JPH01177967A - Barrel finishing method for inorganic hard body - Google Patents

Abstract

PURPOSE:To make it possible to inexpensively and largely manufacture an inorganic hard body having a fine lustrous surface by adding a mixture of a specific grain and an abrasive grain into liquid such as water or the like to use for the finishing of the inorganic hard body such as glass or the like. CONSTITUTION:A mixture of an abrasive grain and at least one kind selected of such grains as a walnut grain made by crushing the outer shell of the walnut, and a ceramic and a plastic grain which are porous at least on their surfaces is used as a barrel-finishing medium, and added into liquid such as water or the like, and then used for the barrel-finishing or glass, ceramics and an inorganic hard body such as a crystal. Thus the inorganic hard body having excellent weight accuracy and a lustrous surface with no struck or scratched flaw can be inexpensively and largely manufactured.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a barrel polishing method for inorganic hard bodies.

[Prior Art] As a method for polishing inorganic hard bodies such as glass, ceramics, crystals, etc., a surface grinding plate with holes or holes is placed parallel to another flat plate, and a predetermined shape of the object to be polished is placed in the trough or hole. There is a cold working method in which an object is placed and the grinding plate is rotated in a predetermined direction while supplying a predetermined abrasive together with a solution such as water to polish the object. There is also a chemical polishing method in which a polished object processed to a predetermined surface roughness by the cold working method described above is treated with a chemical such as a hydrofluoric acid solution to obtain a glossy mirror surface. Further, as disclosed in Japanese Patent Application Laid-Open No. 61-151028, regular hexahedral glass is cut from a glass plate material, and this regular hexahedral glass is placed in a container.
There is also a method of manufacturing glass spheres having a glossy surface by rotating the container for a predetermined period of time while heating the container to a temperature higher than its softening temperature.

[Problems to be Solved by the Invention] The above-described cold working method has disadvantages in that the number of objects that can be polished at one time is limited and the processing cost is high due to the large number of processing steps. In addition, in the chemical polishing method using chemicals described above, the components that make up the polished object may be selectively eluted from the surface and a so-called yellow layer may be generated on the surface, especially for transparent objects such as glass. This is extremely inconvenient. Furthermore, according to the method disclosed in JP-A No. 61-151028, in order to obtain high gravity I accuracy when manufacturing glass bulbs, a glass material is cut into regular hexahedrons with high precision, and this regular hexahedral glass is It has to be softened in an inert gas atmosphere, making it a very complicated manufacturing process.
In addition, since the glass is processed by heating it above its softening temperature, there is a high possibility that the glasses will fuse together if they come into contact with each other, making it difficult to manufacture high-quality glass polishing balls at low processing costs. It was complicated.

The present invention has been made to solve the above-mentioned problems, and its purpose is to provide a method capable of polishing a large amount of inorganic hard bodies such as glass, ceramics, crystals, etc. with high polishing accuracy and at low cost. There is a particular thing.

[Means for solving the problem] The object to be polished is placed in a barrel tank containing barrel media (also called polishing stone), water, surfactant, etc., and the object to be polished is polished by rotating the barrel tank. The barrel polishing method itself has been known for a long time, but since the conventional barrel polishing method uses alumina balls, steel balls, sintered balls mainly composed of silica, etc. as barrel media, The barrel polishing method can only be applied when the object is metal or precious stones with relatively high hardness; barrel polishing is applied to polish inorganic hard materials such as glass, ceramics, and crystals, which have a lower hardness than the metals and precious stones mentioned above. There is no example in the past.

The name of the present invention refers to walnut grains (hereinafter simply referred to as walnut grains) obtained by crushing the outer shell (shell covering the fruit) of walnuts, ceramic grains with at least a porous surface ( Hereinafter, simply referred to as porous ceramic granules), plastic granules with at least a porous surface (
By using a mixture obtained by adding abrasive grains to porous plastic particles (hereinafter simply referred to as porous plastic granules) as the barrel media, it is possible to polish inorganic hard materials such as glass, ceramics, and crystals, which was impossible with the conventional barrel polishing method. For the first time, barrel polishing of the body became possible.

Therefore, the present invention provides barrel polishing of an inorganic hard body in the presence of water and a mixture of at least one selected from the group consisting of walnut grains, porous ceramic grains, and porous plastic grains and abrasive grains. This is a barrel polishing method for inorganic hard bodies.

The present invention will be explained in detail below.

Examples of the inorganic hard body to be polished in the barrel polishing method of the present invention include inorganic hard bodies such as glass, ceramics, and crystals. The inorganic hard body suitably used has a hardness within a predetermined range, and in the examples below, the abrasion degree (FA) value shown in the measurement method is 50 to 1.
000, particularly preferably 50 to 200. Among the glasses, ceramics, and crystals mentioned above, glasses with relatively low hardness for boat fishing are most suitable for barrel polishing by the method of the present invention.

These inorganic hard bodies may have various shapes such as spheres, spherical bodies, ellipsoids, and amorphous bodies having no edges.

In the method of the present invention, the media used for barrel polishing the inorganic hard material is a mixture of at least one selected from walnut grains, porous ceramic grains, and porous plastic grains and abrasive grains.

In the present invention, grains such as walnut grains, porous ceramic grains, and porous plastic grains are used because (
i) These grains act as a carrier to hold the abrasive grains used as an abrasive material due to the irregularities existing on their surfaces, (ii) These grains alleviate collisions between objects to be polished. (iii) When water is added to the mixture obtained by mixing these particles with abrasive grains to form a slurry, this slurry has a viscosity suitable for polishing inorganic hard materials such as glass. This is because of the following reasons.

As such grains, walnut grains are most preferably used. The size of the walnut grains is preferably 6 to 60 mesh. When the walnut grains exceed 60 meshes and the grain size becomes fine, the abrasive retention ability and the frictional force between the object to be polished and the media decrease, causing a decrease in the grinding force.
If the grain size becomes coarser than the mesh, the risk of collision between the objects to be polished increases, and it becomes difficult to obtain a mirror finish on the surface of the object to be polished, making it difficult to obtain a high-quality polished product without dents or scratches. Because it will disappear.

Also, porous ceramic granules or porous plastic granules may be used instead of walnut granules. The sizes of these porous ceramic granules and porous plastic granules are determined as appropriate, taking into account their properties, the type and size of the abrasive grains used at the same time, and the class of the object to be polished. Ru.

Next, examples of the abrasive grains used together with the above grains include inorganic abrasive grains such as alumina, silica, silicon carbide, green carbon, cerium oxide, zirconium oxide, iron oxide, and chromium oxide. The type and particle size of the inorganic abrasive grains are selected depending on the desired surface roughness of the object to be polished. In other words, the surface roughness (Rmax) is 100 Å
In order to obtain the following glossy surface, the grain size of the abrasive grains is changed and the following three steps are carried out: (1) A fine barrel process in which the weight of the object to be polished, including the machining allowance, is adjusted to a predetermined value; (2) A fine barrel process The weight of the workpiece adjusted to a predetermined level is adjusted more precisely, and the workpiece is polished to a glossy surface. It is usually necessary to carry out a finishing barrel process to achieve a roughness of 100 Å or less.
The coarse barrel process (①) has a particle size of #240 to #800.
' Relatively coarse abrasive grains such as alumina, silica, silicon carbide, green carbon, etc. are used, and in the middle barrel process (2), abrasive grains such as alumina, silica, silicon carbide, green carbon, etc. with a particle size of #800 to #2000 are used. In addition, the finishing barrel process (■) uses fine cerium oxide with a particle size of #2000 or more.
It is preferable to use abrasive grains such as zirconium oxide, iron oxide, and chromium oxide.

By going through these steps (1), (2), and (2), the object to be polished has a high degree of weight accuracy and a glossy surface (roughness of 100 Å or less) without any dents or scratches.

The amount of the abrasive grains added is 5 to 50% by weight based on the granules.
It is preferable that The reason for this is that if it is less than 5% by weight, the grinding force will decrease and a significantly longer polishing time will be required, and even if it is more than 50% by weight, there will be no improvement in the grinding force, and on the contrary, the viscosity of the slurry will increase. This is because this may lead to a decrease in the grinding force.

In the present invention, water is added to a mixture of grains such as walnut grains and abrasive grains. Water uniformly disperses grains and abrasive grains and provides fluidity, especially when polishing glass.
The polishing speed also depends on the chemical durability of the glass, and is largely due to the ability to scrape away the soft layer that forms on the glass surface due to the chemical action of the liquid used, which is said to further improve the polishing speed. The amount added is 0°8 to 0.8 to the weight of grains such as walnut grains.
It is preferable to set it to 2.0 times. If the water addition I is less than 0.8 times, the fluidity of grains such as walnut grains holding abrasive grains deteriorates, leading to a decrease in grinding force and causing scratch marks on the surface of the polished object. This is because, if the amount of water added is more than 2.0 times, the viscosity of the slurry consisting of grains such as walnut grains, abrasive grains, and water decreases. This is because the grinding force of the grains decreases and collisions between the objects to be polished occur.

A surfactant can also be added to the water, and even when water and a surfactant are used, the total amount of water and surfactant added is 0°8 to 2% relative to the M amount of the granules. It is preferable to set it to .0 times. Further, it is preferable to add the surfactant in an amount of about 1 to 10% by weight based on water.

According to the method of the present invention explained above, grains such as walnut grains and abrasive grains as an abrasive material are used together, so that polishing of glass, ceramics, crystals, etc., which was impossible with the conventional barrel polishing method, is possible. Barrel polishing of inorganic hard bodies such as the following is possible, and inorganic hard bodies having a high degree of weight accuracy and a glossy surface without dents or scratch marks can be produced in large quantities at low cost.

[Example 1] The present invention will be described in detail below, but the present invention is not limited to these Examples.

Example] As shown in Table 1, the degree of wear (FA) is 60 to 450.
Ten types of glass balls (each having a diameter of 5 mm) with different hardness within the range of A sample with a measurement surface roughness of 9 is held in a fixed position on a cast iron flat plate that rotates horizontally at 60 revolutions per minute.
Applying a load of
The abrasion weight of K7 glass) was also measured, and the degree of abrasion was calculated using the following formula.

In a barrel tank (inner volume 7.51㎡) to which walnut grains (16 mesh), abrasive grains and water have been added in advance, the above glass bulb ~
A rough barrel process, a medium barrel process, and a finishing barrel process were carried out using 100 pieces of each of (2). The amount of walnut particles added, the roughness and amount of abrasive grains added, the amount of water added, and the polishing time in each step are shown in Table 1-.

For example, in the case of glass bulbs, a rough barrel process to remove large defects on the surface and adjust the weight is performed using walnut particles (
16 mesh>2500g, alumina abrasive<#240)
1,200 g of water and 2,800 g of water were used for 30 hours, followed by a medium barrel process to improve the surface roughness using walnut grains (16 mesh > 2,300 g) and alumina abrasive grains (#80
0) Conducted for 25 hours using 700g and 3000g of water,
Finally, a finishing barrel process for mirror polishing is carried out using 3000g of walnut grains (16 meshes), cerium oxide (Ce0
2) It was carried out for 10 hours using 700 g of abrasive grains (#2000 or more) and 3500 g of water (each step was carried out by the centrifugal barrel polishing method, and the barrel tank rotation speed in each step was:
all at 1.70 rpm). As a result, the glass bulb■
1, and has a high level of weight accuracy and surface roughness (Rmax
A mark-free glass sphere with a glossy surface of less than 100 Å was obtained.

As a result of carrying out the rough barrel process, medium barrel process, and finishing barrel process for other glass bulbs ~ [stock] under the conditions shown in Table 1, all of them had a high level of heavy engineering precision and a surface appearance of 1.
A mark-free glass sphere with a glossy surface of less than 00 Å was obtained.

(Leaving space below) Example 2 Example 1 above was carried out using 16 mesh walnut grains, but Example 2 is an example in which the grain size of the walnut grains was varied. It is shown below.

Table 2 shows the polishing conditions and evaluation in the rough barrel process.

First, in the case of the glass bulb ■, the walnut particles are 2 mesh or 3 mesh.
When the grain size was coarse and mesh, severe marks were observed that could not be removed in the subsequent process. Further, when the walnut grains exceeded 60 meshes and the particle size became fine, defects existing before polishing could not be removed even though polishing was performed for more than 100 hours. On the other hand, when the particle size of the walnut grains is 6 to 30 mesh, the grain barrel process can be carried out well, and then the middle barrel process and the finishing barrel process (these conditions are as follows: (The conditions are almost the same as those for the middle barrel process and finishing barrel process), the weight accuracy of hardness and the surface ■
It was possible to obtain a glass sphere having a glossy surface with a thickness of 100 Å or less and without any marks.

Furthermore, in the case of the glass bulb (2), when the walnut grains exceeded 60 meshes and the grain size became fine, the result was obtained that, as in the case of the above-mentioned glass bulb (2), defects existing before polishing could not be removed.

In addition, in the case of relatively hard glass 1 (wear degree 60), when the grain size of the walnut grains was coarse (2, 3, and 4 meshes), it was observed that severe marks were generated that could not be removed in the post-process.

From the above experimental results, the grain size of the walnut grains in the coarse barrel process is preferably 6 mesh or more and 30 meshes or less, but when the grain size of the walnut grains is 30 mesh in the glass bulb (2), the polishing result is good, but the polishing time is Since the polishing time is as long as 80 hours, in consideration of polishing efficiency, it is most preferable to use walnut grains of less than 30 meshes, particularly 20 meshes or less.

In addition, glass bulbs ■ and ■ were subjected to a rough barrel process and a medium barrel process (these conditions are almost the same as the conditions for the coarse barrel process and medium barrel process for glass bulbs ■ and ■ in Table 1). After polishing to the surface condition of
As shown in Figure 3, the finishing barrel process was carried out by changing the grain size of the walnut grains.

As is clear from Table 3, when the grain size of the walnut grains in glass bulb (■) is as coarse as 3 mesh, the surface roughness decreases to 1000 in 10 hours of polishing due to the occurrence of dents and scratch marks.
It didn't even reach humans. Further, when the grain size exceeds 60 mesh, it is possible to reach a surface roughness of less than 100 by continuing polishing for 100 hours or more, but there is a problem in that the polishing time is too long.

On the other hand, when the grain size of the walnut grains was 6 to 60 mesh, a surface roughness of 100 Å or less could be achieved in a relatively short polishing time. Especially in the case of 10 to 60 meshes,
An excellent glossy surface with a surface roughness of 40 Å or less could be obtained.

In addition, for a relatively soft glass bulb (wear degree 450), the surface roughness is 100 Å with a mesh of walnut grain size 6.
It was not possible to achieve the following, and it was necessary to use walnut grains with a mesh size of 10 or more.

(Left below) In Examples 1 and 2 above, the rough barrel process and the middle barrel process were performed at 91. Although the rebarrel polishing process was performed in three steps: the middle barrel process and the finishing barrel process, it is also possible to omit the middle barrel process and perform only the rebarrel process and the finishing barrel process, or it is possible to perform the polishing process using only a single process. In addition, it is not necessarily necessary to use a mixture of the above grains and abrasive grains in all of these steps, and the mixture may be used only in one culm (especially the finishing barrel process). . Furthermore, the particle size of the walnut grains can be changed according to the degree of each grain.

Further, in Example 1.2 above, a centrifugal barrel polisher was used, but other barrel polishers may also be used. In addition, the barrel polishing time can be arbitrarily varied, and in particular, the polishing time in the rough barrel process should be set to the time necessary to polish the L1 machining allowance. It is not limited to the time in

[Effects of the Invention] As described above, according to the barrel polishing method of the present invention, a mixture of grains such as walnut grains and abrasive grains is added to a liquid such as water to wet polish an inorganic hard body. From this, an inorganic hard body having a high degree of weight accuracy and a glossy surface free of dents and scratches can be produced in large quantities at low cost.

Claims (1)

[Claims] (1) At least one selected from the group consisting of walnut grains obtained by crushing walnut shells, ceramic grains with at least a porous surface, and plastic grains with at least a porous surface, and abrasive grains. A method for barrel polishing an inorganic hard body, comprising barrel polishing the inorganic hard body in the presence of water and a mixture of the inorganic hard body.