JP2001252815A - Cutting edge changing cutting tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting tool having a cutting edge changing type medium and small diameter cutting tool and allowing a cutting tool edge part to be fixed to a shank with good accuracy in the axial and radial directions and with high rigidity. SOLUTION: This cutting edge changing cutting tool is formed by an edge part having a connecting shaft part integrally formed with the rear end side of the edge part and a shank part having a connecting shaft part integrally formed with the edge part side of the shank part. The edge part and the shank part are removably connected. The edge part and the shank part are taper-fitted and fixed. The surface roughness of the taper fitting part is RA of 1 μm or less. Furthermore, a coating is applied to the taper fitting part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting tool having a replaceable blade portion, and more particularly to a medium / small diameter cutting tool having a replaceable blade portion and a shank portion of the cutting tool.

[0002]

2. Description of the Related Art When a diameter is 0. From a few millimeters to more than 10 millimeters
Small-diameter cutting tools are widely used as solid tools made of cemented carbide or high-speed tool steel, but there are many advantages of being formed integrally, but there are also disadvantages due to the integration. In particular, as a disadvantage, the tool cost is higher than that of a tool with a replaceable cutting edge (a throw-away type).
, Because solid type cutting tools made of cemented carbide are expensive,
It is uneconomical. If damaged, the cost of repolishing is high. In addition, there is a problem in re-polishing accuracy.

[0003] Further, with regard to cutting tools having a diameter as large as 10 or more millimeters, various throw-away type cutting tools have been put into practical use. A type in which a polygonal plate-like insert is clamped and fixed with a screw or the like is used for a cutting tool having a relatively large diameter, and there is a type in which a medium diameter of about several tens of millimeters is fixed by sandwiching called a keyinger method. Further, it has been applied to cutting tools having a diameter of several millimeters. Recently, a method of fixing a cutting tool blade and a shank by shrink fitting, which includes a cutting tool blade and a shank, has been used. (As an example, JP-A-11-77443)

[0004]

According to the present invention, the shrink-fitting method has a problem that it takes time to heat, insert, set, and cool down in order to make the cutting tool of a medium or small diameter replaceable. Furthermore, in the method using heat, no matter how much the heating method is improved, a certain amount of time is required for cooling, and the cooling time more affects the mounting accuracy than the heating method.

[0005] Therefore, in view of the above-mentioned problems, in the present invention, the cutting tools of medium and small diameters are exchangeable with the cutting edge, and the cutting tool blade portion is highly accurate in the axial direction and the radial direction with respect to the shank. An object of the present invention is to provide a cutting tool that can be attached to and fixed to a cutting tool.

[0006]

According to the present invention, a blade having a connecting shaft integrally formed at the rear end of the blade and a connecting shaft formed integrally with the blade of the shank. A cutting part comprising a shank part comprising: a blade part exchangeable cutting tool for detachably connecting the blade part and the shank part, wherein the blade part and the shank part are fixed by taper fitting, A blade-part-replaceable cutting tool characterized in that the fitting part has a surface roughness of 1 μm or less in Ra, and the invention according to claim 3 further comprises a connecting shaft at a rear end side of the blade part. A blade portion integrally formed, and a shank portion integrally formed with a connecting shaft on the blade portion side of the shank portion, the blade portion removably connecting the blade portion and the shank portion. An exchangeable cutting tool, wherein the blade portion and the shank portion are fixed by taper fitting. A blade portion replaceable cutting tool which has been subjected to coating the tapered fitting portion.

In the present invention, the reason why the surface roughness of the tapered fitting portion is set to 3.2S or less at the maximum height Ra is to increase the runout accuracy after fixing. This is because, for example, the effect on the runout accuracy is greater than that of the straight fitting.
Further, Ra is preferably 1S or less. The reason why the length of the fitting shaft portion is set to at least one time the effective blade length is that if the length is less than one time, the length of the taper fitting is insufficient and it is difficult to obtain accuracy. Although it depends on the effective blade length, approximately 1 to 1.5 times, sufficient fixing strength and runout accuracy can be obtained.

Further, when the tapered fitting portion is coated,
Depending on the thickness of the film, surface roughness can be compensated. When the surface roughness is rough, it can be compensated by coating with a thin film. The film quality at this time may be a film such as TiAlN having excellent wear resistance used for the cutting edge. The thickness may be the same. Further, when the film used for the cutting edge is a film having excellent lubricity as an upper layer such as TiAlN having excellent wear resistance, there is an advantage that the friction can be reduced and the tapered hole portion can be protected.

[0009]

FIG. 1 shows an embodiment of the present invention. As shown in FIG. 2, the blade portion is made of ultrafine cemented carbide, has a diameter of 10 mm, has two blades, and has a surface roughness of a tapered shaft portion. Is 0.8 in Ra
S, the length of the tapered shaft part is 1.2 times the effective blade length,
Further, when the TiAlN-CrN coating was performed, three samples were prepared, one covering only the cutting edge portion, one covering the tapered shaft portion, and one covering the tapered shaft portion only with the lubricating film.
The blade 1 of the cutting tool has a length of 33 mm, and the taper shaft portion 2 for fixing is provided at the end of the cutting blade. The taper is 1/100, the end diameter is 7 mm, and the length is 20 mm. The main body 3 is composed of an adapter part 4 and a shank part 5 and has a tip diameter of 10 mm, a tapered hole part 6 fitted to the tapered shaft part 2 of the blade part 1, a gradient of 3 degrees from the tip, and a diameter of 16 mm. It extends straight to the end of the straight shank. The length of the tapered lower part of the neck is 86 mm, and the length including the shank is 170
mm, and the total length including the blade portion is 183 mm. The adapter part 4 is made of special steel tempered to HRC45 at a distance of 35 mm from the tip of the main body 3, and the shank part 5 is a K-type cemented carbide, both of which are joined by a spigot and a screw. The configuration is shown in FIG. Since the main body 3 is finished with the special steel part and the cemented carbide part fastened when machining this cutting tool, the concentricity, cylindricity, etc. are 0.002 mm or less, which are sufficient values for high-speed cutting. I have.

The blade 1 was arbitrarily selected and repeatedly attached to and detached from the main body 3, and the runout accuracy of the outer periphery of the cutting blade based on the shank was recorded. Here, the blade portion and the main body tried the press-fitting method and the shrink-fitting method. Among the products of the present invention, in the case of the press-fitting method, the mounting is performed by using a special jig so as not to hurt the cutting edge portion, and slowly press-fitting and extracting until the fillet of the cutting edge head comes into contact with the end face of the main body tip. Was based on a method of inserting a bar into a through hole provided in the main body and extruding the same using a dedicated jig. In the shrink fit method, the attachment and detachment were performed by heating with hot air. This was subjected to cutting to evaluate the cutting state. For comparison, a conventional method using the collet 7 shown in FIG. 4 is added. Using a structural carbon steel S50C material as a workpiece, the amount of protrusion from the machine tool was fixed at 70 mm, and straight machining was performed by downward cutting. The cutting conditions are 1 mm in depth, 0.1 mm feed per blade,
Pick feed 3 mm, dry cutting in a straight line. Table 1 shows the results.

[0011]

[Table 1]

The cutting sound is a sound generated during cutting due to chatter and vibration of the tool, and is affected by tool rigidity and cutting conditions. The surface properties are evaluated comprehensively based on the roughness of the cut surface, peeling, gloss, and the like. These are all affected by the rigidity of the tool installation and the run-out accuracy of the cutting edge when the cutting ability of the cutting edge is the same, and the product of the present invention shows a marked improvement over the conventional product.

Although the cutting tool of the present invention showed a superior value as compared with the conventional example, it is obvious that the cutting tool is based on the good gripping rigidity and the gripping accuracy obtained by the present invention. Although the ball cutting tool has been exemplified in the above embodiment,
It goes without saying that a scare blade or any other shape can be applied.

[0014]

As described above, by applying the present invention, the blade can be attached and fixed to the shank with high accuracy in the axial and radial directions and with high rigidity, thereby achieving excellent accuracy. In addition, even when the tapered fitting portion was coated, a cutting tool with excellent precision was obtained.

[Brief description of the drawings]

FIG. 1 shows a front view of an example of the present invention.

FIG. 2 shows a front view of the blade part of FIG.

FIG. 3 shows an axial sectional view of FIG. 1;

FIG. 4 shows a front view of an example of a conventional product.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Blade part 2 Tapered shaft part 3 Cutting tool main body 4 Adapter part 5 Shank part 6 Tapered hole part 7 Collet

Claims (6)

[Claims] 1. A blade portion having a connecting shaft integrally formed on the rear end side of the blade portion, and a shank portion having a connecting shaft integrally formed on the blade side of the shank portion. A blade-exchangeable cutting tool for detachably connecting the blade portion and the shank portion, wherein the blade portion and the shank portion are fixed by taper fitting, and the surface roughness of the taper fitting portion is reduced. Ra
Characterized in that the cutting tool is 3.2S or less. 2. The blade-replaceable cutting tool according to claim 1, wherein the fitting shaft and the fitting hole are each formed to have a taper of 1/50 or less. Cutting tools. 3. The cutting tool according to claim 1, wherein the length of the fitting shaft is at least one time longer than the effective blade length. 4. A blade portion having a connecting shaft integrally formed on the rear end side of the blade portion, and a shank portion having a connecting shaft integrally formed on the blade side of the shank portion. A blade-part-replaceable cutting tool for detachably connecting the blade part and the shank part, wherein the blade part and the shank part are fixed by taper fitting, and the taper fitting part is coated. An exchangeable cutting tool, characterized in that: 5. The cutting tool according to claim 1, wherein the coating of the tapered fitting portion is made of the same material and the same thickness as the cutting portion. Type cutting tool. 6. An exchangeable cutting tool according to claim 3, wherein the coating of the tapered fitting portion is a film having high lubricity.