JPH07186029A - Spherical surface formation working method and device - Google Patents

Abstract

PURPOSE:To provide a spherical surface formation working method and device in which a work can be worked in an electrolytic improcess dressing method without limitation of an outer diameter of the work. CONSTITUTION:A working surface 4 of a grinding wheel 3 is moved to a position deflected from a position where it crosses a rotation axis of a work 1 to face it with an electrolytic dressing electrode 5, the working surface 4 of the grinding wheel 3 is electrolyticly dressed, and the work held by a holder 2 to be freely rotatable at the rotation axis of the work 1 is processed to have a spherical surface. The electrolytic dressing electrode 5 and the work 1 can thus be disposed to be apart from each other, and the work 1 is kept without getting in contact with the holder 2 or the electrolytic dressing electrode 5, so spherical surface working in an electrolytic improcess dressing method can be performed without limitation of an outer diameter of the work 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for spherically processing highly brittle materials for optical elements such as glass and ceramics.

[0002]

2. Description of the Related Art In recent years, an electrolytic in-process dressing method has been developed which prevents a grindstone from being clogged or crushed while grinding a workpiece. The electrolytic in-process dressing process is briefly explained.By using a metal-bonded grindstone, the bond material at the interface in contact with the workpiece of this grindstone is electrolyzed to eliminate unnecessary abrasive grains along with the bond material. Get rid of. As a result, there is no clogging of the whetstone,
Since the abrasive grains are always projected on the processed surface of the grindstone and the processed surface of the grindstone is uniformly dressed, the processing under constant processing conditions can be performed.

Japanese Patent Application Laid-Open No. Hei 3 (1999) -311 discloses a method for spherically processing an optical material by using this electrolytic in-process dressing method.
There is one disclosed in Japanese Patent Publication No. -60973. FIG. 7 shows the main part of this spherical surface generating apparatus. The holder 25 is configured to be rotatable around a shaft core 26, and the holder 25 holds a work 27. Shaft core 2 of holder 25
6, the grindstone 28 is held rotatably about an axis 29 inclined by an angle θ.

The processing surface 30 of the grindstone 28 is formed in the same shape as the curvature R of the spherical surface to be created. A (-) electrode 31 for electrolytic dressing is provided with a slight gap s from the processed surface 30.
Is provided. Further, the (+) electrode 32 is provided so as to always contact the outer peripheral portion of the grindstone 28. The surface shape of the (−) electrode 31 is formed to be similar to the processed surface 30 of the grindstone 28. A nozzle 33 is arranged near the (−) electrode 31. And the nozzle 3
3 is connected to a coolant supply device (not shown),
The (-) electrode 31 and the processing surface 30 of the grindstone 28 are configured so that the weakly electrically conductive coolant 34 can be supplied to the gap. By applying a DC voltage from the power supply device 35 between the electrodes 31 and 32, the machining surface 30 of the grindstone 28 can be electrolyzed.

A spherical surface processing method having the above configuration will be described. First, the work 27 held by the holder 25 is rotated about the shaft center 26, and the grindstone 28 is rotated about the shaft center 29. Then grindstone 28 and work 2
By moving 7 forward, they come into contact with each other to perform grinding. At this time, the processed surface 30 of the grindstone 28 and the (-) electrode 3
While supplying the weakly electric coolant 34 from the nozzle 33 between the first and second terminals, a DC voltage is applied between the electrodes 31 and 32 by the power supply device 35. Thereby, the processed surface 3 of the grindstone 28
At 0, electrolysis is generated and electrolytic dressing is performed.

That is, since the electrolytic dressing is continuously performed during the processing of the workpiece, even if a grindstone having a higher mesh than that of the spherical surface creating processing which does not use the electrolytic dressing is used, the spherical surface can be created with high accuracy without causing clogging. Processing becomes possible.

[0007]

In the above spherical surface forming process, when the curvature of the spherical surface to be created is R, the processing diameter of the grindstone is d, and the angle θ between the grindstone axis and the work axis center line, the relational expressions ( sin θ = d / 2R). Therefore, the outer diameter of the grindstone applicable to the spherical shape to be created is limited, and generally only the grindstone having the outer diameter of 1.2 to 2 times the outer diameter of the work can be used.

Further, in the electrolytic in-process dressing method, the (-) electrode is arranged so as to face the surface of the grindstone to be electrolytically dressed while the spherical surface is processed. Therefore, if a grindstone having the same outer diameter is used to process a work having a large outer diameter, the (-) electrode comes into contact with the work or the holder. Therefore, there is a drawback that the outer diameter of the work that can be used is limited.

The present invention has been made in view of the above conventional problems, and provides a spherical surface forming method and an apparatus therefor which can be processed by the electrolytic in-process dressing method without limiting the outer diameter of the work. The purpose is to provide.

[0010]

1 and 2 are conceptual views showing a spherical surface forming process according to the present invention. FIG. 1 shows a state of a grindstone and a work at a position where electrolytic dressing is performed, and FIG.
The state of a grindstone and a work at the time of spherical surface processing is shown. The present invention is a spherical surface machining apparatus having a rotatable holder 2 for holding a work 1, a grindstone 3 for machining the work, and a means for dressing a machining surface 4 of the grindstone 3 by an electrolytic in-process dressing method. The grindstone 3 that is movable between a position where the processing surface 4 intersects the rotation axis of the workpiece 1 and a position that is displaced from the rotation axis, and when the processing surface 4 of the grinding stone 3 is in a position that is displaced from the rotation axis, This is a spherical surface processing apparatus including an electrolytic dressing electrode 5 arranged at a position facing the processing surface 4.

[0011]

Function: The working surface 4 of the grindstone 3 is moved to a position deviated from the position intersecting the rotation axis of the work 1, and the electrode 5 for electrolytic dressing is moved.
And the machined surface 4 of the grindstone 3 is electrolytically dressed,
The machining surface 4 is moved to a position intersecting the rotation axis of the work 1, and the work 1 held by the holder 2 and rotatable by the rotation axis of the work 1 is spherically machined.

[0012]

【Example】

(First Embodiment) A first embodiment of the present invention will be described with reference to FIGS. FIG. 3 shows the state of the grindstone and the work at the position where electrolytic dressing is performed, and FIG. 4 shows the state of the grindstone and the work during spherical surface processing.

The work 7 to be machined is held by a holder 8 and can be rotated about a rotation axis A by a work rotation drive device (not shown). The work 7 can be moved in the direction of arrow a along the rotation axis A by a work moving device (not shown). The spindle shaft 9 holds a grindstone 10 and is provided so as to be rotatable about a rotation axis B by a grindstone rotation driving device (not shown). Further, the spindle shaft 9 is the spindle 1
It is rotatably held at 1. The central axis of the spindle 11 is the rotational axis position B1 when the machining surface 12 of the grindstone 10 is in the electrolytic dressing position and the rotational axis position when the machining surface 12 of the grindstone 10 intersects the rotational axis A of the workpiece 7. B2
And the center of the spherical center O of the spherical surface to be formed as a center, and is configured to be swingable in the direction of arrow b by a swing drive device (not shown).

The grindstone 10 has a cup shape, and the processed surface 12 is formed in the same shape as the spherical surface to be created. Further, since the grindstone (# 400) 10 is composed of a sintered alloy obtained by mixing abrasive grains such as diamond powder and a metal powder such as Cu, Sn or Fe, and heat-treated, it has conductivity. . A (-) electrode 13 is arranged facing the processed surface 12 of the grindstone 10 with a gap of 0.1 mm to 0.3 mm. Further, the (-) electrode 13 is fixed to a device body (not shown) by a support member (not shown). The surface shape 14 of the (-) electrode 13 is formed in a shape similar to the processed surface 12 of the grindstone 10. And grindstone 10
The (+) electrode 15 is always provided in contact with the outer peripheral portion of the. Both electrodes 13 and 15 are connected to a power supply device 17 via a lead wire 16 and are configured so that a DC voltage can be applied. A nozzle 18 is arranged near the (−) electrode 13. And the nozzle 18
Is connected to a coolant supply device (not shown),
The weak electric coolant 19 can be supplied to the gap between the (-) electrode 13 and the processed surface 12 of the grindstone 10.

When the grindstone 10 is swung in the direction of the arrow b from the rotary shaft position B1 to the rotary shaft position B2, the nozzle 20 supplies the weak electric coolant 21 to the position where the grindstone 10 and the workpiece 7 come into contact with each other. It is arranged so that it can. A spherical surface processing method having the above configuration will be described. First, Fig. 3
As shown in FIG. 5, the central axis of the spindle 11 is positioned at the rotational axis position B1 by a swing drive device (not shown). By this operation, the processed surface 12 of the grindstone 10 is positioned so as to face the (-) electrode 13. Then, the grindstone 10 is rotated about the rotation axis B by a grindstone rotation driving device (not shown). Next, the weak electric coolant 19 is jetted between the processed surface 12 of the grindstone 10 and the (-) electrode 13 by the nozzle 18. Then, a DC voltage is applied between the (-) electrode 13 and the (+) electrode 15 by the power supply device 17, and the processed surface 1 of the grindstone 10 is
Electrolytically dress 2. At this time, the work 7 held by the holder 8 is rotated by a work rotation drive device (not shown) about the rotation axis A, and the processed surface 12 of the grindstone 10 is rotated.
And the workpiece 7 is waiting before the position where it abuts.

After electrolytic dressing, as shown in FIG. 4, the central axis of the spindle 11 is swung in the direction of the arrow b from the rotational axis position B1 to the rotational axis position B2 about the spherical center O of the spherical surface to be created. Then, the central axis of the grindstone 10 is moved to the rotational axis position B2. Next, the work 7 is moved along the rotation axis A by the arrow a.
Gradually move in the direction of. Then, the workpiece 7 is the grindstone 1
The machined surface 12 of 0 is contacted. Spherical processing is performed on the contact portion between the processed surface 12 of the grindstone 10 and the workpiece 7 while supplying the weakly electric coolant 21 from the nozzle 20.

If the spherical surface machining is continued as it is, the machined surface 12 of the grindstone 10 may be clogged. Therefore, the spindle 11 should be clogged before the clogged.
Is moved from the rotary shaft position B2 to the rotary shaft position B1 which is the electrolytic dressing position, and the machined surface 12 of the grindstone 10 is electrolytically dressed. By repeating the state of FIG. 3 and FIG. 4,
Perform spherical processing.

According to this embodiment, the grindstone is configured to move between the electrolytic dressing position and the spherical surface processing position. Therefore, the (−) electrode and the work can be arranged separately. Therefore, even if a work having a large outer diameter is used, the work or holder does not come into contact with the (-) electrode, and it is possible to favorably perform spherical surface creation processing to which the electrolytic in-process dressing method is applied.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 5 shows the state of the grindstone and the work at the position where electrolytic dressing is performed, and FIG. 6 shows the state of the grindstone and the work at the time of spherical surface processing. The same parts as those in the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

The (-) electrode 13 is the processed surface 12 of the grindstone 10.
It is formed longer than the width 24 in the moving direction of the grindstone 10.
Therefore, even if the central axis of the grindstone 10 is moved from the rotational axis position B1 to the rotational axis position B2 side, the state where the processed surface 12 of the grindstone 10 and the (-) electrode 13 face each other is long. It has a structure that can be kept only for a while. Further, since the side surface 23 of the grindstone 10 roughly grinds the work 7, the side surface 23 of the grindstone 10 has a roughness that does not cause clogging even when roughly grinded. The processed surface 12 of the grindstone 10 is # 1.
000 is used.

A spherical surface processing method in this embodiment will be described. First, as shown in FIG. 5, the central axis of the spindle 11 is positioned at the rotational axis position B1 by a swing drive device (not shown). By this operation, the processed surface 12 of the grindstone 10 is positioned so as to face the (-) electrode 13. And grindstone 1
0 is rotated about the rotation axis B by a grindstone rotation driving device (not shown). Next, attach the weak electric coolant 19 to the nozzle 1
8, the jetting is performed between the processed surface 12 of the grindstone 10 and the (−) electrode 13. Thereafter, a DC voltage is applied between the (−) electrode 13 and the (+) electrode 15 by the power supply device 17,
The processed surface 12 of the grindstone 10 is electrolytically dressed. At this time, the holder 8 is moved in advance so that the work 7 comes to a position where it comes into contact with the side surface 23 of the grindstone 10.

Then, as shown in FIG. 6, the central axis of the grindstone 10 is gradually moved from the rotational axis position B1 to the rotational axis position B2 in the direction of arrow b around the spherical center O of the spherical surface to be created. By this movement, the side surface 23 of the grindstone 10 is moved to the work 7
Abut the outer peripheral portion of. Further, set the grindstone 10 to the rotary axis position B2.
By moving it toward, the rough cutting is performed from the outer peripheral portion of the work 7. At this time, the processed surface 1 of the grindstone 10
No. 2 is still facing the (-) electrode 13, and performs electrolytic dressing together with rough cutting of the work 7. The electrolytically dressed processing surface 12 is brought into contact with the workpiece 7 to perform highly accurate spherical surface processing of the spherical surface that is actually created. The grindstone 10 is swung from the rotary shaft position B1 to the rotary shaft position B2, and the grindstone 1
When the machining surface 12 of 0 moves to a position where it intersects with the rotation axis A, the rough cutting of the work 7 is completed. After that, the work 7 is machined on the machined surface 12 of the grindstone 10 in the same manner as in the first embodiment to obtain a predetermined spherical surface.

According to this embodiment, since the (-) electrode is made long, the work can be processed by the side surface of the grindstone while electrolytically dressing. Therefore, even if a grindstone having a processed surface having a higher mesh (# 600 to # 1200) than that of the first embodiment is used, clogging of the grindstone does not occur, so that highly accurate spherical surface creation processing can be performed. Is. Further, since the rough cutting is performed on the side surface of the grindstone during the movement from the electrolytic dressing position, the processing time can be shortened.

[0024]

As described above, according to the present invention, since the grindstone is configured to be moved between the electrolytic dressing position and the spherical surface processing position, the electrolytic dressing electrode and the work can be arranged separately. Therefore, in the spherical surface generating process of the optical element, since the work and the holder do not come into contact with the electrolytic dressing electrode, it is possible to perform the spherical process by the electrolytic in-process dressing method without limiting the outer diameter of the work.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing spherical surface processing of the present invention.

FIG. 2 is a diagram showing the spherical surface processing of FIG. 1;

FIG. 3 is an enlarged sectional view of an essential part of the spherical surface processing apparatus showing the first embodiment of the present invention.

FIG. 4 is a diagram showing the spherical surface processing of FIG. 3;

FIG. 5 is an enlarged sectional view of an essential part of a spherical surface processing apparatus showing a second embodiment of the present invention.

FIG. 6 is a diagram showing the spherical surface processing of FIG. 5;

FIG. 7 is a cross-sectional view of essential parts showing a conventional spherical surface processing apparatus.

[Explanation of symbols]

 1 Work 2 Holder 3 Grindstone 4 Processing Surface 5 (-) Electrode 6 Worked Work 7 Work 8 Holder 9 Spindle Shaft 10 Grinding Stone 11 Spindle 12 Processing Surface 13 (-) Electrode 14 Surface Shape 15 (+) Electrode 16 Lead Wire 17 Power supply device 18 Nozzle 19 Weak electric coolant 20 Nozzle 21 Weak electric coolant 22 Work piece 23 Side surface 24 Width 25 Holder 26 Shaft core 27 Work piece 28 Grinding stone 29 Shaft core 30 Work surface 31 (-) electrode 32 (+) electrode 33 Nozzle 34 Low-power coolant 35 Power supply

Claims (2)

[Claims] 1. A spherical surface processing method for dressing a rotationally driven grindstone by an electrolytic in-process dressing method for surface processing of a work held by a holder, and a position where a working surface of the grindstone intersects a rotation axis of the work. A spherical surface processing method characterized by moving to a position further displaced and performing electrolytic dressing, and moving the work surface of the grindstone to a position intersecting the rotation axis of the work to process the work. 2. A rotatable holder for holding a work,
In a spherical machining apparatus having a grindstone for machining the work and a means for dressing the machined surface of the grindstone by an electrolytic in-process dressing method, a position where the machined surface intersects with the rotation axis of the work and a position displaced from the rotation axis And a grinding stone movable between the grinding stone and a machining surface of the grinding stone, and an electrolytic dressing electrode arranged at a position facing the machining surface when the machining surface is displaced from the rotation axis.