JPS6165780A - Grinding belt - Google Patents

Abstract

PURPOSE:To prolong the life of a grinding belt greatly by attaching low- hardness miracle particles in a specific percent by volume to the grinding belt. CONSTITUTION:In this grinding belt, 20-70% by volume of its high-hardness abrasive grains 2 are substituted by lower hardness miracle particles 3 having a morse hardness of 2-7 and a particle size equal to or a little larger than that of the high-hardness grains 2. Consequently the low-hardness miracle particles 3 suppress excessive crush of sharp cutting edge of the abrasive grains in the early period of grinding, and the cutting edges work with effective grinding effect. In the middle and finishing stages of grinding, the low-hardness miracle particles 3 are crushed to a moderate degree, and their wear becomes larger than the high-hardness abrasive grains 2. This can suppress drop of the grinding force as well as generation of a failure of the belt being burnt by the processing heat.

Description

[Detailed Description of the Invention] Industrial Field of Application This invention relates to the improvement of an abrasive belt that is attached to a belt abrasive machine and used for grinding and polishing metals, wood, etc., and makes effective use of abrasive grains. The present invention provides an abrasive belt with excellent abrasive power and durability.

Conventional technology abrasive belts are made of fused alumina, which has a predetermined grain size.
High-hardness abrasive grains such as silicon carbide and alumina zirconia are coated and fixed in a single layer or multiple layers (but 2 to 3 layers) on one side of a paper or woven fabric substrate using a bonding agent such as phenol resin or glue. Most abrasive belts are of the so-called closed-foot type in which the surface of the base material is entirely covered with abrasive grains, and some open-coated belts are used for woodworking purposes.

During actual polishing work, when the workpiece is a soft material, closed-coat type polishing belts often generate grinding chips, and these chips firmly adhere between the abrasive grains and cause clogging. This often results in a rapid decline in polishing ability. In addition, since the number of abrasive grains is large, the number of active abrasive grains increases as the polishing time progresses, and the area of the flank wear surface of the abrasive grains also increases.
Currently, only a small portion of the tip of the abrasive cutting edge is used until it reaches the end of its life.

In order to eliminate the drawbacks of this closed coat abrasive belt, I
Oven-foot polishing belts are used in some cases, in which abrasive grains are attached to about 50 to 80% of the base ion area that should be occupied by four grains. However, although this type has good chip ejection, due to its structure, the load applied to each abrasive cutting edge is large, so the abrasive cutting edge is crushed in the initial stage of polishing, and the abrasive grains are not consumed effectively. Due to its lack of rigidity as a tool compared to closed-coat types, it has a much shorter lifespan than closed-coat types, and is limited to very narrow applications such as woodworking in sacrificial grinding work and polishing soft metals.

Therefore, expensive abrasive grains are not effectively utilized in any type of abrasive belt, which is a major cause of the cost increase of belt grinding processing as well as shortcomings in terms of performance.

Problems to be Solved by the Invention The present invention solves the problem of abrasive grain flank wear caused by the large number of abrasive grains in the middle to late stages of research, which is a drawback of the closed coat type. Horizontal 0 increase'. Furthermore, the polishing power decreases and processing burns occur, and only a small portion of the abrasive grains are used until the end of its life. The abrasive grains are not effectively consumed by crushing, and secondly, the rigidity of the abrasive belt is insufficient due to its structure, which solves the problem of not being able to make sufficient cuts in the middle and later stages of polishing, and dramatically increases the durability of the abrasive belt. This is what we are trying to achieve.

Means for Solving the Problems In order to improve the above-mentioned drawbacks of conventional abrasive belts, the present invention, as a result of various studies, replaced some of the high-hardness abrasive grains used in the abrasive belts with abrasive grains. By using mineral particles that are approximately the same size or slightly larger than the grains and have a Mohs hardness of 2 to 7 (E[If), the fracture of the abrasive cutting edge in the early stage of polishing is suppressed, and the grinding resistance in the middle and late stages of polishing is reduced. By suppressing the decrease in polishing force that would result from an increase in polishing force and the occurrence of processing burn, and by making effective use of abrasive grains while also taking into account the rigidity of the polishing cloth, it is possible to obtain a polishing belt that has a significantly longer lifespan than conventional belts. I found this.

The present invention will be explained below based on the drawings. Figures 1 and 2
In the figure, the treatment and polishing that suits the purpose (approximately the same or slightly larger particle size and Mohs hardness of 2 to 7
The low-hardness mineral particles 3 are uniformly dispersed in a single layer and firmly fixed by a base adhesive layer 4 and an upper adhesive layer 5. To apply high-hardness abrasive grains and low-hardness mineral particles to the surface of a base material in a uniformly dispersed state, mix them well in advance and apply the electrostatic a-loading method or gravity drop method to the base material coated with the base adhesive. Apply by. Generally, abrasive grains are applied to abrasive belts using an electrostatic coating method, but in the case of mixed particles, it may not be possible to apply the abrasive grains at the correct mixing ratio due to differences in particle size and specific gravity. A method may also be used in which a predetermined amount of one is applied first, and then the other is applied to the remaining portion of the base material.

Figure 3 is composed of two layers of high hardness abrasive grains 2 and hardness particles 3; It is effective to apply the coating in one layer or three layers.

In the polishing belt of the present invention, the interrelationship between the hardness and particle size of the high-hardness abrasive grains and the low-hardness mineral particles, and the a-loading ratio are important.

The abrasive grains used in the polishing belt are fused alumina, silicon carbide, alumina-zirconia, etc., and the hardness of these abrasive grains is 8 or more on the old Mohs hardness. In addition to the above abrasive grains, there are so-called super abrasives such as diamond abrasive grains! Standing can also be used effectively. Ayu hard mineral particles used in place of some of these high hardness abrasive grains are suitably mineral particles with a hardness of 2 to 7 on the old Mohs scale, including gypsum, quartzite, sand, calcite, barite, fluorite, and apatite. , wollastonite, feldspar,
Silica stone can be used effectively.

If the hardness is less than 2, it is soft! Therefore, even if the particle size is larger than the abrasive grain, it is not effective in protecting the abrasive cutting edge, and particles larger than 7, which is close to the hardness of high-hardness abrasive grains, are not effective in protecting the abrasive cutting edge. Even if the grain size of high-hardness abrasive grains and low-hardness mineral particles decreases in the middle and late stages of polishing, N wears out without crushing, causing an increase in the number of low abrasive piles and reducing the polishing power. The correlation is that if the abrasive grain is #36, the low hardness particle is preferably about ##30 to #36, and if the abrasive grain is 60, the low hardness particle is preferably about #54 to ##60. .

When the low hardness particles have a hardness of 2 to 4, there is no problem even if particles coarser than the above particle size range are mixed, and even better results may be produced.

Next, regarding the coating ratio of high hardness abrasive grains and low hardness abrasive grains, the volume ratio occupied by the particles (in the case of a single layer, the area ratio occupied by the base material is 80: 20 to 30 near 0 is the ideal range. Purpose of the invention 1: Effective range. High hardness abrasive grains are 80
If it is more than 30%, the same drawbacks as the conventional glue oxide coat type will occur, and if it is less than 30%, the number of active abrasive grains will be too small, which will actually lead to a decrease in polishing power. The hardness of the particles must be such that they do not have a negative chemical effect on the workpiece during one polishing.

Hereinafter, the excellence of the abrasive belt of the present invention will be specifically explained with reference to Examples.

Example 1 Brown fused alumina abrasive #46 as high hardness abrasive grains
Using silica sand (hardness 7) with a particle size of about #36 to #46 as hardness mineral particles, the ratio of alumina to silica sand was 70:30/l and a volume ratio of 50:50. Two types of settings were made to ensure this. Apply phenolic resin adhesive to a cotton cloth base material that has been treated to suit the purpose, first apply silica sand to one side at 30% and the other side at 50%, and then apply alumina to the remaining amount. applied to the area.

Then, a top-stretching agent was applied using a conventional method to firmly fix each particle to obtain two types of abrasive belts.

Example 2 High hardness abrasive grains, brown fused alumina abrasive ##4
6, but the hardness f and m particles are Guho sand (hardness 3
) with a particle size of ##30 to ##46: A grain size was used, and the ratio of alumina and non-silting sand was 70:3 (+9.
Two types of abrasive belts were prepared in the same manner as in Example 1, with a volume ratio of 50:50.

In order to conduct a comparative test with the abrasive belts obtained in Examples 1 and 2, a closed coat type (conventional general product) with a coating density of 100% using #46 brown alumina abrasive, and a coating density of 70%. and 50% open coat type abrasive belts were also created.

A comparative test was conducted by polishing stainless steel SO8304 with these polishing belts, and the results are shown in Table 1 as a ratio when the conventional general product is set as 100.

Effects of the Invention As is clear from the results in Table 1, when comparing the total polishing amount and life time of the conventional general product, that is, the closed coat type abrasive belt, and the abrasive belt of the present invention, both of the abrasive belts of the present invention are superior to the conventional abrasive belt. Compared to the general product, the life time was extended by 30 to 60%, the total amount of polishing increased accordingly, and the quality of the polished surface was the same. In particular, compared to an open-coat type abrasive belt with the same abrasive coating rate, the life and abrasive amount are 2 to 3 times longer1. Does it have a cutting edge? It has a strong polishing action, and in the middle and later stages of polishing, particles of low hardness are moderately crushed + Q wear is large compared to high hardness abrasive grains, so it does not interfere with polishing 11 use, and high hardness abrasives Because the grains are open-coated, the rigidity of the flanks of the abrasive grains is high.
Therefore, the polishing force is reduced, the abrasive grains are effectively worn down to the end, and the durability is improved.

[Brief explanation of drawings]

The first Ciil is an enlarged sectional view of the abrasive belt of the present invention, and the second Ciil is an enlarged sectional view of the abrasive belt of the present invention.
11 is a perspective view of the abrasive belt of the present invention, and FIG. 3 is an enlarged sectional view showing another embodiment of the present invention. 1...Base material 2...High hardness grinder 3...Low hardness material 4...Basic adhesive layer 5...Top adhesive layer

Claims (1)

[Claims] A single layer or two to two layers of high-hardness abrasive grains such as fused alumina, silicon carbide, alumina/zirconia, and diamond are applied to the surface of the base material.
In an abrasive belt made of coated abrasive paper coated and fixed in three layers, 20 to 70% by volume of the high-hardness abrasive grains are replaced with high-hardness abrasive grains, and particles that are approximately the same as or slightly larger than the high-hardness abrasive grains are used. An abrasive belt characterized by using low-hardness mineral particles having a diameter of 2 to 7 on the Mohs hardness.