JPS62162403A - Diamond cutting tool - Google Patents

Abstract

PURPOSE:To enhance the yield of a diamond cutting tool whose crystal orientation is selected in its tip section to prolong the life thereof, by setting the rake face of the cutting tool to be inclined from the (110) plane to the (111) plane at a specified angle. CONSTITUTION:In a diamond cutting too, the rake face Ra is inclined at an angle of 10+ or -5 deg. or 5-15 deg. with respect to the (110) plane B so that the (111) plane C which is inclined crystallographically at an angle of about 35 deg. with respect to the (110) plane B, is inclined at an angle alpha with respect to the rake face Ra. The angle alpha is 20-30 deg.. further, the (1-1-1) plane D having a risk of cleavage in relation to cutting, simultaneously with the (111) plane C, the (1-1-1) plane D is inclined crystallographically at about 70 deg. with respect to the (111) plane C so that the inclined angle of the (1-1-1) plane D with respect to the rake face Ra is 130-140 deg.. Further, reference numeral Re in the figure denotes a flank.

Description

[Detailed description of the invention] [Industrial usage Wf]

This invention provides disks etc. made of non-ferrous metal materials such as At and Cu, or non-metal materials such as Bunastick.
This article relates to a diamond cutting tool used for high-precision cutting.

[Prior art]

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 less surface roughness. This results in a good machined surface. However, no matter how hard diamond is, it will gradually wear out if used for a long time. The surface roughness of the cut surface caused by a worn cutting tool decreases,
This results in increased surface waviness, making it impossible to obtain workpieces with the required accuracy. In particular, when machining workpieces that require extremely high precision specifications on the surface, a worn tool bit cannot provide the desired surface specifications with the required precision, which poses a major problem. Also, in that case, it is necessary to convert it to a new byte. Regarding the above-mentioned diamond cutting tools, a prior art technique for prolonging the tool life by focusing on how to set the crystal orientation of the cutting edge was disclosed in Japanese Patent Publication No. 58-37082.
Known as the invention of

[Problems to be solved by the invention]

By the way, in the invention of the above-mentioned Japanese Patent Publication No. 58-37082,
The crystal orientation of the front flank that forms part of the cutting edge is (110)
No. 6 is constructed so that it is located between or approximately in the middle between the (100) plane and the (100) plane. Therefore, the inventor of the present application tested the lifespan of a large number of diamond cutting tools with crystal orientations set as described above, but the results showed considerable variation due to individual differences. According to an investigation into the cause, it was predicted that the (111) plane, which is a cleavage plane, and the crystal orientation of the (111) plane are greatly involved in the life span. In other words, for the front flank, (100) and (110)
If the crystal orientation is defined only in relation to the plane, it will be difficult to provide cutting tools with a specified lifespan with a high yield.
For example, in the part of the cutting edge involved in cutting, the angle (111
) or (III) planes, the diamond is likely to cleave due to cutting resistance, causing chipping and wear on the cutting edge, making it impossible to achieve a sufficiently long life. This invention has been devised in view of the above-mentioned problems and to effectively solve them. Therefore, an object of the present invention is to provide a diamond cutting tool in which the crystal orientation of the cutting edge portion is selected in order to extend the life of the cutting tool, and the yield can be made as high as possible.

[Means to solve the problem]

In the diamond cutting tool according to the present invention, the crystal orientation of the front flank surface forming a part of the cutting edge is the (110) plane and the (100) plane.
) plane, and the rake face is set to be a plane inclined by IO°±5° from the (110) plane toward the (III) plane.

[Action/effect]

Generally, the normal intersection angle between the rake face and the flank face, that is, the normal cutting edge angle, is formed to be an acute angle that is close to a right angle. Therefore, the usual rake angle is about 2 degrees, which can be approximated to 0 degrees and described below. Therefore, when the direction of action of the cutting force acting on the cutting edge is determined from the ratio of the principal force and the thrust force, it is generally required that the force acts at an angle of about 38° to 50° with respect to the rake face. From this,
The cleavage plane of the crystal is approximately 38° to 50° to the rake plane.
It can be seen that cleavage is more likely to occur if they intersect at or at an angle close to that. Figure 1 shows (100) plane A and (110) plane of a diamond cutting tool according to the present invention when the rake angle is 0°.
of surface B, as well as (III) and C and (
111) is an explanatory diagram schematically showing the inclination angles α and β of each crystal orientation of the face with respect to the rake plane. As shown in the figure, according to the diamond cutting tool of the present invention, the rake face Ra is 10°±5°, that is, 5° with respect to the (110) plane B.
The (111) plane C, which is tilted by approximately 35 degrees crystallographically with respect to the (110) plane B, is tilted by an angle α with respect to the rake surface Ra. and,
The inclination angle α is expressed as α=35°−(lO°±5°), which is 20@~30°. In addition, regarding the (l l 1) face that is involved in cutting at the same time as the (111) face C and has the risk of cleavage, (111)
) The plane is crystallographically approximately 70° with respect to the (111) plane C.
Since it is inclined, the inclination angle β of the (Ill) face with respect to the rake surface Ra is β=180°−70°+α = 1! It is expressed as θ° + [35° - (10' ±5°)], which is 130° to 140°. Note that Re in the figure indicates a flank surface. In this way, the direction of the cutting force F acting on the part of the cutting edge involved in cutting is greatly tilted with respect to the direction of the (111) plane C and the (I l l) plane, which are the cleavage planes, so that the cleavage The probability of this occurring is greatly reduced. As is clear from the above explanation, according to the diamond cutting tool of the present invention, the yield can be made as high as possible in the diamond tooling tool in which the crystal orientation of the cutting edge is selected in order to extend the tool life.

【Example】

Diamond cutting tools with various crystal orientations are made to cut aluminum alloy (AI-Mg type), and the lifespan is defined as the number of processes until a surface roughness of 0.05 μmRmax or less is obtained. A lifespan test was conducted on the diamond bite. The cutting conditions at that time were: rotation speed: 2400 rpm, feed: 0, 0.2 mm/
rev, depth of cut -10 μm, cutting fluid: molten oil, workpiece: 3.5 inch disc (aluminum alloy). According to the test results shown in Figure 2, the rake face was (work 10)
The longest life was obtained when the surface was tilted by about 10° from the plane toward the (111) plane. Note that each point in this data is expressed as the arithmetic average of 10 or more results of repeated life tests for one byte. Therefore, even if we take into account that diamond lifespan variations are influenced by defects in the diamond itself in addition to crystal orientation, this data is highly accurate and reliable because lifespans are repeatedly confirmed. .

[Brief explanation of drawings]

Figure 1 shows a (100) diamond cutting tool according to the present invention.
Explanatory diagram schematically showing the inclination angle with respect to the rake plane of each crystal orientation of plane A and (110) plane B, as well as (I I I) plane C and (111) plane that are likely to cleave, 2nd The figure is a graph showing the life test results of a diamond cutting tool, including data of an example according to the present invention. A...(100) side, B...(+10) side, C...
(111) plane, D... (l l 1) plane, F... cutting resistance, Ra... rake surface, Re... flank surface, α...
・Inclination angle of the (111) plane to the rake face, β...(
111) Angle of inclination of face with respect to rake face Patent applicant: Kobe Steel, Ltd. (and 1 other person) Representative patent attorney: Seihaku Bo (and 2 others)

Claims (1)

[Claims] (1) The crystal orientation of the front flank that forms part of the cutting edge is (
In a diamond cutting tool set between the (110) plane and the (100) plane, the rake face is 10
A diamond cutting tool characterized by being set on a surface inclined at ±5°.