JPH0214896Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an indexable milling tool in which a plurality of positive indexable tips are attached to the outer periphery of the tip of the tool body along the axial direction of the tool body.

[Prior Art] In recent years, throw-away type milling tools have been used in end mills, etc., in which a plurality of positive throw-away tips are removably attached to the outer periphery of the tip of the tool body along the axial direction. is becoming widely used.

Figures 22 to 28 show a conventional indexable milling tool of this type (hereinafter abbreviated as a milling tool).
The reference numeral 1 in the figure indicates the tool body of this milling tool.

This tool body 1 has a substantially cylindrical shape with its base end rotatably held by a drive source such as an end mill around an axis Chip pockets 2 that are formed at multiple locations (four locations in the figure) spaced at equal intervals in the circumferential direction, with portions of the pockets being largely removed toward the outer periphery.
...and the tool body 1 of this chip pocket 2...
Inclined surface 3 for mounting the chip facing the rotation direction of...
is formed. A tip mounting seat 4 is formed on each inclined surface 3 for mounting a tip on the tool body 1, and a throw-away tip 5 is mounted on the tip mounting seat 4, as shown in FIGS. 27 and 28.
The main cutting edges 8, which will be described later, in each other's rotation loci are connected in the axial direction and detachably attached.

As shown in FIGS. 24 to 26, the chip 5 is formed into a plate shape with an approximately rhombic appearance.
Main cutting edges 8, 8 are formed on a pair of opposing sides 7, 7 of the sides 7 of the upper surface 6, and a lower surface 9 serving as a mounting surface is formed from these main cutting edges 8, 8. The flanks 1 of these main cutting edges 8, 8 are on the sides leading to
0 and 10 are formed. and,
The cutting edge tip 1 of the upper surface 6 along the main cutting edge 8
A rake face 13 of the main cutting edge 8 extending from the main cutting edge 1 to the rear end 12 of the cutting edge is formed of a convex curved surface such that the main cutting edge 8 draws a substantially arcuate shape. Here, the convex curved surface forming the rake face 13 is the upper and lower surfaces 6 and 9.
The maximum thickness part 14 in between is the cutting edge tip 1 of the main cutting edge 8.
1 and the rear end 12 of the cutting blade.

By the way, in the case of the chip 5 in which the rake face 13 is formed as a convex curved surface, the cutting edge angle γ at the tip of the cutting edge is large, and the cutting edge strength is excellent, and its unique cutting action reduces cutting resistance and It is known that it has unique advantages such as reduced generation of cutting heat.

As shown in FIG. 22, the tip 5 is mounted, for example, on the tip mounting seat 4 of the tool body 1 at a positive inclination angle α with respect to the axis X of the tool body 1 (the rake face 13 is (if parallel to the angle corresponding to the positive axial rake angle)
The longer the angles β and ε of the tangent of the rake face 13 to the axis X of the main cutting edge 8 are positive, the better the cutting performance and smoothness will be. It is also known that chip removal performance can be obtained.

[Problems to be Solved by the Invention] However, in the case of the chip 5 mounted on the conventional milling tool, the rake face 13 of the chip 5 is formed so that the maximum thickness portion 14 thereof is connected to the main cutting edge 8. As shown in FIG.
While the tangential angle β of the rake face 13 gradually increases in the positive direction toward , the tangential angle ε gradually increases in the negative direction from the center toward the cutting edge tip 11. Therefore, the problem is that the cutting edge tip 11 of the main cutting edge 8 with a negative tangent angle ε reduces the excellent cutting effect of the cutting edge rear end 12 with a positive tangent angle β. It was hot.

In order to solve this problem, when attaching the tip 5 to the tool body 1, it is necessary to make sure that the angle ε between the axis X of the tool body 1 and the tangent at the cutting edge tip 11 is at least not negative. .
That is, the inclination angle α of the chip 5 must be larger than that shown in FIG. 22 above.

However, in this case, in order to obtain a predetermined clearance angle for the chip 5 with the chip 5 attached to the tool body 1, as shown by the dashed line in FIG. must be formed. In such a case, not only will the area of the lower surface 9 of the chip 5 decrease and the seating rigidity and machining accuracy of the chip 5 will decrease, but also the thickness near the tip 11 of the cutting edge will become thinner (relief An increase in the angle θ results in a decrease in the blade angle γ), resulting in a problem that the strength of the cutting edge decreases.

On the other hand, since the above-mentioned milling tool in question here has a plurality of throw-away tips installed along the axial direction of the outer periphery of the tool body 1, the sum of the cutting forces due to all the throw-away tips 5... To a large extent, it is difficult to obtain high tool rigidity due to its structure, so there is a problem that chatter, vibration, etc. are likely to occur in the entire tool body 1.

[Purpose of the invention] This invention was made in view of the above circumstances.
The purpose of the present invention is to provide a milling tool that can improve the seating rigidity, processing accuracy, and cutting edge strength of a positive throw-away chip by reducing the relief angle, and can effectively prevent chatter and vibration. .

[Means for Solving the Problems] The milling tool of this invention has a polygonal plate-shaped positive throw-away tip with main cutting edges formed on at least one pair of opposing sides of the upper surface, which is attached to the outer periphery of the tool body. A plurality of positive throw-away tips are placed on the surface, with one main cutting edge facing outward from the tool body, with the upper surface serving as the rake face, and having a positive rake angle in the axial direction of the tool body. In an indexable milling tool in which the cutting blades are mounted so as to be continuous in the axial direction of the tool body along their rotation locus, the positive indexable tip has a rake face along the main cutting edge on the upper surface, The maximum thickness between the upper and lower surfaces of the main cutting edge is located at a location that is biased towards the cutting edge from the center between the cutting edge tip and the cutting edge rear edge, and a pair of edges formed on opposite sides When viewed from the side in a direction along an imaginary line connecting the maximum thickness portions of the main cutting edge, the shape of the side portion is formed by a convex curved surface that is symmetrical with respect to the imaginary line.

[Example] Figures 1 to 7 show an example of a milling tool of this invention, and parts common to those shown in Figures 22 to 28 are denoted by the same reference numerals. The explanation will be omitted.

In FIGS. 1 and 2, in the milling tool of this example, a throw-away tip 20 is detachably mounted on a tip mounting seat 4 of a tool body 1. The throwaway tip 20 mentioned above is
As shown in FIG. 3 to FIG.
. . . Main cutting edges 24, 24 are formed on a pair of opposing sides 23, 23, and the cutting edge angle is a positive indexable tip smaller than 90 degrees. Then, the main cutting edge 2 of the upper surface 21
The rake face 27 of the main cutting edge 24 from the cutting edge tip 25 to the cutting edge rear end 26 along the main cutting edge 2
4 is formed by a convex curved surface drawing a substantially arc shape. Here, the convex curved surface forming the rake face 27 of the main cutting edge 24 has a maximum thickness part 29 between the upper and lower surfaces 21 and 28 of the cutting edge tip 25 and the cutting edge rear end 26 of the main cutting edge 24. It is formed so as to be located at a location biased towards the cutting edge tip 25 side from the center 30 of the cutting edge.
That is, as shown in FIG. 5, the cutting edge portion l2 where a positive tangential angle is obtained is longer than the cutting edge portion l1 where a negative tangential angle is obtained. Further, the convex curved surface is formed by the opposing main cutting edge 2.
When the side surface of this chip 20 is viewed from the direction along the imaginary line Y connecting the maximum thickness parts 29 and 29 of No. 4 and 24 (arrow A in FIG. 3), as shown in FIG. , the shape of the side portions 23, 23 is a curved line symmetrical with respect to the virtual line Y. Further, the cutting edge tip 25 of the main cutting edge 24 is
The acute corners on the sides are chamfered into an arc shape.

The throw-away chips 20 having such a shape are mounted on the chip mounting seat 4 of the tool body 1 at an inclination angle α, as shown in FIGS. 6 and 7. The main cutting edges 24 are mounted so as to be continuous in the axial direction of the tool body 1 along their rotation loci.

However, for such chip 20,
The rake face 27 of the main cutting edge 24 is located at a location where the maximum thickness portion 29 is biased toward the cutting edge 25 side from the center 30 between the cutting edge tip 25 and the cutting edge rear end 26 of the main cutting edge 24. It is formed by a convex curved surface.
Therefore, even when the tip is mounted on the tip mounting seat 4 of the tool body 1 shown in FIGS. The length of the rake face 27 that forms a positive tangent angle β to the axis X that reaches the rear end 26 of the blade, that is, the negative cutting edge portion l1
The more positive cutting edge portion l2 can be made much longer than the conventional one. Therefore, it is possible to fully obtain excellent cutting effects such as improved cutting performance and chip removal performance when cutting at a positive rake angle using this type of chip having a convexly curved rake face.

In addition, since the main cutting edge 21 drawing a convex curve has the effect of diffusing the width of the chips, the distortion within the chips can be reduced, and as a result, the cutting resistance can be greatly reduced. Therefore, the tool rigidity can be increased, and the occurrence of chatter and vibration in the tool body 1 can be greatly suppressed.

Furthermore, since the clearance angle can be reduced and the area of the lower surface 28 of the chip 20 can be made sufficiently large, seating performance and machining accuracy are excellent, and since the blade angle can be set sufficiently, the life of the chip 20 can be extended. It can be extended.

[Other Embodiments] FIGS. 8 to 10 show a second embodiment of the milling tool of this invention.

8 to 10, the throw-away tip 31 attached to the tool body 1 is formed into a diamond shape in plan view, and the rake face 33 of the main cutting edge 32 has its maximum thickness portion 34 above the Main cutting edge 3
It is formed by a convex curved surface located at the cutting edge tip 35 of No. 2.

However, according to such a chip 31, the first
Even when mounted on the tool body 1 shown in FIGS. positive tangent angle β over the entire length of
can be obtained. Therefore, according to the chip 31, the effects obtained in the chip 20 shown in the first embodiment can be further improved.

11 to 14 show a third embodiment of the milling tool of this invention.

11 and 12, the milling tool of this example has a plurality of openings (in the figure, four ) spiral chip pockets 41... are formed. Here, the inclined surface 42 for attaching the chip of each of the chip pockets 41 is
There are multiple (2 each in the figure) along the axial direction.
A chip mounting seat 43... is formed. Throwaway chips 44 are mounted on these chip mounting seats 43, respectively.

Here, the throw-away tip 44 is formed into a parallelogram plate shape in plan view, and the cutting edge existing on the outer peripheral side of the tool body 41 is the main cutting edge 45.
It is said that The rake surfaces 46, 46 of the main cutting edges 45, 45 are arranged at the cutting edge tips 47, 4 of the main cutting edges 45, 45, as in the second embodiment.
It is formed with a convex curved surface so that the chip thickness is greatest at point 7.

And these throwaway tips 44...
is the tip mounting seat 43 of the tool body 40...
As shown in FIGS. 12 and 13, the main cutting edges 45 are mounted so as to be continuous in the axial direction of the tool body 40 in their rotation loci.

However, even in the case of the milling tool in this example, the first
Although it is possible to obtain the same effects as those of the first embodiment shown in FIGS.
This is particularly effective for this type of tool body 40, which has relatively low rigidity due to its spiral shape.

15 to 19 show a fourth embodiment of the milling tool of this invention, in which a chip 60 having a rectangular external appearance is machined so that the machined wall surface is as shown in FIG. 18.
This shows an example where it is attached to a tool body. In this chip 60, a pair of opposing sides 6 of the top surface 61
Main cutting edges 63, 63 are formed at 2, 62.
In this chip 60, the rake face 66 of the main cutting edge 63 is formed by a convex curved surface with its maximum thickness portion 67 located at the cutting edge tip 64 of the main cutting edge 63. In the milling tool of this embodiment, the tip 60 located at the lowermost end of the tool body is mounted obliquely with respect to the axis X direction. In addition, in each of the other embodiments, the chip 20,
44 may be mounted at an angle with respect to the axis X, if necessary, as shown in FIG.

Accordingly, this chip 60 can provide the same effects as those shown in the first embodiment.

In each of the above embodiments, the shape of the convex curved surface at the main cutting edges 24, 32, 45, and 63 is approximately arcuate, but the shape is not limited to this, and other quadratic curves may be used. It may also be something that depicts
Further, the upper surfaces 21, 61 may have flat portions formed in a planar shape for a predetermined length before and after the maximum thickness portions 29, 34, 67.

Depending on the shape of the processed wall surface, the chips may be arranged as shown in FIGS. 20 and 21, for example, by arranging the chips 60 of the fourth embodiment above, or The example tip 44 may be arranged at an angle with respect to the axis X so as to be at the lowest position.

[Effects of the invention] As explained above, the milling tool of this invention has a polygonal plate-shaped positive throw-away tip with main cutting edges formed on at least one pair of opposing sides of the upper surface, which is attached to the outer periphery of the tool body. A plurality of positive throw-away tips are placed on the surface, each with one main cutting edge facing outward from the tool body, with the upper surface serving as the rake face, and having a positive rake angle in the axial direction of the tool body. In an indexable milling tool in which the cutting blades are mounted so as to be continuous in the axial direction of the tool body along their rotation locus, the positive indexable tip has a rake face along the main cutting edge that is The maximum thickness between the upper surface and the lower surface forming the seating surface is located at a location that is biased towards the cutting edge tip side from the center between the cutting edge tip and the cutting edge rear end of the main cutting edge, and The shape of the part is formed by a convex curved surface that is symmetrical with respect to the imaginary line when viewed from the side in a direction along the imaginary line connecting the maximum thickness parts of the pair of main cutting edges formed on the opposing sides. It is composed and formed.

Therefore, this milling tool provides excellent cutting effects when cutting at a positive rake angle using chips with this type of convex curved rake face, such as improved cutting performance and chip removal performance. Obtainable. Furthermore, this cutting resistance can be reduced, tool rigidity can be increased, and chatter and vibration can be effectively prevented from occurring.

Furthermore, the clearance angle can be reduced to ensure a sufficiently large area on the bottom surface of the tip, resulting in excellent seating performance and machining accuracy.Also, the cutting edge angle can be set to a sufficient angle, extending the life of the throw-away tip. be able to.

[Brief explanation of the drawing]

Figures 1 to 7 show a first embodiment of the milling tool of this invention, and Figure 1 is a front view of the milling tool;
Fig. 2 is a bottom view of the tip, Fig. 3 is a front view of the throw-away tip attached to the cutting tool, Fig. 4 is a view taken from arrow A in Fig. 3, and Fig. 5 is a view taken from arrow B in Fig. 3. FIG. 6 is a front view showing the rotation locus of the throw-away chip on the processing surface, and FIG. 7 is a side view thereof. Figures 8 to 10 show a second embodiment of the milling tool of this invention. Figure 8 is a front view of the throw-away tip attached to the milling tool, and Figure 9 is the same as that of Figure 8. A view taken along arrow C, and FIG. 10 is a view taken along arrow D in FIG. Figures 11 to 14 show a third embodiment of this invention, with Figure 11 being a front view of the milling tool, Figure 12 being a bottom view, and Figure 13 showing the machining surface of the throw-away tip. FIG. 14 is a front view showing the rotation trajectory, and a side view thereof. Figure 15~
Fig. 19 shows a fourth embodiment of the milling tool of this invention, Fig. 15 is a front view of the throw-away tip attached to the milling tool, and Fig. 16 is a view taken in the direction of arrow E in Fig. 15. , FIG. 17 is a view taken along arrow F in FIG. 15. In addition, FIG. 20 and FIG. 21 are a front view and a side view showing the rotation locus of a milling tool of a modified example in each embodiment. Figures 22 to 28 show conventional examples of the milling tool of this invention. Figure 22 is a front view of the milling tool, Figure 23 is its bottom view, and Figure 24 is attached to the milling tool. Fig. 25 is a view taken in the direction of arrow G in Fig. 24, Fig. 26 is a view taken in the direction of arrow H in Fig. 24, and Fig. 27 shows the rotation locus of the throwaway chip on the machined surface. A front view, and FIG. 28 is a side view thereof. 1, 40, 51...Tool body, 20, 31, 4
4,60... Throwaway tip, 21,61
...Top surface, 23... Side part, 24, 32, 45, 6
3...Main cutting edge, 28...Bottom surface, 25, 35, 4
7, 64... Cutting blade tip, 26... Cutting blade rear end, 2
7, 33, 46... rake face, 29, 34, 67
...Maximum thickness part, 30...Center, Y...Virtual line.

Claims (1)

[Claims for Utility Model Registration] A polygonal plate-shaped positive throw-away tip with main cutting edges formed on at least one pair of opposing sides of the upper surface, and a plurality of positive throw-away tips on the outer peripheral surface of the tool body. One main cutting edge of the chip is directed outward from the tool body, the upper surface is used as the rake surface, and a positive rake angle is formed in the axial direction of the tool body. In an indexable milling tool that is mounted continuously in the axial direction of the tool body, the positive indexable tip has a rake surface along the main cutting edge and a lower surface forming the upper surface and the seating surface. A side where the maximum thickness part between the two sides is located at a location biased toward the tip of the cutting blade from the center between the tip and rear end of the main cutting edge, and where the shapes of the sides are opposite to each other. characterized by being formed by a convex curved surface that is symmetrical with respect to the imaginary line when viewed from the side in a direction along the imaginary line connecting the maximum thickness portions of the pair of main cutting edges formed in the main cutting edge. Throw-away milling tool.