JP4741194B2 - Throw-away tip for face milling - Google Patents

Description

  The present invention relates to a throw-away tip attached to a throw-away type front milling cutter used as a rotary tool in a machine tool such as a machining center.

Conventionally, as a throw-away tip to be mounted on a throw-away type front milling cutter used as a rotary tool in a machine tool such as a machining center, a throw-away having an all-round breaker groove 22 on a rake face as shown in FIG. A chip 21 is known (see Patent Document 1). In such a throw-away tip, a positive rake angle is given from the breaker groove to the cutting edge, so that cutting resistance during milling is reduced.
Utility Model No. 2548434

  Generally, in front milling, a negative rake type throw-away tip (1998 JIS B 0170, hereinafter abbreviated as a negative tip) is used from the economical viewpoint that both front and back surfaces can be used and from the viewpoint of excellent strength. May be. However, when using such a negative tip, it is necessary to attach it to the milling cutter at a negative position for both the axial rake and radial rake (1998 JIS B 0172) due to shape constraints. (1998 JIS B 0170; hereinafter, abbreviated as a positive tip), the cutting resistance becomes larger.

  As a result, when face milling is performed using a negative tip having a breaker configuration (all-round breaker) as disclosed in Patent Document 1, the cutting force is large, so that the machine spindle is deflected. Cutting is performed in a state where the rear of the cutter is slightly lifted, and the cutting resistance is suddenly released at the position where the cutter comes out of the work material. Thus, there is a problem that a machining mark is generated due to the biting of the trailing edge on the machining surface of the work material.

  In particular, in finishing, in order to increase the surface roughness of the work material, the sub-cut angle (1998 JIS B 0172) must be made as small as possible, and the approach angle (1998 JIS B 0172) must be made small. As a result, since the radial rake angle (radial rake) of the outer peripheral cutting edge acting as the main cutting edge becomes negative, the cutting resistance increases, so the above phenomenon is more remarkable.

  The present invention has been made to solve the above-described problems of the prior art, and in a throw-away tip attached to a throw-away type front milling cutter used as a rotary tool in a machine tool such as a machining center, It is an object of the present invention to provide a throw-away tip that is capable of high-quality processing with low resistance while being excellent in durability and durability.

In order to solve the above-mentioned problem, the throwaway tip for front milling according to the present invention has a polygonal shape and a substantially flat plate shape, both of which are rake faces and a side face that forms a flank. Two breakers extending along two adjacent sides of the polygonal shape in a plan view in a negative throwaway tip having a ridge line portion as a cutting edge and a corner R cutting edge at a corner where the cutting blades intersect each other Two concave cutting blades are formed by the grooves reaching each other of the two sides while intersecting each other in the vicinity of the corner R cutting blade,
In, along with lower than other portions of said cutting edge along the height in all areas of the corner R cutting edge to the respective breaker groove, the corner R cutting edge located at the two sides of its both sides the It is characterized in that it is formed so as to incline upward from the bottom of each concave cutting blade to reach the highest central region .

  According to such a configuration, even in finishing with a small approach angle, the radial rake angle of the outer peripheral cutting edge acting as the main cutting edge is brought closer to the positive direction in the corner R cutting edge region in which the breaker groove is formed. Therefore, cutting resistance can be reduced and high quality processing can be performed.

  In addition, the breaker groove is formed in parallel with the cutting edge, and the breaker groove extends in any two adjacent corner R cutting edges. It is desirable in that the rake angle in the radial direction of the blade can be reduced and the same effect can be obtained when the blade is attached to a reverse-handed cutter.

  Further, the fact that a rake face inclined at a positive rake angle from the cutting edge to the bottom of the breaker groove is formed, the axial rake angle of the front side cutting edge acting as a secondary cutting edge in a more positive direction. Since it can approach, it is desirable at the point which can reduce the cutting resistance in a front cutting edge more.

  In addition, it is desirable that lands are formed at least on the cutting edge portion excluding the corner R cutting edge from the viewpoint of suppressing the occurrence of cutting edge damage and maintaining the cutting edge strength regardless of variations in cutting resistance.

According to the throw away tip for front milling of the present invention, the main surface is polygonal and has a substantially flat plate shape. In the negative throw-away tip provided with corner R cutting edges at the corners where the cutting edges intersect with each other, the two breaker grooves extending along two adjacent sides of the polygonal shape in plan view are the corners. Two concave cutting edges are formed by reaching each other of the two sides while intersecting each other in the vicinity of the R cutting edge, and the height in all regions of the corner R cutting edge in a side view. together were lower than other portions of said cutting edge along the each breaker groove, the corner R cutting edge is inclined upwardly respectively from the bottom of each concave cutting edge located at the two sides of its both sides Most by formed a structure are possible to reach the high-level of the central region, the radial rake angle of the outer peripheral cutting edge which acts as a main cutting edge, positive in the area at the corner R portion breaker groove is formed Te Therefore, it is possible to reduce cutting resistance, to achieve high-quality machining that is economical and excellent in strength, and that does not cause machining traces.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1A and 1B show a first embodiment of a front milling throwaway tip (hereinafter abbreviated as a chip) according to the present invention, wherein FIG. 1A is a plan view and FIG. 1B is a B direction of FIG. An arrow side view, (c) is a C direction arrow side view of (a).

  In FIG. 1 (a), the chip 1 according to the first embodiment of the present invention has a substantially flat plate-like main surface 2 that is a rake face, and two main surfaces 2 ( 2 ′) and a cutting edge 4 are provided at the ridge line where the side surface 3 serving as a flank intersects. Here, the tip 1 is a negative tip whose angle between the main surface 2 and the flank 3 is 90 °, and a corner R cutting edge 5 is formed at a corner where the cutting edges 4 intersect each other. Such a negative tip has only one side of the main surface 2 as a rake face, and a positive tip whose angle between the rake face and the flank 3 is less than 90 ° can be used only on one side. In addition to being economically superior in that it can be used, it has the advantages of high rigidity and high cutting edge strength.

  According to FIG. 1, the breaker groove 8 is formed on the main surface 2 in parallel and adjacent to the cutting edge 4, and the breaker groove 8 extending to the corner R cutting edge 5 is formed. That is, as shown in FIGS. 1B and 1C, the breaker groove 8 and the intersecting portion of the corner R cutting edge 5 adjacent to the breaker groove 8 have a cross-sectional shape of the breaker groove 8. It is formed as a concave cutting edge 12 whose cutting edge height gradually changes along, and the height of the corner R cutting edge 5 is lower than the other cutting edge portions.

  Normally, when such a negative tip is attached to a front milling cutter 6 as shown in FIG. 4, both the axial rake (α) and the radial rake (β) are in a negative position due to the restriction of the shape of the negative tip. It is necessary to arrange, and cutting resistance becomes high. In particular, an increase in cutting resistance was more remarkable in finishing work performed by reducing the sub-cut angle γ and reducing the approach angle δ in order to increase the surface roughness of the work material.

However, when the chip 1 of the present invention is used, as shown in FIG. 5 (b), the negative radial rake angle at the corner R cutting edge of the main cutting edge is reduced by the arrangement of the concave cutting edge 12. , As close to zero as possible, or shift to a positive value. As a result, cutting resistance during face milling is reduced, damage to the cutting edge such as chipping is suppressed, and machining traces remain on the surface of the work material due to deflection of the cutter or machine spindle due to large cutting resistance. Therefore, it is possible to stably obtain a high-quality processed surface without causing any trouble. 5A is a schematic diagram showing a radial rake angle at the cutting edge position of the arrow a1 of the tip 1 of FIG. 1, and FIG. 5B is a cutting of the arrow a2 of the tip 1 of FIG. It is a schematic diagram which shows the radial direction rake angle in a blade position. Here, in the conventional chip, the cutting edge position in the corner R cutting edge is in the position of FIG. 5A and the rake angle is β _A , but according to the present invention, the corner R cutting edge is As described above, the rake angle β _B at the corner R cutting edge 5 can be made smaller than β _A by using the concave cutting edge having a low cutting edge height.

  FIG. 2 shows a second embodiment of the chip 1 of the present invention, where (a) is a plan view, (b) is a side view in the direction of arrow B in (a), and (c) is ( The C direction arrow side view of a) is shown, respectively.

  The configuration is basically the same as that of the first embodiment described above, but both ends of the breaker groove 8 extend to both adjacent corner cutting edges 5, and both sides of the corner R cutting edge 5 are cross-sectional shapes of the breaker grooves 8. It becomes the structure which became the concave cutting blade 12 from which cutting edge height changes gradually. This makes it possible to reduce the rake angle in the radial direction of the outer peripheral cutting edge even at the time of high cutting, and the same effect can be obtained even when attached to a reverse-handed cutter. An excellent chip can be obtained.

  FIG. 3 shows a cross-sectional view taken along the line AA in FIG. 1A and a cross-sectional view taken along the line AA in FIG. In both the first embodiment shown in FIG. 1 and the second embodiment shown in FIG. 2, a rake face 10 inclined at a rake angle ε from the cutting edge 4 to the bottom 9 of the breaker groove 8 as shown in FIG. Thus, the axial rake angle (α−ε) of the front-side cutting edge acting as the secondary cutting edge 4b can be made closer to the positive direction, and the cutting resistance is further reduced. be able to.

  The width of the breaker groove 8 parallel to the cutting edge 4 is preferably formed so as to substantially include the arc of the corner R cutting edge 5. By adopting such a configuration, the axial rake angle of the cutting edge from the cutting edge tip of the outer peripheral cutting edge 4 to the breaker groove bottom 9 is reduced, and it approaches zero as much as possible, or shifts to a positive value. Therefore, finishing using this region enables high-quality processing with lower cutting resistance.

  Moreover, as shown in FIG. 3 which is an AA cross section of the chip 1 in FIG. 1, the land 11 is formed on the cutting edge portion excluding the corner R cutting edge 5, so that the cutting resistance varies regardless of the cutting resistance. Generation | occurrence | production of a cutting blade damage can be suppressed and cutting blade strength can be maintained.

  As mentioned above, although embodiment of this invention was illustrated, this invention is not limited to embodiment mentioned above, It cannot be overemphasized that it can be made arbitrary, unless it deviates from the objective of invention.

  For example, in the present invention, in addition to the embodiment described above, the main surface may be a shape such as a triangle, a rhombus, or a parallelogram in addition to a quadrangle. Further, the breaker groove 8 can be applied to other shapes that are normally used as long as the corner R cutting edge is included in addition to the rectangular shape as in the embodiment.

(A) is a plan view, (b) is a side view in the direction of arrow B in (a), and (c) is a side view in the direction of arrow C in (a) of the throw-away tip according to the first embodiment of the present invention. It is. (A) is a plan view, (b) is a side view in the direction of arrow B in (a), and (c) is a side view in the direction of arrow C in (a) of the throw-away tip according to the second embodiment of the present invention. It is. It is AA sectional drawing of Fig.1 (a), and AA sectional drawing of Fig.2 (a). (A) is a side view of the state which attached the throwaway tip of this invention to the front milling cutter, (b) is a D direction arrow side view of (a). FIG. 1A is a schematic diagram showing a radial rake angle at the cutting edge position indicated by an arrow a1 in FIG. 1 and a rotation trajectory of the cutting edge in a state where the throw-away tip of FIG. 1 is attached to the front milling cutter; FIG. 2 is a schematic diagram showing a radial rake angle and a rotation trajectory of the cutting edge at a cutting edge position indicated by an arrow a2 in FIG. 1. It is a top view of the conventional throw away tip.

Explanation of symbols

1 Throw away tip (chip)
2, 2 'Main surface 3 Side surface 4 Cutting edge 5 Corner R cutting edge 6 (Front milling) Cutter 8 Breaker groove 9 Breaker groove bottom 10 Rake face
11 Land 12 Concave cutting edge α Axial rake β Radial rake γ Sub-cut angle δ Approach angle ε Rake angle

Claims (4)

The main surface is polygonal and has a substantially flat plate shape. The ridgeline where the two main surfaces, which are both rake faces, and the side surface that forms the flank face is the cutting edge, and the corner R is at the corner where the cutting edges intersect In negative throw away inserts with cutting edges,
In plan view, two breaker grooves extending along two adjacent sides of the polygonal shape cross each other in the vicinity of the corner R cutting edge and reach each other out of the two sides. A concave cutting edge is formed,
In a side view, along with lower than other portions of said cutting edge along the height in all areas of the corner R cutting edge to the respective breaker groove, the corner R cutting edge is located on the two sides of its both sides A throwaway tip for front milling, wherein the throwaway tip is formed so as to incline upward from the bottom of each concave cutting blade to reach the highest central region .   2. The front milling throwaway tip according to claim 1, wherein the breaker groove is formed in parallel with the cutting edge, and the breaker groove extends in any two adjacent corner R cutting edges. .   The rake face for face milling according to claim 1, wherein a rake face inclined at a positive rake angle is formed from the cutting edge to the bottom of the breaker groove.   4. The front milling throw-away tip according to claim 3, wherein lands are formed at least on the cutting edge portion excluding the corner R cutting edge.

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