JPH07328907A - Spherical surface creative processing method and device thereof - Google Patents

Abstract

PURPOSE:To complete a spherical surface from rough processing to finish processing with the same grinding wheel in the spherical surface creative processing by the electrolytic in-process dressing method. CONSTITUTION:A sliding member 12 for removing an oxide film stuck on a processing surface 5 is provided to face the processing surface 5 of a grinding wheel 3, and a means for moving the sliding member 12 into contact with or apart from the processing surface of the grinding wheel is provided. For rough processing, the sliding member 12 is brought into contact with the processing surface 5 of the grinding wheel to remove the oxide film, and the protruded quantity of abrasive grains is increased to allow quick cutting. For finish processing, the sliding member 12 is separated, and the protruded quantity of the abrasive grains is decreased to allow precision finishing. A brush made of an abrasion-resistant material such as brass, carbon fibers, or quebracho or FRP fibers is used for the sliding member 12.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, as an example of this kind, Japanese Patent Laid-Open No.
The invention described in Japanese Patent No. 60973 is known. As shown in FIG. 8, the grinding apparatus disclosed in the publication discloses a cup that grinds the work 21 while rotating the work 21 while being held by the work holder on an axis inclined with respect to the rotation axis of the work 21. The (+) electrode 22 for applying the electrolytic in-process dressing method is connected to the outer peripheral portion of the grinding wheel 23 on the processed surface 25 of the die grinding wheel 23 and is formed in a shape similar to the radius of curvature of the finished surface (-). ) The electrode 24 is provided so as to face the processing surface 25 of the grinding wheel 23 and maintain a slight gap S. Further, the weak electric coolant 26 is supplied to the gap S between the processed surface 25 of the grinding wheel 23 and the (−) electrode 24 from a nozzle 27 of a coolant supply device (not shown).

In the processing of the work piece 21 by the apparatus of this structure, the work surface 21 of the grinding wheel 23 is brought into contact with the work piece 21 while the work piece 21 and the grinding wheel 23 are rotated on their respective axes to perform grinding. At the same time, a voltage is applied to the (+) electrode 22 and the (−) electrode 24 by the power supply device 29, and the processed surface 25 of the grinding wheel 23 and the (−) electrode 24 are applied.
The weakly electrically-conductive coolant 26 is supplied to a slight gap S between and, and the processed surface of the grinding wheel 23 is subjected to electrolytic in-process dressing.

[0004]

However, in the above-described conventional processing method, in order to improve productivity, two types, a low-mesh grinding wheel in the roughing process and a high-mesh grinding wheel in the finishing process, are used separately. There is. Therefore, there is a problem that the number of processing steps is two and productivity is lowered.

Therefore, the present invention has been made in view of the above problems, and provides a spherical surface forming method and an apparatus therefor capable of completing roughing to finishing of a grinding step with the same grinding wheel. The purpose is to do.

[0006]

In order to achieve the above object, the present invention provides, as a means according to claims 1 and 2, a work holder which rotates while holding a work, and an inclination with respect to a rotation axis of the work. In a spherical surface creation processing device equipped with a cup-type grinding wheel that grinds a workpiece while rotating on the axis and a mechanism that dresses the processing surface of the grinding wheel during grinding by the electrolytic in-process dressing method, grinding wheel grinding While arranging the sliding member facing the surface,
The sliding member can be brought into and out of contact with the processed surface of the grinding wheel during the grinding process. The sliding member is made of a material having abrasion resistance enough to remove the oxide film formed on the grinding wheel surface by electrolytic dressing.

Further, as a means according to claim 2, when the work is ground, roughing and finishing are processed by the same grinding wheel, and at the time of roughing, the sliding member is brought into contact with the processing surface of the grinding wheel. In the finishing process, the sliding member is separated from the surface of the grindstone to be processed, and the spherical surface forming method is adopted.

[0008]

As an operation according to claims 1 and 2, when an oxide film is formed on the surface of the grinding wheel by electrolytic dressing and the oxide film adheres to the surface of the grinding wheel, the surface of the grinding wheel during spherical surface generation processing The amount of oxide film adhered is controlled by bringing the sliding member into and out of contact with.

According to the third aspect of the present invention, when the work is ground, the sliding member is brought into contact with the work surface of the grinding wheel to remove the oxide film adhering to the work surface during the rough work. The amount of protrusion of the particles becomes large. Further, in the finishing process, the sliding member is separated from the processed surface of the grinding wheel, so that the oxide film is easily attached to the processed surface of the grinding wheel, and the protrusion amount of the abrasive grains is reduced. As a result, it becomes possible to perform the rough machining to the finishing machining of the work in one step by using the grinding wheel of the mesh having a high machining efficiency.

[0010]

Embodiments of the present invention will be specifically described below with reference to the drawings. In addition, in each of the embodiments, the same reference numerals are given to the same components, and the description thereof will be omitted.

[0011]

Embodiment 1 FIGS. 1 to 4 show Embodiment 1 of the present invention,
FIG. 1 is a cross-sectional view of a main part of a spherical surface generating / processing apparatus, FIG. 2 is a view showing an arrangement of (−) electrodes and sliding members on a processing surface of a grinding wheel, and FIGS. 3 and 4 are sliding on the processing surface of a grinding wheel. It is a figure explaining operation of a member.

The work 1 is held by a holder 2 and is rotated about a rotation axis X of a spindle 14 by a driving device (not shown) and is movable back and forth in the direction of arrow b. On the other hand, the cup-shaped grinding wheel 3 is mounted on the spindle 4, is rotated by a driving device (not shown) about a rotation axis Y diagonally located with respect to the rotation axis X, and can be moved back and forth in the direction of arrow a. I am configuring. The grinding wheel 3 is made of a sintered alloy obtained by specially blending abrasive grains such as # 400 diamond powder and metal powder such as copper, tin, and iron and heat-treated, and has conductivity.

Further, as a mechanism of electrolytic improdressing, a (-) electrode 6 is arranged facing the processed surface 5 of the grinding wheel 3, and the (-) electrode 6 is made of copper or carbon graphite and has a spherical surface. It is formed so as to approximate a shape (a spherical surface to be created), and one end thereof is supported by the support member 9 via an air cylinder 13.

On the other hand, a (+) electrode 7 is slidably arranged on the outer peripheral surface of the grinding wheel 3 with respect to the outer peripheral surface thereof. With this configuration, a DC pulse current is supplied from the power supply device 8 to the (−) electrode 6 and the (+) electrode 7, and a gap S is formed between the (−) electrode 6 and the processed surface 5 of the grinding wheel 3. Is a coolant 11 from a coolant supply device (not shown).
By being supplied through the processing surface 5 of the grinding wheel 3
Is electrolytically improbed.

However, when the processed surface 5 of the grinding wheel 3 is electrolytically improbed with the (-) electrode 6, an oxide film is produced and adheres to the dressed processed surface 5.
This oxide film reduces the grinding performance of the grindstone by clogging the surface of the grindstone, so that the production efficiency becomes a problem especially during rough machining. Therefore, it is necessary to remove this oxide film.

Therefore, as shown in FIGS. 1 and 2, a sliding member 12 is provided so as to face the processing surface 5 of the grinding wheel 3 and remove the oxide film adhered to the processing surface 5. This sliding member 12 is made of brass, carbon fiber, Kevlar or F
By using a brush made of a wear-resistant material that can withstand removal of an oxide film such as RP fiber, and moving in the direction of arrow Z while being supported by the support portion 9 via the air cylinder 13, a grinding wheel It is configured such that it can be brought into contact with and separated from the processed surface 5 of 3.

With the spherical surface generating apparatus having this structure, the work 1
When machining, while rotating the grinding wheel 3,
(-) The weakly conductive coolant 11 is supplied to the gap S between the electrode 6 and the processed surface 5 of the grinding wheel 3. On the other hand, by supplying a DC pulse current to the (−) electrode 6 and the (+) electrode 7 by the power supply device 8, electrolytic improdressing is started on the processed surface 5 of the grinding wheel 3.

Next, the work 1 is advanced to the grinding wheel 3 side and brought into contact with the grinding wheel 3 to start grinding of the work 1. At the time of rough grinding in the initial stage of this processing, FIG.
As shown in FIG. 4, a brush is brought into contact with the processed surface 5 as a sliding member 12 to remove the oxide film 15 and cause the abrasive grains 16 to protrude from the processed surface 5 by 10 to 20 μm, thereby providing a high-speed cut suitable for rough processing. Make it possible.

Next, when the rough machining progresses and the finish grinding is started, the brush is detached from the machined surface 5 as shown in FIG. As a result, the oxide film 15 easily adheres to the processed surface 5 of the grinding wheel 3, and as shown in FIG. 4, the protrusion amount of the abrasive grains 16 from the processed surface 5 is reduced to 5 μm or less, which is suitable for low-speed cutting in finishing. To be in a good state.

According to this embodiment, the abrasive grains 16 are used during rough grinding.
Since a large amount of protrusion is secured, the spherical surface generation processing time can be shortened, and since the amount of protrusion of the abrasive grains 16 is reduced during finishing processing, a surface roughness is small and a highly accurate machined surface can be obtained. The brush 12 used in the present embodiment can be replaced with a brush for dressing such as WA, which has been conventionally used for grinding, to obtain the same effect.

[0021]

Second Embodiment FIGS. 5 and 6 show a second embodiment of the present invention,
FIG. 5 is a cross-sectional view of a main part of the spherical surface generating / processing apparatus, and FIG. 6 is a diagram illustrating a sliding member. In the present embodiment, it is formed in a cylindrical shape and is loosely fitted to the outer circumference of the holder 2 while rotating in the same manner as the spindle 14, and is provided so as to be movable back and forth in the arrow z direction with respect to the holder 2 by an air cylinder (not shown). The brush is attached as the sliding member 17 in a ring shape at the cylindrical end of the support member 18, which is different from the first embodiment, and other configurations are the same as the first embodiment.
Is the same as.

In the grinding process in this case, the support member 18 is moved forward to bring the brush into contact with the processing surface 5 of the grinding wheel 3 during rough grinding, and the support member 18 is retracted to move the brush to the grinding wheel 3 during finish grinding. It is performed by detaching it from the processing surface 5.

According to this embodiment, the brush has a large operating area, and since the brush itself is in contact with the processing surface 5 of the grinding wheel 3 while rotating, the brush is less likely to be caught, so that the efficiency of the spherical surface is improved. Generating process can be performed. Others have the same effects as those of the first embodiment.

[0024]

[Embodiment 3] FIG. 7 is a sectional view showing a main part of a spherical surface generating apparatus according to Embodiment 3 of the present invention. In this embodiment, the sliding member 1
A brush similar to that of the first embodiment is used as 9, and a vibrator 20 constituted by a piezoelectric element made of lead zirconate titanate or the like is attached to a supporting portion of the brush, and the processed surface 5 of the grinding wheel 3 is vibrated while the brush is vibrated. The structure is different from that of the first embodiment in that the oxide film 15 is removed by contacting with the first embodiment, and the other structures are the same as those of the first embodiment.

According to this embodiment, by vibrating the brush and bringing it into contact with the machined surface 5 of the grinding wheel 3, it is possible to surely remove the oxide film 15 adhering to the machined surface 5 and the brush itself. It is hard to get stuck. This enables stable and highly efficient rough grinding.

According to the spherical surface forming method and the apparatus thereof of the present invention, in the spherical surface forming processing of an optical element, a grindstone for rough grinding is used with high efficiency and high accuracy from rough grinding to finish grinding. be able to.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part of a spherical surface creation processing apparatus showing a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a sliding member.

FIG. 3 is a diagram for explaining an action of a sliding member on a processed surface of a grinding wheel.

FIG. 4 is a view for explaining the action of the sliding member on the processed surface of the grinding wheel.

FIG. 5 is a cross-sectional view of a main part of a spherical surface creation processing apparatus showing Embodiment 2 of the present invention.

FIG. 6 is a diagram illustrating a sliding member.

FIG. 7 is a cross-sectional view of essential parts of a spherical surface generating / processing apparatus showing a third embodiment of the present invention.

FIG. 8 is an explanatory diagram of a conventional spherical surface generating / processing device.

[Explanation of symbols]

 1 Work 2 Holder 3 Grinding Wheel 4, 14 Spindle 5 Processing Surface 6 (-) Electrode 7 (+) Electrode 8 Power Supply Device 9 Supporting Member 10 Nozzle 11 Weak Electric Coolant 12 Sliding Member 13 Air Cylinder 15 Oxide Film 16 Abrasive Grains

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiya Akita 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd.

Claims (3)

[Claims] 1. A work holder that rotates while holding a work, a cup-type grinding wheel that grinds a work while rotating on an axis inclined with respect to a rotation axis of the work, and grinding processing by an electrolytic in-process dressing method. In a spherical surface creation processing device having a mechanism for dressing the processing surface of the grinding wheel, a sliding member disposed facing the processing surface of the grinding wheel, and the sliding member on the processing surface of the grinding wheel A spherical surface generating device comprising: a means for contacting and separating. 2. The spherical surface forming process according to claim 1, wherein the sliding member is made of a material having abrasion resistance enough to remove an oxide film formed on a grinding wheel surface by electrolytic dressing. apparatus. 3. A work holder that rotates while holding a work, a cup-type grinding wheel that grinds a work while rotating on an axis inclined with respect to a rotation axis of the work, and grinding processing by an electrolytic in-process dressing method. In the method of processing the surface of the work surface into a spherical surface with a spherical surface creation processing device equipped with a mechanism for dressing the processing surface of the grinding wheel, while processing the roughing and finishing of the work with the same grinding wheel, A spherical surface characterized in that a sliding member, which is arranged so as to face the processing surface of the grinding wheel, is brought into contact with the processing surface of the grinding wheel during rough processing, and is removed from the processing surface of the grinding wheel during finishing processing. Creation processing method.