge phenomenon, the tool 6 is brought into contact with the workpiece 7 and the tool is moved. Troubles such as damaging 6 can be avoided.

Then, although it determines the working origin of the XY coordinates, the tool 6 at the position of the machining origin z ₅ Z coordinates obtained by the above distance from the workpiece 7 upwardly, completely from the workpiece 7 on the front side move position until it is free, lowering the tool 6 to a Z-coordinate position z ₁ is the depth of the measurement are determined for XY coordinate measuring. Then, the tool 6 is brought close to the front surface of the workpiece 7 and the coordinates (x ₁ , y ₁ , z ₁ ) of the tip center of the tool 6 when the discharge phenomenon occurs are stored.
Further, in the same manner, the machine tool 1 brings the tool 6 close to the back surface of the workpiece 7 and the coordinates (x ₂ , y ₂ , z ₁₎ of the tip center of the tool 6 when the discharge phenomenon occurs. ) Is stored.
Subsequently, the machine tool 1 similarly brings the tool 6 close to the left side surface of the workpiece 7 and coordinates (x ₃ , y ₃ , center of the tip of the tool 6 when a discharge phenomenon occurs). z ₁ ) is stored.
Further, in the same way, the machine tool 1 brings the tool 6 close to the right side surface of the workpiece 7 and the coordinates (x ₄ , y ₄ , z) of the tip center of the tool 6 when the discharge phenomenon occurs. ₁ ) Memorize.
Note that x ₁ ≠ x ₂ and y ₃ ≠ y ₄ .

Next, the processing origin of the XY coordinate axis of the workpiece 7 is calculated from the discharged position data (step S8). That is, the NC device 11 determines the X coordinate position (= (x ₃ + x ₄ ) / 2) and Y coordinate position (= (y) of the machining origin from the position data of the tool 6 when the above four discharge events occur. ₁ + _y 2) / 2) is calculated. Further, since the Z coordinate position z ₅ of the processing origin is already stored as described above, ((x ₃ + x ₄ ) / 2, (y ₁ + y ₂ ) / 2, z ₅ ) is stored as the processing origin. To do.
In addition, the to-be-processed body 7 of this embodiment assumes that the parallelism of an upper surface and a lower surface is processed with sufficient precision.

The method for obtaining the processing origin is not limited to the above procedure. For example, the machining origin is obtained by various procedures according to the shape of the workpiece 7 and the set machining origin.
Moreover, in this embodiment, although the discharge phenomenon has generate | occur | produced between the to-be-processed body 7 and the tool 6, when the to-be-processed body 7 consists of nonelectroconductive materials, the to-be-processed body 7 and the tool 6 The discharge phenomenon does not occur between. In such a case, a reference member (not shown) made of a dischargeable material is used. The reference member serves as a reference for processing the workpiece 7 or is a member for obtaining the reference. A discharge phenomenon is generated between the reference member and the tool 6, and the tool 6 at this time The processing origin of the workpiece 7 is obtained from the position data. Further, a fixing member (not shown) for fixing the workpiece 7 to the X table 4 is also used as a reference member.

Next, the machine tool 1 starts machining based on the machining origin (step S9).
For example, when a 50 μm deep hole is drilled at the processing origin according to the processing specifications, the machine tool 1 adds 50 μm to the tool 6 from the processing origin + a correction value (the measurement is a non-contact method, so it is necessary to add a correction value such as a minute gap) Is lowered by a distance of Also, according to the machining specifications, when a hole with a depth of 50 μm is drilled at a position 5 mm to the right of the machining origin in the X-axis direction, the machine tool 1 rises by a predetermined distance (Δ) from the machining origin and moves in the X-axis direction. Move 5 mm to the right and lower the tool 6 by a predetermined distance (Δ) +50 μm + correction distance. At this time, in the machine tool 1, the tool 6 has already been rotated at the processing rotation speed, and each component including the tool 6 is thermally saturated (saturated), so that an expansion error can be reduced. . Further, since the tool 6 is positioned in consideration of the vibration state due to the rotation of the tool 6, it can be processed with high accuracy.

Next, the machine tool 1 determines whether or not the machining using the first tool 6 has been completed (step S10). When the machining is completed, the machining using the second tool 6 is usually performed. (Steps S4a to 10a).
If the machining has not been completed, it is determined whether or not the machining conditions have changed (step S11). If the machining conditions have not changed, the process returns to step S9 and the next machining is performed based on the machining origin. To start.
When the machining conditions are changed, the process returns to step S5, the main shaft is rotated under the same conditions as the actual machining, and the next machining is performed according to steps S6 to S9.

  Here, there is a change in the rotational speed of the main shaft 5 as a change in the machining conditions. That is, the vibration state and thermal state of the spindle 5 and the tool 6 are greatly different between when rotating at a low speed and when rotating at a high speed. For this reason, when changing the rotation speed of the main shaft 5, it is preferable to return to step S5 again, rotate the main shaft 5 under the same conditions as the actual processing, and perform the processing according to the above-described procedure. In this way, adverse effects such as vibration errors due to vibrations of the spindle 5 and the tool 6 and expansion errors due to the temperature of each part of the machine due to rotation, etc. can be eliminated.

  Further, as the change in the machining conditions, there is a change in environmental conditions such as the temperature of the place where the machine tool 1 is installed. That is, when environmental conditions such as temperature change, it is preferable to return to step S5 again, rotate the spindle 5 under the same conditions as the actual machining, and perform the machining according to the above-described procedure. In this way, adverse effects such as expansion errors due to changes in room temperature and the like can be eliminated.

Next, the machine tool 1 determines whether or not the machining using the first tool 6 has been completed (step S10). When the machining is completed, the machining using the second tool 6 is usually performed. (Steps S4a to 10a).
That is, the machine tool 1 uses the ATC 10 to remove the first tool 6 from the main shaft 5 and attach the second tool 6 to the main shaft 5.
Steps S4a to 10a are substantially the same as steps S4 to S10 described above. As described above, by performing each step every time the tool is changed, various adverse conditions such as vibration error due to vibration and expansion error due to temperature of each part of the machine due to rotation or the like can be eliminated.

As described above, the machine tool 1 according to the present embodiment uses the tool 6 rotating at the processing rotation number as a measurement probe, vibration error due to vibration of the spindle 5 and the tool 6, temperature of each part of the machine due to rotation, and the like. This eliminates adverse effects such as expansion error due to the displacement of the tool or displacement at the time of tool replacement or fluctuations in the rotation balance, so that the machining origin can be determined with high accuracy, so that extremely precise machining can be performed.
In addition, the machine tool 1 includes an ATC 10 for exchanging a plurality of tools, and causes an accumulated error between tools used in plural. According to the present invention, this can be eliminated. That is, even the machine tool 1 including the ATC 10 can perform more precise machining, and can reduce machining steps due to an error between tools.
Furthermore, automatic machining using a tool having a tool diameter of about 0.1 mm or less (such as a tool for fine machining) can be performed with high accuracy.
The machine tool 1 uses the tool 6 as a measurement probe, but has various application examples.
Next, an application example of the machine tool 1 will be described with reference to the drawings.

[Application example of one embodiment of machine tool]
Hereinafter, application examples of an embodiment of a machine tool of the present invention will be described with reference to the drawings.
6A and 6B are schematic diagrams for explaining the structure of an application example of the embodiment of the machine tool according to the present invention. FIG. 6A is a perspective view, and FIG. 6B is a front view. (C) shows a side view.
In the figure, the machine tool 1 according to the application example is provided with a ring gauge 9 on the X table 4 for measuring the tool diameter or the like of the tool 6 as compared with the machine tool 1 of the above embodiment. Is different. Other components are almost the same as those of the machine tool 1.
Therefore, in FIG. 6, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

The ring gauge 9 is a steel cylindrical member whose inner diameter (= d) is accurately measured in advance.
The ring gauge 9 is attached to the rear side and the left corner of the X table 4, but the attachment position is not particularly limited. Moreover, although the ring gauge 9 is used as a reference device for measuring the tool diameter, the reference device is not limited to the ring gauge 9.

Next, a processing method (including a tool diameter measurement method) of the machine tool 1 having the above configuration will be described with reference to the drawings.
FIG. 7: has shown the schematic flowchart figure for demonstrating the processing method of the application example of one Embodiment concerning the machine tool of this invention.
The machining method of this application example has a step of measuring the tool diameter of the tool 6 compared to the above-described machining method, and measures the machining dimension using the tool 6 after machining, and re-executes as necessary. The point which processes is different. Other methods are almost the same as those of the machine tool 1.
Therefore, in FIG. 7, the same reference numerals are assigned to the same methods as those in FIG. 4, and the detailed description thereof is omitted.

In the figure, as described above, in the machine tool 1, first, the Y table 3, the X table 4 and the spindle 5 return to the origin (step S1), and the workpiece 7 is fixed to the X table 4 (step S2). Then, the origin of the workpiece 7 is measured (step S3), the tool 6 is attached to the spindle 5 (step S4), the spindle 5 is rotated under the same conditions as the actual machining (step S5), and the rotation is continued. In this state, the position of the main shaft 5 is stabilized (step S6).
Note that the origin of the ring gauge 9 (the point where the central axis of the ring gauge 9 intersects the upper surface of the X table 4) is measured in advance and the measurement data is stored in the NC device 11.

Next, the tool diameter of the tool 6 is measured using the discharge phenomenon between the tool 6 and the ring gauge 9 in a state where the main shaft 5 is rotated under the same conditions as the actual machining (step S6.1).
At this stage, the origin of the ring gauge 9, the machine origin, the shape of the ring gauge 9, the shape of the tool 6, the tool length and tool diameter when the tool 6 is stationary, the thermal displacement at the end of the spindle 5, etc. are controlled. Since it is input to the means, the machine tool 1 can move the tool 6 to the vicinity of the origin of the ring gauge 9.

Next, the tool diameter measuring step (step S6.1) using the discharge phenomenon will be described with reference to FIG.
FIG. 8 is a schematic enlarged view of a ring gauge and a tool for explaining a tool diameter measurement process of an application example of an embodiment according to the machine tool of the present invention. FIG. 8A shows a center axis coordinate of the ring. (B) shows a plan view in a state where the tool is located at the center axis coordinate of the ring gauge, and (c) shows a plan view when obtaining the tool diameter.
In the figure, the machine tool 1 moves the tool 6 rotating at the machining rotational speed to the origin of the ring gauge 9 based on the measurement data of the origin of the ring gauge 9 measured in advance and stored in the NC device 11. Furthermore, the tool 6 is moved to a position away from the inner surface on the front side of the ring gauge 9 by a predetermined distance, and then, for example, fine feed or ultra-low speed feed approaching 0.5 μm is performed. If a discharge occurs between the tool 6 and the ring gauge 9 immediately before the tool 6 gradually approaches and comes into contact with the ring gauge 9, the discharge detection means 8 detects this discharge, and a discharge detection signal is sent to the NC device 11. Is output. When receiving the discharge detection signal, the NC device 11 stops the approach of the tool 6 and stores the coordinates (x ₆ , y ₆ , z ₆ ) of the tip center of the tool 6 at this time.

Next, in the same manner, the machine tool 1 brings the tool 6 close to the inner surface on the back surface side of the ring gauge 9 and coordinates (x ₆ , y ₇ , z ₆ ) is stored.
Subsequently, the machine tool 1 similarly brings the tool 6 close to the inner surface of the left side surface of the ring gauge 9 and coordinates (x ₈ , y ₈ , center of the tip of the tool 6 when a discharge phenomenon occurs). z ₆ ) is stored.
Further, the machine tool 1 moves the tool 6 closer to the inner surface of the right side surface of the ring gauge 9 in the same manner, and the coordinates (x ₉ , y ₈ , z) of the tip center of the tool 6 when a discharge phenomenon occurs. ₆ ) Memorize.

Next, the origin of the ring gauge 9 is calculated from the discharged position data. That is, the NC device 11 determines the X coordinate position (= (x ₈ + x ₉ ) / 2) and Y coordinate position (=) of the origin of the ring gauge 9 from the position of the tool 6 when the above four discharge events occur. (Y ₆ + y ₇ ) / 2) is calculated. The machine tool 1 moves the tool 6 to the calculated X coordinate position and Y coordinate position of the origin, as shown in FIG.

Next, as shown in FIG. 8 (c), the machine tool 1 moves the tool 6 to a position away from the inner surface on the front side of the ring gauge 9 by a predetermined distance, and then approaches, for example, 0.5 μm. Perform minute feed or ultra-low speed feed. If a discharge occurs between the tool 6 and the ring gauge 9 immediately before the tool 6 gradually approaches and comes into contact with the ring gauge 9, the discharge detection means 8 detects this discharge, and a discharge detection signal is sent to the NC device 11. Is output. When the discharge detection signal is input, the NC device 11 stops the approach of the tool 6 and stores the coordinates ((x ₈ + x ₉ ) / 2, y ₁₆ , z ₆ ) of the tip center of the tool 6 at this time.

Next, the machine tool 1 moves the tool 6 closer to the inner surface on the back side of the ring gauge 9 in the same manner, and the coordinates ((x ₈ + x ₉ ) of the tip center of the tool 6 when the discharge phenomenon occurs. / 2, y ₁₇ , z ₆ ) are stored.
Subsequently, the machine tool 1 similarly brings the tool 6 close to the inner surface of the left side surface of the ring gauge 9, and the coordinates (x ₁₈ , (y ₆₎ of the tip center of the tool 6 when the discharge phenomenon occurs. + Y ₇ ) / 2, z ₆ ) is stored.
Further, in the same manner, the machine tool 1 brings the tool 6 close to the inner surface of the right side surface of the ring gauge 9 and coordinates (x ₁₉ , (y ₆ + y) of the tip center of the tool 6 when the discharge phenomenon occurs. ₇ ) / 2, z ₆ ) is stored.

Next, the NC device 11 is rotated from the measured coordinates ((x ₈ + x ₉ ) / 2, y ₁₆ , z ₆ ) and ((x ₈ + x ₉ ) / 2, y ₁₇ , z ₆ ). The tool diameter D ′ of the tool 6 is calculated by the formula D ′ = d− (| y ₁₆ −y ₁₇ |). In addition, the tool diameter D of the rotating tool 6 from the measured coordinates (x ₁₈ , (y ₆ + y ₇ ) / 2, z ₆ ) and (x ₁₉ , (y ₆ + y ₇ ) / 2, z ₆ ). ″ Is calculated by the formula D ″ = d− (| x ₁₈ −x ₁₉ |). Then, the two calculated tool diameters are averaged to obtain the tool diameter D (= (D ′ + D ″) / 2) of the rotating tool 6. Then, the NC device 11 re-inputs the tool diameter that has already been input as a new value D.
If it does in this way, the tool diameter (tool diameter in the state which has a heat fluctuation | variation or vibrates) of the tool 6 rotating with the process rotation speed can be measured accurately. In particular, when the tool 6 is an extremely thin end mill or drill, an error caused by heat or vibration can be corrected, which is advantageous in improving machining accuracy.

The method for obtaining the tool diameter is not limited to the above procedure. For example, the obtained D ′ may be used as the tool diameter D (= D ′).
Although not shown, the tip position of the tool of the tool 6 rotating at the machining rotational speed can be obtained using the upper surface of the ring gauge 9 in the same manner as the method for obtaining z ₅ described above. .
Furthermore, the timing for measuring the tool diameter is usually performed before processing, but may be performed during processing or after processing as necessary.

  Next, the machine tool 1 detects a discharge phenomenon between the tool 6 and the workpiece 7 by bringing the spindle 5 to the vicinity of the workpiece 7 while rotating the spindle 5 under the same conditions as the actual machining ( In step S7), the machining origin of the workpiece 7 is calculated from the discharged position data (step S8), and machining is started based on the machining origin (step S9).

Next, when it is necessary to perform high-precision machining, the machine tool 1 measures the machining dimension using the tool 6 as a measurement probe after the machining is finished, and the measurement result deviates from a predetermined machining dimension standard. Then, reworking is performed based on the measurement result (step S9.1).
If it does in this way, the processing dimension after the end of processing can be measured efficiently. Moreover, it is possible to measure by using a tool as a measurement probe for a place where the measurement probe does not enter by utilizing the micro discharge phenomenon. Furthermore, since the automatic follow-up process is performed on the measurement result, the productivity can be greatly improved and the reliability of the processing accuracy can be improved.

Next, the machine tool 1 determines whether or not the machining using the first tool 6 has been completed (step S10). When the machining has been completed, the first tool 6 is usually used although not shown. The next machining using the second tool 6 is performed in substantially the same manner as the machining performed.
If the machining has not been completed, it is determined whether or not the machining conditions have changed (step S11). If the machining conditions have not changed, the process returns to step S9 and the next machining is performed based on the machining origin. To start.
If the machining conditions have changed, the process returns to step S5, the spindle is rotated under the same conditions as the actual machining, and the next machining is performed by the same procedure.

Thus, the machine tool 1 of this application example can accurately measure the tool diameter in the actual machining state. Further, the machining accuracy can be further improved by using the measured tool diameter of the tool rotating at the machining speed.
In addition, the tool can be used as a measurement probe to efficiently measure the machined dimensions after machining, and automatic follow-up machining is performed on the measurement results, greatly improving productivity and machining. The reliability of accuracy can be improved.

[First Embodiment of Processing Method]
The present invention is also effective as a processing method, and the processing method of the present embodiment is a processing method of the workpiece 7 by the machine tool 1.
In the machining method of the present embodiment, as shown in FIG. 4, the tool attachment step (step S4) for attaching the first tool 6 used for machining to the spindle 5 of the machine tool 1, and the same conditions as the actual machining of the spindle 5 The spindle rotation process (step S5) for rotating at, and the position of the spindle 5 is measured every predetermined time while the spindle 5 is rotated, and the amount of deviation between the current measurement value and the previous measurement value is within a predetermined dimension. Stabilization process (step S6) for repeated measurement until the tool 6 is brought close to the workpiece 7 to detect the discharge phenomenon between the tool 6 and the workpiece 7 and output a discharge detection signal A discharge detection step (step S7), an origin calculation step (step S8) for calculating a machining origin of the workpiece 7 from the discharged position data, and a machining position based on the calculated machining origin of the workpiece 7 Move spindle 6 to open A processing step (step S9), when the machining conditions are changed, there is a method of executing the steps from spindle rotation process (step S5) to processing step (step S9) again.

Further, when the machining using the first tool 6 is finished, a tool attaching step (step S4a) for attaching the second tool 6 to the spindle 5 and a spindle rotating step (step for rotating the spindle 5 under the same conditions as actual machining) S5a) and a stabilization step of measuring the position of the main shaft 5 at predetermined time intervals while the main shaft 5 is rotated, and repeatedly measuring the deviation amount between the current measurement value and the previous measurement value within a predetermined dimension. (Step S <b> 6 a) and discharge that causes the second tool 6 to approach the vicinity of the workpiece 7, detects a discharge phenomenon between the second tool 6 and the workpiece 7, and outputs a discharge detection signal A detection step (step S7a), an origin calculation step (step S8a) for calculating the machining origin of the workpiece 7 from the discharged position data, and a spindle to the machining position based on the calculated machining origin of the workpiece 7 Move 6 to open machining There as a method having the processing step (step S9a).

  Examples of changes in the machining conditions include changes in the rotational speed of the spindle 5 and changes in environmental conditions such as the temperature of the place where the machine tool 1 is installed. It is possible to eliminate an adverse effect such as a vibration error due to or an expansion error due to the temperature of each component of the machine tool 1.

  Further, by the stabilization process (steps S6 and 6a), the thermal displacement and balance fluctuation of the main shaft 5 are stabilized, and by confirming that it has been stabilized, the reliability of the machining accuracy can be improved.

  Preferably, in step S3, when the spindle 5 of the machine tool 1 is stopped, an origin measurement step of measuring the origin of the workpiece 7 in advance using a measuring instrument may be provided. Thus, by measuring the origin of the workpiece 7, the positional relationship between the machine origin of the machine tool 1 and the workpiece 7 can be obtained, and the machining can be efficiently advanced.

  As described above, according to the machining method of the present embodiment, the tool 6 rotating at the machining rotational speed is used as a measurement probe, vibration errors due to vibration of the spindle 5 and the tool 6, temperature of each part of the machine due to rotation, etc. This eliminates adverse effects such as expansion error due to the displacement of the tool or displacement at the time of tool replacement or fluctuations in the rotation balance, so that the machining origin can be determined with high accuracy, so that extremely precise machining can be performed. In addition, precise machining can be performed without being affected by changes in machining conditions. Furthermore, even when the tool 6 is replaced, precise machining can be performed. That is, it is possible to effectively eliminate accumulated errors between a plurality of tools used, and to reduce a machining step due to an error between tools.

[Second Embodiment of Processing Method]
The machining method of the present embodiment is a machining method of the workpiece 7 by the machine tool 1 according to the application example.
As shown in FIG. 7, the machining method of the present embodiment has a tool diameter measurement step (step S6.1) for measuring the tool diameter of the tool 6, as compared with the machining method of the first embodiment, and The difference is that after machining, the machining dimension is measured using the tool 6, and an additional machining step (step S9.1) is performed for re-machining as necessary. Other methods are almost the same as the processing method of the first embodiment.
Therefore, in FIG. 7, the same reference numerals are assigned to the same methods as those in FIG. 4, and the detailed description thereof is omitted.

  In this embodiment, the control means of the machine tool 1 uses a discharge phenomenon and a predetermined reference device (such as a ring gauge 9) to measure the tool diameter of the tool 6 in the actual machining state (step S6). .1). In this way, the machining accuracy can be further improved by using the measured tool diameter of the tool 6 rotating at the machining rotational speed.

  Preferably, after machining, the machining dimension is measured using the tool 6 as a measurement probe, and when the measurement result deviates from a predetermined machining dimension standard, reworking is started based on the measurement result. (Step S9.1) may be included. If it does in this way, the processing dimension after the end of processing can be measured efficiently. Moreover, it is possible to measure by using the tool 6 as a measurement probe for a place where the measurement probe does not enter by utilizing the micro discharge phenomenon.

Thus, according to the machining method of the present embodiment, the tool diameter in the actual machining state can be accurately measured. Further, the machining accuracy can be further improved by using the measured tool diameter of the tool 6 rotating at the machining rotational speed.
Furthermore, using the tool 6 as a measurement probe, the machining dimension after machining is efficiently measured, and automatic follow-up machining is performed on the measurement result, so that productivity can be greatly improved. The reliability of processing accuracy can be improved.

The machine tool and the machining method of the present invention have been described with reference to the preferred embodiments, but the machine tool and the machining method according to the present invention are not limited to the above-described embodiments, and the scope of the present invention. Needless to say, various modifications can be made.
For example, a continuity detecting means (not shown) is provided between the tool 6 of the machine tool 1 and the workpiece 7 described above, and the continuity state between the workpiece 7 and the tool 6 is detected during machining. When conduction is detected, a non-conduction detection signal may be output, and when the non-conduction detection signal is input, the control unit may recognize that the tool 6 has been damaged and issue an automatic stop and / or alarm. If it does in this way, breakage of the tool 6 will be automatically detected during a process, and if it breaks, it will stop automatically, for example, it will alert | report by an alarm, Therefore Loss time can be reduced.

  As described above, the machine tool and the machining method of the present invention are effective when machining a workpiece with high accuracy. However, the machine tool and the machining method are not limited to machining, and include, for example, a tool measuring device and a tool measuring tool. It can be effectively applied as a method.

FIG. 1 is a schematic diagram for explaining the structure of an embodiment of the machine tool of the present invention, (a) showing a perspective view, (b) showing a front view, c) shows a side view. FIG. 2: has shown the schematic enlarged view of the principal part for demonstrating the discharge detection means in a Z-axis direction of one Embodiment concerning the machine tool of this invention. FIG. 3: has shown the schematic enlarged view of the principal part for demonstrating the discharge detection means in the X-axis direction of one Embodiment concerning the machine tool of this invention. FIG. 4: has shown the schematic flowchart figure for demonstrating the processing method of one Embodiment concerning the machine tool of this invention. FIG. 5 is a schematic view of a tool and a workpiece for explaining an electric discharge detection process of an embodiment according to the machine tool of the present invention, (a) is a perspective view, and (b) is a perspective view. The top view is shown and (c) has shown the side view. 6A and 6B are schematic diagrams for explaining the structure of an application example of the embodiment of the machine tool according to the present invention. FIG. 6A is a perspective view, and FIG. 6B is a front view. (C) shows a side view. FIG. 7: has shown the schematic flowchart figure for demonstrating the processing method of the application example of one Embodiment concerning the machine tool of this invention. FIG. 8 is a schematic enlarged view of a ring gauge and a tool for explaining a tool diameter measurement process of an application example of an embodiment according to the machine tool of the present invention. FIG. 8A shows a center axis coordinate of the ring. (B) shows a plan view in a state where the tool is located at the center axis coordinate of the ring gauge, and (c) shows a plan view when obtaining the tool diameter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Machine tool 2 Bed 3 Y table 4 X table 5 Spindle 6 Tool 7 Work piece 8 Discharge detection means 9 Ring gauge 10 ATC (automatic tool changer)
11 NC unit (numerical control unit)
12 control amplifier 13 continuity sensor 20 post 21 arm 51 spindle holder 81 excitation coil 82 detection coil 83 potential difference applying means 84 closed loop circuit

Claims (10)

A spindle to which a tool is attached, a driving means for rotating the spindle, a table on which a workpiece is placed, a moving means for moving the spindle and / or the table, and a control means for controlling the driving means and the moving means. A machine tool with which
A discharge detection means for detecting a discharge phenomenon between the workpiece or the reference member and the tool in an actual machining state and outputting a discharge detection signal;
When the discharge detection means outputs the discharge detection signal, the control means calculates a machining origin from a tool position when the discharge phenomenon occurs, and starts machining based on the calculated machining origin. Machine tool to do. In a processing method of a workpiece by a machine tool that processes the workpiece using a tool such as an end mill,
A tool attachment step of attaching a first tool used for machining to the spindle of the machine tool;
A spindle rotating step of rotating the spindle under the same conditions as actual machining;
A discharge detection step of causing the tool and the workpiece or reference member to approach each other, detecting a discharge phenomenon between the tool and the workpiece or reference member, and outputting a discharge detection signal;
From the position data when the discharge is detected, an origin calculation step for calculating the processing origin of the workpiece,
A machining step of starting the first machining by arranging the spindle at a machining position based on the calculated machining origin of the workpiece;
A processing method characterized by re-executing the steps from the spindle rotating step to the machining step in accordance with changes in machining conditions.   The machining method according to claim 2, wherein the change in the machining condition is a change in the rotational speed of the main shaft.   The processing method according to claim 2, wherein the change in the processing condition is a change in an environmental condition such as a temperature of a place where the machine tool is installed. In a processing method of a workpiece by a machine tool that processes the workpiece using a tool such as an end mill,
A tool attachment step of attaching a first tool used for machining to the spindle of the machine tool;
A spindle rotating step of rotating the spindle under the same conditions as actual machining;
A discharge detection step of causing the tool and the workpiece or reference member to approach each other, detecting a discharge phenomenon between the tool and the workpiece or reference member, and outputting a discharge detection signal;
From the position data when the discharge is detected, an origin calculation step for calculating the processing origin of the workpiece,
A machining step of starting the first machining by arranging the spindle at a machining position based on the calculated machining origin of the workpiece;
A tool changing step of exchanging the first tool and the second tool after the completion of the first machining;
A machining method, characterized in that a second machining is performed on the second tool by executing again the processes from the spindle rotating process to the machining process.   6. The machining method according to claim 2, further comprising: an origin measurement step of measuring the origin of the workpiece in advance using a measuring instrument when the spindle of the machine tool is stopped. The processing method as described in.   In the machining method, with the spindle rotating step and the spindle rotated, the position of the spindle is measured every predetermined time, and the deviation amount between the current measurement value and the previous measurement value is within a predetermined dimension. The processing method according to any one of claims 2 to 6, further comprising a stabilization step of repeatedly measuring up to.   8. The method according to claim 2, wherein the machining method includes a tool diameter measuring step of measuring a tool diameter of the tool in an actual machining state using the discharge phenomenon and a predetermined reference device. The processing method according to claim 1.   The control means measures the machining dimension using the tool as a measurement probe after the machining is completed, and starts re-machining based on the measurement result when the measurement result deviates from a predetermined machining dimension standard. The processing method according to any one of claims 2 to 8, wherein the processing method is characterized. The continuity detection means provided in the machine tool detects a continuity state between the workpiece and the tool during machining, and outputs a non-conduction detection signal when non-conduction is detected.
9. The control device according to claim 2, wherein when the non-conduction detection signal is input, the control unit recognizes that the tool is damaged and issues an automatic stop and / or an alarm. The processing method described.

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