KR20170052115A

KR20170052115A - Cutting tool tip with micro pattern

Info

Publication number: KR20170052115A
Application number: KR1020150154153A
Authority: KR
Inventors: 박형욱; 김동민
Original assignee: 울산과학기술원
Priority date: 2015-11-03
Filing date: 2015-11-03
Publication date: 2017-05-12

Abstract

The purpose of the present invention is to provide a cutting tool tip with a micro-pattern, forming a micro-pattern on a surface of a tip made of a CBN material to have increased durability as compared to the tip made of a general CBN material. To achieve the purpose, according to the cutting tool tip with a micro-pattern, the present invention enables the micro-pattern to be formed on an upper surface of a corner unit coming in contact with a workpiece.

Description

[0001] The present invention relates to a cutting tool tip with a micro pattern,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a tip for a cutting tool having a micropattern formed therein, and more particularly to a tip for a cutting tool in which a micropattern is formed at a portion contacting the workpiece to thereby extend the tool life.

Most cutting tools include a body portion and a tip attached to the body end to directly cut the workpiece.

For example, the patent publication No. 2012-0003445 discloses a tool part including a cutting edge; And a shank portion connected to the tool portion at a first end, the cutting tip comprising at least a portion of each groove extending in a circumferential direction at least partially around at least a portion of the shank portion, The configuration of the cutting tool including the three grooves, the caulking structure for the care of the shank portion against the opening of the toolholder, and the tip comprising the axial stop to limit the axial movement of the shank portion relative to the opening of the toolholder Lt; / RTI >

In addition, the registered patent No. 175214 provides a chip breaker type cutting tool disposable tip that efficiently discharges chips generated during cutting and at the same time improves the attachment stability of the tip itself. The chip breaker- And the surface of the land to be mounted on (contact with) the holder is made wider so as to have the same height throughout the land portion of the surface to be welded and the entire surface of the isceland portion.

In addition, in Japanese Patent No. 910592, one aspect of the present invention relates to a tip bonded to a shank of a working tool, comprising: a tip body having a tip mixed with an abrasive for strengthening hardness in a metal material; And at least one coupling protrusion including a metal material and an abrasive material and being integrally sintered with the tip body and protruding in a direction in which the shank is to be joined. .

In addition, in Japanese Patent No. 1052658, a concave portion and a plurality of convex portions are provided on the side of a tip having a basic shape of a regular triangle having an apex angle of a corner at an acute angle, and the concave portion and the convex portion are provided on the side surface of the holder, And in this state, the tip is pressed by the clamping means against the seat bottom surface of the seat groove and the side surface of the seat, thereby restricting the tip.

As described above, the cutting tool tip is combined with the body portion in various forms, and is configured to be replaceable so that the tip can be easily replaced when the tip is worn out.

On the other hand, a cemented carbide can be used as a material for a cutting tool tip. The above-mentioned cemented carbide is widely used because it has excellent cutting characteristics with respect to price.

In addition, CBN can be used as a material for a tip for high-quality surface appearance. CBN stands for Cubic Boron Nitride and is known to have the highest hardness after diamond. In addition, CBN has an advantage over diamond in stability against ferrous materials to be processed.

In accordance with these features, a variety of cutting tool configurations using CBN tips have also been proposed. For example, Publication No. 2008-0097436 discloses the construction of milling inserts and milling insert tools for thread milling of CBN, and the construction of CBN composite materials and tools is disclosed in EP 1409123, Japanese Patent No. 817999 discloses a CBN sintered body and a cutting tool structure using the CBN sintered body.

However, CBN having the above-mentioned excellent characteristics is disadvantageous in that it is more expensive than cemented carbide. Therefore, it is necessary to extend the service life of CBN itself and use it as a processing tip that is cost competitive.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a tip for a cutting tool in which a micropattern is formed on the tip surface of a CBN material and a micropattern having a longer life than a general CBN material tip is formed .

In order to achieve the above object, the present invention provides a tip for a cutting tool in which a micropattern is formed, wherein the tip is formed with a micropattern on an upper surface of a corner portion in contact with the workpiece.

Preferably, the tip is a CNB material.

More preferably, a tip portion of the tip upper corner portion includes a rim portion having no micro pattern formed thereon.

More preferably, the micropattern is characterized in that a plurality of linear grooves having a constant width are arranged at equal intervals.

More preferably, the straight groove is formed in an inclined shape with respect to the horizontal at an angle of 50% of the angle formed in the tip corner portion.

More preferably, when both ends of the adjacent linear grooves are connected, an isosceles triangle is formed.

More preferably, the width of the straight groove is 90 to 110 mu m do.

More preferably, the depth of the straight groove is 20 to 60 占 퐉 do.

More preferably, the interval is a straight groove width of +/- 10%.

More preferably, the width of the rim is 50% to 100% of the width of the straight groove .

The tip of a cutting tool having a micropattern according to the present invention is characterized in that a micropattern is formed in which a sloped groove is continuously formed in a corner portion where cutting occurs due to contact with a work among the surfaces of the tip, It has the effect of reducing the friction between the chip and the surface of the tool tip which are continuously contacted by the cutting, thereby extending the life of the entire tip.

1 is a schematic view of a tip for a cutting tool in which a micropattern is formed according to the present invention,
FIG. 2 is a schematic view of the micropattern shown in FIG. 1,
Figure 3 is a photograph of the surface of an embodiment,
4 is a graph of surface characteristics of the embodiment,
5 is a configuration diagram of a cutting test apparatus,
6 is a driving condition of the shelf,
Fig. 7 is a graph for the tool acting force according to the tool feed rate,
8 is a photomicrograph of a chip produced according to the tool feed rate,
9 is a graph of the friction coefficient according to the tool feeding speed,
10 is a table showing the cutting parameter values according to the tool feeding speed,
Fig. 11 is a graph of the tool acting force according to the linear velocity,
12 is a micrograph of a chip generated according to a linear velocity,
13 is a graph of the friction coefficient according to the linear velocity,
14 is a table showing cutting parameter values according to the linear velocity,
15 is a graph showing flank wear,
16 is a graph showing a crater wear width,
17 is a graph showing the crater wear length,
18 is a flank wear photograph,
19 is a crater wear photograph.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, as shown in FIG. 1, a tip for a cutting tool having a micropattern according to the present invention has a micropattern 20 at a corner of a tip 10, which is solidified in a quadrangular plane and has a fixing hole at the center thereof. .

At this time, the shape of the tip 10 may be rhombic or triangular, and the micropattern 20 may be formed at the corner where the workpiece and the tip 10 contact with each other even in the above-described shape.

The material of the tip 10 is CBN (Cubic Boron nitride).

1, the micro pattern 20 can be formed at all corners, and at this time, when one of the coater portions is worn, cutting can be performed using another corner portion.

2, the micropattern 20 includes a plurality of straight grooves 22 inclined at an angle a with respect to the horizontal and a gap 23 between the straight grooves 22. As shown in FIG.

The linear grooves 22 are not formed in the rim portion 21 of the tip 10 and have the same width and arrangement as the other linear grooves 22 but have different lengths.

The length of the linear groove 22 is longest at the diagonal line of the center of the corner of the tip 10 and small at the periphery thereof to form a triangle as a whole.

That is, the overall shape of the micropattern 20 is formed in an isosceles triangular shape located at the rim 21 of a constant width.

The angle a is preferably 45 degrees in the case of the square tip 10, and it is preferably formed to be 1/2 of the angle for symmetry when the angle of the corner is not 90 degrees, such as the rhombus.

The width of the straight groove 22 is preferably set in the range of 90 탆 to 110 탆. If the width is less than 90 탆, processing is difficult and inadequate. When the width exceeds 110 탆, the effect of reducing friction is insufficient, which is inappropriate.

The depth of the linear groove 22 is preferably 20 to 60 占 퐉. Also, when the depth is less than 20 탆, processing is difficult and inadequate. When the depth is more than 60 탆, the effect of reducing friction is insignificant.

At this time, it is preferable that the interval 23 is set to be equal to the width of the straight groove 22 or within ± 10%. If it is out of the above range, it is economically disadvantageous because it is difficult to process, or the number of straight grooves 22 formed in the entire micropattern 20 is small and the effect of reducing friction is insignificant.

The rim portion 21 can be set in conjunction with the width of the straight groove 22, and 50% to 100% of the width of the straight groove 22 is suitable.

If the rim portion 21 is less than 50% of the width of the straight groove 22, it is disadvantageous in terms of strength. If the rim portion 21 is more than 100%, it is inadequate because of the effect of chip flow.

Meanwhile, the micropattern 20 may be formed by a pattern formed on the metal mold during the initial sintering. In the case of the CBN tip 20, the micropattern 20 may be formed by using a micro discharge machining apparatus (EDM).

In particular, since the CBN usually includes a conductive metal binder, the micropattern 20 can be formed using an electric discharge machining apparatus (EDM). At this time, after the CBN tip 20 is immersed in the discharge solution, the micropattern 20 is processed through the electrode.

Hereinafter, the present invention will be described in more detail by way of examples.

Example

The CBN tip (CB7025, Sandvik) was processed in a layer-layer manner using a micro-discharge machining apparatus to form a micropattern.

In particular, during the discharge process, the electrode was transferred at a rate of 1 to 2 占 퐉 / s in the downward direction of the electrode in order to take account of the change in length of the electrode, and the tip was transferred and processed at a rate of 4 mm / s in the pattern length direction.

Comparative Example

A CBN tip (CB7025, Sandvik) without a micropattern was prepared.

Test Example 1 (pattern shape)

The surface of the example was photographed using SEM, and the characteristics of the pattern were examined using a non-contact three-dimensional surface analyzer (NANO View-E1000, NANO SYSTEM).

FIG. 3 is a SEM photograph of the surface of the SEM tip. FIG. 4 is a graph of the size of the groove. It can be seen from FIG. 3 that the micropattern was clearly generated. The depth was 50 μm, confirming that an appropriate surface roughness was formed.

Test Example 2 (Cutting Test)

A, B, C and D were prepared by using the tools equipped with the examples and the comparative examples. AISI material (C 0.98-1.1 wt%, Cr 1.4 wt%, Mn 0.35 wt%, Si 0.25 wt%, P 0.25 wt% ) Was mounted on a shelf of TSL-6 (S & T Dynamics, Korea) to perform cutting work (FIG. 5).

At this time, the three-dimensional force acting on the tip was measured using a piezo electric sensor (Kistler 9257B, Switzerland) and processed through a computer including a DAQ program.

6, and chips generated during machining were photographed using an electron microscope (SEM; Hitachi S4800, Japan). Tool wear was measured using an optical microscope (Leica VZ100, Switzerland) .

Fig. 8 is a graph showing the coefficient of friction according to the feeding speed, Fig. 9 is a graph showing the coefficient of friction according to the feeding speed, Fig. FIG.

11 is a graph showing the shape of the chip according to the linear velocity, FIG. 12 is a graph showing the friction coefficient according to the linear velocity, FIG. 13 is a graph showing the linear velocity And a cutting parameter value according to the following formula.

On the other hand, flank wear (MRR), crater wear width, and crater wear length are shown in Figs. 14, 15 and 16, respectively. And the frank wear photograph and the crater wear photograph are shown in Figs. 17 and 18, respectively.

7 to 18, it is confirmed that the embodiment in which the micropattern 20 is formed is more effective in terms of machining force and tool life than a general tip in which no micropattern is formed.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, And all of the various forms of embodiments that can be practiced without departing from the technical spirit.

10: Tip 20: Micro pattern
21: rim 22: straight groove
23: Interval

Claims

In a tip for a cutting tool in which a micropattern is formed,
Wherein the tip comprises a micropattern formed on an upper surface of a corner portion in contact with the workpiece.

The tip of a cutting tool according to claim 1, wherein the tip is CNB material.

The tip of a cutting tool according to claim 2, wherein a tip portion of the tip upper corner portion includes a rim portion on which a micropattern is not formed.

[4] The tip of a cutting tool according to claim 3, wherein the micropattern is formed by arranging a plurality of straight grooves having a constant width at equal intervals.

The tip of a cutting tool according to claim 4, wherein the straight groove is formed at an angle of 50% of an angle formed in the tip corner portion and inclined relative to the horizontal.

The tip of a cutting tool according to claim 5, wherein the tip of the adjacent straight groove is an isosceles triangle.

[Claim 7] The method of claim 6, wherein the width of the straight groove is 90 to 110 [ A tip for a cutting tool in which a micropattern is formed.

[Claim 7] The method according to claim 7, wherein the depth of the straight groove is 20 to 60 [ A tip for a cutting tool in which a micropattern is formed.

The tip of a cutting tool according to claim 8, wherein the gap is a linear groove width of ± 10%.

[12] The method of claim 9, wherein the width of the rim is 50% to 100% Wherein the tip of the cutting tool has a micro pattern formed thereon.