JPH0557528A - Mirror grinding with electrolytic product and its device - Google Patents

Abstract

PURPOSE:To reduce the manufacturing time and cost of a grinding wheel by easily producing it with simple and inexpensive equipment, and save the labor of grinding wheel change by reproducing the grinding wheel on a processing machine. CONSTITUTION:A conductive liquid is flowed between a conductive grinding wheel 10 having a contact surface 12 with a workpiece 16 and an electrode 20 opposite to the contact surface, voltage is applied between the grinding wheel and the electrode to form an electrolytic product 11 on the grinding wheel contact surface, and a workpiece is ground with the electrolytic product. This device is composed of the conductive grinding wheel having the contact surface with the work piece, the electrode opposite to the contact surface, a means 30 flowing the conductive liquid between the grinding wheel and the electrode, and means 40 and 42 applying voltage between the grinding wheel and the electrode, and the grinding wheel uses material including no abrasive grain and having high oxidation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing method and apparatus in the field of machining, and more particularly to a method and apparatus for performing mirror polishing by electrolytic products without using abrasive grains.

[0002]

2. Description of the Related Art A conductive grindstone such as a cast iron fiber bonded diamond grindstone is used, and an electrolytic dressing method and apparatus for a conductive grindstone in which a voltage is applied to the grindstone and the grindstone is electrolytically dressed by the same applicant as the present application. Kohei
It has been disclosed in Japanese Patent Application No. 1-188266 (Japanese Patent Application No. 63-12305) and has succeeded in mirror-finishing a semiconductor material such as silicon which is an electronic material. In addition, an electrolytic in-process dressing grinding method (Electrolytic Inproc
ess Dressing: A method and a device called “Elid grinding method” have been developed and announced by the applicant of the present application (RIKEN Symbodium “Latest Technology Trend of Mirror Grinding”, held on March 5, 1991).

In this Elid grinding method, a grindstone having a contact surface with a work, an electrode facing the contact surface, a nozzle for flowing a conductive liquid between the grindstone and the electrode, and a voltage applied between the grindstone and the electrode. A device comprising a power source and a power feeding body for applying a voltage. A voltage is applied between the grindstone and the electrode while the conductive liquid is flowing between the grindstone and the electrode, and the grindstone is dressed electrolytically.

FIG. 6 shows a dressing mechanism by the Elid grinding method. At the start of grinding of the grindstone (A), the electric resistance between the grindstone and the electrode is small and a relatively large current (5
10A) flows. Thereby, the metal portion (bond) on the surface of the grindstone is dissolved by the electrolytic effect, and the non-conductive diamond abrasive grains are projected. Further, if the power is continued, iron oxide (F
An insulating film mainly composed of e ₂ O ₃ ) is formed on the surface of the grindstone, increasing the electric resistance of the grindstone. This reduces the current,
The dissolution of the bond is reduced, and the protrusion of abrasive grains (grinding of the grindstone) is substantially completed (B). When grinding is started in this state (C), the coating particles release grinding dust, and the diamond abrasive grains wear away as the work is ground. When the grinding is further continued (D), the insulating coating on the surface of the grindstone is removed by abrasion, the electric resistance of the grindstone is lowered, the current between the grindstone and the electrode is increased, the dissolution of the bond is increased, and the protrusion of the abrasive grains (grinding stone Is reopened. Therefore, during grinding by the Elid grinding method, excessive elution of the bond is suppressed by forming / removing the coating as shown in (B) to (D), and the protrusion of the abrasive grains (sharpening of the grindstone) is automatically adjusted. It The above-described cycles shown in (B) to (D) are hereinafter referred to as Elid cycles.

[0005]

Various wheels such as a cast iron fiber bond wheel and a bronze bond wheel have been conventionally used for the above-mentioned wheel used for Elid grinding. There was a problem. That is, a large number of grindstones of a desired shape are used to manufacture a press mold,
It usually takes several months to make this whetstone, and whetstone 1
It cost hundreds of thousands of yen per piece. For this reason, not only the production period of the press die and the like is prolonged, but also the die production cost is increased.

[0006] In the manufacturing process of a cast iron bond grindstone or the like, it is necessary to heat the metal part (bond) to 1000 ° C or more to sinter the metal part (bond) and then to bond it to the base metal by brazing or the like, which is complicated. This is because an expensive high-temperature furnace is required. Therefore, a normal die manufacturer could not produce a grindstone in-house.
The present invention solves such a problem, can be easily manufactured with simple and inexpensive equipment, can reduce the manufacturing time and manufacturing cost of the grindstone, and can regenerate the grindstone on the processing machine, and therefore the replacement of the grindstone An object of the present invention is to provide a mirror-polishing method and device that can save the trouble of.

[0007]

In order to solve the above problems, the inventor of the present invention has noticed that the main component of the film formed on the surface of the grindstone during electrolytic dressing is an oxide having high hardness, The present invention has been completed by studying mirror polishing with this coating or electrolytic product. That is,
According to the present invention, a conductive liquid is caused to flow between a conductive grindstone having a contact surface with a workpiece and an electrode facing the contact surface, and a voltage is applied between the grindstone and the electrode to grind the grindstone. A method for mirror-polishing with an electrolytic product is provided, in which an electrolytic product is formed on the contact surface, and a workpiece is polished with the electrolytic product.

Further, according to the present invention, a conductive grindstone having a contact surface with the workpiece, an electrode facing the contact surface, and a means for flowing a conductive liquid between the grindstone and the electrode, Consisting of means for applying a voltage between the grindstone and the electrode,
There is provided a specular polishing apparatus using an electrolytic product, wherein the grindstone is a highly oxidizable material that does not contain abrasive grains.

The whetstone is preferably made of an aluminum material.

[0010]

According to the above-described method and apparatus of the present invention,
Since the grindstone is made of a conductive material that does not contain abrasive grains, preferably an aluminum-based material, the grindstone can be easily manufactured only by machining the aluminum-based material. Further, since the electrolytic product is formed on the contact surface of the grindstone and the workpiece is polished by this electrolytic product, the grindstone can be easily regenerated on the processing machine.

Therefore, the grindstone can be easily manufactured with simple and inexpensive equipment, the manufacturing time and the manufacturing cost of the grindstone can be reduced, and the grindstone can be regenerated on the processing machine. Therefore, the labor of exchanging the grindstone can be saved. It is possible to provide a mirror polishing method and apparatus capable of performing the above.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram schematically showing a mirror polishing apparatus according to the present invention. In this figure, 10 is a substantially disk-shaped conductive grindstone having a vertical axis, and this grindstone 10 is horizontally rotatably fixed to an upper head of a processing machine (not shown). This upper head can move horizontally and vertically with the grindstone 10.

Below the upper head, a table 14 of the processing machine is provided around a vertical axis. This table 1
4 is normally completely fixed, but it may be movable horizontally and / or vertically. A work piece, that is, a work 16 is fixed to the upper surface of the table 14 via a holder 15 in a generally known manner. When the work piece 16 is a conductor, the holder 15 is preferably insulated in order to insulate the work piece 16 from the table 14. The lower surface of the grindstone 10, that is, the contact surface 12 with the work 16 is a horizontal polishing surface, and the work 16 is polished by bringing the contact surface 12 of the rotating grindstone 10 into contact with the work 16.

Below the portion of the grindstone 10 that does not come into contact with the workpiece 16, an electrode 20 having a shape that substantially matches the shape of the contact surface 12 of the grindstone 10 is provided facing the contact surface 12 of the grindstone 10. A plurality of nozzles 30 are provided around the grindstone 10, so that a weakly conductive cutting fluid, that is, a coolant is caused to flow between the grindstone 10 and the electrode 20 via a supply pipe (not shown). This nozzle 30
Is preferably provided so that the coolant also flows between the grindstone 10 and the work 16.

Further, the apparatus is provided with a power supply 40,
A + voltage is applied to the grindstone 10 via the power supply body 42 that comes into contact with the circumferential surface of the grindstone 10, and the electrode 20 has a − voltage.
The voltage can be applied. This power supply 40
Is preferably a pulse power source or a power source in which pulse and DC are mixed. The grindstone 10 is made of a highly oxidizable material that does not contain abrasive grains. Table 1 shows a comparison of the characteristics of iron-based materials, copper-based materials, and aluminum-based materials. The iron-based oxide film is easy to peel off in a certain mass, and the time that contributes to polishing is short. In addition, the oxide film of copper-based material elutes too quickly. On the other hand, with aluminum-based materials, dressing of the base material is performed by electrolysis, but the oxide coating, that is, the formation of alumina is faster than that, and dressing and coating formation occur in parallel, and the base material of the resulting coating is formed. Since it is strongly bonded to the material and the oxide coating, that is, the alumina is formed into a substantially granular shape, it has a function similar to that of abrasive grains. Therefore, it was found that the aluminum-based material is most suitable for mirror-polishing with the electrolytic product.

[0016]

[Table 1]

In use, a cycle similar to the Elid cycle described above, that is, a cycle of dressing, coating formation, polishing with a coating, and abrasion of a coating, produces a coating and polishes a work with the coating. FIG. 2 shows a polishing mechanism using an electrolytic product. As shown in the figure, the polishing is performed by a grindstone 10, that is, an oxide film 11 formed on the surface of aluminum, for example, alumina. Therefore, by balancing the wear of the coating and the formation of the coating, the coating can be held appropriately at all times, and the grindstone can be regenerated in the processing machine to save the labor of exchanging the grindstone. Example 1 A super duralumin machine, which is an aluminum-based material, was ground with a grindstone (diameter 180
mm-thickness 10 mm), this was used as the positive electrode, the counter electrode was used as the negative electrode, and polishing was performed using the grinding machine, power supply, work material, etc. shown in Table 2. In this polishing, a constant pressure incision is desirable because polishing is performed while generating electrolytic products, and the vertical load (FZ load) was adjusted to be within 2 kgf. The obtained results are shown in FIGS.

[0018]

[Table 2]

(1) Change in current / voltage due to electrolysis FIG. 3 shows changes in current / voltage. The current reduction was caused by the deposition of electrolysis products. The coating thickness is about 1 after about 20 minutes of energization.
70 μm, electrolytic coating such as cast iron (40 to 50 μm)
3 to 4 times the thickness was obtained. The electrolysis product is milky white and seems to be an alumina-based component. Microscopic observation of the electrolysis product showed that particulate alumina was bonded to the aluminum base material. (2) Mirror polishing property Fig. 4 shows the load change of polishing process. Total cutting depth is 70
Up to 90 μm, the load value did not become so high. (3) Processed Surface Roughness The roughness pattern of the nitrogen silicon finished surface is shown in FIG. # 600
The processed surface (FIG. 5A) of (Rmax 1.503 μm) was matte with no gloss, but this surface was polished and Rmax 0.1.
A good mirror surface with a gloss of 70 μm (FIG. 5B) was obtained. This mirror surface was comparable to the Elid ground surface with a # 2000 wheel.

[0020]

According to the above-described grindstone and the manufacturing method thereof according to the present invention, since the grindstone is made of a conductive material containing no abrasive grains, preferably an aluminum-based material, it is easy to machine the aluminum-based material. A grindstone can be manufactured. Further, since the electrolytic product is formed on the contact surface of the grindstone and the workpiece is polished by this electrolytic product, the grindstone can be easily regenerated on the processing machine.

Therefore, it can be easily manufactured with simple and inexpensive equipment, the manufacturing time and the manufacturing cost of the grindstone can be reduced, and the grindstone can be regenerated on the processing machine. Therefore, the labor of exchanging the grindstone can be saved. It is possible to provide a mirror polishing method and apparatus capable of performing the above.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing an electrolytic dressing device according to the present invention.

FIG. 2 is a diagram showing a polishing mechanism by an electrolytic product.

FIG. 3 is a diagram showing changes in current and voltage due to electrolysis.

FIG. 4 is a diagram showing a load change of polishing.

FIG. 5 is a diagram showing surface roughness before and after polishing.

FIG. 6 is an explanatory diagram showing an Elid cycle in the Elid grinding method.

[Explanation of symbols]

 10 Grinding Stone 12 Contact Surface 14 Table 16 Workpiece 18 Upper Head 20 Electrode 30 Nozzle 40 Power Supply 42 Feeder

Claims (3)

[Claims] 1. A conductive liquid is caused to flow between a conductive grindstone having a contact surface with a workpiece and an electrode facing the contact surface,
A voltage is applied between the grindstone and the electrode to form an electrolytic product on the contact surface of the grindstone, and a workpiece is polished by the electrolytic product, which is a mirror polishing method using the electrolytic product. .. 2. A conductive grindstone having a contact surface with a workpiece, an electrode facing the contact surface, a means for flowing a conductive liquid between the grindstone and the electrode, and the grindstone and the electrode. And a means for applying a voltage therebetween, wherein the grindstone is a highly oxidizable material that does not contain abrasive grains. 3. The mirror-polishing device with electrolytic products according to claim 2, wherein the grindstone is an aluminum-based material.