JPS59142066A - Resinoid grindstone - Google Patents

Abstract

PURPOSE:To improve heat radiation performance and prevent deterioration of bond due to generated heat and improve the grinding ratio by applying special plating onto the cubic system boron nitride (CBN) grinding grains and using the combination of thermosetting resin, solid lubricating agent, and metal powder in a specific rate, for bond layer. CONSTITUTION:The CBN grinding grain having a diameter of 10-300mum can be used, and Ni-plating is carried-out, since grinding ratio can be increased and the close adhesion performance to grinding grain can be improved, and corrosion- proofness can be improved, and further Co-plating is applied for an intermediate layer, and finally Ni- plating is applied for an outer layer. The amount of grinding grains is 10-50vol%. Phenol resin, epoxy resin, etc. can be used, and the amount is preferably 25-60vol%. MoS2, hexagonal system BN, etc. can be used as solid lubricating agent, and heat generation is prevented by reducing the friction between a material to be ground and a grindstone, and the amount is preferably 10-25vol%. Metal powder is to have the high thermal conductivity, such as AG, Cu, etc., and the amount is preferably 7- 15vol%. These substances are mixed uniformly, and molded by using a mold, and hardended by heating. Thus, a CBN resinoid grindstone having a specially high grinding ratio can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a remade grindstone in which cubic boron nitride (hereinafter referred to as CBN) abrasive grains are bonded with a thermosetting resin.

CBN has a hardness second only to diamond, is stable even at high temperatures, and does not react with iron, making it superior to diamond for grinding special steel.

Resin bond type grindstones using CBN abrasive grains are currently mainstream. In this type of grindstone, metal-plated abrasive grains are generally used due to the adhesion between the abrasive grains and the bond, heat dissipation properties, etc. Various metals such as Ni, Cu, Co, and Ag are known, and among them, Ni is said to be excellent (Japanese Patent Publication No. 52-49197).

The bond layer is mainly made of thermosetting resin, but it is also known to have various additives added thereto. For example, Ag powder, Cu powder, etc. are added to improve heat dissipation. Also, MoS2°C (graphite), hexagonal BN
There are also powders such as those used alone or in combination with the above metal powders. The reason for adding a solid lubricant is to prevent deterioration of the bond due to heat generation by reducing the friction between the work material and the bond during grinding, and thereby prevent a decrease in the holding power of the abrasive grains.

Many aspects of the cutting, grinding, and other mechanisms of whetstones are still unknown, and for this reason, whetstone evaluations are often based on the results of use. Important characteristics of a grinding wheel include the ratio of the amount of wear of the grinding wheel to the amount of work material ground (referred to as the grinding ratio), the amount of grinding per unit time, etc.

It is an object of the present invention to provide a CBN resinoid grindstone having these characteristics, particularly a high grinding ratio.

Therefore, in the grindstone of the present invention, the CBN abrasive grains are plated in a specific manner, and the bond layer is composed of a thermosetting resin, a solid lubricant, and a metal powder in a fixed proportion.

It has been found that the object of the present invention can only be achieved by combining these elements.

The present invention will be explained in detail below.

As CBN abrasive grains, ordinary ones having a diameter of 10 to 300 μm can be used. The abrasive grains are first plated with Ni. The reason why Ni was chosen is that compared to when this part is made of other metals, the grinding ratio is higher, it has better adhesion to the outer abrasive grains, and it has better corrosion resistance. Ni plating is performed using the usual method, i.e., the abrasive grains are chemically cleaned, sensitized, and activated, and then placed in an electroless plating bath, such as a mixed bath of nickel sulfate, sodium hypophosphite, sodium acetate, and sodium succinate. This can be done by electroless electrolytic plating, which involves soaking the abrasive grains and depositing Ni on the surface of the abrasive grains. The amount of the plating layer in this part (inner layer) is 1 to 6% by volume based on the final plated abrasive grain, that is, the abrasive grain that has been plated to the outer layer. ) is suitable.

The Ni-plated abrasive grains are further coated with C as an intermediate layer plating.
o Plating. As a result of testing various metals, it was found that C'o is optimal for the intermediate plating layer. C
The amount of the O layer is preferably in the range of 12 to 60 inches based on the above criteria.

This cobalt plating can be performed by either electrolytic plating or electroless plating.

Finally, the outer layer is plated with Ni again. The reason for this is N
This is because i has good corrosion resistance and excellent rustlessness.

Co has a risk of rusting, and Cu will rust unless post-treated.

In the above, the reason why the grinding ratio increases by using Co as an intermediate layer is because Co is the strongest metal against deformation (creep) at high temperatures, so it is less susceptible to deterioration due to grinding heat, so it is presumed that there is less chance of abrasive grains falling off. be done.

Next is the composition of the whetstone, the abrasive grains (including the plated part)
The amount of 10 to 5 is generally known as this - grindstone.
It is 0%. Resins can be used in cars such as phenolic resin, epoxy resin, and unsaturated polyester resin, and the amount is 25%.
~60% is suitable. If it is less than 25 inches, the abrasive grain holding power of the bond becomes small and the abrasive grains often fall off. If the number is more than 60 inches, the protrusion height necessary for abrasive grain car grinding (the amount of abrasive grain protruding from one bond surface) cannot be obtained, making grinding impossible.

The solid lubricant is MoS2. Most of the known materials such as hexagonal BN, graphite, and fluorinated graphite can be used, and these are used in the form of powder. This lubricant has the effect of preventing heat generation by reducing the friction between the work material and the grindstone (bond), and is preferably 10 to 25%. If it is less than 10L%, the lubrication effect will be small and heat generation will increase, and if it is more than 25L%, the retention of abrasive grains in the bond will be poor.
Grinding wheel wear increases.

It is desirable that the metal powder has as good a thermal conductivity as possible, specifically Ag, Cu, etc. These powders are preferably about 60 μm or less. The amount is suitable between 7 and 15 inches. If it is less than 7 inches, the heat dissipation effect will not be sufficient, and as a result, the grinding ratio of the whetstone will decrease.

If it exceeds 15%, grinding resistance becomes large, which is not preferable.

In the manufacturing method of this grindstone, first, the above-mentioned components are blended and mixed uniformly. At this time, it is desirable to coat the CBN abrasive grains with a coupling agent in advance in order to increase their adhesive strength with the resin. ′
The mixture mixed with camphor is filled into a predetermined mold, set on a press and molded at a predetermined temperature and pressure, and after cooling to a certain extent, it is removed from the mold. This is heated in a dryer or the like to complete curing.

In actual products, this grindstone is formed by being bonded to base metals of various shapes, and is integrated with the alloy to form a grinding wheel.

The CBN particles used in the examples have a size of 105 to 125 μm.

This was plated as follows.

A Ni 3.8% Co32.5% Ni 1
．． 7%B All layers Ni C All layers C.

D Inner layer Co 36.3% Ni 1.7 E Ni 3.8 Intermediate layer + outer layer Co 34.1
Part F Inner layer + Intermediate layer Ni 36 pieces Co 1.
7chi G Co 3.9% Intermediate layer + inner layer Ni 33.9
HCo 3.9% Ni 32.2% Co 1.7
These abrasive grains were used to form whetstones under various conditions.

The resin used was phenolic resin, and the solid lubricant was MoS2.
The powder and metal are Ag powder (6O, pyn7F).

The plating abrasive grains were coated with a coupling agent in advance to improve bonding with the resin.

The molding is done using an aluminum base metal 1 (J I
This was done while bonding the grindstone layer 2 to the tip of the peripheral surface of the S6 AZ type).

This whetstone is used in a universal tool grinder (CFIA-Makino Milling Co., Ltd.).
40 type] and was ground under the following conditions. (Dry intermittent grinding) Grinding wheel peripheral speed 1160 m/min Depth of cut 50 μm Table speed 4 m/min Work material Cutting steel (SKH-57 equivalent, Rockwell C hardness 68) Grinding wheel 6AZ 100DX3WX2XX38.IH The results are described below.

1 A 30% 10% 10% 50% 1
502 B tt tt
tt 803 Cu
1304
D 〃 〃 〃 〃
1305 E n
1506 p.
tt tt tt
807 G 〃 〃 〃
708 H〃
709A30%
None 20chi 50L% 8010A//10%
None 60chi 70 (WA means white alundum abrasive) Experiment No. 3.4.7.8 When the inner layer is Co, C.

Directly adhering Ni to the abrasive grains is more difficult and less workable than Ni, and tends to cause peeling of the abrasive grains and metal plating.

When the outer layer of the experimental floor 3.5.6.8 is made of Co, it has poorer corrosion resistance than Ni and may rust over a long period of time.

From the comparison between experiments Nnl and NQII, the performance of the grinding wheel is reduced to about 1/3 when metal powder and solid lubricant are not used. This is due to the deterioration of the bond due to heat generation, which reduces the holding power of the abrasive grains.
It can be assumed that this is because a large proportion of abrasive grains fall off without contributing to grinding.

From a comparison of experiments Nll and M2, it is clear that the difference is due to the difference in metal plating since the bond and abrasive grains are the same. In other words, it can be said that this is due to the difference between Ni and Co, which are the main components of metal plating.

From the comparison of experiments Nα1.9.10, it was found that the bond is different, that is, metal powder is not used in Nn9, and lubricant is not used in Nn1O, so the rate of abrasive grains falling off due to deterioration of the bond due to grinding heat is large. It can be assumed that the performance is inferior.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the grindstone of the present invention. In the figure, 1 is an alloy, and 2 is a grindstone layer.

Claims (1)

[Claims] (1) Metal-plated cubic boron nitride abrasive grains 10-50
Volume 1, thermosetting resin 25-60 volume, solid lubricant 1
Resinoid grinding wheel (2) plating, characterized in that the plating metal of the abrasive grains is nickel in the inner layer, cobalt in the middle layer, and nickel in the outer layer. For abrasive grains including metal, the inner layer nickel has a volume of 1 to 6, and the cobalt in the middle has a volume of 12 to 60.
2. The resinoid grindstone according to claim 1, wherein the outer layer contains 1 to 5 nickels of nickel.