JPH11188522A - Throw-away type end mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the dischargeability of chip and minimize the cutting resistance by setting the difference in level between the cutting edge and chip upper surface of a button tool throw-away tip to a specified range, and setting the rise angle from the face to the upper surface and the space of breaker depth to a specified range. SOLUTION: In a helical end mill, an end mill is axially divided into an intermediate edge part and a bottom edge part which are blocks of the same dimension axially having a handle part and a chip 6a as minimum unit, and both the parts are fastened by a through bolt. In a button tool tip 6a in which the discharging direction of chip is unstable, the angle α of the rise part is set to 40-60 deg. in order enhance the dischargeability, so that the chip is formed into a spiral form with a small diameter. The difference in level (h) between a cutting edge 65 and a chip upper surface 54 is set to 0-0.5 mm. A breaker depth (d) is set to 1/4-1/7 of the space (n) from the cutting edge ridge line to the same height position of the face. According to this, the contact time between chip and the face can be shortened, and the cutting resistance can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throw-away type end mill, and more particularly to a throw-away type end mill using a round piece-shaped throw-away tip.

[0002]

2. Description of the Related Art Conventional end mills include a solid end mill type 101 shown in FIG.
And a throw-away type end mill 301 shown in FIG. 7 are generally known.

[0003] Among them, roughing end mill type 2
01 and the solid end mill type 101 each have advantages such as a small cutting power and a smooth finished surface when the cutting depth is small; and a good discharge of chips during rough machining; There is a problem that if it is lost, it becomes unusable.

On the other hand, in the case of the throw-away type end mill 301, if only the throw-away tip 302 is lost instead of the end mill body, the throw-away tip 302 can be replaced, so that only the lost throw-away tip 302 can be replaced. Good. Furthermore, in the case of a throw-away type end mill, which has recently been put into practical use and in which blocks of the same size with each throw-away insert as the smallest unit are stacked so as to be freely splittable in the axial direction, even if the tool body is damaged, By replacing the block with a new block, the same end mill can be used continuously.

[0005] Among the throw-away type end mills, the bottom side portion is divided into blocks B which can be used for the inner engraving of the mold, and as shown in FIG. A helical end mill 401 on which a chip (hereinafter abbreviated as a round piece chip) 402 is mounted or an end mill using only a round piece chip 502 as shown in FIG. Like the radius end mill 501 configured as above, a round piece tip 5 is provided on the bottom side of the tool body.
02 was attached.

The reason why the round piece chips 402 and 502 are used as in the end mills 401 and 501 is that a throwaway chip (hereinafter, referred to as a Sarae blade) is used as a Sarae blade.
(Abbreviated as a chip) has a very high cutting resistance during processing, and therefore, when a polygonal chip such as a triangle or a rhombus is attached to the bottom surface with a Sarae blade, there is a problem that the chip is easily broken. For this reason, round piece chips 402 and 405, which are hard to lose, may be used.

Further, in the case of the radius end mill 501, as shown in a schematic view in FIG.

However, in the case of the end mill using a round piece tip, the round piece tip is of a negative type or, in the case of a positive type, gradually lowers from the cutting edge ridge to the center screw head. In any case, there was a problem in the chip discharge direction and the chip discharge property. Also, the cutting resistance has not always been reduced to a satisfactory degree.

[0009]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, the present invention relates to a throw-away type end mill in which a round piece tip is detachably mounted on the bottom side.
An object of the present invention is to increase the chip dischargeability and reduce the cutting resistance.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a round piece chip having a positive shape,
A rising portion was provided on the rake face and the angle was made steep. In addition, the upper surface of the rising end is arranged at the same height or higher as the cutting edge.

Further, the depth of the breaker up to the rising portion of the rake face is within a certain range as compared with the interval from the cutting edge ridge line to the same height position of the rake face.

That is, according to the present invention, a tip pocket is formed on a peripheral surface of a tool body which rotates around an axis, a throw-away tip is mounted on the tip pocket, and the tip pocket is projected from the bottom surface of the tool body to form a positive type round. An end mill equipped with a piece-shaped throwaway tip, wherein the round piece throwaway tip has a step between a cutting edge and a tip upper surface of 0 to 0.
0.5 mm, the rising angle from the rake face to the top face is 40 ° to 60 °, and the breaker depth d is １ ／ to 1/4 of the distance n from the cutting edge ridge line to the same height position of the rake face. It is an object of the present invention to provide a throw-away type end mill characterized in that it is 1/7.

[0013]

According to the present invention, the round piece tip is made positive, the rising portion is provided on the rake face and the angle is made steep, so that the chips do not slide on the rake face but hit the wall. As a result, it is well curved and the discharge property is improved, and the contact time between the chip and the rake face is shortened, so that the cutting resistance is also reduced.

In general, in the case of a round piece chip in which the chip discharge direction is not stable, the angle of the rising portion is increased to 40 ° to 60 ° in order to enhance the discharge property so that the chip is formed in a spiral shape having a small diameter. Need to be At this time,
If the height of the upper surface of the insert is lower than the cutting blade, the chips are unlikely to curl in a spiral shape, and the discharging property is deteriorated. On the other hand, if the height is higher than 0.5 mm, the chips will feel as if they are caught on the ridge on the upper surface, and the cutting resistance may increase.

If the breaker depth d is deeper than 1/4 of the interval n from the ridgeline of the cutting edge to the same height position of the rake face, the strength of the cutting edge is reduced.
If it is shallower than 7, chips will slide on the rake face, and there is a possibility that both the discharge performance and the cutting resistance will deteriorate.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 to 3 show a helical indexable end mill (hereinafter abbreviated as a helical end mill) E according to the present embodiment. As shown in an exploded perspective view of FIG. Is divided into multiple parts in the axial direction.
It is divided into an intermediate blade portion 2 and a bottom blade portion 3 which are blocks of the same size with the handle portion 1 and each chip 6, 6a as a minimum unit,
It is fastened by bolts 4 penetrating each. In each unit, a chip pocket 5 is provided, and a plurality of rows of chips 6 and 6a are arranged in an axial spiral.

As shown in FIG. 2, a round piece tip 6a is arranged on the bottom side of the bottom blade portion 3 among the tips 6, 6a.
Further, the round piece insert 6a is mounted on the bottom surface 9 side of the tool body T so as to protrude from the bottom surface 9 by a tip radius r or more, so that even the helical end mill E can perform the sinking process.

Further, since the above-mentioned units are stacked so as to be freely divided in the axial direction, for example, if the intermediate blade portion 2 is constituted by only one as shown in FIGS. Is a short helical end mill E, and a helical end mill E having a long cutting edge length can be formed by stacking a plurality of intermediate blade portions 2.

FIG. 3 is a schematic bottom view showing the arrangement of the chips 6 and 6a in the circumferential direction. The chips 6, 6a are arranged at regular intervals with respect to the axis center C in the circumferential direction of the tool body T as shown in FIG. 3A, or the position of the round piece chip 6a as shown in FIG. Only the position is shifted from the equally-spaced position, whereby the cutting force acts substantially uniformly along the circumferential direction, and chatter vibration is suppressed as much as possible.

FIG. 4 is a sectional view taken along line XX of FIG.
As shown in the figure, the round piece chip 6a is a positive type chip, and a rising portion 62 is provided on the rake face 61 and the angle α is made steep, so that the chips can be removed from the rake face 61.
Instead of slipping, it hits the wall surface 63, so that it bends well and dischargeability is improved, and the contact time between the chip and the rake face 61 is shortened, so that cutting resistance is also reduced.

In general, in the round piece chip 6a in which the chip discharge direction is not stable, the angle α of the rising portion is increased to 40 ° to 60 ° in order to enhance the discharge property, and the chip is formed in a spiral shape having a small diameter. It is necessary to make it. At this time, if the height of the chip upper surface 64 is lower than the cutting blade 65, the chips are unlikely to curl in a spiral shape, and the discharging property is deteriorated.

The step (height) h between the cutting blade 65 and the chip upper surface 64 is preferably larger than 0.1 mm. On the other hand, if the step h is higher than 0.5 mm,
4 may be caught on the ridge 67, and the cutting resistance may increase.

Regarding the breaker depth d, the depth d is set to be 1/1 / n of the distance n from the cutting edge to the same height position of the rake face.
If it is deeper than 4, the strength of the cutting blade 65 decreases,
On the other hand, if the depth is smaller than 1/7, the chips will slide on the rake face, and there is a possibility that both the dischargeability and the cutting resistance may deteriorate.

Here, a method of fixing each unit constituting the helical end mill will be described.

As shown in FIG. 1, below each unit,
A fixing hole 8 is formed in which a localization 8a, which is a spline-shaped convex portion, is provided along the circumference. On the other hand, corresponding positions of the intermediate blade portion 2 and the bottom blade portion 3 are fitted to the localization 8a. Since the slit-shaped concave portion 7a is formed on the peripheral surface, the intermediate blade portion 2 and the bottom blade portion 3 are fitted in accordance with the orientation 8a,
Fix with bolts 4. The localization 8a and the slit-shaped recess 7a are formed at regular intervals.

Also, by using a block constituted like the intermediate blade portion 3 and the bottom blade portion 3, the intermediate blade portions 2 can be stacked in an arbitrary number. Several different lengths of 4 are prepared in advance.

An advantage of using the split type helical end mill E is that the cutting resistance can be reduced by setting the length of the cutting edge to be shorter if necessary.

The helical end mill E of the present embodiment
In this example, the chips 6 other than the round piece chip 6a were formed into a vertically long parallelogram. An advantage of this configuration is that the width of the tip pocket 5 can be reduced, and the bolt 4
Can be increased, so that the strength of the tool body T can be increased.

The present invention is not limited to the above embodiment, but may be a radius end mill as a matter of course, and any form can be adopted without departing from the object of the invention.

EXPERIMENTAL EXAMPLE As shown in Table 1, grooving and shoulder processing were performed using the helical end mill E equipped with round piece chips 6a having different shapes and sizes, and the cutting resistance and chip shape were evaluated. Groove processing conditions are: And In addition, the condition of shoulder processing, And

The results are summarized in Table 1.

[0033]

[Table 1]

In Table 1, * indicates that the value is outside the scope of the present invention. In the same table, sample No. 1 is of a type in which the rake face 61 is gradually lowered toward the center, and sample numbers 2 and 6 are such that the height h of the chip upper surface 64 with respect to the cutting blade 65 is out of the range, and the sample number 7 is , 11 have the rising angle α of the rake face 61 outside the range, and the sample numbers 12 and 15 have the ratio of the breaker depth d to the interval n from the cutting edge ridge line 66 to the same height position of the rake face 61 outside the range. there were. All of these samples had high cutting resistance, and most of them had poor chip shapes.

On the other hand, all of the samples other than the samples outside the range of the present invention had good cutting resistance, chip shape and chatter.

[0036]

As described above, according to the present invention, the round piece tip is made positive, a rising portion is provided on the rake face and this angle is made steep, and the breaker depth is reduced. Since the distance from the blade ridge line to the same height position of the rake face is set to 1/4 to 1/7, the chip does not slide on the rake face but hits the projection, so that the chip is curved and the dischargeability is improved, and the chip is improved. Therefore, the contact time between the rake face and the rake face is shortened, so that the cutting resistance is also reduced.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a throw-away type end mill of the present invention.

FIG. 2 is a front view of the end mill of FIG.

FIGS. 3 (a) and 3 (b) are schematic bottom views showing the tip mounted state of the end mill of FIG. 1;

FIG. 4 is a sectional view taken along line XX of FIG. 1;

FIG. 5 is a front view of a conventional solid end mill.

FIG. 6 is a front view of a conventional roughing end mill.

FIG. 7 is a front view of a conventional indexable end mill.

FIG. 8 is a front view of a conventional helical end mill using a round piece tip.

FIG. 9 is a front view of a radius end mill using a conventional round piece tip.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Handled part 2 Intermediate blade part 3 Bottom blade part 4 Bolt 5 Tip pocket 6 Tip 6a Round piece tip 61 Rake face 62 Rising part 63 Wall surface 64 Chip upper surface 65 Cutting blade 66 Cutting edge ridge 67 Ridge 7 Boss 7a Recess 8 Fixing hole 8a Localization E Helical end mill β (interval) angle α Rising angle γ Tip radius h Step (height) d Breaker depth n Angle

Claims (1)

[Claims] A tool pocket is formed on a peripheral surface of a tool body rotating about an axis, and a throw-away chip is mounted in the chip pocket and protrudes from a bottom surface of the tool body to form a positive, round piece-shaped throw. An end mill equipped with an away tip, wherein the round piece throwaway tip has a step between the cutting edge and the tip upper surface of 0.1 to 0.5 mm,
The rising angle from the rake face to the top face is 4
0 ° to 60 ° and the breaker depth d is 1/4 to 1 of the distance n from the cutting edge ridge to the same height position of the rake face.
The indexable end mill is characterized in that the end mill is / 7.