JPH0511923Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to a small-diameter throw-away end mill suitable for small diameters, for example in the range of 15 to 25 mm, and particularly used for cutting keyways and molds. It is something.

(Prior Art) Conventionally, end mills of this type have been disclosed, for example, in Japanese Patent Publication No. 53-44270, US Pat. No. 3,354,526, and the like.

The former publication discloses a so-called center-cut end mill in which a square plate-shaped throw-away tip is arranged within two flutes, and the nose of one of the throw-away tips is aligned with the axis center line of the tool body. It is in a position that exceeds the

In the latter specification, triangular chips are located on both sides of the tool body in a substantially parallel relationship.

(Problem that the invention aims to solve) However, these end mills have a peripheral cutting edge formed by one side of a square or a triangle, and the tool rigidity is not very high, so it is difficult to perform deep groove machining or drilling of small diameters. It was something that I couldn't do.

This invention has a center cutting edge tip and a peripheral cutting edge tip attached to the tool body.In particular, by improving the configuration of the center cutting edge tip, we aim to solve the problems of the cutting edge length and tool rigidity at the outer cutting edge edge. That is.

(Means for Improving the Problems) The present invention was developed in view of the above-mentioned points, in which a center cutting tip and a peripheral cutting tip are arranged at one end of the rod-shaped tool body, and
This indexable end mill has been improved so that the center cutting edge tip and the peripheral cutting edge tip each have a front cutting edge ridge formed in the diametrical direction of the tool body, and an outer cutting edge ridge formed in the axial direction of the tool body. It provides:

That is, in the center cutting edge tip, between a pair of diagonal corners, the front cutting edge ridge and the outer cutting edge ridge are at right angles to each other, and when this diagonal corner is used as a reference, the non-cutting ridges are parallel to each other. It has a hexagonal plate shape that is rotationally symmetrical through the .

In addition, in the cutting rotation locus formed when the center cutting tip is placed in the tip seat of the tool body, there is a gap between the front cutting edge ridge starting near the rotation center and the outer cutting edge ridge located at the outer periphery. , and the uncut edges intersecting with each other are positioned so as to be inclined. Furthermore, the front cutting edge of the center cutting edge is located rearward in the axial direction of the tool body than the front cutting edge of the peripheral cutting edge, and extends from the vicinity of the rotation center to the outer periphery. It intersects with the ridge at approximately the middle diameter region, creating a concave relationship. Further, the outer cutting edge of the center cutting edge is located rearward than the outer cutting edge of the outer cutting edge of the outer cutting edge due to the interposition of the non-cutting edge, and is connected to the outer cutting edge of the outer cutting edge of the outer cutting edge. It is something.

(Function) The indexable end mill of the present invention achieves an effective cutting action by forming the central cutting edge into a specified hexagonal plate shape. That is,
In the rotation locus formed by the center blade tip and the peripheral blade tip, the front cutting edge of the center blade tip, which is located somewhat rearward in the axial direction, starts near the center of rotation and is approximately at the middle diameter of the peripheral blade tip. It intersects with the front cutting edge ridge and cuts in a well-balanced manner in a so-called concave relationship. On the other hand, the peripheral cutting edge of the central cutting edge has an inclined non-cutting edge interposed between it and the front cutting edge, so it is located axially rearward than the outer cutting edge of the peripheral cutting edge. In addition, since the rotary locus is connected to the outer peripheral cutting edge ridge of the outer peripheral cutting tip, the effective cutting edge length in the axial direction can be increased, and it can be applied to deep grooves and deep holes.

Furthermore, the indexable end mill of the present invention functions so that tool rigidity is not impaired due to the structure of the center cutting tip. That is, the chip seat in the center cutting chip has an inclined side wall interposed between the side wall located near the axis center line and the side wall extending in the diametrical direction so as not to reduce the strength of the tool body.

(Example) Hereinafter, an example of the indexable end mill of the present invention will be described with reference to the drawings.

1 to 4, reference numeral 1 indicates a rod-shaped indexable end mill, and a tool body 2
and shank 3. The tool body 2 has a flute groove 4 in the axial direction.
5 are formed, and a center blade tip 8 and a peripheral blade tip 9 can be installed in the chip seats 6, 7 of the flute grooves 4, 5, respectively, using, for example, a center mounting hole 10 and a mounting screw 11. ing. In this case, in the illustrated example, two peripheral cutting tips 12, 13 are further mounted in the tip seats 14, 15 in order to increase the length of the cutting edge in the axial direction.

The center cutting edge 8 has a hexagonal plate shape as clearly shown in FIG. By intersecting at right angles, a right-angled corner is formed. Further, the center-center cutting tip 8 is rotationally symmetrical with respect to this right-angled corner, and non-cutting edges 18 are formed in parallel to each other in the intermediate portion thereof. Furthermore, in order to smoothly dispose of chips, the center blade tip 8 has a section around the center boss surface 19.
A chip breaker 20 is formed, and
A convex curved edge 21 forming a so-called spiral blade is formed on the front cutting edge 16 near the center of rotation.
Note that, as this convex curved edge 21, a rounded arc shape or a linear chamfer shape is applied.

The rotational cutting trajectories of the center edge tip 8 and the peripheral edge tip 9 are as shown in FIG.

That is, the front cutting edge edges 16 and 22 of the central cutting edge tip 8 and the peripheral cutting edge tip 9 intersect in a concave relationship, as clearly shown in FIG. Therefore, the front cutting edge 16 of the center cutting edge 8 is located somewhat rearward in the axial direction than the front cutting edge 22 of the outer peripheral cutting edge 9, and is approximately in the intermediate diameter region. It intersects with the front cutting edge ridge 22. In this case, the peripheral cutting edge 9 has a diamond-shaped plate shape as shown in FIG. 6, and its front cutting edge ridge 22 has an inclination angle θ directed inward with respect to the diametrical line. It is something that Also,
Regarding the position where the front cutting edge edges 16 and 22 of the center blade tip 8 and the peripheral blade tip 9 intersect,
For those shown in Figures 1 to 4, if expressed as radius R, the outer diameter D of the cutting edge is usually D/3.5~
D/4.5, and the inclination angle θ is set to 2° to 4°.

Further, the outer peripheral cutting edge ridges 17 and 23 of the center cutting edge tip 8 and the outer peripheral cutting edge tip 9 are designed to partially overlap and continue on the rotary cutting locus, as shown in FIG.

Furthermore, the peripheral cutting tips 12 and 13 have a square plate shape, and are arranged to increase the effective length of the cutting edge in the axial direction, as described above. Therefore, the outer cutting edges 24 and 25 of the outer cutting edges 12 and 13 are continuous with the outer cutting edges 17 and 23 on the rotary cutting locus.

Therefore, in the indexable end mill of the present invention, for example, when the outside diameter D of the cutting edge is 16 mm, the ones shown in FIGS. 1 to 4 have a center blade tip 8, a peripheral blade tip 9, 12 ,1
3, the length of the cutting edge in the axial direction of the tool body 2 can be set to about 18 mm. Regarding the angular relationship between the center edge tip 8 and the peripheral edge tip 9, the rake angle α in the axial direction is usually in the range of α = 0° to +10°, and the rake angle β in the radial direction is in the range β = 0° to -15°. Set within.

In this embodiment, the outer peripheral edge tip 9 is a diamond-shaped plate, but is not limited to this. If so, for example, a circular plate shape or a square plate shape can be selected as appropriate. Further, if the length of the cutting edge in the axial direction is not required depending on the cutting conditions, only the center cutting edge tip 8 and the peripheral cutting edge tip 9 are sufficient.

(Effects of the Invention) The indexable end mill of the present invention has the improved shape and cutting edge configuration of the center blade tip 8, and therefore has the following effects.

First, the outer diameter D of the cutting edge can be reduced. This is because in the indexable end mill of the present invention, the outer diameter D of the cutting edge can be set to 15 to 16 mm. That is, this is because tool rigidity is not impaired due to the configuration of the tip seat 6 in the center cutting tip 8, and the core thickness of the tool body 2 can be increased due to the angular configuration of the rake angle α in the radial direction.

Second, it has become possible to drill small diameter holes and create deep grooves. This is because an effective cutting action can be obtained from the cutting edge configurations of the center edge tip 8 and the peripheral edge tip 9. In other words, the product of the present invention, which is equipped with a center cutting edge 8 and a peripheral cutting edge 9, has a cutting speed of 8 mm for a workpiece made of S55C (H _B 230).
This is because when cutting deep grooves, stable cutting was obtained without vibration. In this case, the tool specifications of the invented product are that the cutting edge outer diameter D is 16 mm, the effective cutting edge length in the axial direction is 10 mm, and the cutting conditions are: cutting speed V = 100 m/min, lateral feed F _t = 200 mm /min,
The vertical feed F _v = 100 mm/min. In addition,
The conventional product for comparison was a two-flute type with a square plate throw-away tip, but the effective cutting edge length was short, and under the cutting conditions mentioned above, it caused chatter at a depth of about 5 mm, causing problems. It was hot.

Furthermore, when the present invention was applied to a type equipped with peripheral cutting tips 12 and 13 as shown in FIGS. 1 to 4, effective groove cutting was achieved. In this case, the tool specification is the cutting edge outer diameter D
was 16 mm, the effective length of the cutting edge was set to 18 mm, and the cutting conditions were the same as those described above. As a result, a keyway with a groove depth of 16 mm and a groove length of 100 mm could be stably cut.

[Brief explanation of drawings]

Fig. 1 is a front view showing one embodiment of the indexable end mill of the present invention, Fig. 2 is a bottom view, Fig. 3 is a partial right side view, Fig. 4 is a partial left side view, FIG. 5 is an enlarged front view showing the center blade tip;
FIG. 6 is an explanatory diagram showing the rotational cutting locus of the cutting blade. 1... Indexable end mill, 2... Tool body, 8... Center blade tip, 9... Peripheral blade tip, 16, 22... Front cutting edge ridge, 17, 23...
Outer cutting edge ridge, 18...non-cutting edge.

Claims (1)

[Claims for Utility Model Registration] At one end of the rod-shaped tool body 2, a center blade tip 8 and a peripheral blade tip 9 are arranged, respectively. Front cutting edge 1 in the diameter direction of 2
6 and 22, respectively, and outer peripheral cutting edge ridges 17 and 23 are respectively formed in the axial direction of the tool body 2. The center cutting edge tip 8 has a pair of diagonal corners. The front cutting edge 16 and the outer cutting edge 17 are in a right-angled relationship with each other, and when this diagonal corner is taken as a reference, the hexagonal plate is rotationally symmetrical with respect to the non-cutting edges 18 that are parallel to each other. In addition, in the cutting rotation locus formed when the tip is placed in the tip seat 6 of the tool body 2, there is a front cutting edge ridge 16 starting near the center of rotation and an outer cutting edge ridge 17 located at the outer periphery. In between, the non-cutting edges 18 intersecting each other are located so as to be inclined, and the front cutting edge 16 is closer to the axis of the tool body 2 than the front cutting edge 22 of the peripheral cutting edge 9. By being rearward in the direction and extending from the vicinity of the center of rotation to the outer circumferential side, it intersects the front cutting edge 22 of the peripheral blade tip 9 in the approximately intermediate diameter region, creating a concave relationship, and the center blade tip 8 The outer cutting edge 17 of the outer cutting edge 17 is located rearward than the outer cutting edge 23 of the outer cutting edge 9 and is connected to the outer cutting edge 23 of the outer cutting edge 9 through the interposition of the non-cutting edge 18. Features a throw-away end mill.