JPH0128961Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a throw-away tip that has a polygonal shape in plan view and has two minor cutting edges at its corner portions.

[Conventional technology]

A polygonal negative throw-away tip used for face milling etc. has two minor cutting edges at the corners of the polygon in order to use all the main cutting edges on each side of the polygon, both on the top and bottom surfaces. Some have blades.

Conventionally, as such a throw-away chip, a throw-away chip 1 as shown in FIGS. 17 to 20 is known. This throwaway chip 1 has a substantially equilateral triangular shape in plan view, and has an upper surface 11 and a lower surface 12 that are parallel to each other, and a side surface 13 that is directly illuminated with respect to the upper surface 11 and the lower surface 12.
It has a configuration with. Each side edge formed by the side surface 13, the upper surface 11, and the lower surface 12 serves as a main cutting edge 14, 15, respectively.
Furthermore, at the corner between the side surfaces 13 and 13, a minor cutting edge 16 is formed at one end on the upper surface 11 side to connect to the main cutting edge 14, and at the other end on the lower surface 12 side to connect to the main cutting edge 15. A sub-cutting edge 17 is formed. Flank surfaces 18, 1 of these minor cutting edges 16, 17
9 is formed into a straight plane, and has a positive clearance angle so that the sub-cutting edge can perform cutting with a positive rake. The flanks 18 and 19 intersect with each other between the auxiliary cutting edges 16 and 17, and a ridgeline portion 20 is formed there. Note that the other two corner portions are also formed in the same manner.

21 to 24 show a face milling cutter 22 with the above-mentioned tip 1 attached to a cutter body 21, in which one main cutting edge 14 of the tip 1 is located outside the cutter body 21, and The angle between the minor cutting edge 16 and the axis of the cutter body 21 is
In this conventional example, the main cutting edge is fixed at a negative rake angle and the minor cutting edge is fixed at a positive rake angle. The face milling cutter 22 is configured to perform rough cutting with the main cutting edge 14 and finish cutting with the auxiliary cutting edge 16.

[Problem that this idea attempts to solve]

However, as shown in FIG. 24, when the conventional throw-away tip 1 is attached to the cutter body 21 and performs frontal cutting, the portion of the ridgeline portion 20 on the side of the sub-cutting edge 16 cuts over a wide area. Since it is involved in cutting for a long time, there have been problems such as poor surface finish, increased cutting resistance, and chip damage.

In addition, in the conventional throw-away chip 1, since the two flank surfaces 18 and 19 intersect with each other, the thickness of the chip, the clearance angle of the auxiliary cutting edge,
Depending on the angle formed by the main cutting edge and the minor cutting edge connected to it, and the length of the minor cutting edge, the minor cutting edges 16 and 17 are
The gap t between the two ends is determined. For this reason, it is not possible to increase the length of the main cutting edge and increase the maximum cutting depth shown by e in Figure 21, and to increase this, the size of the chip itself must be increased. There was a problem that it was not possible.

[Means for solving problems]

This invention was made in order to solve the above-mentioned problem, and the side surface between the two flanks of the corner portion is formed by a notch surface consisting of a concave twisted curved surface.

〔Example〕

An embodiment of this invention will be described below with reference to FIGS. 1 to 8. In addition, in these figures, the same reference numerals are given to the parts having the same configuration as those of the conventional example, and detailed explanation thereof will be omitted.

1 to 4 show the throw-away tip 3 according to this invention, FIG. 1 is a front view thereof, FIG. 2 is a side view thereof, and FIG. 3 is a direction of arrow D in FIG. 1. The arrow view in Fig. 4 is the arrow E in Fig. 1.
It is an enlarged view of a part. Since the throwaway chip 3 shown in these figures has the same configuration as the conventional throwaway chip 1 except for the shape of its corner portion, the corner portion will be explained below.

In the corner portion between the side surfaces 13, 13, at one end on the upper surface 11 side, a minor cutting edge 31 connected to the main cutting edge 14 and having a predetermined length is provided with a relief surface 32 that is a straight plane and has a positive relief angle. At the other end on the lower surface 12 side, a minor cutting edge 33 connected to the main cutting edge 15 and having a predetermined length is formed with a straight plane and a relief surface 34 having a positive relief angle. It is formed. A notch surface 35 consisting of a concave twisted curved surface is formed in the side surface portion between the two flank surfaces 32 and 34, and the notch surface 35 forms a flank portion 36.
is formed. Since the notch surface 35 is composed of a concave twisted curved surface, the intersecting ridge 37 between the notch surface 35 and the upper surface 11 and the lower surface 12,
38 is a concave curve concave toward the inside of the chip 3. Note that the other two corner portions are also formed in the same manner.

5 to 8 show a face milling cutter 42 with the above-mentioned tip 3 attached to a cutter body 41, FIG. 5 is a front view thereof, FIG. 6 is a bottom view thereof, and FIG. 7 is a front milling cutter 42. Its side view, FIG. 8, shows an enlarged view of the portion indicated by arrow F in FIG. In these figures, the tip 3 has the main cutting edge 14 located outside the cutter body 41, as in the conventional example, and the minor cutting edge 31 and the axis of the cutter body 41 at an angle of 90°. is installed.

By the way, in the above chip 3, since the relief part 36 is formed between the auxiliary cutting edges 31 and 33, when it is attached to the milling cutter main body 41 and performs front cutting as shown in FIG. , auxiliary cutting edges 31 and 3
It is possible to shorten the contact length between the part between 3 and the workpiece, thereby preventing deterioration of the finished surface, reducing cutting resistance, and extending the life of the chip. In particular, notch surface 3
5 is formed by a concave twisted curved surface, the clearance angle of the portion of the ridge line 37 adjacent to the sub-cutting edge 31 is positive with respect to the workpiece W, which prevents deterioration of the finished surface and improves the life of the chip. can be made even more reliable. In addition, in the case of the chip 3, the notch surface 35 is interposed between the flank surfaces 32 and 34, each of which is a straight plane, so that the flank surfaces 32 and 34 do not intersect directly. There is no geometrical restriction on the positional relationship between the minor cutting edges 31 and 33 formed by the surfaces 32 and 34, and therefore the distance l between the minor cutting edges 31 and 33 is Can be set small. As a result, the length of the main cutting edge can be increased, and the maximum cutting depth shown by e in FIG. 5 can be increased.

In addition, although the above embodiment describes a chip having an equilateral triangular shape in plan view, it is not limited to this, and other chips may be used as long as they have two minor cutting edges at the corner of the main cutting edge. It may be polygonal. For example, the chip 5 shown in FIGS. 9 to 16 has a substantially square shape in plan view, and the same parts as in the above embodiment are given the same reference numerals. Further, in the above embodiment, the notch surface 35 made of a concave curved surface is provided between the auxiliary cutting edge 31 and the auxiliary cutting edge 33, but there is no need to limit it to this, and the auxiliary cutting edge 31 and the auxiliary cutting edge A cutout surface having a U-shape in plan view may be provided between the cutting edge 33 and the cutting edge 33 .

[Effect of idea]

As explained above, according to the throw-away tip of this invention, since the side surface between the two flanks of the corner portion is formed by the notch surface consisting of a concave twisted curved surface, it is possible to When installed and performing frontal cutting, the contact length between the part between both secondary cutting edges and the workpiece can be shortened, thereby preventing deterioration of the finished surface and reducing cutting resistance. This has the effect of extending the life of the chip, and since the notch relief part is formed between the two minor cutting edges at the corner, the geometrical relationship between the two minor cutting edges can be adjusted. This has the effect that the distance between the two minor cutting edges can be made closer, and the main cutting edge can be made longer accordingly.

[Brief explanation of the drawing]

1 to 4 are views showing a throw-away tip which is an embodiment of this invention, in which FIG. 1 is a plan view thereof, FIG. 2 is a side view thereof, and FIG. 3 is a view similar to that shown in FIG. 1. FIG. 4 is an enlarged view of the arrow E portion in FIG. 1, and FIGS.
The figures show the throw-away tip attached to the cutter body, in which FIG. 5 is a front view, FIG. 6 is a bottom view, and FIG. 7 is a side view.
FIG. 8 is an enlarged view of the arrow F part in FIG. 5, showing the state in which a workpiece is being cut, and FIGS. 9 to 12 show throw-away tips of other embodiments. Figure 9 is its front view,
10 is a side view thereof, FIG. 11 is a view taken in the direction of arrow G in FIG. 9, FIG. 12 is an enlarged view of the portion indicated by arrow H in FIG. 13 is a front view of another throw-away tip, FIG. 14 is a bottom view of the tip, FIG. 15 is a side view of the tip, and FIG. 16 is a side view of the tip; This is an enlarged view of the part indicated by the middle arrow I, showing a state in which a workpiece is being cut. FIGS. 17 and 20 are views showing an example of a conventional throw-away tip, and FIG. 18 is a side view, FIG. 19 is a view taken in the direction of arrow A in FIG. 17, and FIG. 21 is a side view of the same.
An enlarged view of part B in Figure 7, and Figures 21 to 24 are views showing the conventional throw-away tip attached to the cutter body, with Figure 21 being a front view thereof, and Figure 22 showing its front view. FIG. 23 is a bottom view, FIG. 23 is a side view, and FIG. 24 is an enlarged view of portion C in FIG. 21, showing a state in which a workpiece is being cut. 3...Throwaway tip, 11...Top surface,
12... Bottom surface, 13... Side surface, 14, 15... Main cutting edge, 31, 33... Minor cutting edge, 35... Notch surface, 36... Relief part.

Claims (1)

[Scope of utility model registration request] It has a polygonal shape in plan view, and has an upper surface and a lower surface that are parallel to each other, and side surfaces that are perpendicular to these upper and lower surfaces. A throw-away chip in which sub-cutting edges are formed at one end of the top surface of the corner portion and the other end of the bottom surface of the corner portion, and a positive relief angle is provided to the relief surfaces forming these sub-cutting edges. 2. A throw-away chip according to claim 1, wherein the side surface between the two flanks of the corner portion is formed by a cutout surface having a concave twisted curved surface.