JPH0857766A - Glass polishing-grinding wheel - Google Patents

Abstract

PURPOSE: To improve the durability of lubricating action in polishing and prevent the lowering of machining speed due to the influence of solid lubricants. CONSTITUTION: Solid lubricants 2 with the average grain diameter being not more than 1/5 of polishing abrasive grains 4 and with coupling agents 3 applied to the peripheries, and the polishing abrasive grains 4 are dispersedly disposed in a binder 5 to form a glass polishing-grinding wheel 1. At the time of disposing the solid lubricants in the binder, the grains of the solid lubricants are thereby prevented from coming off, and the lowering of surface accuracy of a workpiece is not generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing grindstone suitable for processing glass such as optical parts.

[0002]

2. Description of the Related Art As a polishing grindstone for polishing a work piece, there is known one in which abrasive grains and a solid lubricant are integrated with a binder. The solid lubricant is used to suppress the processing resistance generated between the binder on the surface of the grindstone and the object to be processed during the polishing process, and to perform the polishing process of the object to be processed smoothly.

Conventionally, as a polishing grindstone in which abrasive grains and a solid lubricant are dispersedly arranged in a binder, Japanese Patent Publication No. 55-288.
No. 29, the average particle size 3 to 5 μ having a solid lubricating action.
It is disclosed that m carbon fluoride and abrasive grains are integrated by a binder.

[0004]

However, in the case of processing the surface with high surface accuracy such as polishing of glass, it is necessary to set the average grain size of the polishing abrasive grains to 5 μm or less. Therefore, even if the above-mentioned polishing whetstone is used as a polishing whetstone for glass, the average particle size of carbon fluoride serving as a solid lubricant is
The average grain size of the polishing abrasive grains will be the same or larger.

As a result, as shown in FIG.
When the polishing abrasive grains 13 therein come into contact with the glass 14 that is the object to be processed and the glass 14 and the carbon fluoride 15 come into contact with each other, the polishing abrasive grains 13 try to bite into the glass 14. Will interfere with the action. As a result, the abrasive grains 13 are less likely to act on the glass 14, the processing time of the glass 14 increases as the processing speed decreases, and the resistance to the carbon fluoride 15 increases, so that the carbon fluoride 15 drops off. As a result, the amount of lubrication increases, and the lubricating effect cannot be obtained during polishing.

Further, if the average particle diameter of the carbon fluoride 15 is reduced in order to reduce the processing resistance of the carbon fluoride 15 generated during the polishing process, the contact area with the binder 12 becomes small, so The carbonized carbon 15 often comes off from the binder 12, that is, the polishing grindstone due to processing resistance with the glass 14. Furthermore, since the carbon fluoride 15 which does not have a good adhesiveness with the binder 12 is used as the solid lubricant, the carbon fluoride 15 is often dropped from the grinding wheel.

The present invention has been made in view of the above problems, and an object of the present invention is to improve the sustainability of the lubricating action during polishing and to prevent the reduction of the processing speed due to the influence of the solid lubricant. .

[0008]

SOLUTION: A glass in which a coupling agent is applied around the solid lubricant having an average particle diameter of ⅕ or less of the abrasive grains and the abrasive grains are dispersed in a binder. Use a grinding wheel for polishing.

[0009]

Since the average particle size of the solid lubricant is 1/5 or less of the abrasive grains, the amount of protrusion of the solid lubricant on the surface of the grindstone can be suppressed smaller than that of the abrasive grains. As a result, the polishing abrasive grains during the polishing process sufficiently dig into the glass that is the object to be processed, and the polishing process can be performed without a decrease in the processing speed due to the influence of the solid lubricant.

Further, since the coupling agent for increasing the binding force with the binder is applied around the solid lubricant, the solid lubricant with a small binding force with the binder or the solid lubricant with a particle size smaller than that of the abrasive grains is used. Even if the agent is used, the solid lubricant does not easily fall off and the durability of the lubricating action is improved.

[0011]

【Example】

(First Embodiment) FIG. 1 shows a manufacturing process of a glass polishing grindstone according to an embodiment of the present invention. First, a polyimide resin powder serving as a binder for a grinding wheel and N-methylpyrrolidone serving as a solvent thereof are weighed in a weight ratio of 1: 2, mixed and dissolved to prepare a resin solution. obtain. On the other hand, 2/3 volume of cerium oxide having an average particle diameter of 1.4 μm used as abrasive grains is weighed with respect to a powder of a polyimide resin serving as a binder of a polishing grindstone. Further, molybdenum disulfide used as a solid lubricant has an average particle size of 0.2 μm in a wet ball mill.
1/20 volume is weighed with respect to the total amount of the polyimide resin and cerium oxide. This weighed molybdenum disulfide was used as a silane coupling agent (Nihon Unicar Co., Ltd., silane coupling agent A-1100).
The film of the silane coupling agent is applied to the periphery of molybdenum disulfide by immersing the film in the above solution, removing from the solution, and drying.

Next, the weighed cerium oxide is added to the resin solution and mixed so that the cerium oxide is uniformly dispersed in the resin solution. The mixture of the cerium oxide and the resin solution is dried in a drying oven at 70 ° C. to evaporate and remove the solvent N-methylpyrrolidone. Molybdenum disulfide coated with a film of a silane coupling agent is added to a powder obtained by pulverizing the solid substance obtained by the evaporation removal in an automatic mortar, and mixed sufficiently. Then, this mixture is compression-molded in a mold, and the molded body obtained here is fired at 200 ° C. for 12 hours to obtain a polishing grindstone.

FIG. 2 shows a schematic diagram of the polishing grindstone manufactured in this manufacturing process. In the polishing grindstone 1, molybdenum disulfide serving as a solid lubricant 2 having a silane coupling agent 3 applied to the periphery thereof and cerium oxide serving as the polishing abrasive grains 4 are dispersed and arranged in a polyimide resin of a binder 5 and bonded. Has been done. Less than,
The operation of this embodiment will be described.

FIG. 3 shows the state of the glass polishing process in this embodiment. A glass (optical glass material BSL7) 9 having a diameter of 20 mm is polished by the polishing grindstone 1. The polishing grindstone 1 has an average particle diameter of the solid lubricant 2 of 0.2 μm,
Sufficiently smaller than the average particle size of the abrasive grains 4, 1.4 μm.
Therefore, since a gap 8 is formed between the abrasive grain surface 6 on the surface of the grindstone 1 and the solid lubricant surface 7, the polishing abrasive grain 1 sufficiently penetrates into the glass 9 which is the workpiece, and NR (Newton ring) Good polishing is performed in 93 seconds without any habit.

Further, since the silane coupling agent 3 for increasing the bonding force with the binder 5 is applied around the solid lubricant 2, even if the solid lubricant 2 having a particle size smaller than that of the abrasive grains 4 is used. Therefore, the solid lubricant 2 does not fall off easily, and the durability of the lubricating action is improved. The effects of the average particle size of the solid lubricant 2 and the application of the silane coupling agent 3 are reflected in the processing time and the surface accuracy of the glass 9. Table 1 shows the relationship between the average particle size of the solid lubricant and the polishing processing time, and also shows whether or not the coupling agent is applied and the evaluation of NR habit.

The manufacturing method of the grinding wheel is the same as above.
It was manufactured by changing only the average particle size of the solid lubricant.

[0017]

[Table 1]

Here, the case where the coupling agent was applied was indicated as "yes", and the case where it was not applied was indicated as "absent". Also, N
Regarding the evaluation of R-habit, the one in which no sagging was observed on the polished surface of the glass 9 in the interference fringe photograph was good, and the one in which it was confirmed was defective. No. 1 is the polishing whetstone used in this example,
The results are as shown above. No. 2 and No. 3 are polishing wheels with a smaller average particle size of the solid lubricant than the No. 1 polishing wheel, and there is almost no difference in processing time from the No. 1 polishing wheel, and there is no NR habit. I was able to obtain clear glass. Further, when the average particle diameter of the solid lubricant is ⅕ or less of that of the abrasive particles, it was found that there was almost no difference in the glass processing time.

Comparative examples (Nos. 4 to N) with respect to this example are as follows.
o.10) is shown. The No. 4 polishing whetstone does not contain a solid lubricant. This polishing grindstone has a processing time as short as 90 seconds until the polishing is completed, but since solid lubricant is not added, sagging occurs. The polishing whetstones of No. 5 to No. 9 are obtained by adding a solid lubricant larger than ⅕ of the average particle diameter of the polishing abrasive grains and applying a coupling agent around the solid lubricant. Since these polishing wheels add a solid lubricant, the processing resistance can be reduced, and the NR habit is improved. However, since the average particle size of the solid lubricant is larger than ⅕ of the abrasive grains, the abrasive grains cannot sufficiently act on the glass. As a result, the glass processing time was delayed compared to the No. 1 polishing whetstone.

No. 10 polishing grindstone is one in which a solid lubricant is added and a coupling agent is not applied. The difference between the presence and absence of the coupling agent was confirmed by comparing this polishing whetstone with the No. 1 polishing whetstone. The processing time was almost the same regardless of the presence or absence of the coupling agent, but NR habit was confirmed in the polishing grindstone to which the coupling agent was not applied. This is because if you do not apply a coupling agent around the solid lubricant,
The binding force between the solid lubricant and the binder is weakened, and the solid lubricant is prone to shedding, so the lubrication effect during polishing is reduced, and it is thought that this is the result of the workpiece vibrating during processing. To be

In this embodiment, since the average particle size of the solid lubricant is sufficiently smaller than 1/5 of the abrasive grains, a gap is formed between the abrasive grain surface of the grindstone surface and the solid lubricant surface. The abrasive grains do not hinder the action of trying to dig into the glass to be processed, and the lens can be processed smoothly. Further, since the coupling agent is applied around the solid lubricant, even if the solid lubricant is small, it can be firmly bonded to the binder, and the solid lubricant can be prevented from falling off.

(Second Embodiment) FIG. 4 is a schematic view of the manufactured grinding wheel of the second embodiment. The manufacturing method of the grinding wheel is the first
The description is omitted because it is similar to the embodiment. In the polishing grindstone 10 of this embodiment, as the solid lubricant 2, carbon fluoride, which has an excellent lubricating effect but does not have a good adhesiveness with the binder 5, is used, and the titanium coupling agent 1 is used as the coupling agent.
1 is used. The same parts as those of the first embodiment other than this are designated by the same reference numerals, and the description thereof will be omitted.

A glass (optical glass material BSL7) having a diameter of 20 mm is polished by the polishing grindstone 10. Further, as a comparative example, a polishing grindstone that does not add a solid lubricant, and a polishing grindstone that does not apply a coupling agent around the solid lubricant,
The same glass was polished. Table 2 shows N of each grinding wheel
The size of R habit is shown as PV value (PEAK TO VALLEY).

[0024]

[Table 2]

The PV value of the polishing grindstone to which the solid lubricant without coupling treatment is added is as high as the PV value of the grindstone without the solid lubricant. This is because carbon fluoride without coupling treatment is used as the solid lubricant, so the adhesive strength with the binder cannot be obtained sufficiently, and the solid lubricant immediately falls off from the binder, and during the polishing process. This is because the lubricating effect of can not be fully exerted.

On the other hand, it was found that the PV value of the polishing grindstone to which the solid lubricant with coupling treatment was added was remarkably small. In this example, since the average particle diameter of the solid lubricant is sufficiently smaller than ⅕ of the polishing abrasive grains, a gap is formed between the abrasive grain surface of the grindstone surface and the solid lubricant surface. The action of cutting into the lens to be processed is not obstructed, and the lens can be processed smoothly.

Further, since the coupling agent is applied around the solid lubricant, even if carbon fluoride having a small binding force with the binder is used as the solid lubricant, the solid lubricant can be firmly bonded to the solid lubricant. It is possible to reduce the dropout of the agent. Although cerium oxide was used as the abrasive grains in each of the above-mentioned examples, synthetic diamond, zirconium oxide, or aluminum oxide may be used.

As the solid lubricant, tungsten dioxide or graphite can be used in addition to molybdenum dioxide and carbon fluoride used in the above-mentioned embodiments, and these solid lubricant and abrasive grains can be used in any combination. Is possible. In addition to the silane-based and titanium-based coupling agents used in the above-described examples, zircoaluminate-based coupling agents may be used.

Further, in each of the above embodiments, the amount of the solid lubricant added is 8.33% by volume with respect to the binder,
This is because the addition amount of solid lubricant is 10% by volume with respect to the binder.
If it exceeds the above range, the abrasive retaining ability of the binder is reduced, resulting in a polishing wheel with a slow processing speed. On the other hand, if it is less than 2% by volume, the action as a solid lubricant is reduced and a polishing wheel with a high processing resistance is obtained. This is because it causes a habit.
Therefore, the amount of solid lubricant added is 2% by volume of the binder.
It is preferably 10% by volume or less.

[0030]

The average particle diameter of the solid lubricant is sufficiently smaller than that of the abrasive grains, and the coupling agent is applied around the solid lubricant, so that the processing speed is prevented from lowering due to the influence of the solid lubricant. As well as being able to prevent shedding of the solid lubricant,
The durability of the lubricating action during polishing is improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a method of manufacturing a polishing grindstone of the present embodiment.

FIG. 2 is a schematic view showing a polishing grindstone of a first embodiment.

FIG. 3 is a diagram showing a state of glass polishing processing in the polishing grindstone of the first embodiment.

FIG. 4 is a schematic view showing a polishing grindstone of a second embodiment.

FIG. 5 is a diagram showing a state of polishing processing of glass in a conventional polishing grindstone.

[Explanation of symbols]

 1 Polishing Whetstone 2 Solid Lubricant 3 Silane Coupling Agent 4 Polishing Abrasive Grain 5 Binder 6 Abrasive Grain Surface 7 Solid Lubricant Surface 8 Gap 9 Glass 10 Polishing Grindstone 11 Titanium Coupling Agent 12 Binder 13 Polishing Abrasive Grain 14 Glass 15 Carbon fluoride

Claims (1)

[Claims] 1. A solid lubricant having a coupling agent applied to the periphery and having an average particle diameter of ⅕ or less of the abrasive grains, and the abrasive grains are dispersed and arranged in a binder. Polishing whetstone for glass.