JPS5837082B2 - diamond tools - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides disks etc. made of non-ferrous metal materials such as AI and Cu, or non-metal materials such as plastic, etc.
This invention relates to the improvement of diamond bits used for cutting with high precision.

In general, by using a diamond cutting tool for high-precision cutting of non-ferrous and non-metallic materials as mentioned above, it is relatively easy to obtain a machined surface with a so-called mirror finish with good surface roughness. As is well known.

The reason for this is that diamond has high hardness, and therefore the cutting edge of the cutting tool can be made extremely sharp.As a result, this sharp cutting edge is transferred to the workpiece, resulting in a machined surface with good surface roughness. It will be possible.

By the way, no matter how hard a diamond cutting tool is, it will gradually wear out if used for a long time.

The cutting surface produced by a worn cutting tool deteriorates the surface roughness and increases surface waviness, making it impossible to obtain a workpiece with the required precision.

In particular, when machining workpieces that require extremely high precision specifications on the surface, a worn bit will not be able to change the surface specifications to the required precision, which poses a major problem.

Also, in that case, it is necessary to convert it to a new byte.

The present invention has been made by focusing on the above-mentioned problems of conventional cutting tools, and provides a diamond cutting tool that enables consistently high-precision machining over a long period of time by minimizing wear on the cutting edge of the cutting tool. The purpose is to

In order to achieve the above object, in the present invention, the crystal orientation of the front edge surface forming a part of the cutting edge is set to the (1 1 0) plane and the (1 1 0) plane.
100) plane, or approximately in the middle of the plane.

Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 shows an example of cutting a disk material (for example, a magnetic disk AI material) using a diamond cutting tool.

A material (workpiece) 1 is attached to a lathe chuck 2 and rotates at a rotational speed of about 1500 rpm, and a diamond cutting tool 3 normally travels from the inner circumference toward the outer circumference to perform machining.

In this case, the cutting edge of the cutting tool usually consists of a side nib surface 7, a front nib surface 6, and a squimen 503 surface, as shown in FIG. 2, and the intersection of these three surfaces becomes the so-called cutting point 4.

In machining with a diamond tool, a good cutting surface that is close to a mirror surface can be achieved by first cutting on the horizontal double-edge surface, and then vanishing the traces on the front double-edge surface.
This is thought to be caused by the processing mechanism of going L.

Therefore, from this, the conditions for the long-life tool cutting edge to stably perform high-precision machining are (1) less wear on the lateral grooved surface (to maintain good cutting quality), and (2) the front grooved surface It can be seen that it is necessary to meet two conditions: moderate wear (to have a moderate burnishing effect).

Therefore, when examining the wear condition of each surface that forms the cutting point 4 as shown in Figure 3 a, b, and c, the amount of wear on each surface is generally the same as that of the front nipped surface shown in Figure C. 6 wear surface 8
is the thickest 《, the worn surface 9 of the horizontal nipped surface 7 shown in Figure b
It was found that the wear surface 10 of the rake surface 5 becomes smaller in the order shown in FIG.

Further, according to the results of analyzing the worn surface 8 of the front nib surface 6, which has the largest amount of wear, by X-ray diffraction, it was found that this worn surface 8 is approximately a (110) crystal plane.

From this, it is understood that diamond wears well along the (110) crystal plane.

Therefore, it can be seen that the amount of wear on the wear surface 8 can be controlled by setting the position of the (110) plane in an appropriate direction.

From this point of view, the present inventors conducted further experiments and found that a configuration in which the front nip surface 6 is located between or approximately in the middle between the (110) plane and the (100) plane allows the wear surface 8 of the front nip surface 6 to have an appropriate size. As a result, it has been found that the burnishing action is moderately effective, which satisfies the second condition for a long-life cutting tool mentioned above.

Moreover, by making the front nib plane 6 have the above-mentioned crystal orientation, the crystal orientation of the lateral nib face 7 also becomes an intermediate crystal plane determined by the cross-cutting angle η shown in FIG. It has been found that the wear surface 9 of the surface 7 can also satisfy the first condition for a long-life cutting tool, which is to reduce wear and maintain good cutting ability.

FIG. 4 shows 20
Aluminum alloy (J
This is an example of the results of investigating the relationship between the cutting tool life and the crystal orientation of the front edge surface when cutting a magnetic disk substrate made of IS A5086).

Note that the cutting conditions at this time are as follows.

Disc substrate inner diameter: 168 mm Outer diameter: 356 mm Rotation speed: 800 to 200 O r.
p, m Depth of cut of cutting tool: 15-25μm Feeding speed of tooling tool: 30-70μm/rotation cutting speed: 7
~18m/sec (board inner edge) 15~37m/sec
(Outer Edge of Substrate) That is, cutting was performed by moving the cutting tool from the inner edge of the disk substrate toward the outer edge while keeping the rotational speed of the disk substrate constant.

In Fig. 4, the vertical axis indicates the life of the cutting tool (whether a single cutting tool was able to process a number of disk substrates with the specified accuracy), and the horizontal axis shows the front edge crystal orientation of each cutting tool (that is, the 3rd
The inclination angle θ) from the front overhang surface to the (110) plane position as shown in FIG. b is shown.

Note that each measurement point in FIG. 4 is a plot of the average value of tool life when the same tool tool is processed five times before and after the same tool is re-ground.

In Fig. 4, the cutting tool whose crystal orientation θ is O (degrees) indicates that the front cutting surface coincides with the (110) plane, and the tool life in this case is extremely short, at most 3~ Only four disk substrates can be processed with a certain precision.

In addition, the bite whose crystal orientation θ is 45 (degrees) indicates that the front edge plane coincides with the (100) plane.
In this case as well, only about 10 substrates can be processed at most.

On the other hand, the (110) and (10) crystal orientations are
0) face, all of the tools selected have longer lifespans than the first two, and in particular, the tool with the front nipped face tilted 22.5 degrees from the (110) face, that is, the front A cutting tool whose warped surface is exactly halfway between the (110) and (100) surfaces has an extremely long life.

For processing mass-produced products such as disk substrates, it is desirable for the cutting tool life to be on average 80 to 90 pieces/piece or more from the point of view of practicality. ) plane and (100) plane, approximately 22.5±10 (degrees) is appropriate.

On the other hand, the above θ is small (in this case, the cutting tool is
becomes approximately (110).

) The bite or θ is large (in this case, the bite has a front nip surface 6 of approximately (100).

) Both bites have a short lifespan.

The reason for this is that one or two of the long-life tool conditions cannot be satisfied due to increased wear on the worn surface 8 and increased wear on the worn surface 9.

Although the above explanation has been given using the case of machining an aluminum alloy disk substrate as an example, the present invention can also be applied to machining of other soft nonferrous metal materials (e.g., aluminum, copper, copper alloy) and plastic materials. Although there was some variation in the absolute value of the tool life depending on the material, cutting conditions, etc., the relative trend of the tool life was exactly the same as in the case of FIG. 4.

As described above, according to the cutting tool of the present invention, extremely high precision machining can be continued for a long period of time, and cutting that requires extremely high quality surface specifications such as magnetic disks and optical disks. It is extremely effective when applied to processing.

[Brief explanation of the drawing]

Figure 1 shows an example of cutting a disc material using a diamond cutting tool, Figure 2 shows the cutting edge of the cutting tool, and Figure 3 shows the state of wear on each surface that forms the cutting point. FIG. 4 is a characteristic diagram showing the effects of the present invention. In the figure, 3...diamond bite, 4...
...cutting point, 5 ... rake surface, 6 ...
...Front side, 7... Lateral side.

Claims (1)

[Claims] 1. The crystal orientation of the front nigration surface that forms part of the cutting edge is (1
10) A diamond tool characterized by being constructed as if it were between a plane and an (ioo) plane. 2. The diamond tool according to claim 1, wherein the crystal orientation is located between the (110) plane and the (ioo) plane.