JPH0760509A - Tip for cutting tool coated with ultra-hard film and manufacture thereof - Google Patents

Abstract

PURPOSE:To manufacture a high-quality tip easily at a low cost for a tip for a cutting tool coated with ultra-hard film such as diamond film by polishing only part of a rake face directly composing a cutting edge in the ultra-hard film. CONSTITUTION:A corner part 5 directly composing a cutting edge except for a center part 3 in a rake face of a base material is set high, and only ultra-hard film on the corner part 5 is finished to be smoother than surface roughness when the film is produced for forming a tip for a cutting tool. For this tip, a surface of the base material is processed with more than one sorts of elements of groups Ia, III, IVb, Vb preliminarily, it is then coated with the ultra-hard film in a vapor phase synthesis method, and only the ultra-hard film on the high corner part is polished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is for a super hard film-coated cutting tool used for processing metals such as aluminum alloys, cermets, ceramics, structural materials such as plastic composite materials, mechanical parts, optical parts and electronic parts. The present invention relates to a chip and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, many cutting tools have been proposed in which a diamond film is attached to the surface of various base materials, and a throwaway tip having a diamond film formed on the surface of cemented carbide is also known.

[0003]

However, in this throwaway tip, the diamond formation film thickness is 3 or less.
~ 5μm, its surface roughness is 1-3μm Rmax and smooth,
Since the roundness of the cutting edge is also slightly developed, it is generally used as the cutting edge. In addition, if the cutting edge surface is to be polished, the entire surface will be polished, which requires time and effort, and uniform finishing is difficult. On the other hand, the conventional diamond film has a low adhesion strength to the cemented carbide as the base material, and there is a fundamental problem that it is difficult to obtain a thickness and an adhesion strength that can be polished in practice.

[0004]

[Means for Solving the Problems] In solving the problems of adhesion strength between a diamond film and a cemented carbide and the surface polishing of a diamond film, the inventors of the present invention stopped the polishing finish at a necessary minimum portion, The test was repeated focusing on two points of increasing the adhesion strength of the film by applying a treatment in advance.

As a result, the central part 3 of the rake face of the substrate shown in FIG. 1 which is not directly involved in the construction of the cutting edge is sandblasted except for the corner part 5 to provide a step 4 to lower the rake face and a high corner on the rake face. Only the film formed on the portion 5 was polished. Formation of a film So-called film formation is performed by a known or novel vapor phase synthesis method, and the substrate is preliminarily subjected to the following treatment.

That is, the base material is treated in the presence of one or more elements of group Ia, group III, group IVb, group Vb or a compound thereof to allow the element to be present in the binder phase metal of the surface layer of the substrate. Prevents diffusion of the binder phase metal to the surface of the substrate during film formation by the vapor phase synthesis method. By the above-mentioned treatment, the ultra-hard film has high adhesion strength and its thickness is increased from 3 to 5 μm in the past to more than 20 μm all at once. Although the tool life is improved by this, the cutting resistance increases due to the rough rake face, and it is necessary to polish the surface of the generated film, which was less necessary in the past, but the rake face is polished only at high corners. Therefore, it can be easily and uniformly carried out in a short time.

The details of the present invention will be described below with reference to examples. In addition, in each of the examples, compared with the conventional technology, the case where the base material is a cemented carbide represented by the WC-Co system is shown. It goes without saying that the present invention can also be carried out on other cermets having a base material such as In addition, it is of course possible to add a known or new process such as grinding the surface of the base material before the treatment before or after the process shown in the examples.

[0008]

【Example】

[Embodiment 1] FIG. 1 shows the effect of the present invention 4
An example of a throwaway tip with a cutting edge at the corner, WC-
The 5% Co cemented carbide chip 1 is formed so low that the rake face central portion 3 has a step 4 of about 10 to 30 μm while leaving the corner portion 5. When a diamond film is formed on this chip by the vapor phase synthesis method, the film is formed on the entire surface and in the lower central part 3
When the carbon paste is applied to the above, the diamond film is formed on the high corner portion 5 and the side surface and at least the corner R portion 6. Since the surface roughness of the formed film is about 1 to 3 μmRmax, it is possible to use a relatively rough surface for cutting, but a high cutting resistance and in many cases a highly accurate cutting surface is required. Therefore, the following finishing process is applied.

The surface of the corner 5 is ground to a surface roughness of about 0.1 μm Rmax or less using a skiff or a diamond wheel. Since the corner portion 5 is formed to be high, a plurality of chips can be arranged and efficiently polished at once. In addition, the part that directly constitutes the cutting edge, such as the corner R part 6 of the tip,
That is, it is of course possible to polish the flank. It should be noted that such polishing is performed by preliminarily treating the surface of the cemented carbide chip with boric acid at 300 ° C.
(H ₃ BO ₃ ) After dipping in the melt for 20 minutes, in a hot filament CVD device, pressure 100 Torr, gas composition H ₂ -0.5Vol%
It was possible to use CH _{4 with} a chip temperature of 850 ℃ for 6-10 hours. The film thickness by film formation is 15 to 20 μm,
The surface roughness was 1 to 2 μm Rmax, and the residual film thickness at the polishing site after polishing was 10 to 15 μm.

The step 4 is 10 to 30 μm, and the corner 5 of the cemented carbide chip 11 before film formation is masked with vinyl tape and subjected to SiC sandblasting to form this shape (abrasive grain SiC # 80, sprayed). Pressure 4 kg / cm ² , spraying time 30 seconds each).
The shape and size of the corner 5 can be freely selected depending on the cutting direction and conditions. Examples 2 and 3 are examples in which the processing method of this chip is changed.

[0011]

Example 2 The same cemented carbide 11 as in Example 1 was heat-treated under the following conditions using a hot filament CVD apparatus. Heat treatment Filament temperature 2150 ℃ Base material surface temperature 850 ℃ Pressure 100Torr Gas composition Heat treatment 1: H ₂ -1% CH ₄ , 1.5Hr Heat treatment 2: H ₂ -1% CH ₄ , 1.5Hr Heat treatment 3: H ₂ -2% CH ₄ , 1.5Hr Heat treatment 4: H ₂ -2% CH ₄ , 3.5Hr Gas flow rate 500sccm

Soot removal and inspection After the heat treatments 1, 2, 3 and 4 are finished, the base material is taken out, and the carbon-based deposit (soot) generated on the surface of the base material is wiped off with a paper napkin. The surface of the base material was observed with a scanning electron microscope (SEM) to check that the deposit was removed and the size and amount of the deposit.

Coating of ultra-hard film The process of coating diamond was started when the formation of deposits disappeared and the formation of precipitates became saturated. The coating conditions are as follows. Filament temperature 2150 ℃ Substrate temperature 850 ℃ Pressure 100Torr Gas composition H ₂ -0.5% CH ₄ , 10Hr Gas flow rate 500sccm

After coating with the ultra-hard film, the rake face was polished only on the corners raised by the skiff machine, and the corner R flank was polished with a tool grinding plate using a # 800 diamond wheel.

The states and cutting test results of the coated article and the coated article subjected to polishing are shown in Table 1 and Table 2, respectively.

[0016]

[Table 1]

[0017]

[Table 2]

The cutting test conditions are as follows. Processing method Wet / continuous turning Work material A390-T6 Al-18% Sil Cutting speed 800 m / min Feed 0.1 mm / rev Cutting fluid 10% Emulsion Tool SPGN120308 Holder FP14L-33

[0019]

[Example 3] A boric acid melt was used as a treatment before forming a superhard film on the surface of the cemented carbide chip 11 by a vapor phase synthesis method.
Experiments were conducted using borax melt, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, and saturated saline solution, respectively. However, borax, sodium hydroxide, potassium hydroxide, saturated saline solution were used. The treatment effect was recognized in the order of. Also, instead of C, N with N atoms present
_{Since the} effect was obtained even by the treatment in an atmosphere of ₂ , NH _3, etc., the treatment in the present invention is performed by treating in the presence of one or more elements of the respective group elements Ia, III, IVb and Vb or the compounds thereof. Considered a legal requirement.

The finishing of the surface of the ultra-hard film has been shown by conventional mechanical polishing with skiff or diamond, but in the practice of the present invention, other known or novel processing methods such as high energy processing such as laser and ion beam are used. Of course, it doesn't matter.

[0021]

According to the present invention, on the rake face of the chip, the corners that directly constitute the cutting edge are raised and only the part is polished, so that film formation and polishing are performed during the manufacturing. The finishing is selectively uniform and easy. Moreover, the corners can be easily formed by sandblasting, and the substrate is pre-treated so that the adhesion strength of the film becomes strong, so that the film surface can be finished to have a surface roughness of about 0.1 μmRmax or less. Since the rake face to be finished is limited to the corner portion, the time required for finishing is short, and the cost is greatly reduced to 1/12 to 1/6 in the square throwaway tip. Of course, finishing allows high precision and long life cutting.

[Brief description of drawings]

FIG. 1 is a perspective view of a throwaway tip showing one of embodiments.

[Explanation of symbols]

 1 cemented carbide tip 2 diamond film 3 central part of rake face 4 step 5 corner 6 corner R

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiromi Tomimori, 2-80 Hotori-cho, Sakai City, Osaka Prefecture Osaka Diamond Diamond Industry Co., Ltd. Within Mondo Kogyo Co., Ltd.

Claims (3)

[Claims] 1. A cutting method in which a superhard film made of diamond and / or diamond-like carbon is formed by a vapor phase synthesis method on a base material in which a corner of the surface of a base material on which a rake face is to be formed is provided with a step, and the height is raised. In a tool tip, a rake surface is formed by forming a step and raising only a super hard film on a corner to finish the surface smoother than the surface roughness at the time of film formation. 2. The surface of the base material on which the rake face is to be formed is subjected to sandblasting except the corners to lower the height except the corners,
An ultra-hard film made of diamond and / or diamond-like carbon is formed on the base material by a vapor phase synthesis method, and only the ultra-hard film on the high corner of the rake surface is finished to be smoother than the surface roughness at the time of film formation. A method for manufacturing a tip for a super-hard film-coated cutting tool, comprising: 3. A step of treating a substrate in the presence of one or more elements of group Ia, group III, group IVb, group Vb or a compound thereof, and forming a rake face of the treated substrate. On the surface,
A step of sandblasting except the corners to lower the parts other than the corners, and a step of forming a super-hard film made of diamond and / or diamond-like carbon on the surface of the blasted base material by a vapor phase synthesis method. And a rake face, which comprises a step of finishing only the ultra-hard film on a high corner to be smoother than the surface roughness at the time of film formation, the method for manufacturing an insert for a super-hard film-coated cutting tool.