JPH0360970A - Polishing surface plate - Google Patents

Abstract

PURPOSE:To reduce incurring of a dispersion loss and the occurrence of a drop of diamond grinding grain during polishing and to perform high-efficient polishing of ceramics and a rigid metal by a method wherein micropowder of copper or tin is fixed in a dispersed state to a porous substance of thermosetting resin. CONSTITUTION:The working surface of a polishing surface plate forms a porous substance of thermosetting resin having a continuous pore having porosity of 30-70 volume %. Micropowder of copper or tin is fixed in a dispersed state to the porous substance to produce a desired polishing surface plate.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is a polishing tool used for highly accurate and efficient surface polishing of difficult-to-grind materials such as ceramics and cemented carbide using diamond abrasive grains. Regarding the board.

(Prior art) Conventionally, superhard materials such as ceramics, metal oxides, and ferrites are extremely hard, and ceramics also have brittle properties, so conventional abrasive grains such as silicon carbide, garnet, and alumina have been used. It was difficult to process the surface with high precision and efficiency due to the polishing method used. For this reason, in general, diamond is fixed to the tip of a tool to make a turning tool, diamond fine powder is electrodeposited to the tip of a thin metal to make a cutting tool, or a diamond is fixed to a metal or hard binder to make a grindstone. We use the following. However, these methods are suitable for drilling, zero-curved surface machining, local machining, etc., and are not suitable t1 methods for machining flat surfaces with high accuracy.

Further, as a method of polishing superhard materials, there is a method using a diamond grindstone, but in general, in superhard materials, there is a tendency for the polishing resistance to increase rapidly once polishing is started.

For this reason, even though a diamond grindstone has a certain level of polishing ability immediately after dressing, as grinding continues, the grinding resistance increases, heat generation burns the material to be polished or the grindstone, and the wheel of the grindstone eventually stops. Before this happens, it is necessary to perform re-dressing to restore the grinding force and continue polishing, but there are problems in that dressing the diamond grindstone is complicated and requires a large amount of work.

On the other hand, as a surface processing method, for example, the object to be polished is pressed onto a cast iron surface plate, and free abrasive grains are intermittently supplied together with the polishing liquid.
A so-called lapping polishing method is used in which polishing is performed by rotating a surface plate, but using diamond abrasive grains in this method is uneconomical because of the large loss of expensive abrasive grain powder, and the use of highly hard abrasive grains is uneconomical. Since the grains are pressed against the object to be polished, there are problems such as creating deep scratches on the object, and further polishing the surface plate, which tends to cause uneven wear and deviations in dimensional accuracy.
At present, there is still no satisfactory method for polishing superhard materials such as ceramics with high precision and efficiency.

(Problems to be Solved by the Invention) In view of the above-mentioned problems, the present inventors conducted intensive research and found that a polishing surface plate fixed with fine metal powder of copper or tin has a diamond abrasive grain (hereinafter referred to as " The present invention was completed based on the discovery that it has an excellent affinity for diamond abrasives (hereinafter referred to as "diamond abrasive grains"), and exhibits extremely good polishing power on superhard materials in lapping polishing using diamond abrasive grains. The purpose of the present invention is to have excellent retention of diamond abrasive grains as an abrasive in lapping polishing, to have good dimensional stability, to exhibit preferable polishing power for ultra-hard materials such as ceramics, and to have good flatness and To provide a polishing surface plate capable of easily correcting deviations in shape accuracy such as flatness.

(Means for Solving the Invention) The above-mentioned object is to provide a polishing surface plate of a polishing machine that performs lapping polishing with abrasive grains, in which the working surface of the polishing surface plate has continuous pores with a porosity of 30 to 70% by volume. This is achieved by a polishing surface plate which is a porous body of thermosetting resin and has fine copper or tin powder dispersed and fixed therein.

The copper or tin metal fine powder used in the present invention preferably has a high purity of 99% or more, and these can be used alone or in combination.

The average particle size of the above-mentioned fine powder is not particularly limited, but if the particle size is too small, it tends to fall off from the porous body, and if the particle size is too large, the holding power of the diamond abrasive grains tends to be small, so it is preferable. is 200 μm or less, more preferably 10 to
The particle size is preferably 150 μm, more preferably about 60 to 100 μm, and particles with a narrow particle size distribution are preferred. Also,
Regarding the shape of the metal fine powder, it is preferable to use a spherical shape close to a true sphere rather than an irregularly shaped granular one because it has a high polishing rate and excellent surface roughness. When there are many impurities such as iron, these impurities react with acids and the like that are curing catalysts for the thermosetting resin, causing foaming, making it difficult to mold a homogeneous structure.

In addition, fine tin powder has better retention power for smaller diamond abrasive grains than fine copper powder, and specifically, it has a favorable polishing effect in lapping polishing using diamond abrasive grains of 6 to 10 μm or less. tend to bring about Further, in the present invention, it is also effective to use fine lead powder in combination with the above-mentioned fine metal powder.

In the present invention, the cured product of thermosetting resin refers to a thermosetting resin whose precursor is cured by heat or the action of a reaction catalyst, and is a hard material that hardly dissolves in water, organic solvents, etc. It changes into a resin with excellent thermal stability. Specifically, the thermosetting resins used here include phenolic resins, melamine resins,
It is preferable to select a urethane resin, an epoxy resin, a fer resin, a furan resin, or a silicon resin, with phenol resins and melamine resins being particularly preferred. Note that the above-mentioned synthetic resins may be used alone or in combination.

Regarding the properties of the thermosetting resin according to the present invention, it is preferable that the resin itself or its precursor exhibits a liquid state, or that it exhibits a liquid state when dissolved in water or a solvent. Particularly preferred are those having the following.

The polishing surface plate of the present invention has the above-mentioned thermosetting resin combined with the above-mentioned fine metal powder of copper or tin, and further has a porosity of 30 to 7.
A porous body having 0% by volume of continuous pores, the pore diameter of which is preferably 500 μm or less. The pores reduce the loss of expensive diamond abrasive grains during polishing, and also effectively prevent clogging of the polishing layer and reduce temperature rise due to accumulation of polishing heat. If the porosity is smaller than sO volume %, the above effects cannot be fully exhibited, the polishing rate will be low, and the stability of the polishing action will be insufficient. Further, when the porosity is greater than 70% by volume, the porous body becomes a brittle structure, and preferable polishing is ensured within the above-mentioned limited range.

The content of the metal fine powder is not particularly limited, but if the content is too low, the holding power of the diamond abrasive grains tends to decrease, and if the content is too high, it tends to become a porous body with a brittle structure. The amount is preferably about 5 to 25% by volume, more preferably about 10 to 20% by volume. In addition, it is preferable that the metal fine powders are bonded so that they do not easily fall out of the porous body, and each fine powder is not separated in an independent dispersed state, but is interconnected with each other and is in a substantially continuous state. It is extremely preferable that the By doing so, the dimensional stability against heat, water, solvents, etc. is improved, and the diamond abrasive grain retention effect is increased.

The polishing surface plate according to the present invention can be manufactured, for example, as follows. That is, the above-mentioned thermosetting resin stock solution,
A liquid synthetic resin such as a solution or an emulsion is mixed with the above-mentioned fine copper or tin powder, a pore-forming material, and, if necessary, a curing catalyst for the thermosetting resin, and sufficiently stirred. The mixture obtained here has a high viscosity as a liquid synthetic resin and also contains a large amount of fine powder metal, so it takes on the form of an extremely viscous slurry or paste. Therefore, in order to uniformly stir this and obtain a homogeneous product, a high viscosity stirring device and a kneader are required.
It is preferable to use . Furthermore, unless it is made into a viscous slurry or paste, the metal added has a high specific gravity and will settle, making it difficult to obtain a homogeneous product. That is, specifically, at least 8 at the temperature at the time of adjustment.
It is preferable to have a viscosity of approximately 000 cps or more.

Here, as the pore-forming material, organic fine powder such as starch or its derivatives is suitable. More specifically, examples include starch extracted from rice, corn, potatoes, etc., or processed or classified starches thereof. In addition, inorganic acids or organic acids are generally used as catalysts for thermosetting resins, but
In the case of the present invention, fine metal powder of copper or tin is used as a raw material, so adding these acids will cause a reaction with the copper or tin, causing undesirable phenomena such as foaming due to oxidation of the metal, and even dissolution. , which has a significant negative impact on manufacturing. Therefore, it is preferable to use as little amount of these acids as possible.
More preferably, salts consisting of a strong acid and a weak base, ie, salts exhibiting acidity in an aqueous solution, hydrochlorides of organic amines, etc. are preferably used.

Next, the viscous material is cast into a mold having a desired shape, and then left standing and heated in an atmosphere of, for example, 50 to 100°C. At this stage, a mild initial condensation reaction of the thermosetting resin begins,
The viscous material gradually gels, and then assimilation begins and a porous structure is formed by the pore-forming material.

After completion of heating and pre-solidification, the pre-solidified product is removed from the mold and subsequently heated to a temperature of, for example, 80 to 100°C to remove any intervening moisture or solvent, and then further heated to, for example, 120 to 200°C.
Gradually raise the temperature to 00°C. At this stage, crosslinking and curing of the resin progresses in earnest, resulting in the desired porous structure with hard physical properties. The thermosetting reaction of the thermosetting resin may be carried out in an atmosphere of an inert gas such as nitrogen gas in order to prevent the oxidation reaction from occurring at the same time.

The polishing surface plate obtained in this way has continuous pores,
The appearance is similar to that of metal, and the denser the pores, the stronger this tendency, and it is also suitable for the purpose of the present invention. Also,
The produced porous body preferably has a plate shape.

The polishing surface plate may be formed from a single piece of material, but it may also be formed from a combination of a plurality of materials.

(Effect of the invention) When the polishing surface plate of the present invention is used for lapping and polishing using a slurry containing diamond abrasive grains as a polishing liquid, the diamond abrasive grains are contained in the polishing surface plate and are converted into fine powder of copper or tin. It is fixed in a half-buried form, reducing the scattering and falling off of diamond abrasive grains during polishing, and can efficiently polish ceramics, hard metals, etc. Because it is a porous material, the heat associated with polishing is effectively dissipated, and because it is a thermosetting resin, there is little deformation or distortion due to temperature changes, and fine particles of polishing debris are trapped in the pores. , rapid clogging phenomenon can be prevented, and polishing efficiency can be significantly improved. This effect can only be obtained with a porous material, and for example, even if it is a mixture of resin and metal, the above effect will be insufficient in a non-porous material, and rather the resin will deteriorate due to heating. No, there is even a tendency to be inferior to that of metals. Furthermore, if the dimension or shape of the surface becomes out of order, it also has the ripple effect of being able to be easily corrected using ordinary tools, unlike when it is made solely of metal.

The main polishing action of lapping using the polishing surface plate of the present invention is slightly different from that of conventional lapping. In other words, in conventional lapping polishing, a large amount of free abrasive grains are interposed in the gap between a rotating surface plate and the object to be polished, and as these loose abrasive grains roll, the surface of the object to be polished is polished little by little. However, when the polishing surface plate of the present invention is used, the diamond abrasive grains as free abrasive grains contained in the polishing liquid bite into the polishing surface plate of the present invention, and half of the diamond abrasive grains are absorbed into the polishing surface plate of the present invention. The diamond abrasive grains are embedded in the surface plate, with half of the diamond abrasive grains protruding from the surface, and the surface of the surface plate is coated with a single layer of diamond abrasive grains. The object to be polished is polished using the shearing force of the diamond abrasive grains. For this reason,
By applying the polishing surface plate of the present invention, it is now possible to perform lapping polishing using diamond abrasive slurry as the polishing liquid, which was rarely done because it was extremely uneconomical. ceramics,
Efficient flat precision finishing is possible for superhard materials such as cemented carbide metals and metal oxides.

Furthermore, the polishing surface plate of the present invention allows for easy modification of its surface shape, so-called dressing. In other words, since polishing is performed using the action described above, there is relatively little wear on the surface plate itself, but if used for a long time, the polishing power will decrease and the flatness of the working surface will become uneven, which requires correction. becomes. In this case, the surface plate of the present invention can use metal for the porous body of thermosetting resin; for example, a dresser on which a plurality of pellets of metal bonded diamond grinding wheels are arranged is pressed against the surface plate, and the surface plate is An example of this method is to modify the surface of the surface plate by rotating it. Therefore, it is not necessary to remove the surface plate from the polishing machine and perform correction work using a machine tool such as a lathe, and according to the surface plate of the present invention, correction work can be performed easily and efficiently. It is.

The polishing surface plate of the present invention is used in a so-called single-sided lapping method in which an object to be polished held on a support is pressed against a rotating surface plate for polishing. It can also be applied to a double-sided simultaneous lapping method in which the object to be polished is held between two rotating upper and lower surface plates and both the upper and lower sides of the object to be polished are simultaneously polished. Hereinafter, the present invention will be explained in detail with reference to Examples. Before that, the method of the polishing test in this example will be described.

<Polishing Test Method> An alumina-based cemented carbide ceramic thin plate having a square shape of 3 cm on a side was prepared as an object to be polished. This was pasted and fixed on the surface of the support using wax, and pressed onto the surface plate with a pressing force of 400.
The object to be polished was polished using a single-sided lapping type polishing machine in which the surface plate rotated at a rotational speed a o rpm while applying pressure at f/crnt and supplying a polishing liquid.

The above polishing liquid is a slurry containing 5% of diamond abrasive grains with an average particle size of 10 μm or 6 μm, and is heated at 20 C for 30 minutes.
It was supplied intermittently at a ratio of C. Each polishing time was 30 minutes, and this was repeated five times to measure the amount of polishing and the maximum surface roughness (Rmax).

(Example 1) As the metal fine powder, pure copper with a purity content of 99.7% or more and a spherical shape with an average particle size of 100 μm was selected. = As the resin content, water-soluble resol resin (Sumito Pux PR $ 61 manufactured by Sumitomo Dures ■) was selected. Aqueous solution with solid content of 85%) and water-soluble melamine resin (Sumitex M- manufactured by Sumitomo Chemical Co., Ltd.)
3) was selected, and zinc nitrate and ferrous chloride were also selected as curing catalysts for the cough synthetic resin. In addition, a purified product of potato starch was used as a pore-forming material.

570ml of the above water-soluble resol resin 65% aqueous solution
and 180 m# of a 60% water-soluble melamine resin aqueous solution, and while stirring this at room temperature, zinc nitrate, which is a catalyst,
f and 4 g of ferrous chloride were each added as powders. While continuing to stir this, potato starch IQOf was added, and sufficient stirring was performed until a uniform state was obtained. Next, 1000 g of fine copper powder was added little by little while stirring, and stirring was continued to form a homogeneous slurry-like mixed stock solution. This was cast into a plate-shaped mold made of hard vinyl chloride, immersed in a 60°C hot bath, and left for 16 hours. The obtained pre-solidified product was taken out of the mold, put into a ventilation dryer at 80°C and dried for 5 days, and then put into a heat treatment machine.
The temperature was raised from room temperature to 140° C. over 6 hours, and heat treatment was performed at that temperature for 4 hours. The obtained product contained copper at a volume ratio of about ttS% and had a porous structure with a porosity of about 4t%. Moreover, the appearance had a color tone and metallic luster peculiar to copper, and it was extremely lightweight. Furthermore, microscopic examination revealed that the pores were almost continuous, and the copper powders were evenly distributed in a manner that they were connected to each other.

The porous structure obtained by the above method is molded and used as a material for a polishing surface plate, and three of these are arranged in a radial combination, with an outer diameter of ff1g5mff1° and an inner diameter of tt as a whole.
It was formed into a donut disk shape with a diameter of 1.0 mm, and concentric grooves of a width of 4 mm and a depth of 5 mm were formed on its surface.
It was carved into intervals and used as a polishing surface plate. This was installed as a surface plate in a single-sided lapping polisher, and the polishing test described above was conducted to evaluate its performance.

The results of the polishing test are shown in Table 1, and the amount of polishing was large and the maximum surface roughness (Rmax) was small, indicating excellent polishing performance, and this performance continued even after repeated polishing.

(Example 2) A polishing surface plate was prepared in the same manner as in Example 1 except that the amount of potato starch was 75F. The porosity of this material was about 51%, with a mixture of continuous pores and independent pores.

The results of the polishing test are shown in Table 1, and excellent polishing amount and maximum surface roughness were maintained after repeated polishing about three times.

(Example 3) A polishing surface plate was created in the same manner as in Example 1, except that non-spherical granular copper powder with an average particle size of 100 μm, made of pure copper with a purity of 99.7% or more, was used as the fine metal powder. did. The porosity of this material was about 41%, and most of the pores were continuous.

The results of the polishing test are shown in Table 1. The polishing amount and the durability of the finished roughness were good, but the polishing amount and surface roughness were better when spherical copper powder was used.

(Example 4) Fine metal powder with a purity of 99.5% or more and an average particle size of 70
A polishing surface plate was prepared in the same manner as in Example 1, except that tin powder in the form of micrometer particles was used. The porosity of this material is approximately 45
%, most of the pores were continuous. The polishing test was conducted using diamond abrasive grains having an average particle size of about 6 μm.

The results of the polishing test are shown in Table 1. Although the amount of polishing was moderate, the surface roughness was small and excellent, and its durability was good. This indicates that the polishing plate of the present invention using tin powder is sufficiently effective on finer diamond abrasive grains.

(Comparative Example 1) A polishing surface plate was prepared in the same manner as in Example 1 except that the amount of potato starch was 501. The porosity of this material was about 22%, and most of the pores were independent pores.

The results of the polishing test are shown in Table 1. As the number of times of polishing increased, the amount of polishing decreased and the maximum surface roughness also tended to increase, indicating that a clogging phenomenon was occurring.

(Comparative Example) In place of the polishing surface plate used in Example 1, a polishing test was conducted using a surface plate having the same shape and made entirely of a copper plate.

Claims (1)

[Claims] In a polishing surface plate of a polishing machine that performs lapping and polishing with abrasive grains, the working surface of the polishing surface plate is a porous body of thermosetting resin having continuous pores with a porosity of 30 to 70% by volume, and is made of copper or A polishing surface plate characterized by dispersing and fixing fine tin powder.