JP2022080020A - Discharge truing method - Google Patents

Abstract

To provide a discharge truing method improved in machining accuracy.SOLUTION: A discharge truing method for a conductive grindstone 1 that is used in a machining machine that has an X table, a Y table and a Z table includes: a first step of making a discharge circuit 20 connected to a conductive grindstone and a cylinder electrode 2 apply voltages while moving the conductive grindstone and the cylinder electrode relatively in a Z direction so as to perform electro-discharge machining of the cylinder electrode; a second step of making the discharge circuit apply voltages while moving a grindstone surface of the conductive grindstone in a circumferential direction along a side surface of the cylinder electrode from a first direction in an X direction, so as to perform electro-discharge machining of the grindstone surface of the conductive grindstone, after finishing the first step; and a third step of making the discharge circuit apply voltages while moving the grindstone surface of the conductive grindstone in the circumferential direction along the side surface of the cylinder electrode from a second direction which is opposite to the first direction in the X direction, at a position different in the Z direction from a position in the second step so as to perform electro-discharge machining of the grindstone surface of the conductive grindstone, after finishing the second step.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a discharge trueing method.

Patent Document 1 discloses an on-machine discharge trueing / dressing method in which an electrode having a desired shape is created by a tool attached to a spindle, and the created electrode is used to perform discharge trueing / dressing of a grindstone to be replaced on the spindle. Has been done.

Japanese Patent Application Laid-Open No. 63-283861

The discharge truing method described in Patent Document 1 still has room for improvement in that it realizes high-precision machining.

Therefore, the present disclosure provides a discharge trueing method with improved processing accuracy.

The discharge trueing method of the present disclosure is described.
A processing machine having an X table movable in the X direction, a Y table movable in the Y direction perpendicular to the X direction, and a Z table movable in the Z direction perpendicular to the X direction and the Y direction. This is a method of discharge-growing the conductive grindstone used in
The conductive grindstone is attached to the Y table to rotate around the first rotation axis parallel to the Y direction, and a cylindrical electrode is attached to the Z table to rotate around the second rotation axis parallel to the Z direction. In a state of being rotated to, the surface of the conductive grindstone and the side surface of the cylindrical electrode are brought into contact with each other, and the conductive grindstone and the cylindrical electrode are relatively moved in the Z direction while the conductive grindstone is moved. The first step of applying a voltage by a discharge circuit connected to the columnar electrode to discharge the columnar electrode, and
After the completion of the first step, the conductive grindstone attached to the Y table is rotated about the first rotation axis, and the cylindrical electrode attached to the Z table is rotated on the second rotation axis. The surface of the conductive grindstone is moved from the first direction toward the side surface of the columnar electrode in the X direction in a state of being rotated to the center, and then a circle is formed along the side surface of the columnar electrode. A second step of electric discharge machining of the surface of the conductive grindstone by applying a voltage through the discharge circuit while moving in the circumferential direction.
After the completion of the second step, the conductive grindstone attached to the Y table is rotated about the first rotation axis, and the cylindrical electrode attached to the Z table is rotated on the second rotation axis. In a state of being rotated to the center, the surface of the conductive grindstone is placed at a position different from that of the second step in the Z direction from the second direction opposite to the first direction in the X direction. After moving toward the side surface of the electrode, while moving in the circumferential direction along the side surface of the cylindrical electrode, a voltage is applied by the discharge circuit to perform electric discharge machining on the grindstone surface of the conductive grindstone. The third step to do and
including.

According to the present disclosure, it is possible to provide a discharge trueing method with improved processing accuracy.

Schematic perspective view showing the processing apparatus according to the embodiment of the present disclosure. A flowchart showing a discharge tsuruing method in the processing apparatus of FIG. Schematic perspective view showing the first step of the discharge trueing method of FIG. Schematic perspective view showing the second step of the discharge trueing method of FIG. Front view showing the operation of the conductive grindstone and the cylindrical electrode in the second step of the discharge trueing method of FIG. Front view showing the positional relationship between the tip shape of the conductive grindstone and the cylindrical electrode in the second step of the discharge trueing method of FIG. Schematic perspective view showing a third step of the discharge trueing method of FIG.

(Background to the invention)
The conductive grindstone for grinding precision machined parts such as optical elements corrects the rotational runout or shape of the wheel and adjusts the amount of protrusion of the abrasive grains to improve the grinding accuracy. Rotational runout or shape correction of the wheel is called truing, and adjustment of the amount of protrusion of abrasive grains is called dressing.

Further, in order to improve the grinding accuracy, it is advisable to execute turwing on the processing machine. For example, in Patent Document 1, on a machine of a machining center, an electrode attached to a rotating shaft is created by a tool attached to the spindle, and then a metal bond grindstone is attached to the spindle instead of the tool, and the created electrode is used. Disclosed is a method of performing discharge trueing / dressing of a metal bond grindstone.

In the discharge twruing / dressing method described in Patent Document 1, the discharge twruing is performed by bringing the created electrode and the metal bond grindstone together while rotating them and bringing them close to each other, and at the same time supplying a discharge current. When the distance between the created electrode and the metal bond grindstone becomes smaller than a predetermined value, a pulse-controlled discharge current flows, and the processing of the metal bond grindstone proceeds. As a result, the cross-sectional shape of the grindstone is transferred to the inverted cross-sectional shape of the electrode.

As the created electrode is consumed, it becomes impossible to transfer an accurate shape to the metal bond grindstone. Therefore, in the method described in Patent Document 1, the electrode is regenerated after the roughing discharge tsuruing, and the finishing processing discharge tsuruing is performed. It is proposed to do.

However, in the discharge truing method of Patent Document 1, since the electrode is consumed at the same time as the electric discharge machining is started, the shape of the consumed created electrode is transferred to the metal bond grindstone when the discharge truing is completed. Further, even if the discharge trueing is divided into roughing and finishing, it is not guaranteed that the electrodes will have exactly the same shape when regenerated.

Generally, in the field of optical elements such as lenses and mirrors, or mold processing for molding them, submicron shape accuracy is required. However, the conductive grindstone that has been discharge-trued according to Patent Document 1 has a problem that high-precision machining is difficult.

Therefore, the present inventor (or others) studied a discharge turreting method with improved processing accuracy, and came up with the following invention.

The discharge trueing method according to one aspect of the present disclosure is
A processing machine having an X table movable in the X direction, a Y table movable in the Y direction perpendicular to the X direction, and a Z table movable in the Z direction perpendicular to the X direction and the Y direction. This is a method of discharge-growing the conductive grindstone used in
The conductive grindstone is attached to the Y table to rotate around the first rotation axis parallel to the Y direction, and a cylindrical electrode is attached to the Z table to rotate around the second rotation axis parallel to the Z direction. In a state of being rotated to, the surface of the conductive grindstone and the side surface of the cylindrical electrode are brought into contact with each other, and the conductive grindstone and the cylindrical electrode are relatively moved in the Z direction while the conductive grindstone is moved. The first step of applying a voltage by a discharge circuit connected to the columnar electrode to discharge the columnar electrode, and
After the completion of the first step, the conductive grindstone attached to the Y table is rotated about the first rotation axis, and the cylindrical electrode attached to the Z table is rotated on the second rotation axis. The surface of the conductive grindstone is moved from the first direction toward the side surface of the columnar electrode in the X direction in a state of being rotated to the center, and then a circle is formed along the side surface of the columnar electrode. A second step of electric discharge machining of the surface of the conductive grindstone by applying a voltage through the discharge circuit while moving in the circumferential direction.
After the completion of the second step, the conductive grindstone attached to the Y table is rotated about the first rotation axis, and the cylindrical electrode attached to the Z table is rotated on the second rotation axis. In a state of being rotated to the center, the surface of the conductive grindstone is placed at a position different from that of the second step in the Z direction from the second direction opposite to the first direction in the X direction. After moving toward the side surface of the electrode, while moving in the circumferential direction along the side surface of the cylindrical electrode, a voltage is applied by the discharge circuit to perform electric discharge machining on the grindstone surface of the conductive grindstone. The third step to do and
including.

According to such a configuration, it is possible to provide a discharge truing method with improved processing accuracy.

In the first step,
By moving the Z table, the conductive grindstone and the cylindrical electrode may be relatively moved in the Z direction.

According to such a configuration, the shape accuracy of the cylindrical electrode can be improved.

In the second step,
By moving the X table and the Z table, the conductive grindstone is placed on the side surface of the cylindrical electrode from the first direction.
The conductive grindstone may be moved along the circumference of the cylindrical electrode by moving the X table and the Y table.

With such a configuration, the shape accuracy of the conductive grindstone can be improved.

In the third step,
By moving the X table and the Z table, the conductive grindstone is arranged on the side surface of the cylindrical electrode from the second direction.
The conductive grindstone may be moved along the circumference of the cylindrical electrode by moving the X table and the Y table.

With such a configuration, the shape accuracy of the conductive grindstone can be improved.

By driving the X table and arranging the conductive grindstone at an intermediate position between the positions of the X table at the end of electric discharge machining in each of the second step and the third step, the conductive grindstone is placed. It may further have a fourth step of aligning the center of rotation of the second rotation axis with the center of rotation of the second rotation axis in the X direction.

According to such a configuration, the work can be machined in a state where the conductive grindstone is positioned, so that the machining accuracy of the work can be improved.

The grindstone surface of the conductive grindstone has a semicircular cross section and has a semicircular cross section.
At the end of the electric discharge machining of the second step and the end of the electric discharge machining of the third step, the position of the center of the semicircle of the grindstone surface in the Y direction and the position of the second rotation axis in the Y direction They may match.

According to such a configuration, the work can be machined in a state where the conductive grindstone is positioned, so that the machining accuracy of the work can be improved.

(Embodiment 1)
[overall structure]
FIG. 1 is a schematic perspective view showing a processing apparatus 100 according to the first embodiment.

The processing apparatus 100 has an X table 3, a Y table 4 arranged on the X table 3, and a Z table 5. The X table 3 is movable in the X direction. The Y table 4 can move in the Y direction orthogonal to the X direction. Further, the Z table 5 is movable in the Z direction orthogonal to the X direction and the Y direction. That is, the processing device 100 is a processing device having three axes of X-axis, Y-axis, and Z-axis, and is, for example, a vertical machining center.

The X table 3, the Y table 4, and the Z table 5 can be driven with an accuracy of nanometers by a numerical control device (not shown).

A spindle 6 is fixed to the Y table 4, and a disk-shaped conductive grindstone 1 is attached to the Y table 4. The conductive grindstone 1 is rotated by the spindle 6 about a first rotation axis 6a (see FIG. 3) parallel to the Y direction. As the conductive grindstone 1, for example, a metal bond grindstone in which diamond abrasive grains are hardened with a metal bond can be used. The conductive grindstone 1 is configured, for example, by forming a grindstone surface 1a having a semicircular cross section on the side surface of a disk-shaped wheel.

Further, a C-axis 7 is arranged on the Z table 5, and a cylindrical electrode 2 is attached to the tip of the C-axis 7. The C-axis 7 is a spindle having an indexing function to which a jig for holding the cylindrical electrode 2 is attached. The cylindrical electrode 2 rotates about a second rotation axis 7a (see FIG. 3) parallel to the Z direction by the C axis 7. As the cylindrical electrode 2, for example, a rod material such as a copper-tungsten alloy having a diameter of 6.0 mm can be used. A − electrode is connected to the conductive grindstone 1 from the discharge circuit 20 by a contact terminal (not shown), and a + electrode is connected to the cylindrical electrode 2 by a contact terminal (not shown) from the discharge circuit 20.

[motion]
With reference to FIG. 2, a discharge trueing method of the conductive grindstone 1 in the processing apparatus 100 will be described. FIG. 2 is a flowchart showing a discharge trueing method in the processing apparatus 100 of FIG.

First, the first step of electric discharge machining of the cylindrical electrode 2 is executed (step S101).

In the first step, the cylindrical electrode 2 is attached to the C-axis 7 arranged on the Z table 5 of the processing apparatus 100. At this time, the cylindrical electrode 2 is attached so that the rotation axis of the cylinder electrode 2 and the rotation axis of the C axis 7 match with desired accuracy. Further, the conductive grindstone 1 is attached to the spindle 6 of the Y table 4.

FIG. 3 is a schematic perspective view showing a first step of the discharge truing method of FIG. As shown in FIG. 3, in a state where the conductive grindstone 1 is rotated around the first rotating shaft 6a and the cylindrical electrode 2 is rotated about the second rotating shaft 7a, the grindstone surface of the conductive grindstone 1 is rotated. The 1a and the side surface 2a of the cylindrical electrode 2 are brought into contact with each other. Here, while the conductive grindstone 1 and the cylindrical electrode 2 are relatively moved in the Z direction, a voltage is applied by the electric discharge circuit 20 (see FIG. 1) connected to the conductive grindstone 1 and the cylindrical electrode 2. The side surface 2a of the cylindrical electrode 2 is electric-discharge machined.

The conductive grindstone 1 and the cylindrical electrode 2 can be relatively moved by moving the Z table 5 by the numerical control processing program of the numerical control device. That is, by moving the Z table 5 from a position where the conductive grindstone 1 and the cylindrical electrode 2 do not overlap in the Z direction, the grindstone surface 1a of the conductive grindstone 1 is moved in the Z direction along the side surface 2a of the cylindrical electrode 2. Scan. When the conductive grindstone 1 and the cylindrical electrode 2 come into contact with each other, the side surface 2a of the cylindrical electrode 2 is electric-discharged by the voltage from the discharge circuit 20.

The electric discharge machining is repeated by relatively moving the conductive grindstone 1 and the cylindrical electrode 2 until the side surface 2a of the cylindrical electrode 2 is uniformly electric discharged.

By the first step, the roundness of the cylindrical electrode 2 is corrected, and the cylindrical electrode 2 having high shape accuracy is formed. In addition, the rotational runout of the conductive grindstone 1 is removed. It is preferable to use an air bearing having a rotational accuracy of about several tens of nm for the C-axis 7 of the processing apparatus 100 for processing precision-machined parts. In this case, when the first step is completed, the cylindrical electrode 2 is processed into a roundness with an accuracy of several tens of nm.

Returning to FIG. 2, after the first step, the second step of electric discharge machining of the grindstone surface 1a of the conductive grindstone 1 is executed (step S102).

FIG. 4 is a schematic perspective view showing a second step of the discharge truing method of FIG. FIG. 5 is a front view showing the operation of the conductive grindstone 1 and the cylindrical electrode 2 in the second step of the discharge trueing method of FIG. The second step is performed in a state where the conductive grindstone 1 is rotated about the first rotation shaft 6a and the cylindrical electrode is rotated about the second rotation shaft 7a, as in the first step. .. As shown in FIG. 4, in the second step, the grindstone surface 1a of the conductive grindstone 1 is moved from the first direction D1 toward the side surface 2a of the cylindrical electrode 2 in the X direction, and the grindstone surface 1a is moved to the side surface 2a. Make contact. Next, the grindstone surface 1a of the conductive grindstone 1 is moved in the circumferential direction along the side surface 2a of the cylindrical electrode 2. In this way, while moving the grindstone surface 1a of the conductive grindstone 1, a voltage is applied by the discharge circuit 20 to perform electric discharge machining on the grindstone surface 1a of the conductive grindstone 1. Here, the first direction D1 in the X direction is the direction from right to left in FIG.

By moving the conductive grindstone 1 in this way, in the second step, the grindstone surface 1a of the conductive grindstone 1 is brought into contact with the right side 12a of the cylindrical electrode 2 to perform electric discharge machining. Here, the right side 12a of the cylindrical electrode 2 is a portion on the right side when the cylindrical electrode 2 is cut on a YZ plane (a plane passing through the broken line S1) passing through the center of the bottom surface of the cylindrical electrode 2 in FIG.

Specifically, as shown in FIG. 5, the grindstone surface 1a of the conductive grindstone 1 is moved in the circumferential direction along the side surface 2a of the cylindrical electrode 2 on the right side 12a of the cylindrical electrode 2 (see FIG. 4). At the same time, a voltage is applied by the discharge circuit 20. In the second step, the conductive grindstone 1 is arranged at an arbitrary position 13 (see FIG. 4) in the Z direction of the side surface 2a of the cylindrical electrode 2, and the conductive grindstone 1 is placed along the side surface 2a of the columnar electrode 2. EDM is performed while moving in the circumferential direction. The conductive grindstone 1 moves the X table 3 and the Y table 4 by the numerical control processing program of the numerical control device in the circumferential direction along the side surface 2a of the cylindrical electrode 2, that is, along the arrow F1 shown in FIG. Can be moved. At this time, in the electric discharge machining, as in the first step, the conductive grindstone 1 is rotated around the first rotating shaft 6a, and the cylindrical electrode 2 is rotated around the second rotating shaft 7a. Will be executed. Coordinates 8 (see FIG. 4) of the X table 3 after the end of the second step are recorded. Coordinates 8 indicate the position of the first rotation axis 6a in the X direction when the second step is completed.

FIG. 6 is a front view showing the positional relationship between the tip shape of the conductive grindstone 1 and the cylindrical electrode 2 in the second step of the discharge truing method of FIG. As shown in FIG. 6, when the height H1 of the Y table 4 that moves the conductive grindstone 1 in the Y direction and the height H2 of the rotation center of the C axis 7 to which the cylindrical electrode 2 is attached are deviated from each other. Of the grindstone surface 1a of the conductive grindstone 1 with respect to the rotation center C1 of the C-axis 7, electric discharge machining in the direction deviated from the Y direction is reduced. Therefore, the semicircular center of the grindstone surface 1a of the conductive grindstone 1 is corrected with respect to the rotation center C1 of the C-axis 7. Therefore, the center height of the semicircle of the grindstone surface 1a of the conductive grindstone 1 and the rotation center height of the C axis can be matched.

Therefore, at the end of the electric discharge machining in the second step, the position H1 in the Y direction of the center of the semicircle of the grindstone surface 1a of the conductive grindstone 1 coincides with the position H2 in the Y direction of the second rotating shaft 7a.

Returning to FIG. 2, after the second step, the third step of electric discharge machining of the grindstone surface 1a of the conductive grindstone 1 is executed (step S103).

FIG. 7 is a schematic perspective view showing a third step of the discharge truing method of FIG. As shown in FIG. 7, in the third step, similarly to the first step and the second step, the conductive grindstone 1 is rotated about the first rotation axis 6a, and the cylindrical electrode is rotated second. This is performed in a state of being rotated around the shaft 7a. As shown in FIG. 7, in the third step, the grindstone surface 1a of the conductive grindstone 1 is subjected to the side surface 2a of the cylindrical electrode 2 from the second direction D2 opposite to the first direction D1 (see FIG. 4) in the X direction. To bring the grindstone surface 1a into contact with the side surface 2a. Next, the grindstone surface 1a of the conductive grindstone 1 is moved in the circumferential direction along the side surface 2a of the cylindrical electrode 2. In this way, while moving the grindstone surface 1a of the conductive grindstone 1, a voltage is applied by the discharge circuit 20 to perform electric discharge machining on the grindstone surface 1a of the conductive grindstone 1. Here, the second direction D2 in the X direction is the direction from left to right in FIG. 7.

By moving the conductive grindstone 1 in this way, in the third step, the grindstone surface 1a of the conductive grindstone 1 is brought into contact with the left side 12b of the cylindrical electrode 2 to perform electric discharge machining. Here, the left side 12b of the cylindrical electrode 2 is a portion on the left side when the cylindrical electrode 2 is cut in a YZ plane (a plane passing through the broken line S1) passing through the center of the bottom surface of the cylindrical electrode 2 in FIG.

Specifically, as shown in FIG. 7, the grindstone surface 1a of the conductive grindstone 1 is moved in the circumferential direction along the side surface of the cylindrical electrode 2 on the left side 12b of the cylindrical electrode 2 by the discharge circuit 20. Apply voltage. In the third step, the conductive grindstone 1 is arranged at a position 14 of the side surface 2a of the cylindrical electrode, which is different in the Z direction from the position 13 of the electric discharge machining in the second step, and is conductive without being moved in the Z direction. Electric discharge machining is performed while the sex grindstone 1 is moved in the circumferential direction along the side surface 2a of the cylindrical electrode 2. Further, as in the second step, the conductive grindstone 1 moves the X table 3 and the Y table 4 by the numerical control processing program of the numerical control device, and moves the X table 3 and the Y table 4 in the circumferential direction along the side surface 2a of the cylindrical electrode 2. You can move it. At this time, in the electric discharge machining, as in the first step, the conductive grindstone 1 is rotated around the first rotating shaft 6a, and the cylindrical electrode 2 is rotated around the second rotating shaft 7a. Will be executed. The coordinates 9 of the X table 3 after the end of the third step are recorded. Coordinates 9 indicate the position of the first rotation axis 6a in the X direction when the third step is completed.

At the end of electric discharge machining in the third step, as in the end of the second step, the position H1 in the Y direction of the center of the semicircle of the grindstone surface 1a of the conductive grindstone 1 and the Y direction of the second rotating shaft 7a. It coincides with the position H2 in.

When the third step is completed, the discharge truthing of the conductive grindstone 1 is completed. In the second step, electric discharge machining of the grindstone surface 1a is performed on the right side 12a of the cylindrical electrode 2, and in the third step, electric discharge machining of the grindstone surface 1a is performed on the left side 12b of the cylindrical electrode 2. Therefore, the shape accuracy of the conductive grindstone 1 is performed. Can be improved. Further, in the second step and the third step, since the electric discharge machining is performed at different positions in the Z direction of the side surface 2a of the cylindrical electrode 2, the conductivity is not affected by the consumption of the cylindrical electrode 2 due to the electric discharge machining. It is possible to perform electric discharge machining of the sex grindstone 1.

After the discharge truing is completed, a workpiece to be machined is attached to the C-axis 7 instead of the cylindrical electrode 2, and the rotation axis is aligned. Then, using the conductive grindstone 1, an arbitrary shape is transferred to the work.

When the grindstone surface 1a of the conductive grindstone 1 is worn due to the processing into the work, the cylindrical electrode 2 is attached to the C-axis 7 again to align the rotation axes, and the second step and the third step are performed. By executing this again, the shape accuracy of the conductive grindstone 1 can be maintained. As a result, high-precision machining can be continuously performed.

[effect]
According to the above-described embodiment, it is possible to provide a discharge trueing method with improved processing accuracy.

By the first step, it is possible to remove the rotational runout of the conductive grindstone 1 while improving the roundness of the cylindrical electrode 2. The shape accuracy of the conductive grindstone 1 can be improved by electric discharge machining of the conductive grindstone 1 in the second step and the third step by using the cylindrical electrode 2 with improved roundness. Therefore, high-precision machining can be realized for the workpiece to be machined.

In the above-described embodiment, an example in which the processing device 100 has three axes has been described, but the axis configuration of the processing device 100 is not limited to this, and the positions of the conductive grindstone 1 and the cylindrical electrode 2 are relative to each other. Any shaft configuration that can be changed to is sufficient.

Further, in the above-described embodiment, an example in which a grindstone in which diamond abrasive grains are hardened by a metal bond is used as the conductive grindstone 1 has been described, but the configuration of the conductive grindstone 1 is not limited to this, and electric discharge machining is performed. Any grindstone having conductivity that can be carried out may be used.

Further, the discharge tsuruing method further includes a fourth step of matching the positions of the rotation center of the conductive grindstone 1 and the rotation center of the second rotation shaft 7a in the X direction after the completion of the second step and the third step. May include.

In the fourth step, the X table 3 is moved to a position of ½ of the distance between the coordinate 8 recorded in the second step and the coordinate 9 recorded in the third step by the numerical control machining program. That is, the conductive grindstone 1 is arranged by driving the X table 3 at an intermediate position between the positions of the X table 3. By moving the X table 3 in this way after the second step and the third step, the positions of the rotation center of the conductive grindstone 1 and the rotation center of the C axis 7 in the X direction can be matched. ..

Further, at this time, the diameter of the conductive grindstone 1 can be calculated by subtracting the diameter of the cylindrical electrode 2 from the difference between the coordinates 8 and the coordinates 9.

In this way, by aligning the rotation center of the conductive grindstone 1 with the rotation center of the C-axis 7 after the truing of the conductive grindstone 1, the work is machined from the state where the conductive grindstone 1 is positioned. Can be started. That is, after the truing of the conductive grindstone 1, the step of matching the positions of the rotation center of the conductive grindstone 1 and the rotation center of the C axis 7 in the X direction becomes unnecessary. As a result, high-precision machining can be performed on the work.

The present disclosure is particularly useful for discharge trueing on a processing machine.

1 Conductive grindstone 1a Grindstone surface 2 Cylindrical electrode 2a Side surface 3 X table 4 Y table 5 Z table 6a 1st rotary shaft 7a 2nd rotary shaft 20 Discharge circuit 100 Processing device

Claims (6)

A processing machine having an X table movable in the X direction, a Y table movable in the Y direction perpendicular to the X direction, and a Z table movable in the Z direction perpendicular to the X direction and the Y direction. This is a method of discharge-growing the conductive grindstone used in
The conductive grindstone is attached to the Y table to rotate around the first rotation axis parallel to the Y direction, and a cylindrical electrode is attached to the Z table to rotate around the second rotation axis parallel to the Z direction. In a state of being rotated to, the surface of the conductive grindstone and the side surface of the cylindrical electrode are brought into contact with each other, and the conductive grindstone and the cylindrical electrode are relatively moved in the Z direction while the conductive grindstone is moved. The first step of applying a voltage by a discharge circuit connected to the columnar electrode to discharge the columnar electrode, and
After the completion of the first step, the conductive grindstone attached to the Y table is rotated about the first rotation axis, and the cylindrical electrode attached to the Z table is rotated on the second rotation axis. The surface of the conductive grindstone is moved from the first direction toward the side surface of the columnar electrode in the X direction in a state of being rotated to the center, and then a circle is formed along the side surface of the columnar electrode. A second step of electric discharge machining of the surface of the conductive grindstone by applying a voltage through the discharge circuit while moving in the circumferential direction.
After the completion of the second step, the conductive grindstone attached to the Y table is rotated about the first rotation axis, and the cylindrical electrode attached to the Z table is rotated on the second rotation axis. In a state of being rotated to the center, the surface of the conductive grindstone is placed at a position different from that of the second step in the Z direction from the second direction opposite to the first direction in the X direction. After moving toward the side surface of the electrode, while moving in the circumferential direction along the side surface of the cylindrical electrode, a voltage is applied by the discharge circuit to perform electric discharge machining on the grindstone surface of the conductive grindstone. The third step to do and
including,
Discharge trueing method. In the first step,
By moving the Z table, the conductive grindstone and the cylindrical electrode are relatively moved in the Z direction.
The discharge trueing method according to claim 1. In the second step,
By moving the X table and the Z table, the conductive grindstone is placed on the side surface of the cylindrical electrode from the first direction.
By moving the X table and the Y table, the conductive grindstone is moved along the circumference of the cylindrical electrode.
The discharge trueing method according to claim 1 or 2. In the third step,
By moving the X table and the Z table, the conductive grindstone is arranged on the side surface of the cylindrical electrode from the second direction.
By moving the X table and the Y table, the conductive grindstone is moved along the circumference of the cylindrical electrode.
The discharge trueing method according to any one of claims 1 to 3. By driving the X table and arranging the conductive grindstone at an intermediate position between the positions of the X table at the end of electric discharge machining in each of the second step and the third step, the conductive grindstone is placed. Further has a fourth step of matching the positions of the center of rotation of the second rotation axis with the center of rotation of the second rotation axis in the X direction.
The discharge trueing method according to any one of claims 1 to 4. The grindstone surface of the conductive grindstone has a semicircular cross section and has a semicircular cross section.
At the end of the electric discharge machining of the second step and the end of the electric discharge machining of the third step, the position of the center of the semicircle of the grindstone surface in the Y direction and the position of the second rotation axis in the Y direction Match,
The discharge trueing method according to any one of claims 1 to 5.

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