JPH05318322A - Conductive tool - Google Patents

Abstract

PURPOSE:To prevent the invasion of a coolant and obstruct the deterioration of a tool subjected to electrolytic dressing by impregnating a resin in a base material consisting of a sintered metal. CONSTITUTION:Diamond grind powder is mixed into a base material consisting of cast iron powder. A mixing material such as carbonyle iron powder and graphite and the like beside cast iron powder is used as the base material of a grinding wheel CIB-D. Then, after a forming process by a press and the like, sintering is performed and epoxy resin is impregnated. Thereafter, a desired conductive tool is obtained by jointing a base metal thereto. By impregnating the resin like this, the air hole in the base material can be eliminated and the invasion of a coolant can be prevented. Consequently, the deterioration of a tool by electrolytic dressing can be obstructed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive tool such as a cast iron bond grindstone used for electrolytic dressing.

[0002]

2. Description of the Related Art Conventionally, cast iron bonded diamond grindstone (hereinafter referred to as CIB-D grindstone: Cast-Iron-Bo).
Ned-Diamond) is a grindstone formed by mixing cast iron powder as a base material with diamond abrasive grains and sintering the mixture, and has a strong holding force for the abrasive grains, and thus has been used for processing ceramics and the like. However, in the CIB-D grindstone, since the bond material that holds the diamond abrasive grains is strong cast iron, the ability to project the diamond abrasive grains from the cast iron bond surface during processing, that is, the self-sharpening ability is low, and it has not been used conventionally. WA (white alundum), GC
(Green carborundum) It was also very difficult to perform a dressing operation (hereinafter referred to as dressing) by co-shaving using a grindstone or the like. Therefore, if the dressing is not done well, the cast iron itself, which is the bond material, will come into direct contact with the work material, eventually causing seizure and inability to process, and the grindstone or work material may be damaged. It was

In recent years, the electrodes are opposed to the machined surface of the CIB-D grindstone with a predetermined gap, and water-soluble coolant is supplied to the gap, the CIB-D grindstone has the (+) pole, and the electrode ( -) It became possible to perform good dressing by passing a direct current or pulse current of several amperes as the pole. That is, this is a method in which an electric current is passed between the CIB-D grindstone and the electrode to cause electrolytic dissolution of Fe ions mainly from the working surface of the CIB-D grindstone by an electrolytic reaction. Since the water-soluble coolant is alkaline, Fe ions become oxides such as Fe2O3 or Fe3O4 and adhere to the surface of the CIB-D grindstone. When the oxide comes into contact with the work material during processing, the oxide drops off from the surface of the grindstone, so that the diamond abrasive grains protrude from the surface of the grindstone and dressing is performed. Further, since the oxide is a passive substance, it has a property that it is difficult for current to flow,
When the oxide grows thick on the surface of the grindstone, the growth of the oxide stops because the electrolytic current is suppressed.
It is an excellent dressing method that enables stable processing with an oxide film most suitable for the IB-D grindstone.

At present, this electrolytic dressing exhibits an excellent ability for mirror-finishing ceramics or the like using a fine-grained diamond grindstone, which is said to be particularly difficult for ordinary dressing, and stabilizes a mirror surface which cannot be obtained by conventional grindstones. Can be provided.

However, the diamond abrasive grains used are fine grains of about 10 μm or less, and since cast iron powder is used as the base material, it is difficult to sinter and it is difficult to increase the density of the grindstone sufficiently. Yes, there were small holes left. If such holes are present, the coolant enters the holes during the electrolytic dressing process, and the holding force of the diamond abrasive grains and the strength of the grindstone itself due to the electrolytic reaction inside the grindstone occur, which makes good processing impossible. In addition, there was a defect that the life of the grindstone was extremely short. Then, as a measure for eliminating the above-mentioned defects, there has been a method of infiltrating a metal such as copper into a grindstone.

[0006]

However, in the above-mentioned electrolytic dressing process, when a CIB-D grindstone used as a conductive tool is mixed with a dissimilar metal such as copper, the behavior and efficiency of the electrolytic reaction change. For example, when commonly used copper is used, copper is gradually eluted as copper ions by an electrolytic reaction in an alkaline environment, so that the coolant penetrates into the CIB-D grindstone, resulting in CIB. -D The grinding wheel life was shortened.

Further, in order to infiltrate a metal such as copper, equipment such as a melting furnace for melting the metal is required, which is very expensive. Furthermore, in the case of copper, the melting temperature is 10
Since the temperature exceeds 00 ° C, a very high processing temperature is required, which causes diamond grains to diffuse into iron,
Since the deterioration progresses remarkably due to oxidation or the like, there is a difficulty that copper must be infiltrated in a vacuum or in a hydrogen atmosphere with the utmost care. It was also very difficult to secure the quality of the D grindstone.

The present invention has been made in order to solve the above-mentioned problems, and an object thereof is to provide a conductive tool provided with a means for preventing coolant from entering the inside of the tool.

[0009]

In order to achieve this object, the conductive tool of the present invention is obtained by impregnating a base material made of a sintered metal with a resin.

[0010]

In the conductive tool of the present invention having the above-mentioned structure, the base material made of a sintered metal is impregnated with the resin to eliminate the pores of the base material and prevent the infiltration of the coolant.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

C using # 2000 diamond abrasive grains
After performing a predetermined electrolytic dressing on the IB-D grindstone, C
The effect of resin impregnation was examined by observing the fracture surface of the IB-D grindstone.

FIG. 1 shows a conventional CI not impregnated with resin.
It is a B-D grindstone, and is a fracture surface of the CIB-D grindstone after performing the electrolytic dressing of 10 A · h. According to it, corrosion due to the infiltration of the coolant is observed in the upper part.

FIG. 2 shows a CIB-D grindstone after immersion of the CIB-D grindstone in a thermosetting epoxy resin which is liquid in the atmosphere, followed by curing the resin in an oven furnace and performing electrolytic dressing of 13 A · h. Is a fracture surface. According to it, corrosion due to slight infiltration of coolant is observed in the upper part.

FIG. 3 shows an oven furnace capable of vacuuming about 100 to further improve the impregnation ability of the epoxy resin.
After the temperature of the epoxy resin is set to reduce the viscosity of the epoxy resin and vacuuming is performed, the CIB-D grindstone is immersed in the epoxy resin, and then the resin is treated in an oven at about 150 ° C. in an atmosphere. It is a fractured surface of a CIB-D grindstone which was subjected to electrolytic dressing of 21 A · h after being cured. According to it, it is found that no corrosion is observed and no infiltration of the coolant due to the effect of the epoxy resin.

Next, the manufacturing process of the CIB-D grindstone will be described with reference to FIG. First, diamond abrasive grains are mixed with a base material made of cast iron powder. As the base material of the CIB-D grindstone, in addition to cast iron powder, there is also a mixed material of carbonyl iron powder and graphite. Next, after molding with a press or the like, sintering is performed to impregnate the epoxy resin. After that, it is joined to the base metal, and truing (correction of grindstone shape and runout) is performed, and inspection is completed.

Next, a comparison will be made between the processing performances of the CIB-D grindstone impregnated with the epoxy resin and the conventional CIB-D grindstone not impregnated with the epoxy resin in a heating / vacuum atmosphere.

An outline of processing is shown below.

Tool: # 2000 CIB-D cup type grindstone Processing machine: Brother CNC precision soft cutting material processing machine FM-50
0 Processing conditions: V1570m / min, D2um, F50m
m / min (V: grinding speed, D: depth of cut, F: feed speed) Electrolytic dressing is performed under the above conditions to evaluate the machining load and the machined surface.

Conventional CIB-D not impregnated with resin
The grindstone has an unstable thrust load during processing, and rubbing marks, which are considered to be marks of strong contact between the cast iron, which is the base material of the grindstone, and the work material are found on the work surface of the work material. The CIB-D grindstone impregnated with the epoxy resin has a stable thrust load during processing, and an oxide film on the working surface of the grindstone is also uniformly formed and retained. The work surface of the work material also exhibited a very good mirror surface, and the surface roughness was RZ 0.03 um, which enabled stable mirror surface processing, which was difficult with conventional grindstones.

As the conductive tool, there is also a grindstone using CBN abrasive grains as the abrasive grains in addition to the CIB-D grindstone. As a base material, it is effective to impregnate a non-ferrous bond material such as bronze with a resin.

[0022]

As is apparent from the above description, the conductive tool of the present invention is obtained by impregnating a sintered metal with a resin such as epoxy to eliminate voids inside the tool.
Since the invasion of the coolant is eliminated, there is no deterioration of the tool due to electrolytic dressing, and it is possible to fully exhibit the capability of electrolytic dressing processing that cannot be obtained with conventional tools.

[Brief description of drawings]

FIG. 1A is a photomicrograph of a metal structure of a conventional CIB-D grindstone not impregnated with an epoxy resin after electrolytic dressing (10 A · h), and FIG. 1B is an explanatory diagram thereof. .

FIG. 2 (A) is C impregnated with epoxy resin in the atmosphere.
It is the microscope picture which image | photographed the metal structure after the electrolytic dressing (13A * h) of the IB-D grindstone, (B) is the explanatory view.

FIG. 3 is a photomicrograph of a metallographic structure of a CIB-D grindstone impregnated with an epoxy resin after being electrolytically dressed (21 A · h) after being evacuated in an atmosphere of 100 ° C.

FIG. 4 is a diagram showing a manufacturing process of a CIB-D grindstone.

Front page continuation (72) Inventor Teruhisa Kojima, 15-1, Naeshiro-cho, Mizuho-ku, Nagoya-shi Brother Industrial Co., Ltd. (72) Inventor Shigeru Tokitsu, 15-1 Naeshiro-machi, Mizuho-ku, Nagoya-shi Brother Industrial Co., Ltd. (72) Inventor Koichi Matsuda 15-1 Naeshiro-cho, Mizuho-ku, Nagoya-shi Brother Industrial Co., Ltd.

Claims (1)

[Claims] 1. A conductive tool used for electrolytic dressing, wherein a base material made of a sintered metal is impregnated with a resin.