JPH04201068A - Cutting method for powder metallurgical product - Google Patents

Abstract

PURPOSE:To prevent a cutter from blinding and to execute a cutting work with a high efficiency by fixing a blocks having a dressing action on to a substrate close to the end face of a powder metallurgical product crossed with the plane including the cut face by a cutter, and executing cutting with a voltage being impressed between the cutter and substrate. CONSTITUTION:A conductive circuit is formed among a cutter 2, powder metallurgical product (rare earth class permanent magnet) 6 and substrate 5, a pulse current is flowed, the dressing of the cutter 2 is continuously executed by this pulse current, and a highly efficient cutting is executed. Moreover, a block 8 composed of the material having a dressing action is fixed to the end face of a powder metallurgical product 6 crossed with the plane including the cut face by the cutter 2, namely onto the substrate 5 at the vicinity of the end face to be cut. Consequently, the dressing of the cutter 2 can be executed automatically by this block 8 each time of cutting, and the clogging of the cutter 2 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is directed to
The present invention relates to a method for cutting powder metallurgy products, such as rare earth permanent magnets, under pressure.

[Conventional technology]

Conventionally, rare earth permanent magnets are produced by a process in which raw material powder is molded into a predetermined shape and size using a molding die, and then sintered, or by melting the raw material and ejecting it onto the surface of a 9-turn roll and ultra-quenching it into flake-like powder. There is a method in which the powder is first prepared, and then this powder is upset and compacted by desired processing such as extrusion. Rare earth permanent magnets produced in this way are often used as they are, but depending on the intended use, some or all of them may be cut to form small-sized magnets. There are cases. It is also necessary to cut rare earth permanent magnets in multiple directions for testing or evaluation purposes.

[Problem to be solved by the invention]

This is because the rare earth permanent magnets mentioned above generally have high hardness.

A diamond cutter is generally used for cutting, and a cutting fluid is used to prevent the cutter and the cut location from generating heat during cutting. However, in the above-mentioned cutting operation for rare earth permanent magnets having a large thickness, the cutter frequently becomes clogged, so it is necessary to interrupt the cutting operation and perform dressing with a force of 2 turrets. In order to improve cutting accuracy, it is also necessary to perform truing (also called reshaping or shaping) of the cutter. This results in more interruptions in cutting work,
There is a problem that cutting requires a large amount of time and man-hours. Furthermore, since rare earth permanent magnets are formed by sintering or compacting raw material powder, they are generally brittle and have poor toughness, making them easy to chip. For this reason, chipping is likely to occur on the surface of the rare earth permanent magnet in the above-mentioned cutting operation, and there are also problems in that the feed speed of the cutter is limited and the quality is degraded.

The present invention solves the problems existing in the above-mentioned prior art, and provides a method for cutting powder metallurgy products that does not cause chimping on the surface of the powder metallurgy product to be cut and allows highly efficient cutting. With the goal.

[Means to solve the problem]

In order to achieve the above object, in the present invention, a substrate made of a conductive material is fixed on a surface plate made of a metal material, and a powder metallurgy product to be cut is fixed on this substrate so that it can rotate freely once. Disc-shaped force.

using a canter, fix a block having a dressing effect on the substrate near the end face of the powder metallurgy product that intersects a plane including the cut surface by the canter; 1. Apply a voltage between the cutter and the substrate; A technical method was adopted in which the cutting was carried out using

In the present invention, a coating made of a material having electrical conductivity and a truing effect can be applied to the upper surface of the powder metallurgy product, or to the upper surface and the end surface to be cut.

[For production]

With the above configuration, a conductive circuit is formed between the cutter, the powder metallurgy product, and the substrate, and the pulse tfL flows reliably, so the cutter can be continuously dressed by this pulse tfL, resulting in highly efficient cutting. It can be carried out. In addition, by fixing a block made of a material that has a dressing effect on the substrate near the end face of the powder metallurgy product that intersects the plane containing the cut surface by the cutter, that is, the end face to be cut, the cutter dressing is automatically performed each time cutting is performed. It can be used to prevent the cutter from clogging. By applying a coating made of a material having conductivity and a truing effect to the top surface of the powder metallurgy product, or to the top surface and the end surface to be cut, the powder metallurgy product S made by Kanter can be improved. It is possible to reduce i''J and shape the shape of one cutter, which has the effect of improving cutting accuracy.

(Embodiment) Fig. 1 is a side view of main parts showing a cutting state in an embodiment of the present invention. It is configured to be able to apply voltage.Next, 4 is an iron surface plate, and 2
For example, radius 120mm, length 150mm, thickness 8IIff
Form into i. Reference numeral 5 denotes a substrate, which is made of conductive graphite and is, for example, 120 mm square and 10 III 11 thick, and is adhered onto the surface plate 4 . Next, 6 is a rare earth permanent magnet, 2 For example, from the composition formula % formula % width + 11011I, length 120mm, H 27
Formed into mm.

It is adhered onto the substrate 5. The adhesive used for the above bonding is a processing adhesive manufactured by Ichika Seiko (product name: Atofix A).
, a softening point of 79°C, and an adhesive strength of 69 kg/cm2).

The surface to which the adhesive is applied is as follows between the surface plate 4 and the base Fi5.
The four corners of the substrate 5 were each approximately 30 mm x 30 mm, and the area between the substrate 5 and the rare earth permanent magnet 6 was arranged to span the entire lower surface of the rare earth permanent magnet 6. 7 is an iron plate, 1m thick
mL is formed so as to cover the entire upper surface of the rare earth permanent magnet 6, and is adhered with the same adhesive as above.

Next, 8 is a block.

With #240GC (green carborundum), the − side is 301. Formed into a prismatic shape with a length of 110 mm.

It is fixed on the substrate 5 near the end face of the rare earth permanent magnet 6 to be cut.

The sample formed as described above was prepared by Nikko Kikai N5 (1,
A cutting test was carried out by attaching the sample to the processing table 1 of a -52ACE type electric discharge compound grinding machine (referred to as COMMEC) by magnetic adsorption. The cutter 2 used for cutting was Asahi Dia's metal bond #20 with an outer diameter of 200 mm and a blade thickness of lff11M.
0 diamond grindstone SD60J68MHX.

The conditions for cutting were a rotational speed of Kaku 2 of 200 rpm.

Cooling water flow rate approximately 8 OL/win, water-soluble grinding oil ratio in cooling water: Noritake Cool C0MMEC-30 grinding oil to 50 parts water! It was added at a ratio of 1 i to 1 i. The discharge voltage during machining was set to 50V, and the feed rate of the machining table l was set to 20+
The relationship between the number of cuts and the drive current when u+/win was investigated. Note that the discharge current value was 0.35 to 0.4 A, and the cutting interval was 4 mm.

FIG. 2 is a diagram showing the relationship between the number of cuts and the drive current in the embodiment of the present invention. In FIG. 2, a, b, and c correspond to modal-like aspects, respectively.

a: Blocks 8 in FIG. 1 are provided on both sides of the end face of the rare earth permanent magnet 6 to be cut.

b = one provided only on one end face of the diblock 8 rare earth permanent magnet 6 to be cut.

C: Block 8 is not installed.

As is clear from FIG. 2, block 8 in FIG.
In the cutting work of m-like C, which lacks.

As the number of cuts increases, the drive current value increases to 2. It can be seen that when the driving current increases sharply and the number of cuttings becomes 4 or more, the value of the drive current exceeds the allowable current value of 6.5A. That is, since clogging occurs particularly on the side surface of the cutter 2 shown in FIG.
This phenomenon is caused by increased cutting resistance. On the other hand, in both cases a and b, the rate of increase in the drive current as the number of cuts increases is extremely small, and even after the number of cuts reaches 12, the current is still below the allowable current value. This tendency is remarkable in That is, by providing the block 8 shown in FIG. 1, the cutter 2 is dressed every time it cuts.

It is recognized that the cutting work progresses smoothly with little clogging of the cutter 2.

FIG. 3 is a diagram showing the relationship between the number of cuts and the drive current in another embodiment of the present invention, and the same aspects are indicated by the same reference numerals. The rare earth permanent magnet in this example is S
mz (Co, Fe, Cu.

Zr)+t S m2 C01g magnet with width 110+*
The block 8 (see FIG. 1) was made of #120WA (white arundum). The cutting conditions were the same as in the previous example except that the feed rate of the processing table l was 10 mm/sin.

As is clear from FIG. 3, similarly to FIG. 2, in C, which lacks the installation of block 8 shown in FIG. If it exceeds 5 times, the drive i current value will be the allowable current value 6.
．． It can be seen that it exceeds 5A. On the other hand, in cases a and b, the increase in the 5 drive current value is gradual regardless of the increase in the number of cuts.

This shows that the installation of block 8 is effective.

In this embodiment, an example in which the substrate is made of graphite has been described, but the substrate is not limited to graphite, and the same effect can be achieved even if the substrate is made of other materials as long as they have conductivity and a cutter dressing effect. In addition, the coating to be applied to the upper surface and the side surface of the rare earth permanent magnet may be formed into a plate shape and bonded with adhesive, or may be formed by applying a slurry of a material that has conductivity and truing action. Moreover, the object of the present invention is not only rare earth permanent magnets but also conductive ceramics (ANN
, Sialon, etc.) or other powder metallurgy products such as soft ferrite.

〔Effect of the invention〕

Since the present invention has the structure and operation as described above,
Not only does it not cause chipping on the surface of powder metallurgy products, it also prevents clogging of the cutter and allows cutting to be performed with high efficiency.

Therefore, the quality of powder metallurgy products can be improved as well.

This has the effect of significantly reducing the time and man-hours required for cutting.

[Brief explanation of the drawing]

FIG. 1 is a side view of a main part showing a cutting state in an embodiment of the present invention, and FIGS. 2 and 3 are diagrams showing the relationship between the number of cuts and drive current in an embodiment of the present invention, respectively. 5 two substrates, 6: rare earth permanent magnet, 7: iron plate. 8 Nibrodsk.

Claims (3)

[Claims] (1) A substrate made of a conductive material is fixed on a surface plate made of a metal material, a powder metallurgy product to be cut is fixed on this substrate, and a rotatable disc-shaped cutter is used, A block having a dressing effect is fixed on the substrate near the end face of the powder metallurgy product that intersects with a plane including the cut surface by the cutter, and cutting is performed by applying a voltage between the cutter and the substrate. Characteristic cutting method for powder metallurgy products. (2) Claim (1) in which a coating made of a material having conductivity and truing action is applied to the upper surface of a powder metallurgy product.
Method of cutting powder metallurgy products as described. (3) The method for cutting a powder metallurgy product according to claim (2), wherein a coating made of a material having conductivity and truing action is applied to the end face of the powder metallurgy product to be cut.