JP2013184267A - Cutting tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a displacement problem and the like in a cutting tool produced by brazing a hard blank comprised of CBN and the like, to a corner of a tool body, the problem occurring when brazing the hard blank, thereby achieving improvement of productivity and cost reduction.SOLUTION: At corners of a polygonal tool body 2, there are formed support seats 4 having a V-shape in a plan view, the support seats concaved by a certain depth on outer peripheral surfaces of the corners and opening toward the upper surface or lower surface of the tool body 2. A hard blank 3, which has a V-shape in a plan view and is fittable to the shape of the support seat, is brazed and joined to the support seat 4, and a cutting edge 5 is formed on the hard blank.

Description

  The present invention relates to a cutting tool such as a cutting insert for turning in which a cutting edge is formed of a hard sintered body such as a CBN (cubic boron nitride) sintered body or a diamond sintered body.

  As shown in FIG. 5, a cutting insert in which a triangular hard blank 12 is brazed to a corner of a tool body (base metal) 11 made of a cemented carbide and a cutting edge is provided on the hard blank 12 has already been provided to the market. Has been.

  Moreover, the following patent document 1, 2 etc. have described the cutting insert which comprised the cutting blade with the hard sintered compact. The cutting insert disclosed in Patent Document 1 is arranged by mechanically engaging a cutting tip with a cavity provided in a corner of a polygonal body (tool body) and brazing it on the body.

  Moreover, the cutting insert of patent document 2 forms a recessed part in the corner part of a chip | tip body, and fits the blade part formed by CBN etc. in the recessed part, and brazes the blade part to the chip | tip body.

JP 2006-526508 A JP 2010-46728 A

  The commercial cutting insert shown in FIG. 5 has a large area of expensive hard blanks, and it is difficult to meet the recent demand for cost reduction. The cutting inserts of Patent Documents 1 and 2 have the same problem. In particular, since the cutting insert of Patent Document 2 has a fitting portion with the tool body in the blade portion itself, the area of the blade portion tends to be larger than the cutting insert of FIG.

  Further, the commercially available cutting insert shown in FIG. 5 is easy to move when the hard blank 12 is brazed to the tool body 11. Because of this movement, the mounting position of the hard blank inevitably shifts, so the hard blank is sized to allow for this shift, which increases the polishing allowance and polishing time for final polishing, which increases costs and productivity. Has a non-negligible impact.

  An object of the present invention is to improve the productivity and reduce the cost of a cutting tool in which a cutting edge is formed of a hard sintered body such as CBN or diamond by solving the problem of misalignment during brazing.

  In order to solve the above-described problems, in the present invention, a plan view V in which an outer peripheral surface of a corner is recessed at a certain depth at an arbitrary corner (right angle corner, acute angle corner or obtuse angle corner) of a polygonal tool body. A letter-shaped support seat is formed, the support seat is released on the upper surface or the lower surface of the tool body, a V-shaped hard blank in a plan view is joined to the support seat, and a cutting blade is formed on the hard blank. Formed. The hard blank can be joined to the support seat by brazing or energization joining.

  Here, the V-shaped hard blank in plan view is composed of a single body of a CBN sintered body or a diamond sintered body, and is made of a cemented carbide or the like on the back surface of the CBN sintered body or the diamond sintered body. It does not matter whether the backing material is integrally formed.

  The hard blank employed in this cutting tool may have a cutting edge length L of about 1.5 mm to 5.0 mm as an appropriate size. Among them, those having a cutting edge having the same length as the standard triangular hard blank (length L is about 1.5 mm to 3.0 mm) are preferable.

  The width of the hard blank is about 0.3 mm to 1.0 mm, more preferably 0.5 mm to 1.0 mm, and the thickness of the hard blank is about 0.5 mm to 2.0 mm. .

  In addition, it is preferable that the tool body is made by embossing a corner support seat. If the tool body is made of cemented carbide made by powder metallurgy, the support seat can be molded by embossing.

  In the cutting tool of the present invention, a V-shaped support seat in a plan view is formed at a corner of a tool body, and a V-shaped hard blank in a plan view is brazed and joined to the support seat. According to this structure, the positioning effect of the hard blank by V-shaped fitting is obtained. As a result, the mounting position of the hard blank is prevented from being misaligned, so that the polishing allowance and polishing time in the final polishing are reduced, and as a result, cost reduction and productivity improvement can be achieved.

  In addition, since the hard blank has a V-shape in plan view, the volume of the expensive hard sintered body (CBN sintered body or diamond sintered body) is significantly reduced compared to that using a triangular hard blank. This also contributes to cost reduction.

  Furthermore, since the hard blank is V-fitted to the tool body and mechanically engaged, it is difficult for the hard blank to slip laterally when the tool is used. In addition, when compared with a triangular hard blank having the same cutting edge length, the area of the joint surface increases, so that the reliability of brazing is also increased.

The perspective view which shows one form of the cutting tool of this invention 1 is an enlarged plan view of the cutting tool of FIG. The top view which shows the other form of the cutting tool of this invention The perspective view of the principal part which shows the example which joined the hard blank which has a lining material Perspective view of a conventional cutting tool with a triangular hard blank joined to the corner of the tool body

  Embodiments of a cutting tool according to the present invention will be described below with reference to FIGS.

  The cutting tool 1 shown in FIG.1 and FIG.2 applies this invention to the rhombus cutting insert. This cutting tool 1 is made by joining a hard blank 3 to an acute corner portion of a tool body (base metal) 2. The hard blank 3 is formed of a CBN sintered body or a diamond sintered body.

  The tool body 2 is a cemented carbide sintered body made by powder metallurgy. The acute corners on the upper and lower surfaces of the tool body 2 are formed with V-shaped support seats 4 in a plan view, in which the corners of the outer peripheral surface 2a are recessed at a certain depth (the depth is equal to a blank thickness t described later). In addition, a V-shaped hard blank 3 in plan view is fitted and brazed to the support seat 4.

  The support seat 4 is an embossed support seat and is released to the upper surface and the lower surface of the tool body 2. The blank 3 is fitted to the support seat 4 so as to fit, and after the brazing on the support seat 4, a grinding finish is performed to generate a cutting edge 5.

  The cutting edge 5 is provided with a negative land or the like for reinforcing the cutting edge as required. The hard blank 3 is provided with either a single body of a hard sintered body or one formed integrally with a backing material 3a such as cemented carbide as shown in FIG.

  The hard blank 3 made of a single hard sintered body is joined to the tool body 2 using an active brazing material (for example, a Ti-containing brazing material). Depending on the area of the joining surface of the backing material 3a, the active brazing material may be used for the hard blank 3 having the backing material 3a. Even in the state where the support seat 4 is left with the sintered skin, the brazing can be performed without any trouble.

  The hard blank 3 is one in which the length L of the cutting edge shown in FIG. 2 is set in the range of 1.5 mm to 5.0 mm, preferably in the range of 1.5 mm to 3.0 mm. . By providing a cutting blade having the same length as that of a conventional standard triangular hard blank, it can be used as a substitute for a tool using the standard triangular hard blank.

  Further, the width W of the hard blank 3 shown in FIG. 2 is preferably set to 0.3 mm to 1.0 mm, more preferably 0.5 mm to 1.0 mm. If the cutting is light, the blank strength will not be insufficient even if the width W is about 0.3 mm. However, when used under general conditions, it is preferable to secure a width W of 0.5 mm or more in order to ensure the strength of the hard blank. For the same reason, the thickness t (see FIG. 1) of the hard blank 3 is preferably about 0.5 mm to 2.0 mm.

  The present invention is applied to all cutting tools having a tool body having a polygonal shape. For example, the present invention can be applied to a cutting insert whose basic shape is a regular triangle, a regular pentagon, a regular hexagon, etc., a cutting insert whose basic shape is a rectangle, and a cutting insert whose basic shape is a square as shown in FIG.

  Any cutting tool can be provided with a hard sintered hard blank 3 at least at one corner. However, if the hard blank 3 is provided at all usable corners, there is no waste and the cost per blade is reduced. I can plan.

A cutting tool having the shape shown in FIG. 1 (tool model number: cutting insert of CNGA120408) was prototyped. The prototype tool is obtained by joining a V-shaped hard blank in plan view to an acute corner of the tool body. The hard blank is made of material CBN, width W = 0.5 mm, cutting edge length L = 2.4 mm, and blank thickness t = 1.0 mm.
The cutting tool was mounted on a tool holder (model number: DCLNR2525M12), and a cutting test was performed under the following conditions.
-Cutting conditions-
Work material: SCM415 round bar (hardness 60HRC)
Cutting speed Vc: 120 m / min
Feed f: 0.15mm / rev
Incision ap: 0.1 mm
Cutting form: Dry cutting Cutting method: Continuous cutting

  As a result of this test, cutting that is functionally comparable to the cutting tool of FIG. 5 in which a triangular hard blank was joined to the corner of the tool body was performed. There was also almost no difference in tool life.

A cutting tool having the shape shown in FIG. 1 (tool model number: cutting insert of CNGA120408) was prototyped. The prototype tool is one obtained by brazing a V-shaped hard blank in plan view on an acute angle corner of the tool body, and by energization joining.
The cutting tool was mounted on a tool holder (model number: DCLNR2525M12), and a cutting test was performed under the following conditions. Before machining, a cutting test was performed to determine whether the blank could be removed using a tool that generated flank wear of 0.4 mm or more.
-Cutting conditions-
Work material: SUJ2 round bar (hardness 60HRC)
Cutting speed Vc: 150 m / min
Feed f: 0.50mm / rev
Incision ap: 0.3 mm
Cutting form: Dry cutting Cutting method: Continuous cutting

  As a result of this test, the brazed tool removed the blank after 55 seconds of machining, whereas the energized joined tool could be machined without being detached even after 180 seconds of machining.

DESCRIPTION OF SYMBOLS 1 Cutting tool 2, 11 Tool main body 3, 12 Hard blank 3a Backing material 4 Support seat 5 Cutting edge

Claims (4)

  A V-shaped support seat (4) in a plan view in which the outer peripheral surface of the corner is recessed at a certain depth is formed at a right-angled corner, an acute corner or an obtuse corner of the tool body (2) having a polygonal shape. (4) is released on the upper surface or lower surface of the tool body (2), and a V-shaped hard blank (3) having a suitable shape in a plan view is brazed and joined to the support seat, and a cutting blade (5 Cutting tool formed).   The cutting tool according to claim 1, wherein a width (W) of the hard blank (3) is set in a range of 0.3 mm to 1.0 mm. The tool body (2) is a sintered body made by powder metallurgy, and the support seat (4) is made by stamping, and the support seat (4) where the sintered skin is left is placed on the support seat (4). The cutting tool according to claim 1 or 2, wherein the hard blank (3) is brazed.   The tool body (2) is a sintered body made by powder metallurgy, and the support seat (4) is made by stamping, and the support seat (4) where the sintered skin is left is placed on the support seat (4). The cutting tool according to claim 1 or 2, wherein the hard blank (3) is electrically joined.

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