JPS5899170A - Manufacture of electrolytic grinding stone - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an electrolytic grinding wheel that can perform grinding while energizing and causing electrolytic action.

Conventionally, it has been known that hydrified, resinoid, silicate, etc. grindstones, in which abrasive grains are bonded and molded into a porous structure using a binder, are treated to conductivity by chemical plating, etc., to give them electrical conductivity and to be used as electrolytic grinding wheels. However, there is a process in which the abrasive grains are bonded and formed into a porous structure with a porosity of about 10 to 60% using a binder, and a process in which metal plating is applied while flowing a plating solution into the porosity of the resulting grindstone to give it conductivity. The manufacturing process is complicated. Since the plating solution does not flow uniformly over the entire grinding wheel, it is difficult to ensure uniform electrical conductivity, and metal plating has the drawback of filling the chip pockets of the grinding wheel. The plating metal that provides electrical conductivity is usually Cu, but this has the disadvantage that it oxidizes during use, increases electrical resistance, and the electrolytic action no longer works, and the porosity also becomes clogged, reducing the mechanical grinding action. be. In addition, worn-out grindstones are reused by dressing them, but since the inside of the grindstone is not uniformly conductive compared to the surface of the grindstone, dressing reduces the electrolytic grinding action.

The present invention proposes a method for manufacturing a high-quality grinding wheel that eliminates such drawbacks, and uses conductive TiC abrasive grains or abrasive grains obtained by adding other abrasive grains to TiC abrasive grains with a volume ratio of 5 to 3.
It is made by mixing 0% frit and 0.5 to 5% lithium compound or molybdenum compound and sintering the mixture.

Among the abrasive grains, abrasive grains such as Si C, BN, etc. have a specific resistance of 1010 μΩ C1 and are resistive insulating abrasive grains, but the Tic abrasive grains have a resistivity of about 70 to 170 μΩ CI and are conductive. Therefore, the present invention uses TiC abrasive grains with low resistivity, mixes other abrasive grains if necessary, and manufactures a conductive whetstone by sintering and forming the TiC abrasive grains. be.

The conductivity of the grindstone can be controlled by blending insulating abrasive grains such as SiC with conductive abrasive grains of TiC, and the drawing shows the change in specific resistance value depending on the ratio.

In sintering and shaping the abrasive grains, a frit is used as a binder, and a lithium compound or a molybdenum compound is added to improve sinterability and form appropriate chip pockets between the abrasive grains. Frit needs to be at least 5% by volume as a binder in order to obtain bonding strength between abrasive grains, and if there is too much binder, chip pockets will be filled and the grinding performance of the abrasive grains will deteriorate, so it should be at most 30% by volume. % or less. As an example, the frit has a weight ratio of NaO:3.
．． 8 parts, 20:5.8 parts, M (IQ: 2.5 parts, Ca
O: 3.5 parts, B20: 8.6 parts, AJL20331.
5 parts, 5i02: 41.9 parts, pbo: 5.9 parts, feldspar: 36 parts, clay: 19 parts, iron oxide: 17 parts, 1 curve lead flower: 2
Although 6 parts was used, products with other component ratios can also be used.

In addition, lithium compounds improve sintering properties and utilize the property of decomposing and vaporizing at sintering temperatures, 11□Go3, Li2
The porosity is controlled by vaporizing O, Mo, O3, etc. By mixing about 0.5 to 5% by volume, the desired porosity can be controlled to about 10 to 60%, and the hardness of the sintered body can be increased by about 20 to 30%.

Next, an example will be explained.

Example 1 140μφTiN with 140μφ TiC at 40% volume ratio
20% of SiC and 20% of 120 μφ SiC were mixed, and 19% of frit and 1% of Li and Co3 were mixed and sintered.

The sintering conditions were kept at 1300°C for 5 minutes and at a pressure of 50Ka/
CG + Fuyaki was formed. The dimensions of the molded whetstone are external diameter 1
A wheel having a diameter of 0.0011 mm and a thickness of 10 mm was molded. The specific resistance of the shaped grindstone was approximately 2.6 ΩC-, and was uniform throughout.

In the grinding process, WC-6%CO was used as the workpiece, and the grinding wheel rotation speed was 1. OOOrpm, pressure 5000, NaN0,
While supplying a 15% aqueous solution as an electrolyte, energization i%
When electrolytically grinding with I2A, the grinding speed is 3010/s
in, and the surface roughness was approximately 3 tt Rwax.

For comparison, the grinding performance was approximately 50% higher than when using a CLI-plated SiC grindstone.

When mechanical grinding was performed with the electrolytic grinding wheel turned off, a grinding speed of about 91 o/sin was obtained.

Example 2 The abrasive grain blending ratio is 60% TiC and 10% TiN.

SiC is 20%, frit is 9% and Li20O3 is 1
%, the specific resistance value of the shaped whetstone was about 1.80C-, indicating good grindability. , Example 3 When the abrasive grain blending ratio is 50% TiC, 30% SiC, 15% frit, and 5% voos, molded abrasive 6
The specific resistance value was about 3ΩC-, and the grindability was good.

In the above, other abrasive grains added to TiC abrasive grains include liN and Si.
Although C was used, other known abrasive grains can be arbitrarily combined in consideration of specific resistance value, hardness, etc.

Further, the frit and the lithium compound are preferably mixed in order to control the abrasive bonding strength and chip pockets.

Sintered #! In addition to hot pressing, current sintering (including discharge sintering) can be used for shaping.

As explained above, the present invention uses conductive SIC abrasive grains and sinters them with a binder frit, so that an electrolytic grinding wheel having the desired conductivity can be easily obtained in the process. During sintering, adjuvants such as lithium compounds are combined and decomposed and vaporized during sintering, making it possible to control porosity, increase the hardness of the sintered body, improve moldability, and improve grindability. A good whetstone can be easily obtained. Formed whetstones can perform not only electrolytic grinding but also high-performance mechanical grinding when the current is turned off, and since the whetstone is homogeneous throughout and has a processable wheel, it is possible to shape the whetstone and modify it. It is easy to use, and a grindstone with a long life can be obtained without losing electrical conductivity and reducing electrolytic action during use.

[Brief explanation of the drawing]

The drawing is an explanatory diagram of the characteristics of the grindstone according to the present invention. patent applicant Hashigami Japax Research Institute Co., Ltd. Representative Kiyoshi Inoue

Claims (1)

[Claims] 5 to 30% frit and 0.5% frit by volume to conductive TiC abrasive grains or abrasive grains obtained by adding other abrasive grains to TiC abrasive grains.
A method of manufacturing an electrolytic grinding wheel by mixing ~5% of a lithium compound or a molybdenum compound and sintering the mixture.