JP2601803B2 - Router end mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a router having a plurality of cutting edges having a right-hand twist on the outer periphery and a plurality of cutting edges having a left-hand twist sequentially formed along the axial direction. It concerns end mills.

[Prior Art] FIGS. 3 (A) and 3 (B) and FIGS. 4 (A) and 4 (B) show conventional router / end mills of this type, respectively. A plurality of cutting blades 3 and 4 having right twist and a plurality of cutting blades 5 and 6 having left twist are sequentially arranged on the outer periphery from the distal end side to the proximal end side at intersection lines 7 and 8, respectively. It is formed. Here, the plurality of cutting blades 3...
Are formed at equal intervals in the circumferential direction.

These cutting edges 3 ..., 4 ..., 5 ..., 6 ... is FIG. 5, respectively (A), as shown (B), the cutting edge 3 ... of the right twist, 4 ... twist angle theta ₁ between a but equal to each other and the cutting edge 5 ... left twist, 6 ... twist angle theta ₂ between the are equal to one another form. And these cutting blades 3 ... 4 ... 5
..., 6 ... are the right and left as shown in as twist angle theta ₁ of the right twist, as shown in FIG. 5 (A) is smaller than the helix angle theta ₂ of the left twist, or FIG. 5 (B) The torsion angles θ ₁ and θ ₂ are formed to be equal to each other.

On the other hand, at the tip of these end mill bodies 1 and 2,
In FIGS. 3 (A) and 3 (B), the cutting edges 9 which form an acute angle for facilitating drilling, and on the same plane in FIGS. 4 (A) and (B). Are formed, respectively.

In the above-described conventional router / end mill having the above-described configuration, each of the plurality of cutting blades 3 having left and right twists along the axial direction on the outer periphery of the end mill bodies 1 and 2.
Since 4 ..., 5 ..., 6 ... are formed, it is possible to offset axial cutting component forces acting during cutting with each other,
As a result, there is an advantage that stable cutting with little fluctuation in the axial direction can be performed.

[Problems to be Solved by the Invention] However, in the above-described end mill, relatively small vibrations are generated in high-speed cutting, and as a result, the finished surface is deteriorated. Therefore, particularly high surface roughness is required. In such a case, or when cutting with heavy cutting (deep cutting) or high feed, there is a disadvantage that efficient machining by high-speed cutting cannot be performed.

Therefore, the inventors of the present application have conducted various experiments in pursuit of the cause of the generation of such relatively small vibrations, and as a result, have come to estimate that the cause is as follows.

That is, in the conventional end mill, the torsion angles θ ₁ of the cutting edges 3.
..., 6 ... twist angle theta ₂ between are equal to each other, yet these cutting 3 ..., 4 ..., 5 ..., because 6 ... are formed at equal intervals in the circumferential direction, the cutting edge 3, 4, 5 , 6 and the adjacent cutting blades 3, 4, 5 in the axial direction and the circumferential direction are constant in any part. Then, each of the cutting blades 3, 4, 5, 6 having a constant interval
When a cutting load acts on the end mill bodies 1 and 2, the vibrations of the end mill bodies 1 and 2 caused by the cutting load always have a substantially constant frequency. However, it was estimated that vibrations that would adversely affect the surface roughness were generated.

[Object of the Invention] The present invention has been made based on the above presumption, and can prevent generation of relatively small vibrations in the end mill main body. It is an object of the present invention to provide a router / end mill capable of (deep cut) and high feed.

[Means for Solving the Problems] The router / end mill according to the present invention includes a plurality of cutting blades having a right twist and a plurality of cutting blades having a left twist, both of which are oriented in one circumferential direction of the end mill body. The angle of the twist of at least one of the cutting edges is set to a different angle from the twist angle of the other cutting edges, and the cutting edge having the right twist and the cutting edge having the left twist are bounded by the respective cutting edges. It is formed so that the intervals between the intersection lines are equal.

[Operation] In the router / end mill of the present invention having the above-described configuration, the circumferential and axial intervals between one cutting edge set at a different helix angle and the adjacent cutting edge are the same as those of the above-mentioned one. It changes continuously from the front end to the rear end along the cutting edge. As a result, the frequency of the vibration generated in the end mill body changes with the rotation of the end mill, and the vibrations cancel each other. As a result, it is possible to prevent the end mill main body from generating vibrations that deteriorate the finished surface.

On the other hand, at the intersection line between the cutting edge having the right twist and the cutting edge having the left twist, the two cutting edges are formed so that their respective intervals are equal to each other. The distance between the cutting edges of both cutting edges, as heading toward the distal or proximal end of the body,
The width gradually increases and decreases according to the difference in the twist angle described above. For this reason, the widths of the tip pockets formed between the cutting edges adjacent in the circumferential direction of the end mill body are also equal to each other at the above-mentioned crossing line, and as the cutting direction goes from the crossing line toward the distal end side and the base end side, The width of the insert pockets will be narrowed according to the gap between the blades, so it is possible to prevent the width of the tip pocket from becoming extremely wide at the leading and trailing edges of the cutting blade, and to prevent chip clogging etc. It is possible to do.

[Embodiment] An embodiment of a router / end mill according to the present invention will be described below with reference to FIGS. 1 (A), (B) and 2 (A).

In FIGS. 1 (A) and 1 (B), reference numeral 11 denotes an end mill main body, and the end mill outer periphery of the end mill has a right-hand twist from the distal end side to the proximal end side. Four cutting edges 12a, 12b, 12c, 12d and four cutting edges 13a, 13b, 13c, 13d having left-handed twist are respectively from 1/2 of the total cutting edge length to 1/3 of the tip side thereof. Are sequentially formed with the intersection line 14 formed within the range as a boundary.

Here, chip pockets 15a, 15b, 15c, 15d are sequentially formed between the cutting edges 12a, 12b, 12c, 12d, and similarly between the cutting edges 13a, 13b, 13c, 13d. Thus, chip pockets 16a, 16b, 16c and 16d are formed.

Then, as shown in FIG. 2 (A), the rotation center 0 among the four cutting edges 12a, 12b, 12c, 12d having a right twist.
Two cutting edges 12a of the positions symmetrical by sandwiching, the helix angle of 12c is a theta _3, two other cutting edges 12b, the twist angle of the 12d is a theta _4. And these θ ₃ and θ ₄ are θ ₃
<Is set to θ _4.

Further, the four cutting edges 13a, 13b, 13
c, the two cutting edges 13a of the symmetrical positions across the rotation center O of the 13d, the twist angle of 13c is a theta _5, two other cutting edges 13b, the twist angle of the 13d is set to theta ₆ I have. And these theta ₅ and theta _6, is set to θ _{5 <θ 6} in the same manner.

Further, the cutting blades 12a to 12d and 13a to 13d are formed such that the intervals therebetween, that is, the widths of the corners of the chip pockets 15a to 15d and the chip pockets 16a to 16d are equal to each other at the intersection line 14. Therefore, the chip pockets 15a to 15d and the chip pocket
The widths of 16a to 16d are such that the narrower tip pockets 15a, 15c, 16a, 16c and the wider tip pockets 15b, 15b, 1c are closer to the distal end side or the proximal end side of the end mill body 11, respectively.
It is formed so that the difference from 5d, 16b, and 16d gradually increases.

Further, θ ₃ , θ ₄ , θ ₅ , and θ ₆ are set so that θ ₃ > θ ₅ and θ ₄ > θ ₆ respectively.

On the other hand, the cutting edge 12
Bottom blade extending from a, 12b, 12c, 12d toward rotation center 0 side
17a, 17b, 17c and 17d are formed respectively.

Thus, in the end mill of the above configuration, as shown in FIG. 2 (A), 2 two cutting edges 12a of the cutting edge 12a~12d with right twist, 12c twist angle theta _3, the other 2 One of the cutting edge 12b, is made smaller than the helix angle theta ₄ of 12d, the circumferential direction and the axial spacing between and between cutting edges 12c and 12d of the cutting edge 12a and 12b from the intersecting line 14 It gradually narrows toward the tip of the end mill body 11,
On the other hand, the distance between the cutting edges 12b and 12c and the distance between the cutting edges 12d and 12a in the circumferential direction and the axial direction gradually increase.

Further, two cutting edges 13a of the cutting edge 13a~13d with left twist, a twist angle theta ₅ of 13c, two other cutting edges 13b, 1
Since the torsion angle θ ₆ is smaller than 3d, the cutting edges 13a and 1
3b and the circumferential and axial intervals between the cutting edges 13c and 13d gradually decrease from the intersection line 14 toward the rear end of the end mill body 11, while the cutting edges 13b and 1d
Conversely, the intervals in the circumferential direction and in the axial direction between 3c and the cutting edges 13d and 13a gradually increase.

Therefore, the frequency of the minute vibration generated when these cutting blades 12a to 12d and 13a to 13d cut the workpiece is
It changes with the rotation of the end mill, and the cutting edges 12a to 12d,
Since the vibrations caused by the cuttings 13a to 13d cancel each other, it is possible to prevent the end mill main body 11 from generating vibrations that deteriorate the surface roughness of the finished surface.

By the way, as described above, in the present invention, the cutting blade 12
The torsion angle between a, 12c and the cutting edge 12d, 12d, and the cutting edge 13a, 1
The reason why the torsion angles of the cutting edge 3c and the cutting edges 13b and 13d are different from each other is to prevent the vibration of the end mill main body 11 by changing the interval between the cutting edges. Therefore, if only for the purpose of preventing the vibration, the end mill body is used at each of the cutting edges 12a to 12d and the cutting edges 13a to 13d.
11 between adjacent cutting edges 12 in the circumferential direction, between 12 and cutting edge 1
It is desirable that the interval between 3 and 13 is not equal at any part.

However, on the other hand, the width dimension of the tip pockets 15 and 16 formed between the cutting edges 12 and 12 and between the cutting edges 13 and 13 is directed toward the distal end side or the proximal end side of the end mill body 11 as described above. Therefore, the narrow tip pockets 15a, 15
c, 16a, 16c and wide chip pockets 15b, 15d, 16b, 16d
Is formed so that the difference between the cutting edges 12 and 12 and the intervals between the cutting edges 13 and 13 are not made equal at any part. Tip pocket at line 14
The width of 15a, 15c, 16a, 16c is the tip pocket 15b, 15
If d, 16b, 16d is narrower than the width dimension, the originally narrow tip pocket 15a, 15c, 16a, 16c will be further narrower toward the distal end side or the proximal end side of the end mill body 11, As a result, the tip pocket 15a is provided at the tip of the cutting blades 12a to 12d or the rear end of the cutting blades 13a to 13d.
15d and 16a to 16d may be extremely wide and narrow, and in particular, chip chips 15a, 15c, 16a and 16c whose width dimensions are extremely narrow may be left with chips.

Therefore, in the present embodiment, in the portion of the intersection line 14, the cutting blades 12a to 12d and 13a to 13d are equally spaced in the circumferential direction, and the tip pockets 15a to 15d and 16a to 16d That is, it does not create a gap. Therefore, according to the present embodiment, the cutting blades 12a-1
At the front end of 2d and the rear end of the cutting edges 13a to 13d, it is possible to prevent cutting clogging or the like from occurring in the narrow tip pockets 15a, 15c, 16a, 16c, thereby promoting smooth cutting. It becomes possible.

Note that the cutting edges 12a, 12c of the torsion angle theta ₃ and cutting 12b, 1
Difference ,, and cutting edge 13a of the 2d twist angle theta ₄ of twist angle theta ₅ and the cutting edge 13b of 13c, for also the difference between the twist angle theta ₆ of 13d, only for purposes of preventing vibration of the above It is desirable that the difference between them is large. On the other hand, if the difference between these torsion angles θ is made small, the width of the chip pockets 15 and 16 becomes more remarkable. Also,
The cutting edges 12a, 12c, 13a and 13c having small torsion angles θ ₃ and θ ₅ have cutting edges 12b, 12d, 13b and 1 having large torsion angles θ ₄ and θ _6.
Since a cutting force greater than 3d acts during cutting, if the difference between the torsion angles θ is too large, the cutting edges 12d, 1
The wear of the cutting edges 12a, 12c, 13a, 13c is remarkably promoted as compared with 2d, 13b, 13d, resulting in shortening the life of the end mill as a whole. On the other hand, if the difference between the torsion angles θ is too small, the vibration prevention effect may not be sufficiently achieved.

Thus, for the difference between these torsion angle theta ₃ theta with ₄ and theta ₅ and theta _6, also the difference in the cutting resistance between the cutting edge during cutting from the viewpoint of reducing Gokutabi, | theta ₃ - [theta] ₄ |
And | θ ₅ −θ ₆ | are desirably set in the range of 1 ° to 10 °.

Although the above embodiment is a solid type made entirely of high-speed steel or cemented carbide, the end mill body may be of a brazing type obtained by brazing a cutting edge tip having a cutting edge. Good.

In the above embodiment, the right-handed torsion angles θ ₃ and θ ₄ and the left-handed torsion angles θ ₅ and θ ₆ are set so that θ ₃ > θ ₅ and θ ₄ > θ ₆ respectively. However, the present invention is not limited to this. For example, as shown in FIG. 2 (B), the twist angle of the left twist is set to θ ₃ and θ ₄ similar to the twist angle of the right twist, or θ ₃ <θ. ₅ , θ ₄ <θ ₆
The same operation and effect can be obtained even if the setting is made such that In addition, the right-handed twist and the left-handed twist each form four cutting edges in the circumferential direction, but the number of cutting edges is not limited to four as long as it is plural.

Furthermore, the torsion angles of the two opposing cutting edges of the four cutting edges are the same, and the torsion angles are alternately increased and decreased. However, the torsion angles of all the cutting edges may be different from each other. The cutting blades having different twist angles may be sequentially formed in the circumferential direction from the one having the smaller twist angle. In any case, in the present invention, the torsion angle of at least one of the plurality of cutting blades having left and right torsion may be set to a value different from the torsion angle of the other.

Furthermore, although the twist direction of each cutting edge is set so that the rake angle of the cutting edge is a positive rake angle, the twist direction may be reversed.

[Effects of the Invention] As described above, according to the router end mill of the present invention, the torsion angle of at least one of the plurality of cutting blades having left and right twists is changed by the torsion angle of the other cutting blade. Since the angle is set to be different from the angle, the circumferential and axial intervals between one cutting edge and the adjacent cutting edge are continuous from the tip of the one cutting edge toward the rear end. The frequency of the vibration generated in the end mill body changes with the rotation, and the vibrations cancel each other. Therefore, even in high-speed cutting, it is possible to prevent the end mill body from generating vibrations that degrade the finished surface, so that even in heavy cutting (deep cutting), a remarkable effect is obtained from low feed to high feed. In addition, the required power can be reduced.

Moreover, the cutting blades having such a twist angle set at different angles are formed so that the intervals between the cutting blades adjacent to each other are equal at the intersection line that is the boundary between the left and right torsion cutting blades. Therefore, the width of the chip pocket formed between the cutting edges can be prevented from becoming extremely wide at the leading or trailing end of the cutting blade. Such a situation can be prevented beforehand and smooth cutting can be promoted.

[Brief description of the drawings]

1 (A) and 1 (B) show an embodiment of a router / end mill according to the present invention. FIG. 1 (A) is a side view, and FIG. 1 (B) is a view taken along the arrow X in FIG. 1 (A). Figures, FIG. 2 (A), (B)
Fig. 3 is a development view of the cutting edge portion of each of those shown in Fig. 1, and Figs. 3 (A) and 3 (B) show a conventional router and end mill. Fig. 3 (A) is a side view, and Fig. 3 (B) is Y in FIG.
Arrow views, FIGS. 4 (A) and (B) show other conventional routers.
5A shows an end mill, FIG. 5A is a side view, FIG. 5B is a view from arrow Z in FIG. 5A, and FIGS. 5A and 5B.
FIG. 3 is a development view of a cutting edge portion in the conventional router / end mill. 11 ... End mill body, 12a, 12b, 12c, 12d, 13a, 13b, 13c,
13d: cutting edge, θ ₃ , θ ₄ , θ ₅ , θ ₆ ... torsion angle.

Claims (1)

(57) [Claims] 1. A plurality of cutting blades having a right twist and a plurality of cutting blades having a left twist both facing one circumferential direction of the end mill main body on the outer periphery of the end mill main body, each crossing an intersection line, In a router end mill formed sequentially along the axial direction, in the cutting edge having the right-handed twist and the cutting edge having the left-handed twist, at least one of the cutting edges is twisted with the corner of the other cutting edge. A router / end mill characterized in that the cutting edge having a right-hand twist and the cutting edge having a left-hand twist are formed so as to be equal to each other at the intersection line, while being set at an angle different from the twist angle. .