JPH08276306A - Cutting tool with chip breaker - Google Patents

Abstract

PURPOSE: To provide a cutting tool with a chip breaker having easy chip breaker installation, the degree of freedom in breaker design, and using an ultrahigh hardness sintered body having relaxed applicable restriction to a small-size tool as a cutting blade. CONSTITUTION: A chip breaker piece 9 separately worked from a sintered body 3 is braze-connected to and provided on the cutting surface 3a of an ultrahigh hardness sintered body 3 connected to the seat groove 2 of a body 1. Thus, connection to the sintered body 3 is done without using excessive space and without decreasing the connection area. In addition, breaker width and breaker height are freely determined.

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 cutting edge made of an ultra-high hardness sintered body used for processing non-ferrous metal (especially aluminum), and particularly to an effective chip breaker in terms of design, economics, etc. The present invention relates to a cutting tool that can be advantageously attached.

[0002]

2. Description of the Related Art A cutting tool for forming a cutting edge with an ultra-high hardness sintered body produced by sintering polycrystalline diamond, cubic boron nitride (CBN), etc. It is common to have a structure in which the united tip is joined to the main body of the tool and a base metal mounted on the main body.

As a representative of such tools, a reamer for finishing a hole will be described as an example here.

FIG. 4 shows a reamer in which a seat groove 2 is provided on the outer periphery of the tip of a main body 1 and an ultrahigh hardness sintered body 3 is joined to the seat groove 2. As described above, a general reamer does not have a chip breaker for chip disposal. However, in the finish cutting of non-ferrous metal with tenacity such as aluminum, thin and hard-to-break chips often extend for a long time, and this often entangles with the tool, resulting in a machining stoppage. I can't do it.

Therefore, as shown in FIG. 5, an R groove 6 is dug on the rake face of the ultra-high hardness sintered body 3 to make it function as a breaker, or as shown in FIG. A base metal 7 having an L-shaped cross section made of ultra-high alloy is brazed to the united body 3, and the base metal 7 is brazed to the seat groove 2 to prevent the protruding portion 7a of the base metal 7 which is to be kept forward in the chip outflow direction. There have been developed those used as breaker projections, and further those used as a breaker surface by bringing the wall surface 5a of the chip pocket 5 close to the cutting edge 4 as shown in FIG.

[0006]

In the reamer of FIG. 5, the R groove 6 curls the chips, but it is not effective enough to divide the chips, and remains unsatisfactory as a chip breaker when processing sticky chips. In addition, the quality of the R groove due to grinding with a grindstone or electrical discharge machining is poor, and the machining cost of the sintered body increases due to the provision of the groove 6, which is disadvantageous in terms of cost and productivity.

On the other hand, in the reamer shown in FIG. 6, chips can be made to collide with the projecting portions of the base metal 7 to divide the chips, so that the chips can be processed more reliably than those shown in FIG. However, since this structure requires an extra mounting space for the base metal 7, it is difficult to apply it to a small size, multi-stage, and complicated tool. Such a structure can be used only for a tool having a diameter of 20 mm or more, for example.

Further, as shown in FIG. 3B, when the distance W (breaker width) from the cutting edge 4 to the breaker protrusion is shortened, the ultra-high hardness sintered body 3 becomes smaller and is sintered to the base metal 7. The brazing area of the body becomes small, the joint strength is insufficient, and the sintered body may come off during cutting. Therefore, it is necessary to set the lower limit value of W to a certain extent, which may cause the chip processing ability to be insufficiently exerted depending on the cutting conditions. Similar problems occur with the reamer of FIG. In addition, this structure has a shape shown in FIG. 3C, and the size of the pocket 5 is smaller than that of the embodiment shown in FIG.

Further, the sandwich structure sintered body shown in FIG. 8 (a) is made into a shape shown in FIG. 8 (b) by grinding or electric discharge machining, and is brazed to the main body 1 as shown in FIG. 8 (c). There is also a reamer with a breaker (appearance is the same as the invention of FIG. 3 (a)), but this has the same rake face quality problem as the one with an R-groove breaker.

An object of the present invention is to provide a cutting tool with a chip breaker which is a solution to these problems.

[0011]

In order to solve the above-mentioned problems, in the present invention, the rake face of the ultra-high hardness sintered body forming the cutting edge is processed separately from the ultra-high hardness sintered body. The chip breaker pieces were joined together.

If the rake face of this type of cutting tool has a poor surface roughness, a small chipping of the cutting edge may occur or aluminum may be welded to the rake face to deteriorate the cutting performance. Therefore, it is preferable that the rake face has a surface roughness of Rmax of 0.1 μm or less by lapping. In addition, since the tip breaker piece made of steel is liable to wear at the part where the chips hit, it is not the life due to the loss of the cutting ability of the original tool, but the life is reduced due to the deterioration of the chip processing ability due to the wear of the chip breaker piece. A suitable material for the chip breaker piece is cemented carbide, which has better wear resistance than steel.

The chip breaker piece is joined to the ultra-high hardness sintered body by brazing at a temperature which does not cause thermal deterioration of the ultra-high hardness sintered body in vacuum using a Ti-containing activated silver brazing material. Alternatively, a method of forming a coating film of a Ti compound in advance on the joint surface of the ultra-high hardness sintered body and silver brazing in the atmosphere or the like is used.

[0014]

[Function] Since the chip breaker piece made of cemented carbide or the like is provided on the rake face of the ultra-high hardness sintered body, it is necessary to form the breaker groove in the ultra-high hardness sintered body which is hard and difficult to process. In addition, the breaker width and the height of the breaker wall can be freely set.

Further, since the base metal 7 used in the reamer of FIG. 6 is not included, the mounting space corresponding to the thickness of the base metal (t _{1 in} FIG. 3B) can be reduced, so that a small diameter, multiple steps, and complexity are achieved. It can also be applied to tools.

Further, as compared with the reamer of FIG. 6, the brazing area of the ultra-high hardness sintered body can be expanded by the width W ₃ dimension of the base metal 7 of FIG. 3 (b), and the joining strength of the brazing portion can be increased. Can be increased.

[0017]

FIG. 1 shows the first embodiment of the present invention. This reamer makes a blank of an ultra-high hardness sintered body as shown in FIG. 1 (b), and uses this blank for the seat groove 2 at the tip of the chip pocket 5.
After brazing, the blade is processed to make a finished product.

The superhard sintered body 3 shown in FIG. 1 is provided with a cemented carbide seat plate 8 integrally formed on the lower surface during manufacturing under high temperature and high pressure (this type is general), and is baked. A chip breaker piece 9 is brazed on the rake face 3a of the united body 3. This chip breaker piece 9 cannot be joined by ordinary brazing because the joining partner is an ultra-high hardness sintered body having a poor brazing material wettability. However, the method described above, namely T
Strong brazing is possible by a method such as brazing in vacuum using the i-containing activated brazing material.

As described above, since the pieces 9 which have been separately processed after the production of the ultra-high hardness sintered body are joined together, it is possible to easily add a protrusion breaker which has a better chip disposal capability than a groove. Also, by designing the breaker width W (see FIG. 3 (a)) to an optimum value or changing the breaker width in the tool axial direction (different W ₁ and W ₂ in FIG. 1 (b)) It is also possible to give direction to the outflow.

In order to join the ultra-high hardness sintered body 3 to the main body 1, first, the chip breaker piece 9 is attached to the rake face 3a.
It is desirable that the method for brazing is followed by brazing the whole body 1 at a temperature lower than the brazing temperature of the piece 9 because of high productivity. However, it is of course possible to reverse the order of brazing (at this time, the brazing temperature of the piece 9 is lower than the brazing temperature for the whole body).

Further, for the chip breaker piece 9, the cost burden increases when an ultra-high hardness sintered body is used, so a cemented carbide having good wear resistance and inexpensive is desirable.

Further, the rake face 3a of the ultra-high hardness sintered body 3
Is preferably lapped to secure a surface roughness of Rmax of 0.1 μm, rather than grindstone polishing or electric discharge machining. This lapped surface is less likely to cause welding when aluminum or the like is rubbed, and brings about an effect of improving chip disposability.

FIG. 2 shows a second embodiment. This reamer adopts a solid type without a seat plate as the ultra-high hardness sintered body 3. In this case, the ultra-high hardness sintered body 3 is brazed to the main body 1 by a method similar to the method of joining the chip breaker pieces 9.

Since the reamer of FIG. 1 has the seat plate 8 and the chip breaker piece 9, the usual brazing method may be used. In this respect,
The second embodiment is more disadvantageous than the first embodiment, but it has an advantage that it can be applied to a tool having a smaller diameter size because the thickness of the ultra-high hardness sintered body is thin because there is no seat plate.

Next, an experimental example will be described.

Two types of reamers with breaker pieces as shown in FIGS. 1 and 2 and a reamer without breaker pieces as shown in FIG. 4 were manufactured as prototypes and comparative tests were conducted. Table 1 shows the dimensions of the prototype reamer (see FIG. 3A for the dimensions of each part).

[0027]

[Table 1]

With this reamer, aluminum (JIS standard 6
The finished hole of the prepared hole having a diameter of 11.5 mm formed in the block No. 061) was finished.

The cutting conditions are as follows: cutting speed V = 100 m / mi
n, feed f = 0.025 mm / blade, 0.050 mm /
There are four types: blade, 0.075 mm / blade, and 0.100 mm / blade.

As a result of the above experiment, in the reamer without the breaker, chips extended long under any feeding condition and clogging the main body, which hindered the machining. However, the reamer of the present invention with the chip breaker has all the feeding conditions. The chips were finely divided into less than 5 mm and did not get caught in the main body.

Further, the conventional reamer with a breaker shown in FIG. 6 is difficult to apply to a small size having an outer diameter of 20 mm or less and a multi-stage / complex tool, and if it is intentionally applied, the ultra-high hardness sintered body becomes too small and easily comes off. However, as for the prototype, even if it is 20 mm or less, the detachment of the sintered body did not occur at all.

The present invention can also be effectively used for tools other than reamers, such as drills, end mills, turning inserts, and throw-away inserts for milling cutters.

FIG. 9 is a throw-away tip made by brazing a cutting piece in which a chip breaker piece 9 is brazed on the rake face of an ultra-high hardness sintered body 3 to a base metal 10, FIG.
0 is a general cutting tool made by brazing the aforementioned cutting piece to the tip of the shank 11, and FIG. 11 is a boring tool made by brazing the same cutting piece to the tip of the quill 12. It is also effective when applied to a tool having such a form.

[0034]

As described above, in the cutting tool of the present invention, since the chip breaker provided on the rake face of the ultra-hard sintered body is created by joining the pieces, the cutting tool of the breaker design is used. The degree of freedom is increased, and at the same time, the breaker can be easily installed at low cost.

Since it is a protrusion type breaker,
The chip cutting performance is improved, and since it is also possible to directly bond the ultra-hard sintered body to the main body, it is possible to apply it to smaller tools.

[Brief description of drawings]

FIG. 1A is a perspective view showing a main part of a reamer according to a first embodiment. FIG. 1B is a perspective view of a blank of an ultra-high hardness sintered body used for the reamer.

FIG. 2A is a perspective view showing a main part of a reamer of the second embodiment. FIG. 2B is a perspective view of a blank of an ultra-high hardness sintered body used for the reamer of the same.

3 (a): Front view of reamer of FIG. 1 (b): Front view of reamer of FIG. 6 (c): Front view of reamer of FIG.

FIG. 4 is a perspective view showing a main part of a conventional reamer.

FIG. 5 is a perspective view of a main part of a conventional reamer having a breaker groove.

FIG. 6 is a perspective view of a main part of a conventional reamer having a breaker protrusion.

FIG. 7 is a perspective view of a main part of a conventional reamer having a breaker wall on the main body.

FIG. 8A is a perspective view of an ultra-high hardness sintered body having a sandwich structure. FIG. 8B is a perspective view of the above sintered body with a chip breaker attached. Perspective view of essential parts of reamer with body joined to body tip

FIG. 9 is a perspective view showing an example (throw-away tip) of another embodiment of the tool of the present invention.

FIG. 10 is a perspective view showing an example (bite) of another embodiment.

FIG. 11 is a perspective view showing an example (boring bite) of still another embodiment.

[Explanation of symbols]

 1 Reamer body 2 Seat groove 3 Ultra-high hardness sintered body 3a Rake surface 4 Cutting edge 5 Chip pocket 5a Wall surface 6 R groove 7 Base metal 7a Projection 8 Seat plate 9 Chip breaker piece 10 Base metal 11 Shank 12 Quill

Claims (3)

[Claims] 1. A cutting tool having a cutting edge made of an ultra-high hardness sintered body, characterized in that a chip breaker piece is provided on a rake face of the ultra-high hardness sintered body. tool. 2. The cutting tool with a chip breaker according to claim 1, wherein the roughness of the rake face of the ultra-high hardness sintered body is Rmax of 0.1 μm or less. 3. The cutting tool with a chip breaker according to claim 1, wherein the chip breaker piece is a cemented carbide.