JPH04294977A - Diamond grinding wheel - Google Patents

Abstract

PURPOSE:To obtain a diamond grinding wheel capable of working a diamond sintered body in a high accuracy with a high work efficiency. CONSTITUTION:A catalytic material thermochemically reacting to diamond is included in the binder of a diamond abrasive grain. Consequently, the catalytic material and diamond are thermochemically reacted by the heat generated by the contact of a sintered body and binder in addition to the mechanical grinding by the abrasive grain, and the polishing quantity is increased.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diamond grindstone used for processing diamond sintered bodies.

0002

[Prior art and its problems] A normal diamond grinding wheel has a structure in which a large number of diamond abrasive grains are bonded to a grinding wheel base using a bonding agent such as metal bond, resinoid bond, or vitrified bond. Grinding is done by mechanically rubbing against the object. However, if the workpiece is a diamond sintered body with the same hardness as the diamond abrasive grains, the diamond abrasive grains will wear out and fall off severely.
A problem arises in that machining efficiency becomes extremely low and that only low finished surface accuracy can be obtained.

On the other hand, various improvements have been made to the bonding agent for diamond abrasive grains to improve its bonding strength and wear resistance, but improvements in the mechanical properties of such bonding agents have not been possible. However, little success has been achieved in machining high-hardness diamond sintered bodies, and wear and drop of diamond abrasive grains are still a factor that determines low machining efficiency and machining accuracy.

[0004] This invention was made in view of the above-mentioned problems, and in addition to the mechanical grinding force of diamond abrasive grains, it provides a bonding agent with an active processing function for diamond, thereby producing a diamond sintered body. The aim is to provide a diamond whetstone that enables highly efficient and highly accurate machining.

[0005]

[Means for Solving the Problems] In order to solve the above problems, the present invention has a structure in which the binder of diamond abrasive grains contains a catalyst material that undergoes a thermochemical reaction with diamond.

When a diamond sintered body is processed using the diamond grindstone configured as described above, the diamond abrasive grains and the binder are flush with each other, and the binder is subjected to a large pressure due to contact with the diamond sintered body. The high heat causes a thermochemical reaction between the catalyst material in the binder and the diamond in the sintered body.

[0007] Thereby, the diamond sintered body is ground by mechanical rubbing by the diamond abrasive grains and thermochemical reaction with the catalyst material, and a large amount of processing can be obtained in a short time. In addition, due to the thermochemical reaction of the catalyst material, the diamond on the surface of the sintered body is decomposed and dissolved as carbon in the catalyst material, and wear of the diamond abrasive grains is suppressed, improving the finishing accuracy of the machined surface. do.

[0008] As the above-mentioned catalyst material, iron, which has a high affinity with diamond, and cobalt, which shows good wettability, are suitable, and other materials such as nickel and platinum group metals can also be used.

In addition, in order to obtain a large thermochemical reaction, the content of the catalyst material is preferably the main component in the binder, and the weight ratio of the catalyst material to the entire binder is 50 to 10.
If it is set within the range of 0%, a large effect of increasing the amount of processing can be obtained.

In this case, it is preferable that the binder is made of a metal material other than the catalyst material, and that the binder as a whole constitutes a metal bond. Thereby, even if the catalyst material is decomposed due to a thermochemical reaction, the binding force of the diamond abrasive grains due to the binder can be stably maintained.

[0011] Furthermore, in order to obtain a uniform state of containing the catalyst material and other components, it is desirable that the catalyst material used in the binder be a highly purified and ultrafine powder, and the particle size is usually #20.
It is preferable that the powder has a purity of 99.5% or more within the range of 5 μm.

Furthermore, in addition to the above structure, the particle size of the diamond abrasive grains bonded by the binder is #140 to #3000.
When the diamond concentration is set in the range of 25 to 200, the mechanical grinding force by the diamond abrasive grains can be sufficiently increased, and the grindstone as a whole can have a large processing capacity.

[0013]

[Example] In order to examine the effects of the present invention, a test product was manufactured and a comparative processing test was conducted between it and a conventional product.

[0014] The diamond whetstones used in the test are shown in Table 1.
Based on the dimensions and specifications, two types of test products, test product A and test product B, and a conventional product C using metal bond as a binder were prepared. The specifications of those binders are shown in Table 2.

[0015]

[Table 1]

[0016]

[Table 2]

[0017] In the binders of test items A and B, F
For e and Co, powders with a purity of 99.5% or more and a particle size range of #20 to 5 μm were used.

Diamond grinding wheels are manufactured by mixing the metal powder of the binder and diamond powder, inserting the mixture into a mold, cold compressing it at a pressure of 2 tons/cm2, and then compressing it in a hydrogen gas atmosphere. The diamond layer was formed by sintering at 700°C.

The workpiece used is a diamond sintered body used for cutting tools, and the processing conditions were as follows:
oscillate at 2.5 MPa between the workpiece and the grindstone.
The rotation speed V of the diamond grindstone was changed to 3000 rpm and 6000 rpm while applying a machining load of 3000 rpm.

[0020] First, the test was conducted at V = 3000 rpm and 60 rpm.
The cumulative amount of polishing was compared between test products A and B and conventional product C when grinding was performed with a polishing area of 12.5 mm 2 at two rotational speeds of 00 rpm. The results are shown in FIGS. 1 and 2.

As is clear from FIGS. 1 and 2, test product A and test product B were superior to conventional product C under two rotational speed conditions.
It shows greater polishing ability compared to
6000 rpm), the amount of polishing showed a significant increase. This is thought to be due to the fact that the higher the rotation speed, the higher the heat generated at the contact area between the binder and the diamond sintered body, so the thermochemical reaction due to catalytic action also increases, resulting in an increase in the amount of polishing.

[0022] Next, the test compared the finished surface roughness (Ra) and flatness when machining was performed at the above two rotational speeds. The results are shown in FIGS. 3 and 4.

[0023] From the results shown in the above figure, test product A containing Fe in the binder showed a large improvement in the finished surface area compared to conventional product C, indicating that Fe plays a major role in improving the finished surface roughness and flatness. I understand what it shows. From this, it can be inferred that the affinity for diamond greatly contributes to improving the finished surface accuracy.

From the above test results, it was found that due to the thermochemical reaction between the Fe and Co contained in the binder and the diamond in the sintered body, polishing was improved compared to conventional products that only had the function of grinding diamond abrasive grains. It was confirmed that the capacity could be significantly increased.

[0025] Furthermore, it has been confirmed that the finished surface accuracy can be improved by selecting the catalyst material.

[0026]

[Effects] As explained above, in this invention, since the binder contains a catalyst material that reacts with diamond, a diamond sintered body can be processed thermochemically as well as by grinding with diamond abrasive grains. This has the effect of increasing processing efficiency and improving finished surface accuracy when processing sintered bodies.

[Brief explanation of drawings]

[Figure 1] Graph showing the cumulative amount of polishing at a rotation speed of 3000 rpm

[Figure 2] Graph showing the cumulative amount of polishing at a rotation speed of 6000 rpm

[Figure 3] Graph showing finished surface roughness

[Figure 4] Graph showing flatness

Claims (6)

[Claims] 1. A diamond whetstone in which the binder of diamond abrasive grains contains a catalyst material that undergoes a thermochemical reaction with diamond. 2. The diamond grindstone according to claim 1, wherein the catalyst material is iron or cobalt. 3. The diamond grindstone according to claim 1, wherein the weight ratio of the catalyst material to the entire binder is set in a range of 50 to 100%. 4. The diamond grindstone according to claim 1, wherein a component of the binder other than the catalyst material is a metal material. 5. The diamond according to claim 1, wherein the catalyst material used as the binder is a powder with a particle size in the range of #20 to 5 μm and a purity of 99.5% or more. Whetstone. [Claim 6] The diamond grain size of the whetstone is #140~
#3000 range, diamond concentration 25-2
The diamond grindstone according to any one of claims 1 to 5, wherein the diamond grindstone is in the range of 00.