JPH06190610A - Diamond tool - Google Patents

Abstract

PURPOSE:To obtain an even finished surface close to mirror finish by forming a flank in a cutting blade of a tip with a polished face without polished mark and by smoothing this cutting blade ridge with chamfering in a tool in which a tip made of a polycrystal diamond is held by a shank. CONSTITUTION:A tip 1 made of a polycrystal diamond is held at the tip end of a shank 3 in the state bonded to an insert 2. The tip 1 is provided with a main cutting blade 5 inclined toward a work 4 by a required angle and an auxiliary cutting blade 6 opposed to the surface of the work 4 by a slight inclination angle alpha, and a required clearance angle beta is formed on a flank 7. In this case, the tip 1 is formed by polishing the flank 7 in the state held by the shank 3 so that no polished mark remains after the cutting face 8 is polished. After than, chamfering 10 is executed by a micro width t (mum) on a cutting blade ridge 11 of the tip 1. The micro width t is set more than twice of the average grain diameter of a diamond crystal and within the range of 1 to 20mum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diamond tool using polycrystalline diamond.

[0002]

2. Description of the Related Art In precision machining of mechanical parts and the like, there is a case where a machined surface having fine irregularities is required without requiring surface roughness up to a mirror surface. For example,
In order to improve the adhesion of the photoconductor layer, a part of the substrate of the electrophotographic photoconductor requires an uneven surface having a surface roughness of 0.2 μm to 1 μm, which is rougher than the mirror surface. .

Conventionally, a tool using single crystal diamond such as natural diamond has been used as a tool for processing a highly accurate finished surface such as a mirror surface.

However, the tool using this single crystal diamond is extremely expensive, and the cutting edge is sharp and the cutting performance is very good. It is regularly transferred to the work piece along with the feed pitch, and since the pitch of the irregularities is rough, the adhesion of the photoreceptor layer is deteriorated.

On the other hand, a tool using polycrystalline diamond for the cutting edge tip can be formed at a relatively low cost compared to single crystal diamond, but since the tip is composed of many diamond crystals, There are large irregularities on the cutting edge from the beginning due to the steps of the crystal interface and the falling of crystals, so when the workpiece is machined, the finished surface roughness varies widely from tool to tool and the surface roughness is 1 μm or less. There is a problem that can not be obtained stably.

Further, even in the case of a polycrystalline diamond tool, when the machining is repeated, the roughness of the cutting edge becomes small due to the wear of the cutting edge, and the machined surface roughness may be improved. Since the surface roughness fluctuates until the temperature becomes stable, the processing performance is not stable, and the workpiece until the surface roughness becomes stable is disadvantageous.

On the other hand, as a method for treating a cutting edge of a diamond tool for obtaining a good finished surface, there is a conventional Japanese Patent Publication No. 3-75.
Japanese Patent No. 282 proposes a method of polishing a flank of a diamond tip to a state without polishing marks, and then polishing a rake surface to finish a cutting edge.

However, the above method is effective for a single crystal diamond tip capable of forming a sharp cutting edge by polishing, but a large unevenness is formed on the cutting edge due to a step at the crystal interface like a polycrystalline diamond tip. In the case of a chip having a groove, even if the flank face and the rake face are polished, large irregularities remain on the cutting edge, and good finishing roughness cannot be obtained.

Therefore, an object of the present invention is to provide a diamond tool which can stably obtain a finished surface having a surface roughness of 0.2 to 1 μm by using low-cost polycrystalline diamond.

[0010]

In order to achieve the above object, the present invention is a diamond tool in which a diamond tip made of polycrystalline diamond is held on a shank, and the flank of the cutting edge of the diamond tip has no polishing marks. It was formed on a polished surface, and the cutting edge was chamfered with a minute width by polishing to smooth the cutting edge.

Further, the present invention has the above structure,
The width of the chamfer is at least twice the average grain size of the diamond crystals forming the diamond tip, and 1 to 20 μm.
The configuration set in the range of m is adopted.

[0012]

In the above structure, the relief surface is a surface having no polishing marks to reduce the microwaviness of the cutting edge, and the chamfering of the cutting edge is then performed to make the cutting edge large. Remove irregularities. In this state, the step of the crystal interface peculiar to polycrystalline diamond and the large unevenness due to the falling of the crystal are removed at the cutting edge, and a finished surface having a uniform surface roughness can be obtained from the beginning of the processing.

In the above structure, in order to obtain a surface roughness of about 0.2 to 1 μm, the unevenness of the cutting edge after chamfering should be 0.
It is preferable to set it in the range of 1 to 0.6 μm. Further, by making the chamfering width twice or more the average grain size of the diamond crystals, it is possible to remove the irregularities due to the falling of the diamond grains.

[0014]

1 and 2 show a diamond tool according to an embodiment. In the figure, reference numeral 1 is a diamond tip made of polycrystalline diamond. The diamond tip 1 is bonded to an insert 2 of cemented carbide or the like, and the insert 2 is fixedly held to the tip of a shank 3.

As shown in FIG. 1, the diamond tip 1 has a main cutting edge 5 which is inclined at a required angle with respect to a workpiece 4.
And a sub cutting edge 6 facing the surface of the workpiece 4 at a slight inclination angle α, and a required clearance angle β is formed on the clearance surface 7 as shown in FIG. In addition, the above insert 2
Instead of the method of joining the diamond tip 1 using, the pressing metal fitting may be attached to the shank 3, and the diamond tip may be detachably attached to the shank via the pressing metal fitting.

3 and 4 show a portion of the diamond tip 1 near the cutting edge. The diamond tip 1 is formed by polishing the rake face 8 in advance and then polishing the flank face 7 while holding it on the shank 3 so that no polishing marks remain. This polishing is performed, for example, with grain size # 8.
This is performed by pressing a grinding wheel of No. 00 on the flank and grinding while feeding in a direction different from the polishing direction.

With the flank 7 thus polished,
Although the micro waviness of the cutting edge in the flank is considerably suppressed, microscopically, due to the bonding structure of the diamond crystals forming the diamond tip 1, the cutting edge has a diamond crystal 9 as shown in FIG. Large irregularities are present due to steps on the crystal interface.

Therefore, next, the cutting edge of the diamond tip 1 is brought into contact with a grinding wheel with a grain size of # 1500, and the average grain size of the diamond crystals 9 is twice or more, and 1 to 2
The chamfering 10 is performed with a minute width t in the range of 0 μm. By carrying out this chamfering 10, the cutting edge of the chip 1 has the unevenness due to the falling of each diamond particle coming in and out as shown by the diagonal lines in FIG.
At the boundary portion a between the flank 7 and the flank 7, a smooth cutting edge 11 having no waviness or unevenness is formed.

Such a cutting edge 11 is smooth as a whole, and since the surface thereof has minute irregularities composed of boundaries of many diamond crystals, when it is processed, it does not reach a mirror surface. A close surface roughness can be obtained, and a uniform finished surface can be stably formed from the beginning of processing.

The width t of the chamfer 10 is usually set in the range of 1 to 20 μm, preferably 5 to 10 μm or less, from the viewpoint of tool life.

Further, the length L of the chamfer 10 is set within a range in which the finished surface roughness is influenced by the auxiliary cutting edge 6 of the diamond tip 1 and cutting conditions, for example, 0.1 mm / rev.
If the feed speed is about the same, the chamfer length L is 1.5 m
Set to about m.

Since the width and length of the chamfer 10 are extremely small as described above, the chamfer 10 does not become an accurate linear surface in the polishing process in which the grinding wheel is brought into contact with the cutting edge of the chip for a short time. As shown in FIG. 6, the straight surface 12 and the curved surface 1
3 becomes a combined shape. That is, the chamfer 10 mentioned here includes a chamfer formed only by a straight surface and a curved surface, and a chamfer formed by combining a straight surface and a curved surface.

The degree of unevenness of the cutting edge 11 formed by polishing the flank 7 and chamfering 10 is preferably about half the finished surface roughness to be obtained. For example, to obtain a surface roughness of 0.2 μm to 1 μm,
The unevenness of the cutting edge 11 is preferably set in the range of 0.1 μm to 0.6 μm.

<Experimental Example> In order to see the effect of the present invention, a cutting comparison test was conducted between the diamond tool of the example and the conventional product.

The product A of the present invention used for the cutting test uses a diamond tip having an average grain size of diamond crystals of about 0.5 μm. In the structure shown in FIGS. 3 and 4, the inclination angle α of the auxiliary cutting edge 6 is The clearance angle β was formed to be 1 to 3 ° and 20 °. In the chamfer 10, the width t was 5 μm, the length L was 1.5 mm, the angle γ was 45 °, and the unevenness of the cutting edge 11 was formed in the range of 0.1 μm to 0.6 μm.

On the other hand, three types of conventional products (B,
C, D) are prepared, diamond tips each made of polycrystalline diamond having the same average grain size as the product A of the present invention are used, and flanks and rake surfaces of the tips are ground to form cutting edges, Except for the chamfer 10, the cutting edge shape was the same.

The workpiece used for the cutting test was a drum for an electrophotographic photosensitive member (diameter φ80 mm, thickness 1.2 mm, total length 35).
5 mm) and the material was aluminum alloy AL5000 series for the photosensitive drum substrate.

The cutting conditions are as follows: rotation speed 3000 rp
m, feed rate 0.1 mm / rev, and depth of cut 0.01 mm.

FIG. 7 shows changes in the finished surface roughness of the product A of the present invention in the cutting test, and FIG. 8 shows the conventional products (B, C, D).
The test result in is shown.

As shown in FIG. 8, the conventional product B has a large variation in the finished surface roughness from the beginning to the end of processing, and the conventional products (C and D) have stable surface roughness around a processing distance of 200 km. The work up to that point was wasted, and the productivity was reduced.

On the other hand, as shown in FIG. 7, the product A of the present invention has a value of 0.
It was possible to obtain a stable finished surface roughness of 4 μm to 0.5 μm and perform highly accurate cutting.

[0032]

As described above, according to the present invention, the tip made of polycrystalline diamond is ground on the flank and the cutting edge is chamfered to obtain a smooth cutting edge. A finished surface having a surface roughness can be stably obtained. Therefore, the conventional break-in process is not required, and the surface process with a desired surface roughness can be performed by using the low-priced multi-bond diamond tip, and the cost reduction and the productivity improvement can be realized. There is.

[Brief description of drawings]

FIG. 1 is a plan view showing a diamond tool of an embodiment.

FIG. 2 is a side view of the above.

FIG. 3 is an enlarged plan view showing the vicinity of a cutting edge of a diamond tip.

4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a diagram schematically showing a crystal structure of a cutting edge of the same as above.

FIG. 6 is an enlarged cross-sectional view showing a chamfer of the above cutting edge.

FIG. 7 is a graph showing changes in finished surface roughness of the product of the present invention in a cutting test.

FIG. 8 is a graph showing changes in finished surface roughness in the conventional product as above.

[Explanation of symbols] 1 Diamond tip 3 Shank 5 Main cutting edge 6 Secondary cutting edge 7 Flank surface 8 Rake surface 10 Chamfering 11 Cutting edge

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masao Hashi, 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica Co., Ltd. Hachioji Business Office (72) Inventor Toyoji, 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica Co., Ltd. Hachioji In-house (72) Inventor Takami Hashimoto 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica Co., Ltd. Hachioji In-plant (72) Inventor Kazushi Kobata, Hoboku-cho, Sakai-shi Osaka Diamond Industry Co., Ltd. (72) Inventor Hideo Maeda 2-80 Hotori-cho, Sakai City Osaka Diamond Industrial Co., Ltd.

Claims (2)

[Claims] 1. A diamond tool in which a diamond tip made of polycrystalline diamond is held on a shank, a flank of a cutting edge of the diamond tip is formed by a polishing surface having no polishing mark, and the cutting edge is finely ground by polishing. A diamond tool characterized by smoothing the cutting edge by chamfering the width. 2. The width of the chamfer is not less than twice the average grain size of diamond crystals forming a diamond tip,
The diamond tool according to claim 1, wherein the diamond tool is set in a range of 1 to 20 μm.