JPH02262950A - Polishing method for ceramics - Google Patents

Abstract

PURPOSE:To equalize the polishing efficiency of a soft pressing frame with the polishing efficiency of a hard ceramics so as to suppress face flagging by arranging, in close contact, a pressing frame, which has the same height as the ceramics substance to be processed and consists of metallic material not subjected to the chemical action of a grindstone, at the peripheral side face of the ceramic substance to be processed so as to polish it. CONSTITUTION:A pressing frame 6, which has the same height as the ceramic substance 5 to be processed and consists of metallic material not subjected to the chemical action of a grindstone 3, is arranged, in close contact, at the peripheral side face of the ceramic substance 5 to be processed so as to polish this substance 5 to be processed with the grindstone 3. As a result, the polishing efficiency of a soft pressing frame 6 and the polishing efficiency of a hard ceramics 5 become almost equal, which decreases such troubles as that the ground powder bites in the marginal part of the ceramics 5 as the substance to be processed and causes face flagging. Accordingly, ceramic parts excellent all in dimension accuracy, shape accuracy, and plane accuracy can be obtained.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a ceramic polishing method for precision polishing the surface of a Viramix component, and in particular, to a ceramic polishing method for precision polishing the surface of a ceramic component. ωl of ceramics that can prevent drooping and provide ceramic parts with low cost and high flatness accuracy.
Regarding polishing methods.

(Prior Art) Hiramix, which has superior heat resistance, corrosion resistance, and mechanical properties compared to conventional materials mainly made of metals and resins, is used in the automotive and medical industries. As a method for precisely polishing the surface of hard brittle materials such as ceramics, methods using lapping and polishing have been known. In lapping or polishing, the material to be polished is pressed with appropriate pressure against a wrap made of cast iron or a polisher made of woven cloth.
Silicon carbide<s r C), cerium oxide (CeO2)
A lapping liquid is prepared by mixing fine abrasive grains such as iron oxide (Fe203), etc., and this lapping liquid is interposed between the polished material (111) and the polisher, and then the polished material and the polisher are relatively This is a method of mirror-finishing the surface of the material to be polished using abrasive grains by moving the material to a mirror finish.This lapping or boring process further smoothes the surface of the material to be polished, which has been precisely finished by grinding, etc., to improve dimensional accuracy and flatness. This improves accuracy.

However, the above-mentioned polishing methods using lapping and polishing have the drawback that the polishing efficiency is low because the addition lff1 is small compared to the amount of work. In addition, in recent years, there has been an increasing demand for higher precision parts, and ceramic parts with even better planar precision are being sought.

For example, ceramic parts that serve as reference surfaces for measuring instruments and Hiramix parts that are used as gauge blocks for dimension measurement are required to have high dimensional accuracy, shape accuracy, and flatness of 1 degree.

Therefore, in addition to the conventional mechanical polishing method, so-called mechanochemical polishing, which uses chemical reactions on the polished surface, is a method for polishing the surfaces of ceramic parts with higher precision and efficiency. method has also been adopted.

This mechanochemical polishing method uses abrasive grains or whetstones that cause a chemical reaction with the material to be polished.The chemical reaction is caused in minute regions that protrude on the surface of the material to be polished, and the generated reaction products are mechanically polished using the abrasive grains. This is a method to improve flatness accuracy.

When actually polishing work is carried out, in order to prevent the surface from sagging at the edge of the material to be polished, the outer circumferential surface of the material to be polished is prepared in advance with the same thickness and the same material as the material to be polished. Attach the holding frame tightly and cover it. Polish the dl polishing material and the holding frame at the same time.

According to the above mechanochemical polishing method, since the material to be polished and the holding frame are made of the same material, the polishing efficiency is the same. I will be polished. At this time, galling of the abrasive grains at the boundary between the two members does not occur, so that the occurrence of surface sagging is effectively prevented. In addition, since the fine protrusions on the surface of the rIII polished material are chemically treated and finished more smoothly, it is possible to obtain ceramic parts with better dimensional accuracy and shape accuracy than with conventional methods. In addition, unlike conventional mechanical polishing methods, we also use a precise polishing method using chemical action, which not only greatly improves flatness accuracy but also significantly improves polishing efficiency and shortens polishing time. can.

(Problem to be Solved by the Invention) However, according to the conventional polishing method, in order to prevent the occurrence of surface sagging at the edge of the material to be polished, ωlW! It is necessary to provide a restraining frame made of the same material as the material, which has the disadvantage of requiring a large amount of cost to prepare the restraining frame.

In other words, in order to improve the finishing accuracy of the edge portion of the material to be polished, it is necessary to set the polishing efficiency of the material to be polished and the holding frame to be equal, and it is necessary to prepare both from the same material. However, in order to do this, it is necessary to prepare a holding frame 5 to 6 times the amount of the material to be polished under the same conditions, and ceramic materials are often hard and difficult to process, which increases the cost of manufacturing the holding frame. .

On the other hand, the dimensions of the frame used for polishing as a holding frame changed and it became impossible to use it again, and the holding frame was discarded each time, so the yield of ceramic products based on raw materials was extremely low and was not worth the cost. There was a problem.

The present invention was made to solve the above-mentioned problems, and by using a cheap holding frame, it is possible to prevent the occurrence of sag on the edge of the material to be polished, and to efficiently produce ceramic parts with high flatness precision. The object of the present invention is to provide a method for polishing the resulting ceramics.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a method for polishing ceramics in which the surface of a ceramic workpiece is mechanochemically polished using a grindstone that has a chemical effect on the C ceramic workpiece.
It is characterized in that a holding frame made of a metal material, which has the same height as the ceramic workpiece and is not affected by the chemical action of the grindstone, is closely disposed on the outer circumferential side of the Hiramix workpiece for polishing.

(Function) According to the method for polishing ceramics having the above configuration, since the holding frame is made of a metal material that is not subjected to chemical action, the holding frame is subjected only to the mechanical polishing action of the grindstone. On the other hand, ceramics as a workpiece are subjected to not only the mechanical polishing action of the grindstone, but also the chemical polishing action that partially reacts with the components of the grindstone.

Therefore, the polishing efficiency of the soft holding frame and the FiirIi efficiency of the hard ceramic are approximately equal, and the boundary between the holding frame and the ceramic is equally polished.

Therefore, abrasive grains are less likely to get caught in the edge of the ceramic workpiece, causing surface sagging. Therefore, it is possible to provide ceramic parts with excellent dimensional precision, shape precision, and planar precision.

In particular, as the holding frame does not use a ceramic material equivalent to the workpiece, it uses an inexpensive general-purpose metal material.
The manufacturing cost and manufacturing time of the restraining frame are significantly reduced. Also, the restraint frame wA! Since ceramic raw materials are not used for FiJ, the yield of ceramic parts compared to raw materials can be greatly improved, which is an excellent effect.

(Example) Next, an example of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a sectional view showing an embodiment of an IIL polishing apparatus for carrying out the method of the present invention.

The polishing device includes a rotary table 2 which is integrally fixed to a rotating shaft 1 and rotates on a horizontal plane, a disc-shaped grindstone 3 fixed to the upper surface of the rotary table 2, and a ceramic (Si) workpiece 5.
3N4) and a disc-shaped sticking plate 4 to which the holding frame 6 is attached integrally, rotating rollers 7a and 7b that rotatably hold the sticking plate 4, a frame 8 that holds the rotating rows 57a and 7b, and a frame 8. It is equipped with a U rotation drive i11 device 9 that is installed on the top and drives the rotating roller 7a, and a pressure device 10 that presses the sticking plate 4 in the direction of the grindstone 3.

Although not shown, the frame 8 is located in the radial direction of the grindstone 30.
A reciprocating drive device is installed to move the grinding wheel back and forth, and the workpiece 5 attached to the sticking plate 4 is configured to rotate on the surface of the grinding wheel and at the same time reciprocate in the radial direction of the magnet 30. There is.

When polishing the workpiece 5, first attach the workpiece 5 to the top surface of the affixing plate 4 as shown in FIGS. 3(a) and (b), and then Four restraining frame elements 6a, 6b, 6c, 6 having the same height as the workpiece 5
d so that they are in close contact with each other and fixed with adhesive or the like. Note that the number of holding frame elements 6a to 6d is increased or decreased depending on the shape of the workpiece 5.

Further, the holding frame elements 6a to 6d are made of a trowel that is not subjected to chemical action by the grinding wheel 3, such as general MIJ steel (88, 8
841), stainless steel (SUS304), mechanical structural steel (845C), etc., are made of general-purpose metal materials that are easy to process and inexpensive.

Further, as the grindstone, a resin bonded grindstone is used, which is made by solidifying chromium oxide (Cr203) powder with a resin material, which causes a chemical reaction with a ceramic component such as Si3N4.

As shown in FIGS. 3(a) and 3(b), the workpiece 5 and holding frame 6, which are integrally attached to the upper surface of the affixing plate 4, are attached to the upper surface of the grinding wheel 3 of the polishing device as shown in FIG. The surface of the workpiece 5 to be polished is placed in contact with the rotating rollers 7a and 7b.
be bound by.

The workpiece 5 is pressed against the upper surface of the grindstone 3 with a predetermined pressure by a pressure device 10.

In this state, the rotary table 2 rotates and the rotary drive device 9 is started at the same time, so that the workpiece 5 is rotated by the drive-side rotary roller 7a. On the other hand, the workpiece 5 is simultaneously reciprocated in the radial direction of the grindstone 3 by a reciprocating drive device (not shown). In this way, the workpiece 5 is polished while changing its position vertically and horizontally with respect to the polishing surface of the grindstone 3, so that the workpiece 5 is polished uniformly over the entire surface with uniform polishing efficiency.

This polishing operation causes a partial chemical reaction between the grindstone (Cr203) and the fine protrusions of the ceramic (Si3N4), and a reaction product that is easily peeled off is formed. This reaction product is mechanically removed by colliding with the abrasive grains. In this way, ceramics are efficiently mirror-finished by mechanochemical polishing, which combines polishing using chemical action and mechanical polishing.

On the other hand, the restraining frame 6 made of soft general structure tj4 (8841) or the like is not subjected to the chemical action of abrasive grains, but only to the mechanical polishing action of a grindstone. Therefore, the ceramic parts and holding frame 6 are roughly equivalent to R111W!
Polished with i efficiency. Therefore, no step is formed at the boundary between the ceramic component and the holding frame 6, and abrasive grains do not get caught in the edge of the ceramic component and cause surface sagging. Therefore, it is possible to efficiently provide ceramic parts with excellent dimensional accuracy, shape accuracy, and planar accuracy.

In particular, since the holding frame 6 is made of a general-purpose metal material (SS41) that is inexpensive and easy to process, the holding frame 6 is easy to manufacture, and its manufacturing cost and manufacturing time are significantly reduced. In addition, since expensive Hiramix raw materials are not used to prepare the holding frame 6, it is possible to improve the yield of ceramic parts based on raw materials by 5 to 6 times compared to conventional methods, and the bulkiness can be greatly improved. can be increased to

Next, a more specific example will be described.

Chromium oxide (Cr20) is used as an abrasive grain with chemical action.
3) A resin-bonded grindstone made by uniformly mixing fine particles and resin powder and compression-molding is mounted on the polishing device, while
A Si3N4 component with +u+1 width of 30HIi and height of 10M and pre-polished to a center line average roughness of 0.5μmRa is pasted on a 100J11 diameter plate, and around it is a general structural part with a thickness of 10#lIN. When a holding frame made of steel (SS41) was attached tightly and polished,
Polishing speed: 10μ71L/Ilr, finished surface roughness: 0.
03 μmrLRa, and almost no surface sagging was observed.

On the other hand, as a comparative example, the same Si3N4 parts and grindstone as those used in the above example were prepared, and the holding frame was made of Si3N4.
When the material formed in step 4 was polished under the same conditions,
Polishing speed 9μm/Ilr, finished surface roughness 0.03μ
mRa, no surface sagging was observed, and almost the same results were obtained in both the Examples and Comparative Examples.

However, according to the method of this embodiment, ceramics (S13N
4) Since there is no need to prepare a restraining frame made of the same product, the manufacturing cost and manufacturing time of the restraining frame can be reduced, and the yield of the product can be improved by 5 to 6 times.

〔Effect of the invention〕

As described above, according to the method for polishing ceramics according to the present invention, since the holding frame is made of a metal material that is not subjected to chemical action, the holding frame is subjected only to the mechanical polishing action of the grindstone.

On the other hand, ceramics as a workpiece are subjected to not only the mechanical polishing action of the grindstone, but also the chemical polishing action that partially reacts with the components of the grindstone.

Therefore, the polishing efficiency of the soft holding frame and the polishing efficiency of the hard ceramic are approximately equal, and the boundary between the holding frame and the ceramic is equally polished.

Therefore, the abrasive grains are less likely to get caught in the edge of the ceramic workpiece and cause sag. Therefore, it is possible to provide a ceramic component with excellent dimensional accuracy, shape accuracy, and planar accuracy.

In particular, since the holding frame does not use a ceramic material equivalent to the workpiece, but instead uses a general-purpose metal material that is inexpensive and easy to process, the manufacturing cost and manufacturing time of the holding frame are significantly reduced. Furthermore, since ceramic raw materials are not used to prepare the restraining frame, an excellent effect is exhibited in that the yield of ceramic parts relative to raw materials can be significantly improved.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of a polishing apparatus for carrying out the method of the present invention, FIG. 2 is a plan view taken along arrow II-II in FIG. 1, and FIGS. 3(a) and (b) are FIG. 3 is a plan view and a sectional view showing a state in which a workpiece and a restraining frame are fixed on a pasted plate, respectively. 1... Rotating shaft, 2... Rotating table, 3... Grinding stone, 4...
... Pasting board, 5... Workpiece, 6... Holding frame, 6a
, 6b. 5c, 5d... Holding frame element, 7a, 7b... Rotating roller, 8... Frame, 9... Rotating drive device, 10
...Pressure device. (j Figure Figure Figure

Claims (1)

[Claims] In a ceramic polishing method in which the surface of a ceramic workpiece is mechanochemically polished using a grindstone that has a chemical action on the ceramic workpiece, the outer peripheral side of the ceramic workpiece has a height equal to that of the ceramic workpiece. A ceramic polishing method characterized by polishing by closely arranging a holding frame made of a metal material that is not affected by the chemical action of a grindstone.