JPS6067003A - Coating cutting tool - Google Patents

Abstract

PURPOSE:To aim at improvements in the durability of a share point, by installing roundness in the share point of a cutting edge, and giving a grinding streak of less than 30 deg. to the cutting edge. CONSTITUTION:Roundness of 5-50mum in radius is installed in a share point. Likewise, a grinding streak 4 is made so as to be paralleled or become an angle alpha of less than 30 deg. with a cutting edge 5. Doing like that, progress in wear is checked at a position of the streak 4, increasing durability in the share point.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvement of the cutting edge shape of a cutting edge that serves as a coating base of a coated cutting tool.

As a method of increasing the durability of cutting tools, there is a coated cutting tool in which the cutting edge is coated with a hard substance such as Ti1l/XTi. With the development and improvement of film quality and coating technology, tools to which the same is applied are becoming commonplace, and the strength of the film and the adhesion between the film and the base tool become particularly important issues as to the quality of the coating film applied to cutting costs.

These factors depend not only on the quality of the film itself, but also on the shape and use of the base tool. For example, in the case of high speed cutting tools, relatively large and highly rigid tools such as gear cutting tools generally have good results, but with low rigid tools such as drills and end mills, the film properties are fully demonstrated. There are cases where this is not possible. In other words, in order to improve coated cutting tools, it is necessary to make development efforts in connection with base metal tools.

Among the types of cutting tools, the demand for small tools with low tool rigidity, such as drills and end mills, is overwhelmingly high. Coating these tools therefore has great application benefits.

The purpose of the present invention is to investigate the cutting phenomenon of coated tools and damage to the coating as well as research on film quality, and to improve tool performance by modifying the base material and cutting shape.

In the present invention, as the shape of the cutting edge of the substrate for coated tools, the tip of the cutting edge is provided with a minute roundness with a radius of 5 to 50 μm, and during the grinding operation to generate the cutting edge, the grinding streaks are set parallel to the cutting edge or It is characterized in that it is provided below.

The present invention will be explained below.

The first point of the present invention is that the cutting edge is rounded with a radius of 5 to 50 μm. When a coating film is applied to an ordinary sharp edge 1 as shown in FIG. 1, the internal stress during coating and the local stress applied to the coating 2 during cutting are large, causing early peeling during cutting. In order to alleviate this problem and maintain machinability, the appropriate roundness described in 4 above is provided. FIG. 2 is a cross-sectional view of the coated tool base 3 and the cutting edge of the coating 2 with minute roundness.

The cutting edge of a cutting tool, especially in a neutral cutting tool, must be ground as sharply as possible in order to obtain free cutting properties. There have been tools with some rounding on the cutting edge, but this causes grinding IJ (Burr) in the grinding process to sharpen the cutting edge.
The cutting edge was damaged during removal, which is different from the present invention.

The second point of the present invention is that in the grinding operation for forming the cutting edge, the grinding streaks are provided parallel to the cutting edge or at an angle of 30° or less.

The wear of the coating during cutting progresses along the grinding marks 4 when the grinding marks 4 are oriented perpendicular to the cutting edge 5 as shown in FIG. On the other hand, in the case of the grooves 4 parallel to the cutting edge 5, the progression of wear and tear is prevented at the grooves 4, thereby increasing durability.

In reality, the scratches 4 do not necessarily have to be exactly parallel to the cutting edge 5, but empirically, the grinding scratches 4 as shown in FIG.
A sufficient effect can be expected if the angle α with respect to the cutting edge 5 is 30° or less.

In the conventional general concept, it was customary to avoid grinding marks parallel to the cutting edge because they would cause grinding wobble on the cutting edge. However, although there are exceptional cases such as flank grinding of round broaches, where it is unavoidable due to machining reasons, this is not the case with other tools.Therefore, regardless of the type of tool, grinding is required when the cutting edge is parallel to the cutting edge. If we are to obtain a good surface, we should give priority to reviewing equipment and establish a grinding technology that does not cause grinding sag.

Examples of the present invention are shown below.

The base material tool is a two-sided end mill with a diameter of 6 mm.
One side is left as being ground, and the other side is approximately 10μm thick on the cutting edge after grinding.
After rounding the radius of
(RC3o) was cut. The result is the same cutting length approximately 2
Judging by m), the rounded ones were able to reduce the amount of wear by about 40%.

Similarly, the base material tools used were those with a diameter of 12mm, one of which was left as ground, and the other had a radius of approximately 15/Im rounded at the cutting edge after grinding, as shown in Figure 5. After finishing with abrasive paper to obtain parallel grinding streaks, coating was applied, and each die steel SKT 4 (11RC3o) was ground 9 times at a circumferential speed of about 25 m/RrR. The results were determined using the same cutting length (approximately 3 m), and the wear amount was reduced by approximately 60% when the grinding grooves were rounded and parallel to the cutting edge.

Figures 6 to 8 show the state of wear of the cutting edge after cutting. Figure 6 shows the wear of the rounded cutting edge, which is in a uniform state. FIG. 7 shows a state in which wear is stopped by grinding marks parallel to the cutting edge. FIG. 8 shows the state of wear of the cutting edge during normal grinding, which is uneven.

According to the present invention, tool wear can be reduced, abnormal excessive wear can be suppressed, and the wear pattern is made uniform over the entire length of the cutting edge, reducing the grinding time during re-grinding. This has the added effect of increasing the number of times that coating can be performed, and as a result, it can also contribute to extending the total life of the coated tool.

As can be seen in the above examples, according to the present invention, the durability of coated HSS tools is extended by 13 to 20 times when used under the same conditions. 1 Generally, coated HSS tools are evaluated to have more than twice the durability of untreated tools in wet cutting of small-diameter end mills, but by combining it with the present invention, it is possible to obtain more than three times the durability. It is something. This makes the coating method suitable.

It also has great economic effects in terms of expanding the scope of use, improving tool performance, and saving resources.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the cutting edge of a normal coated tool, Figure 2
The figure is a cross-sectional view of the cutting edge of a coated tool that has been given a minute roundness, Figure 3 is a perspective view of the main part of a tool that has grinding scratches as in normal grinding, and Figure 4 is the grinding groove of the present invention. FIG. 5 is a perspective view of the main part of a tool having marks, FIG. 5 shows the state of the cutting edge of the present invention, FIGS. 6 and 7 show the wear state after cutting, and FIG.
The figure is an enlarged photograph of the main parts showing the wear state of the cutting edge of a normal grinding machine. 1: Sharp edge, 2: Coating, 3: Base for coated tools, 4: Grinding marks, 5: Cutting edge, angle between α cutting edge and grinding marks Patent attorney Takayoshi Honma / Box 弗 β side Figure 5 Sheep! ! Continuing from page 1 of the 7th curse, 7th Son, Rod βki [Co., Ltd.] Inventor: Shigeyasu Yoshitoshi, 1-1 Nonakakita, Uyo-ku, Osaka Mensakusho, Nippon Tool Co., Ltd. Procedural amendment (method) % formula % 1. Indication of the incident 1982 Patent Application No. 173132 2. Name of the invention Coated cutting tool 3. Person making the amendment (Relationship with 11 Patent Applicant 1-1 Place Marunouchi 2, Chiyoda-ku, Tokyo) Item Mr. 1 and 2
Name (Name) (508) Hitachi Metals Co., Ltd. Representative Norio Kono (1 person, 4 agents, 5 Subject of amendment) ＼ Attachment 1) Contents of amendment 1, Specification No. 7 * Line 12 "Enlarged photo-1 is corrected to [Enlarged perspective view J. 2. Drawings 5 to 8 are corrected to the figures 5 to 8 attached to this document." 2) No. 5 Illustration 7 Figure 6 Illustration eJ threshold

Claims (1)

[Claims] In a coated cutting tool in which the cutting edge is coated with a hard substance, the cutting edge of the cutting edge is rounded with a radius of 5 to 50 pm, and the ground part that forms the cutting edge is parallel to the cutting edge or at an angle of 30 degrees or less. A coated cutting tool characterized by having angular grinding marks added to it.