JPH029573A - Tin surface reference plate of contactless polishing device - Google Patents

Abstract

PURPOSE:To enhance anti-abrasiveness of a tin surface reference board and prolong its lifetime by applying Ni plating to the tin surface reference board, and cutting minor grooves at the surface using a diamond cutter. CONSTITUTION:A surface reference board spindle is furnished to bear and rotate a tin surface reference board 1, and a processing trough is arranged in such a way as surrounding this board 1. Grinding liquid containing free abrasive grains is fed onto this tin surface reference board 1, and the spindle is put into relative rotation with a head for work, and a work attached to the undersurface of this head is polished in the condition that the head is put afloat. At this time, the surface of the board 1 is plated 14 with Ni containing 10-20% P, and minor grooves 13 are cut spirally using a diamond cutter. This Ni plating 14 increases the hardness of the board surface, enhances its anti- abrasiveness, reduces the wear of the minor grooves 13, and prolongs the lifetime, while cutting with diamond cutter enhances the surface accuracy of the tin board.

Description

[Detailed description of the invention] ) technical field The present invention relates to an improvement of a tin surface plate for a non-contact polishing device.

Non-contact polishing is used to polish flat surfaces such as windows and mirrors to highly accurate flat surfaces.

It is called non-contact because there is no contact between the workpiece and the polishing surface plate.

(b) Conventional non-contact polishing method involves rotating a tin surface plate with a spiral groove cut on its surface, supplying polishing liquid onto it, and polishing the workpiece while it is suspended by the dynamic pressure of the polishing liquid. This is the way to do it.

The polishing liquid contains free abrasive grains. The polishing liquid flows violently and the abrasive grains come into contact with the lower surface of the workpiece. Therefore, the lower surface of the workpiece is gradually polished.

Since there is no contact between the surface plate and the workpiece, the polishing speed is slow.

However, a highly flat polished surface with few irregularities can be obtained.

It is most suitable as a polishing method for objects that require high precision and high flatness.

Since there is no contact between the tin surface plate and the workpiece, it falls into the category of non-contact polishing.

However, non-contact polishing is a term that has a broad meaning. Among these methods, the present invention targets a method called float polishing. This is called a float because the workpiece is suspended in the polishing liquid.

Although it is a new technology, float polishing is widely known as a method that uses floating abrasive grains to obtain a highly accurate flat surface.

There are many documents related to non-contact polishing methods. For example, Y, Namba and H, Tsuwa, “Ul
tra-Fine Polishingof 5app
hire Single Crystal, Anna
ls of the CARP embryo 1. p325 (197
7) Y+ Namba and H, Tsuwa,
”Mechanism and SomeAp
plications of Ultra-Fine
Polishing, “Annals of CIRP
271. p511 (1978), etc.

(ii) Problems to be Solved by the Invention In float polishing, a tin surface plate is rotated at high speed and polishing liquid is supplied near the center. The workpiece is pasted onto the workpiece head. Although the workpiece head rotates at high speed, it is supported so that it can move freely in the vertical direction.

The workpiece head is positioned on the upper surface of the surface plate, and both the surface plate and the workpiece head are rotated. Of course, the center of rotation of the gutter to the workpiece is shifted to the side from the center of the surface plate. The rotational motion of the surface plate and the rotational force of the top and bottom; they exist. Therefore, the dynamic pressure of the fluid becomes high and the force 11 workpiece head floats above the polishing liquid.

In order to apply dynamic pressure to the fluid, the rotational force of the surface plate must be efficiently transmitted to the fluid). For this purpose, it is necessary to allow the polishing liquid to stay on the surface plate for a relatively long time.

However, as the surface plate rotates at high speed, due to centrifugal force,
The polishing liquid scatters in the radial direction.

To prevent this, a spiral groove is carved on the top of the surface plate. This groove is not a collection of concentric circles, but a series of grooves whose radius gradually increases. It can also be called a spiral groove, but here it is called a spiral groove.

It has a major groove and a minor groove. It is a groove that is both wider and deeper than Uno (Omizo and Juku). Furthermore, thin small grooves are carved on the upper surface between these grooves. The pz shift is also a spiral groove.

Since this groove is carved in the direction of rotation, it is possible to prevent the polishing liquid from quickly scattering due to centrifugal force.

The action of the large grooves and small grooves allows the polishing liquid to stay on the surface plate for a longer time and to increase the fluid pressure.

In other words, the major and minor grooves play an important role in float polishing.

Because it is necessary to cut large and small grooves into the surface plate of a float float, tin is used because it has good machinability. Tin is also corrosion resistant, making it an ideal material.

However, tin has excellent machinability because it is soft. Being soft has its drawbacks as well.

When Flow I polishing is repeated many times, the soft grooves of the throne plate become worn away by the action of the polishing liquid. In particular, the tips of the small grooves may become worn or crushed, causing them to become round and dull.

If the small grooves become dull, the predetermined dynamic pressure will not be generated even if the surface plate rotation speed is the same.

If the dynamic pressure is insufficient, the workpiece may fall and come into contact with the surface plate. In this case, the contact new calendar occurs, and the desired flatness cannot be obtained.

It also seriously damages the surface plate.

Even if it does not go that far, if the dynamic pressure is insufficient, the machining speed will decrease and the finishing accuracy will deteriorate significantly over time.

This is not to say that there have been no measures taken in the past to deal with such situations. It was known from the beginning that tin wears easily. Of course there are countermeasures.

Conventionally, when the small grooves have worn out into a round shape, the surface plate is removed and all the small grooves are once removed to make them flat. After flattening it, small grooves are carved in a spiral again. This will make the major groove shallower by the height of the minor groove.

This is unavoidable.

Previously, the tin surface plate had to be re-cut once in this manner.

If you re-cut the small grooves many times, you can use the tin surface plate for a long time.

However, recutting is expensive and time consuming.

Rather, it is more convenient to prevent the small grooves from wearing out.

B) Structure In the present invention, the surface of the tin surface plate is hardened to prevent wear and tear. The surface of the tin surface plate is plated with Ni containing 10% to 20% P (phosphorous), and the upper part of the small groove is slightly cut with a diamond cutting tool to achieve highly accurate planarization.

FIG. 1 is a sectional view showing major grooves and minor grooves of a tin surface plate.

The tin surface plate 1 is a circular plate, and a large spiral groove 11 is cut on the surface. The uncut portion remains in a spiral shape.

A small groove 13 is cut into the upper surface of this raised strip 12 in a spiral strip.

In the present invention, the surface is thinly plated with electroless nickel. This part is indicated by thin diagonal lines. This is a nickel plating layer 14.

Although it is called nickel plating, it is nickel containing 10 to 2096 phosphorus. The nickel plating layer 14 is cut with a diamond cutting tool, but carbon C, which is a component of diamond,
reacts easily with nickel. To suppress this reaction,
Phosphorus is added to nickel.

The thickness of the nickel plating N14 is as thin as about 10 to 20 μm.

The plating temperature is about 80 to 90°C, which is quite high. As a result, the tin surface plate may be thermally deformed and warped.

Also, since plating is applied to a surface with many grooves, the plating thickness is not uniform. Due to the non-uniformity, the shape of the small groove changes.

To correct such warpage or unevenness, slightly grind the top of the small groove with a diamond cutting tool.

This grinding allows highly accurate planarization.

(4) Function The appearance and operation method of the polishing device are the same as the conventional ones.

FIG. 4 shows an outline of the non-contact polishing apparatus.

The tin surface plate 1 has a surface plate main shaft 2 attached to the center of the bottom surface.
It rotates with this. A processing tank 3 is provided around the tin surface plate 1.

A polishing liquid supply pipe 4 is provided at the upper center of the polishing surface plate 1. From this, the polishing liquid 5 is supplied onto the tin surface plate 1.

A workpiece head 6 having an axis parallel to the main spindle 2 of the surface plate is provided at a position away from the center of the main spindle 2 of the surface plate.

The ttn workpiece 7 is attached to the lower surface of the workpiece head 6. Although the workpiece head 6 is given a rotational force, it is not restrained in the vertical direction, and therefore floats due to the fluid dynamic pressure of the polishing liquid.

Such operation is the same as the conventional one.

The polishing liquid contains free abrasive grains, which polish the lower surface of the workpiece 7. At the same time, the polishing effect is also exerted on the surface of the tin surface plate.

However, since the tin surface plate of the present invention is nickel plated, it has a much harder surface than that made of pure tin.

Therefore, it has increased physical strength and excellent wear resistance.

Furthermore, it is resistant to acids and alkalis, and has excellent chemical resistance.

For this reason, the small grooves will not wear out even after repeated use. It can extend the lifespan.

In addition, after being plated, it is diamond cut, so
The surface accuracy of the surface plate is high.

a) Example A large groove with a width of 2 fl and a depth of 0.7111 mm was cut in a spiral shape on a tin surface plate. Furthermore, the surface of the raised stripes has a width of 0.3ff.

A small groove with a depth of 013 ff was cut in a spiral shape.

Thoroughly wash off the cutting oil and attach the machining tank to the bottom of the surface plate. Soak in alcohol to remove dirt.

dry. After getting the hang of it, a plating solution was added and electroless nickel plating was performed at 90°C.

When the plating was finished, I washed it under running water to make sure there were no stains or unevenness left. Subsequently, hot air drying was performed.

Remove the processing tank. I used a diamond tool to cut a small portion of the top of the small groove. As a result, ±1μm/φ4
We created 60 high-precision polyrasia planes.

In this way, the tin surface plate of the present invention was manufactured.

I actually performed float polishing using this surface plate.

The polishing liquid is a 296 suspension of 70 Si02.

The workpiece is BK-7 glass of φ160×10t.

Attach this to the workpiece head and perform pre-processing.

After this, float polishing was performed. The conditions are: Surface plate main shaft rotation speed 1100 rp Workpiece head rotation speed 1100 rp Polishing pressure 26
It was 0g/at.

It was confirmed that the nickel-plated tin surface plate of the present invention had good floating properties as well as the conventional one. It was confirmed that there was no contact.

In order to examine the effects of the present invention, polishing was performed for a long time, and changes in polishing rate and dullness of the surface plate surface were examined.

FIG. 2 shows how the polishing rate decreases with polishing time. The horizontal axis is polishing time, and the vertical axis is polishing speed (people/m1n). The solid line shows the surface plate of the present invention plated with Ni. The broken line indicates a conventional surface plate without Ni plating.

In both cases, the initial polishing rate was 450 people/m 1 n.

With the conventional surface plate, the polishing speed decreases significantly, and decreases to about half in 40 hours. This is because the small grooves were worn out.

In the present invention, even after 60 hours, about 370 people/rn1
The polishing rate is n. There is little decrease in polishing speed. This means that there is almost no wear and tear on the small grooves.

FIG. 3 shows the surface roughness of BK-7 glass as a workpiece, measured by changing the polishing time. The horizontal axis is polishing time,
The vertical axis is the surface roughness (human Rms) of BK-7 glass.

The initial roughness is 180 Rms.

In the case of the present invention, polishing for 10 hours resulted in 60 Rml. In the conventional example, it takes 20 hours to reach Rm8 for 60 people. This also means that the tJX grooves of the tin surface plate of the present invention are less likely to wear out.

(1) Effects Since the tin surface plate of the present invention is plated with Ni and has small grooves cut with a diamond cutting tool, it has the following effects.

(1) The wear resistance of the tin surface plate is improved. Extends the life of tin surface plates.

(2) The polishing rate decreased slightly.

(3) Processing time for float polishing can be shortened.

(4) Since it has chemical resistance, it is now possible to mix chemicals such as acids and alkalis into the polishing liquid.

This expands the range of applications for float polish.

(5) It is now possible to stably obtain a highly accurate machining plane.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged sectional view of the tin surface plate of the present invention. Figure 2 is a graph showing the relationship between polishing time and polishing rate (1), which shows the measured values of the present invention and the conventional example. Figure 3 is a graph showing the relationship between polishing time and surface roughness of the workpiece. Graph showing the measured values of the invention and the conventional example Figure 4 is a schematic cross-sectional view of the float porridge device. Board spindle 3...... Machining tank 4...
...... Polishing liquid supply pipe 5 ......
・・Ken Calendar Liquid 6・・・・・・・・・ Workpiece head 7・・・・・・・・・Workpiece 11・・・・・・・・・・・・・・・Oomizo 12...
・・・・・・・・・Rise Article 13・・・・・・・・・・
・・Small groove 14・・・・・・・・・Nickel plating layer Inventor: Miki Kusao Patent applicant: Sumitomo Electric Industries, Ltd.

Claims (1)

[Claims] A tin surface plate 1 having large grooves 11 and small grooves 13 spirally carved on its surface, a surface plate main shaft 2 that supports and rotates the tin surface plate 1, and a processing tank 3 provided so as to surround the tin surface plate 1. , a workpiece head 6 with a workpiece 7 attached to the bottom surface, and a tin surface plate 1
While supplying a polishing liquid containing free abrasive grains onto the surface, the main shaft 2 of the surface plate and the workpiece head 6 are rotated, and the workpiece 7 is polished with the workpiece head 6 floating. It is a tin surface plate used for contact polishing equipment, and the surface is coated with 10% or more of phosphorus.
A tin surface plate for a non-contact polishing device, characterized in that after turning 20% nickel plating, small grooves 13 are cut with a diamond cutting tool.