JPH02152704A - Industrial diamond tip and cutting tool therewith - Google Patents

Abstract

PURPOSE:To make low-unit cost of production achievable by chamfering a ridgeline of diamond octahedral monocrystal into an orthogonal surface to a surface inclusive of this ridgeline and the monocrystal center at lease in the vicinity of a corner part, and constituting a cutting edge with this chamfer and its crossed intersection. CONSTITUTION:A ridgeline 2 of a diamond octahedral monocrystal 1 is chamfered into orthogonal surfaces ({110} surface) 3, 3, 3, 3 to a surface inclusive of this ridgeline and the monocrystal center 0, and a cutting edge is constituted of these chamfered surfaces 3, 3, 3, 3 and an intersection 4 of the chamfered surface 3. In this connection, chamfering of the ridgeline 2 is good enough only in the vicinity of at least a corner part, not performed over the whole ridgeline as shown in illustration. With this constitution, it comes to a crystal orientation equal in the case where a dodecahedral crystal corner part is set to the cutting edge, whereby a lip angle and a rake face also come to the same way, and since they are formed by means of machining, a sharp cutting edge part is securable. In addition, polishing after the said chamfering is also very easy as compared with the case of polishing a flat surface.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a diamond tip for tools using a natural diamond single crystal, and a cutting tool using the diamond tip.

[Technical background]

Diamond single crystals have the highest hardness of all existing substances and have the best properties for use as tools, but they are extremely susceptible to impact and also have defect characteristics unique to crystals, such as cleavage. Furthermore, it is known that even in the same crystal, the polishing properties and strength properties vary greatly depending on the crystal plane, and even on the same crystal plane, depending on the crystal orientation. FIG. 7 schematically shows the differences in the difficulty of polishing in diamond crystals, and the ease of polishing for each crystal face is expressed by numerical value. In the figure, solid arrows indicate directions for easy polishing, and dashed arrows indicate directions for difficult polishing, and it can be seen that there is a large lag in polishing characteristics depending on the direction even on the same crystal plane.

In order to obtain a diamond tool that achieves high cutting performance and stable long life by using diamond single crystal, which has unique properties for each crystal face and direction, it is necessary to In addition to having a strong cutting edge shape, it is necessary to design a cutting edge that properly utilizes the characteristics of crystal planes and crystal orientation in the shape of the cutting edge.

[Problem to be solved by the invention]

BACKGROUND OF THE INVENTION Conventionally, diamond cutting tools used for processing ceramics, etc., have a diamond single crystal tip attached to the tip of a holder by brazing or the like, and the tip is polished to form a cutting edge.

However, with this structure, the cutting edge is formed without taking into account the crystal plane or crystal direction of the raw crystal, so the drawback is that cutting performance varies greatly depending on the crystal plane or crystal direction that forms the cutting edge. was there. In addition, the conventional cutting edge described above has a wedge angle of approximately 90°, but when cutting brittle materials such as ceramics, the cutting force fluctuates sharply, so the cutting edge strength is reduced at the above wedge angle. This has the disadvantage that the blade tends to chip or chip in the middle of cutting, and stable cutting life cannot be obtained over a long period of time.

In order to address these drawbacks of conventional tools, a method has been proposed in which dodecahedral or octahedral crystals of natural diamond are used as tool tips in an unprocessed state. this is,
The corners of a rough diamond crystal are used in their natural state as the cutting edge of a cutting tool, and after each corner is used, they are replaced with the next new rough crystal, and the single crystal is attached to the tool holder as is. .

In the above structure, when a dodecahedral single crystal is used, since the crystal planes at the corners of the crystal intersect at an obtuse angle, there is an advantage that a large wedge angle can be obtained when used as a cutting edge. For example, as shown in Figure 8, four crystal planes ((10
01 side) Corner part 1 where 11.11.11.11 intersect
2 at the tip of the cutting edge and the cutting direction is in the <110> direction, a large cutting edge strength can be obtained.

However, normal natural diamond dodecahedral crystals are
There are very few that have a geometrically accurate shape,
In particular, the corners are often chipped or rounded and do not have a clear corner shape. For this reason, the reality is that it is extremely difficult to obtain sharp cutting edges by using the corner portions of raw crystals as they are. Therefore, when attempting to form a sharp corner portion by polishing, it is necessary to perform surface grinding on all four crystal planes forming the corner portion, but such surface grinding has the disadvantage of increasing processing cost.

On the other hand, natural octahedral crystals have the advantage that the shape of the rough stone is clear and it is easy to obtain sharp corners, but the wedge angles at the corners are smaller than that of natural dodecahedral crystals, so they wear out easily. The disadvantage is that the speed is fast and the lifespan is short.

[Purpose of the invention]

This invention focuses on the characteristics of an octahedral crystal that has a clear shape and is easy to obtain sharp corners, and by applying simple processing to this octahedral crystal, it is possible to cut corners corresponding to the sharp corners of a dodecahedral crystal. A first object of the present invention is to provide a diamond tip for a tool with a cutting edge.

A second object is to provide a long-life cutting tool that uses the above-mentioned diamond tip and takes advantage of the crystal properties of the cutting edge.

[Means for Achieving the Object] In order to achieve the above-mentioned first object, the present invention, as shown in FIGS. A plane (+1101 plane) 3.3.3.3 perpendicular to the plane containing the single crystal center O is chamfered, and this chamfered surface 3.3.3.3 and the chamfered surface 3
A cutting edge is formed by the intersection point 4.

In addition, ridge 8ji! The chamfer No. 2 may not be applied to the entire ridge line as shown in the figure, but may be applied only to at least the vicinity of the corner portion used as a cutting edge.

As can be seen by comparing FIG. 1 and FIG. 8, the chamfered surfaces 3.3.3.3 as described above are the 4
This is the same crystal plane as the pawl crystal plane ((1101 plane) 11.11.11.11. That is, this chamfered plane 3.3.
3. If the intersection 4 of 3 and its chamfered surface is the cutting edge, then the 8th
The crystal orientation is the same as when the corner portion of the dodecahedral crystal shown in the figure is used as the cutting edge, and the wedge angle and rake face are also similar to those of the dodecahedral crystal, and high cutting edge strength can be obtained.

In addition, in the above case, since the intersection 4 of the chamfered surfaces 3, which will be the apex of the cutting edge, is formed by machining, a sharp cutting edge can be obtained, which is much sharper than when using the corner part unmachined. has the advantage of excellent cutting performance.

In addition, the chamfering process described above involves cutting off the ridgeline to form a flat surface. Therefore, the polishing process is much easier than polishing a flat surface, so there is an advantage that it can be formed at low cost.

The diamond tip 1 can utilize all six corners of the octahedral crystal as a cutting edge, so it is much more economical than the conventional structure of one rough stone and one cutting edge. When all six corners are worn out, replace the tip with a new one.

Also, worn ones should be re-polished before use.

On the other hand, in order to achieve the second object, the present invention attaches the diamond tip 1 to the tip of the holder 5, as shown in FIG.
3.3.3 is installed in the direction of the workpiece S so that it is placed at an equal angle to the finished surface of the workpiece S, and the <110> crystal direction is directed in the cutting direction. It is.

This content will be explained below.

Normally, when diamond crystal is used as a tool tip, there are three main components (1001flol) on the rake face.
Of fllll, mainly from the point of view of workability (100
Either one of two crystal planes, 1 plane or (110+ plane), is used. The present inventors compared the polishing difficulty level of both crystal planes and obtained the results shown in FIG.

That is, FIGS. 5(a) and 5(b) respectively show crystal planes (
1101 and (100) show the amount of polishing obtained by changing the polishing direction, and the figure shows the crystal plane (
1101 has a larger polishing amount than (100), and
(a) (b) Both are easy to polish in the <100> direction, <1
It is shown that polishing is difficult in the 10> direction.

In addition, as shown in FIG. 5(b), crystal iTi'1 (10
On 01, the amount of polishing is relatively large in the <100> direction,
There is very little in the <110> direction, indicating that polishing is extremely difficult in the <110> direction.

Crystal planes exhibiting such difficult-to-abrasive characteristics show that the amount of abrasion is small when they come into contact with a polishing disk, and it is naturally assumed that the amount of wear during cutting is also small. Therefore, the present inventors have discovered that it is possible to form a tool with high wear resistance by selecting a crystal plane and a crystal direction that are difficult to grind due to their small grinding [t] and match those of the tool where wear is likely to occur during cutting. I thought. In other words, the crystal plane with high wear resistance ((1
10) The fio01 plane (not the fio01 plane) is the plane where tool wear occurs, and the crystal direction with high wear resistance (<10
The <110> direction, not the 0> direction, was made to coincide with the cutting direction (finished surface creation direction).

In the chip 1 shown in FIG. 1, the (100) plane includes the intersection 4 of the chamfered surfaces 3.3.3.3.
3.3.3 is an equiangular plane, and in that plane <
The 110> direction is the direction shown on the A line. In the cutting tool of this invention, the diamond tip 1 has the above (100)
It is formed by attaching it to the tip of the holder 5 with the surface positioned in a direction parallel to the finished surface of the workpiece 9 and the A line facing the cutting direction.

In this state, as shown in FIG. 4, the rake angle α of the cutting blade is -60°, the clearance angle β is 30°, and a cutting edge with a wedge angle C in the cutting direction of 120'' is obtained.

Note that FIG. 6 shows an example of a clamp device for fixing a diamond chip to a holder. In this clamp device, a diamond tip 1 is inserted between a holder 5 made of steel and a clamp plate 6 through a base 8.8.
A load is applied to the metal plate 6 from above in advance to cause the base 8.8 around the chip 1 to undergo plastic deformation along the shape of the chip 1, and then the metal plate 6 is tightened with the bolt 7. A diamond chip 1 is fixed to a holder 5.

In the above structure, the base 8 functions to accurately position the diamond tip 1 at the above position.

(Effects of the Invention) As explained above, the present invention creates a 7-corner cutting edge of a dodecahedron by chamfering the ridgeline of an octahedral crystal that is easy to obtain in a regular shape. A stable cutting edge shape can be obtained, and a diamond tip having a long life and stable cutting performance can be provided.

In addition, by aligning the corners and cutting direction of the diamond thousand knobs with the male polishing direction of the crystal, it is possible to provide the cutting edge with high wear resistance, resulting in a cutting tool with an extremely long cutting edge life. can do.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a diamond tip according to the present invention, Fig. 2 is a cross-sectional view of the main part of the same, Fig. 3 is a view showing a cutting tool according to the invention, and Fig. 4 shows the cutting edge portion of the same. Figures 5(a) and 5(b) are diagrams showing the polishing characteristics of crystal planes (1101 and (1001), respectively. Figure 6 is a side sectional view showing an example of a clamping device. Figure 7 is a diagram showing the polishing characteristics of diamond crystal planes. Fig. 8 is a diagram schematically showing the polishing characteristics, and is a perspective view showing a dodecahedral crystal. 1...Diamond tip, 2...Ridge line, 4...... Intersection, 9... Work material.

Claims (2)

[Claims] (1) Chamfer the ridgeline of a natural diamond octahedral single crystal to a plane perpendicular to the plane containing the ridgeline and the center of the single crystal, at least near the corner, and cut at the intersection where the chamfered surface and the chamfered surface intersect. A diamond tip for tools that consists of a blade. (2) The diamond tip according to claim (1) is oriented toward the workpiece so that the intersections of its chamfered surfaces are arranged at equal angles to the finished surface of the workpiece, and <1
10> A cutting tool using a diamond tip attached to a holder with the crystal direction facing the cutting direction.