JP2010058179A - Cutting tool and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting tool which is excellent in abrasion resistance, can prevent cutting performance from being deteriorated due to the abrasion of a tip of a cutting blade and maintains the cutting performance during the larger number of pieces of work. <P>SOLUTION: A drill has a rake face 6 of the cutting blade coated with a material 12 (diamond coating for example) having higher abrasion resistance than that of a base material (hard metal for example) of the cutting blade wherein the base material is exposed on the whole of clearances 10 and 13 of the cutting blade or a part connecting with the tip 15 of the cutting blade. Even if an edge at the tip of the coated cutting blade wears due to abrasion, the clearance concurrently wears due to abrasion, so that the tip of the cutting blade can be kept relatively sharp, thereby preventing the cutting performance from being deteriorated due to the abrasion at the tip of the cutting blade and maintaining the cutting performance for the larger number of pieces of work. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a cutting tool with a wear-resistant coating applied to a cutting blade and a method for manufacturing the cutting tool.

When a hole is formed in a carbon fiber reinforced resin composite material using a cutting tool such as a drill, delamination (delamination), fiber fraying, generation of burrs, and the like become problems.
Conventionally, double-angle drills described in Patent Documents 1 and 2 have been used as drills in which such problems are unlikely to occur.
In the double angle drill described in Patent Document 1, a diamond coating is applied to the tip in order to improve wear resistance.
Japanese Utility Model Publication No. 6-075612 JP 2008-036759 A

  However, when a conventional carbon fiber reinforced resin composite material is drilled using a drill with a diamond coating on the tip, wear of the cutting edge tip 15 proceeds as shown in FIGS. 6 (a1) → (a2). Accordingly, the radius R of the cutting edge tip 15 increases, and the cutting performance is significantly reduced.

  The present invention has been made in view of the above-described problems in the prior art, and has excellent wear resistance and a reduction in cutting performance due to wear at the cutting edge tip. It is an object to provide a cutting tool that can sustain the above.

  The invention according to claim 1 for solving the above-described problem is that the rake face of the cutting edge is coated with a material having higher wear resistance than the base material of the cutting edge, and the flank of the cutting edge is provided. A cutting tool in which the base material is exposed at all or a part of the cutting edge portion continuous with the cutting edge tip.

In the invention according to claim 2, the cutting edge portion is formed using a cemented carbide as a base material,
A cutting tool in which the rake face of the cutting edge portion is coated with diamond, and the base material is exposed at all of the flank face of the cutting edge portion or a part continuous with the cutting edge tip of the cutting edge portion. .

  According to a third aspect of the present invention, at least a part of the margin that extends to the flank side and continues to the flank surface along a ridge line that extends rearward in the axial direction from the tip of the cutting edge is continuous to the flank surface. The cutting tool according to claim 1 or 2, wherein the base material is exposed.

  According to a fourth aspect of the present invention, after the coating is applied to the surface of the cutting edge portion including the rake face, the base material is exposed by removing the coating on the flank. 2 is a manufacturing method of the cutting tool according to 2;

  According to a fifth aspect of the present invention, the base material is formed by removing the coating on the flank and the part after applying the coating to the cutting edge part and the part of the surface including the rake face. It is a manufacturing method of the cutting tool of Claim 3 which exposes.

  According to the present invention, the cutting edge is protected by the wear-resistant coating on the rake face, so that the wear resistance is excellent, and even if the edge of the cutting edge of the coating is worn away, the flank is also worn at the same time. Therefore, the cutting edge tip is held relatively sharply, so that a reduction in cutting performance due to wear of the cutting edge tip is suppressed, and the cutting performance is sustained over a larger number of machining operations.

  An embodiment of the present invention will be described below with reference to the drawings. The following is one embodiment of the present invention and does not limit the present invention. The following drills and their shapes are merely examples, and the present invention is not limited thereto.

FIG. 1 is a side view of a drill according to an embodiment of the present invention.
As shown in FIG. 1, the drill of this embodiment has a tip 1 and a shank 2. Two straight grooves 3 are formed in a portion between the tip portion 1 and the shank portion 2.

  FIG. 2 shows an enlarged view of the tip 1 of the drill shown in FIG. FIG. 3 shows an arrow view seen from the direction of the arrow α shown in FIG. FIG. 4 shows an arrow view seen from the direction of the arrow β shown in FIG. FIG. 5 shows a cross-sectional view taken along line XX shown in FIG.

The tip portion 1 is provided with a pair of cutting blades symmetrical about the central axis. The cutting edge is composed of a primary cutting edge 7, a secondary cutting edge 8, and a tertiary cutting edge 9 from the tip. The cutting edge is formed with a rake face 6 and flank faces 10, 13 respectively.
The tip 1 is cross-thinned, and the straight grooves 3 and 3 are continuous with the thinnings 11 and 11. A rake face 6 is formed in a portion recessed by the thinnings 11 and 11 and the straight grooves 3 and 3.

As shown in FIG. 5, the rake face 6 and the cutting edge second flank 10 form an acute angle and meet at the cutting edge tip 15. A cutting edge third flank 13 is formed continuously behind the cutting edge second flank 10 in the cutting direction. The internal angle formed by the cutting blade third flank 13 and the cutting blade second flank 10 forms an angle smaller than 180 degrees. As for the secondary cutting edge 8 and the tertiary cutting edge 9, a cutting edge second flank 10 and a cutting edge third flank 13 are formed. For the primary cutting edge 7, one flank is formed.
The rake face 6 is provided with a diamond coating 12. The base material is exposed at the cutting edge second flank 10. The base material is a cemented carbide. The base material is exposed in the region on the leading edge side in the cutting direction in the third flank 13 of the cutting edge, and the diamond coating 12 is applied to the region on the trailing edge side in the cutting direction. In this way, the base material is exposed on the entire surface of the cutting edge second flank 10 and the region on the cutting edge front edge side in the cutting blade third flank 13. This is to prevent the flank diamond coating 12 from coming into contact with the work material due to wear during cutting. Therefore, regardless of the present embodiment, the base material of the drill may be exposed on the entire flank of the cutting edge. As for the primary cutting edge 7, the base material is exposed on the entire one flank.

In the portion between the straight grooves 3 and 3, margins 5 and 5 are formed on both edges along the straight grooves 3 and 3, respectively. A flat cut relief surface 4 is formed between the margins 5 and 5 on both edges. The margin 5 at the front edge in the cutting direction is formed continuously on the drill rear end side of the cutting edge second flank 10. A flat cut relief surface 4 and a margin 5 at the trailing edge in the cutting direction are continuously formed on the drill rear end side of the third cutting edge relief surface 13. The margins 5, 5, 5, and 5 are in contact with the inner surface of the hole to be processed and support the drill.
Of the margin 5 at the leading edge in the cutting direction, the base material is exposed at least at a part continuing to the cutting edge second flank 10.

As a method for forming the diamond coating 12, first, a method is applied in which the entire tip portion 1 including the rake face 6 is coated with diamond, and then the coating on the flank is removed by grinding to expose the base material. Can do. At the time of coating, the diamond coating can be extended to the rear of the tip portion 1 in the axial direction. Therefore, the coating on a part of the margin 5 continuing to the above-mentioned cutting blade second flank 10 is also removed by grinding to expose the base material.
In order to apply this method, the diamond coating 12 remains in the region on the trailing edge side in the cutting direction that does not need to be removed, but this may be removed.
Although a method of applying a diamond coating to the rake face 6 after masking the flank and the margin 5 is considered, it is difficult to mask the rake face 6 at a high temperature during the formation of the diamond coating. The above method is therefore advantageous.

  As shown in FIG. 2, the primary cutting edge 7 is linear, and the tip angle A ° is an obtuse angle. The secondary cutting edge 8 is arrange | positioned between the primary cutting edge 7 and the tertiary cutting edge 9, and is continuing smoothly in both. At the distance L from the tip, the outer diameter of the blade portion is the maximum outer diameter φD. The distance L corresponds to 1 to 2 times the maximum outer diameter φD.

Next, the operation when using the drill according to the present embodiment will be described.
A drill in which the rake face 6 and the flank faces 10 and 13 of the cutting edge portion are entirely coated with a diamond having the same shape as the drill of this embodiment is a comparative example. The drilling of the carbon fiber reinforced resin composite material is performed using the drill of the comparative example and the drill of the present embodiment, respectively.
FIG. 6 shows a sectional view of a cutting state of the comparative example with a drill. FIG. 7 shows a sectional view of a cutting state by the drill of this embodiment. The work material 14 in the figure is a carbon fiber reinforced resin composite material.

In the drill of the comparative example, as shown in FIGS. 6 (a1) → (a2), when the carbon fiber reinforced resin composite material 14 is perforated, the cutting edge tip 15 increases as the cutting edge tip 15 wears. However, the coating 12 remains on the flank 10 and the R of the cutting edge tip 15 becomes large, resulting in a decrease in cutting performance. In this case, burrs and delamination of the work material 14 occur.
On the other hand, in the drill of the present embodiment, as shown in FIGS. 7 (b1) → (b2) → (b3), the diamond applied to the rake face 6 when the carbon fiber reinforced resin composite material 14 is drilled. The edge of the cutting edge of the coating 12 falls off due to wear, and at the same time the flank face 10 exposed from the base material wears and retreats toward the center, so that the cutting edge 15 is kept relatively sharp and suppresses deterioration of sharpness. It is done.
In addition, the wear of the base material tends to proceed from the tip 1 to the rear in the axial direction. In FIG. 8, 5 is an initial margin forming range, and C is a wear region. As described above, in the drill of the present embodiment, the base material is exposed at least in a part of the margin 5 at the leading edge in the cutting direction that is continuous with the cutting edge second flank 10. Therefore, according to the present drill, the wear of the base material on the margin 5 can be advanced in the same manner as the flank, so that the maximum cutting edge outer diameter portion of the tertiary cutting edge 9 is retracted in the axial direction as indicated by the arrow 5a. The cutting edge tip 15 configured in the vicinity of the maximum outer diameter portion and the vicinity thereof is held so as to be relatively sharp and smoothly continuous from the cutting edge tip 15 on the drill tip side, thereby suppressing deterioration in sharpness. It is done. Therefore, in the drill according to the present embodiment, a reduction in cutting performance due to wear of the cutting edge tip is suppressed, and the cutting performance is sustained over a larger number of processing.

  According to the drill of the embodiment of the present invention described above, the cutting edge is protected by the diamond coating 12 on the rake face 6 and has excellent wear resistance. Defects, burrs and delamination of work materials are reliably prevented, cutting tool life is greatly improved, and stable continuous drilling is possible over a long period of time, reducing work time and tool costs. The effect is obtained.

In the above embodiment, the drill is exemplified as the cutting tool. However, the present invention is not limited to the drill, and is effective for all cutting tools such as a lathe tool and an end mill.
The work material that can effectively use the cutting tool of the present invention is not limited to the above materials. The cutting tool of the present invention can be effectively applied to the work material in which the wear phenomenon of the cutting edge shown in FIG. 6 occurs, and thereby the effect of the present invention can be obtained as shown in FIG. . Specifically, the cutting tool of the present invention can be effectively applied to fiber reinforced resin composites, concrete, and the like. For metal materials that cause seizure on the cutting edge, the process of making the cutting edge unusable is not due to the wear phenomenon shown in FIG. The maintenance principle does not work effectively. The cutting tool of the present invention can be effectively applied to a material having a low viscosity such as a metal casting.

In addition, in order to apply diamond coating to a cemented carbide, it is conventionally known that the cobalt content of the cemented carbide needs to be 6% (weight concentration, the same applies hereinafter) or less. This is because the diamond coating peels off as the cobalt content increases.
Since the cutting edge maintenance principle of the present invention is to reduce the base material of the flank surface by wear during cutting, the base material preferably has a low hardness. Therefore, when applying diamond coating, it is preferable that the cobalt content of the cemented carbide is 6% of the conventional upper limit.
In order to make the most of the principle of maintaining the cutting edge according to the present invention, in the future, "a cutting edge part is formed using a cemented carbide with a cobalt content exceeding 6% as a base material, and a diamond is formed on the rake face of the cutting edge part. It is effective to constitute a “cutting tool” that is covered and is exposed to the base material in the entire flank of the cutting edge or a part of the cutting edge that is continuous with the cutting edge tip.

It is a side view of a drill concerning one embodiment of the present invention. It is an enlarged view of the front-end | tip part 1 of the drill shown in FIG. It is the arrow line view seen from the arrow (alpha) direction shown in FIG. FIG. 3 is an arrow view seen from the arrow β direction shown in FIG. 2. It is sectional drawing in the XX line shown in FIG. It is cutting state sectional drawing by the drill of a comparative example. It is a cutting state sectional view by the drill concerning one embodiment of the present invention. It is a mimetic diagram showing progress of wear of a drill concerning one embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tip part 2 Shank part 3 Straight groove 4 Flat cut relief surface 5 Margin 6 Rake face 7 Primary cutting edge 8 Secondary cutting edge 9 Tertiary cutting edge 10 Cutting edge second flank 11 Thinning 12 Diamond coating 13 Cutting edge third relief Surface 14 Carbon fiber reinforced resin composite (work material)
15 Cutting edge tip φd Outer diameter of primary cutting edge 7 φD Maximum outer diameter of blade

Claims (5)

The rake face of the cutting edge part is coated with a material having higher wear resistance than the base material of the cutting edge part, and the flank of the cutting edge part or a part continuous to the cutting edge tip of the cutting edge part A cutting tool in which the base material is exposed. The cutting edge is formed using cemented carbide as the base material.
A cutting tool in which the rake face of the cutting edge portion is coated with diamond, and the base material is exposed in the entire flank of the cutting edge portion or in a part continuous with the cutting edge tip of the cutting edge portion. The base material is exposed in at least a part of the margin extending to the flank side and extending to the flank side along a ridge line extending rearward in the axial direction from the tip of the cutting edge and continuing to the flank face. The cutting tool according to claim 1 or 2, wherein The manufacturing of the cutting tool according to claim 1 or 2, wherein after the coating is applied to the surface of the cutting edge portion including the rake face, the coating on the flank is removed to expose the base material. Method. The said cutting blade part including the said rake face and the said one part surface are coated with the said coating | cover, Then, the said base material is exposed by removing the coating | cover on the said flank and the said one part. Method of manufacturing cutting tools.

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