JPS6135373Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a regular polygonal throw-away tip.

Conventionally, for example, in indexable end mills, a polygonal indexable tip is often used, and a peripheral cutting edge is formed by a straight portion of the indexable tip. In this case, it is common to use a regular polygonal cutter because of the ease of replacing the worn straight part with another straight part. Furthermore, because the indexable end mill has low rigidity due to its structure and cutting form, the indexable tip for use therewith is required to be capable of reducing cutting resistance. Throwaway chips that meet these demands include those shown in FIG. 1 and FIG. 2, respectively.

The throw-away tip shown in FIG. 1 is intended to directly convert the cutting edge portion on the same circumference of the outer peripheral blade of a conventional integrated staggered end mill, such as a two-flute end mill, into a throw-away tip.
Therefore, in this throw-away chip 1, one of the two opposing straight portions 11a, 11a
A non-cut portion 12a, 12a is formed at each end of the other two opposing straight portions 11b, 11.
A non-cut portion 12b is formed at the center of b. Then, this throw-away tip 1 is placed at two points on the same circumference on the outer periphery of the end mill body, and one of the throw-away tips 1 has a straight portion 11.
a is arranged so that the straight portions 11b of the other throwaway tip 1 form outer peripheral edges.

However, such a throwaway tip 1
In the indexable end mill equipped with the indexable tip 1, the non-cutting portions 12a and 12b divide the chips to reduce cutting resistance, and the uncut portions 12a and 12b of one indexable tip 1 are removed. It can be scraped with the other throwaway tip 1.

However, with this product, when replacing the cutting blade, a pair of throw-away tips 1, 1
Straight portions 11a, 11 of mutually different shapes with respect to
b. Therefore, the operator has to pay extra attention, which reduces work efficiency. Moreover, if the two throw-away chips 1, 1 installed on the same circumference are incorrectly installed by using straight portions 11a, 11a, 11b, 11b of the same shape, the uncut portion of the workpiece
Uncut portions are left at locations corresponding to 2a and 12b.

On the other hand, the throwaway tip 2 shown in FIG.
This is an attempt to convert an integrated roughing end mill into a throw-away type based on the same idea as the throw-away tip described above. That is, this throwaway tip 2
1a to 21d are each formed in a wave shape, and the phase of the crests (troughs) of the waves is the same as that of each straight portion 21a to 21d.
21d, and four pieces are arranged on the same circumference of the outer periphery of the end mill main body, and the linear parts having different phases from each other form outer peripheral blades according to the marks 22a to 22d. be done.

In a throw-away end mill equipped with such a throw-away tip 2, the division of chips can be further improved, but on the other hand,
It is undeniable that the finish has deteriorated. Moreover, the problem of incorrect mounting is the same as in the conventional example described above, and in that case, the shape of the straight portion will appear on the workpiece as it is, further worsening the finished surface.

This idea was created in consideration of the above circumstances, and it not only makes it possible to break up chips into small pieces, but it also makes it possible to reliably prevent incorrect installation without the operator having to pay extra attention. Moreover, it is an object of the present invention to provide a regular polygonal indexable cutting tool that can provide a good finished surface.

The characteristics of this invention are, if we take an end mill as an example,
Contrary to the conventional idea that linear sections of different shapes are located on the same circumference of the end mill body, a straight section is placed in the center of each straight section of the throw-away tip, which is a regular polygon of equal size. A non-cutting part having a length of 1/4 to 1/3 of the length is formed for each throwaway chip, and each throwaway chip is arranged offset from each other in the axial direction so that the straight part is continuous in their rotation locus. That's the point.

An embodiment of this invention will be described below with reference to FIGS. 3 to 5. 4A is a plan view of the end mill of the embodiment, FIG. 4B is a side view thereof, FIG. 3A is a plan view of the throw-away tip attached to the end mill, and FIG. 3B is a side view thereof. It is. The throwaway tip 3 shown in FIGS. 3A and 3B is a square negative tip,
Both end faces are similarly configured rake faces 31, 3.
It is said to be 1. A straight portion 32 and a nose portion 33 are formed at the peripheral edge of the rake face 31 . Also, the chip side surface 3 between the rake faces 31 and 31
A notch groove 35 extending from one rake face 31 to the other rake face 31 is formed in the center of the cutout 4 . By forming this notch groove 35, at the same location in the center of each straight portion 32,
One non-cut portion 36 having the same width is formed. This non-cutting portion 36 is for dividing the chips generated by the straight portion 32 and narrowing the width of the chips. From this point of view,
It is desirable that the width of the non-cut portion 36 be as wide as possible within a design tolerance, which will be described later, and is set to be 1/4 to 1/3 of the length of the straight portion 32 based on experimental results.

As shown in FIGS. 4A and 4B, four throw-away tips 3 configured in this manner are detachably attached to the outer circumference of the end mill body 37 at equal intervals in the circumferential direction. It is installed. As shown in FIG. 5, these four throw-away tips 3 are attached to the end mill body 37 so that the rotation locus of each linear portion 32 on a plane including the axis of the end mill body 37 forms a continuous peripheral blade 38. They are arranged offset from each other in the axial direction of 37. That is, the two throw-away tips 3, 3 on the tip side are shifted by a larger amount than the width of the non-cut portion 36, and the length of the portion between the nose portion 33 and the non-cut portion 36 of the straight portion 32 is greater than the width of the non-cut portion 36. They are staggered so that they are smaller than the original size. As a result, the uncut portion 3 of one throwaway tip 3
The uncut portion left by the tip 6 is removed by the other throwaway tip 3. This means that the two throwaway tips 3 and 3 on the rear end side
The same applies to the time between. In this case, the width of the non-cut portion 36 is the same as that of the nose portion 33 of the straight portion 32 and the non-cut portion 3.
Of course, it must be set shorter than the length of the part between 6 and 6. In addition, the two throwaway chips 3, 3 in the center are connected to each other in the straight part 3.
2 and 32 are arranged so that a part of them overlaps in the rotation locus.

In the indexable end mill configured as described above, since the non-cutting portion 36 is formed in the straight portion 32, it is possible to finely divide the chips, and the non-cutting portion 36 The contact length between the straight portion 32 and the workpiece is shortened, and these two factors work together to reduce cutting resistance. Moreover, while the non-cut portions 36 having the same width are formed at the same location in the center of each linear portion 32, the non-cut portions 36 are shifted from each other by shifting the throw-away tip 3 itself in the axial direction of the end mill body 37. Because of this, the position of the uncut part of the worn straight part and the new straight part is the same before and after the cutting blade is replaced, and therefore, it is possible to prevent incorrect installation without paying any attention when replacing the cutting blade. can be prevented. Moreover, since the non-cutting part 36 is formed in the center part, which is the same location for each linear part 32 of either the upper or lower rake face 31, it is possible to avoid incorrect attachment when using either the upper or lower rake face 31. can be reliably prevented. Further, since the straight portion 32 is formed into a simple straight line, a good finished surface can be obtained.

In the above embodiment, the case where the throw-away type cutting tool according to this invention is applied to a throw-away type end mill is described, but it is not limited to this, and it can be applied to a side milling cutter, and the side edge or cutter width If the cutting edge is wide, a peripheral cutter may be formed, or it may be applied to a flat milling cutter.

Further, in the above embodiment, the throwaway tip 3 is formed in a square shape, but is not limited to this, and may be formed in other regular polygonal shapes such as a regular triangular shape or a regular hexagonal shape.

Further, in the above embodiment, two of the four throw-away tips are paired, and the uncut portion 36 of one throw-away tip 3 is removed by the other throw-away tip 3. However, the present invention is not limited thereto, and all the throwaway chips may be configured to scrape the uncut portions of each other. Alternatively, two pieces may be arranged on the same circumference, and four pieces may be arranged as a pair.
Further, the number of throw-away chips that can be installed may be any number as long as it is two or more.

As explained above, according to the throw-away type cutting tool of this invention, the center part of each straight part of the throw-away tip, which forms a regular polygon of equal size, is placed between 1/4 and 1/4 of the length of the straight part. A non-cutting part with a length of 1/3 is formed for each chip, and the throw-away chips are arranged offset from each other in the axial direction so that the straight parts are continuous in the rotation locus, so the following effects are achieved. can get.

(1) Not only when changing the cutting blade on the same rake face, but also when changing the cutting face, the operator can ensure that the throw-away tip is not inserted incorrectly without paying extra attention. can be prevented.

(2) Cutting resistance can be reduced by dividing chips.

(3) The contact length between the straight part and the workpiece can be shortened by the length of the non-cutting part, and together with the ability to break up chips, the cutting resistance can be further reduced.

(4) A good finished surface can be obtained.

[Brief explanation of the drawing]

1 and 2 each show a conventional throw-away chip, A is a plan view thereof, B is a side view thereof, and FIGS. 3 to 5 are views showing an embodiment of the present invention, Figure 3A is a plan view showing the throw-away tip, Figure 3B is its side view, Figure 4
Figure A is an axial tip end view showing the throw-away type end mill, Figure 4 B is a partially omitted side view, and Figure 5 is an enlarged view showing the rotation locus of the straight section of the throw-away type end mill shown in Figure 4. It is. 3... Throwaway tip, 31... Rake face, 32... Straight line part, 33... Nose part, 34...
... Side surface, 36 ... Non-cutting part, 37 ... End mill body, 38 ... Peripheral cutting edge.

Claims (1)

[Scope of utility model registration request] A plurality of regular polygonal throw-away tips having a cutting edge consisting of a straight part and a nose part and having the same size on the outer periphery of the tip of the tool body, which is rotated about the axis, rotates the straight part above the They are removably mounted spaced apart from each other in the circumferential direction in the direction along the axis, and are recessed in the center of each straight section of the throwaway tip inward toward the rake face. In a throw-away cutting tool in which non-cutting portions are formed with each other having substantially equal widths, the length of the non-cutting portion of the throw-away tip is 1/4 to 1/4 of the length of the straight portion. 3
A throw-away cutting tool characterized in that the throw-away tips are arranged offset from each other in the axial direction so that the straight line portions are continuous in their rotation loci.