JP6691441B2 - End mill - Google Patents

Description

  The present invention relates to an end mill for cutting a material.

Conventionally, various end mills according to the material have been used for cutting the material.
This end mill includes one for roughing that performs rough cutting and one for finishing. After using the end mill for roughing, the end mill for finishing is used to cut the material. . Incidentally, the end mill, the bottom of the substantially cylindrical cutting blade portion, the bottom blade for plane cutting formed by Gash, the outer peripheral portion of the cutting blade portion, the outer peripheral blade arranged in a spiral shape, respectively. (For example, see Patent Document 1).

When using this end mill, the corner in the axial direction where the bottom blade and outer peripheral blade are connected becomes the part that comes into contact with the workpiece most and wears more severely than other parts. The roundness occurs in the part, and it becomes impossible to form a right-angled surface on the material to be cut.
Therefore, if the required right-angled surface cannot be obtained, the end mill must be replaced, and the position of the end mill (cutting blade) must be adjusted each time the end mill is replaced. It took time to reduce the efficiency of the cutting work.

JP, 2011-20193, A

Therefore, as in the end mill 80 shown in FIG. 4A, the gash 82 forming the bottom blade 81 is extended to the cutting edge position of the outer peripheral blade 83, and the cutting edge of the outer peripheral blade 83 located at the tip end portion in the axial direction. It is possible to increase the strength. However, since the outer peripheral surface of the outer peripheral blade 83 is a flank 84, when the gash 82 is extended to the cutting edge position of the outer peripheral blade 83, the outer diameter d1 of the outer peripheral blade 83 at the tip in the axial direction is It is smaller than the outer diameter d2 of the outer peripheral blade 83 except the portion. In this case, since a right-angled surface cannot be formed on the material to be cut, this method has not been used conventionally.
Further, like the end mill 90 shown in FIG. 4 (B), the gash 91 is extended to the intersection point of the outer peripheral blade 92 and the bottom blade 93, and the outer diameter d3 of the outer peripheral blade 92 located at the tip end portion in the axial direction. May be the same as the outer diameter d4 of the outer peripheral blade 92 other than the tip portion. However, in this case, since the outer peripheral blade 92 located at the tip end portion in the axial direction has a sharp shape, it is likely to be chipped when cutting the material to be cut.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an end mill that has a longer life than conventional ones and that can improve the efficiency of cutting work.

The end mill according to the present invention according to the above-mentioned object, a bottom blade for flat surface cutting in the bottom portion, a peripheral blade arranged spirally in the outer peripheral portion, and a cutting blade portion respectively provided with an axial center in the cutting blade portion. In an end mill having a shank part integrally joined together,
The gash forming the bottom blade is extended to a blade tip position of the outer peripheral blade, and a reinforcing blade portion is formed on the outer peripheral blade positioned at a tip portion in the axial direction of the cutting blade portion, and the reinforcement The shape of the blade edge of the blade portion, which protrudes outward in the radial direction from the blade edge of the outer peripheral blade excluding the reinforcing blade portion, has a triangular shape when the cutting blade portion is viewed from the front , and the triangular shape radial projection length of the turned portions is 0.003 times to 0.02 times the outer diameter of the cutting edge portion, the height of the axial direction, 0 of the outer diameter of the cutting blade portion. It is 003 times to 0.05 times.

The end mill according to the reference example has a bottom blade for flat surface cutting at the bottom, a peripheral blade spirally arranged at the outer peripheral portion, a cutting blade portion provided with the cutting blade portion, and an axial center aligned with the cutting blade portion to be integrated. In an end mill having a shank portion connected to
The gash forming the bottom blade is extended to a blade tip position of the outer peripheral blade, and a reinforcing blade portion is formed on the outer peripheral blade positioned at a tip portion in the axial direction of the cutting blade portion, and the reinforcement The outer diameter of the outer peripheral blade in the blade portion is the same as the outer diameter of the outer peripheral blade excluding the strengthening blade portion.

  In the end mill according to the present invention, it is preferable that the outer diameter of the strengthening blade portion is gradually increased toward the tip of the cutting blade portion in the axial direction.

In the end mill according to the present invention, since the gash forming the bottom blade is extended to the blade tip position of the outer peripheral blade, the outer peripheral blade located at the axially tip portion of the cutting blade portion has the above-mentioned sharp shape ( The reinforcing blade has a shape different from that shown in FIG. 4 (B). As a result, when the end mill is used (cutting of the material to be cut), abrasion or chipping of the tip portion in the axial direction can be suppressed more than ever before.
Here, since the blade edge of the strengthening blade portion protrudes outward in the radial direction from the blade edge of the outer peripheral blade excluding this reinforcing blade portion, the conventional end mill (that is, the outer periphery located at the axial tip of the cutting blade portion). As compared with an end mill in which the blade edge does not protrude outward in the radial direction), it is possible to lengthen the period until the roundness occurs in the tip portion in the axial direction of the end mill.
Therefore, by suppressing wear and chipping of the outer peripheral blade and prolonging the period until the tip of the end mill in the axial direction is rounded, a longer life can be achieved than before and the efficiency of cutting work can be improved. it can.

In the end mill according to the reference example, the outer diameter of the outer peripheral blade in the reinforcing blade portion is the same as the outer diameter of the outer peripheral blade excluding the reinforcing blade portion, so that the external contour shape is the same as that of the conventional end mill (that is, the cutting blade). The cutting edge of the outer peripheral blade located at the tip in the axial direction of the section has a shape similar to that of an end mill that does not project outward in the radial direction. However, since the gash forming the bottom blade extends to the cutting edge position of the outer peripheral blade, the outer peripheral blade located at the axially tip end portion of the cutting blade portion becomes the strengthening blade portion.
Therefore, it is possible to suppress wear and chipping of the tip portion in the axial direction of the end mill, to prolong the life of the end mill, and to improve the efficiency of cutting work.

It is a front view of the end mill concerning one embodiment of the present invention. It is a perspective view of the end mill in the axial direction front side. FIG. 3 is a plan view of the end mill viewed from the front side in the axial direction. (A) And (B) is a front view of the end mill which concerns on reference examples 1 and 2, respectively.

Subsequently, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention.
As shown in FIGS. 1 to 3, an end mill 10 according to an embodiment of the present invention includes, for example, a high hardness material, a difficult-to-cut material (a material having a strong stickiness and hardness), a fiber reinforced plastic (in particular, a carbon fiber reinforced plastic). (CFRP)) is used for cutting various materials (material to be cut) and the like, which has a longer life than conventional end mills and can improve the efficiency of cutting work. The details will be described below.

The end mill 10 includes a cutting blade portion 11 formed in a front side region of a cylindrically shaped material, and a shank portion formed in a base side region thereof and integrally connected to the cutting blade unit 11 with their axes aligned. 12 and.
The end mill 10 has a cutting blade portion 11 and a shank portion 12 which are integrally structured (solid type), but the end mill 10 is not limited to this structure, and for example, a cutting blade portion and a shank portion made of different materials. Those joined by friction welding, those in which the cutting edge portion (tip) is brazed to the shank portion (brazing type), and those in which the cutting edge is replaceable (throw away type) may be used.

The material (material) constituting the end mill 10 is, for example, a hard material such as cemented carbide or high speed steel (also referred to as high speed steel), but is not limited to these materials and may be a material to be cut. It can be appropriately selected depending on the material. As described above, when the cutting blade portion and the shank portion are manufactured separately, at least the cutting blade portion is made of the above-mentioned material.
The length in the axial direction of the forming region of the cutting blade portion 11 of the end mill 10, that is, the blade length L, can be variously changed depending on the usage of the end mill, and is not particularly limited, but, for example, 0.5 mm or more and 50 mm. Below (moreover, the lower limit is 1 mm and the upper limit is 10 mm).

The outer diameter φ (diameter of the cutting blade portion 11 during rotation) of the end mill 10 (cutting blade portion 11) can be variously changed depending on the intended use of the end mill and is not particularly limited, but is, for example, 0.5 mm or more. It is about 50 mm or less (further, the lower limit is 1 mm and the upper limit is 20 mm).
The cutting blade portion 11 of the end mill 10 is provided with bottom blades 13 and 14 for plane cutting at the bottom portion (tip portion) and an outer peripheral blade 15 spirally arranged at the outer peripheral portion. The outer peripheral blade 15 is a right blade having a cutting edge on the right side when viewed from the shank portion 12 side, and the twist direction is right twist.

The outer peripheral blade 15 is formed on the outer peripheral portion of the cutting blade portion 11 from the bottom blades 13 and 14 at the bottom toward the shank portion 12 along a groove 16 formed in a spiral shape. The bottom blade 13 and the bottom blade 14 are formed in pairs at the bottom.
A plurality of outer peripheral blades 15 (grooves 16) are formed at equal pitches around the axis of the end mill 10. The number of the outer peripheral blades 15 (grooves 16) is four here, corresponding to the number of the bottom blades 13 and 14, but, for example, depending on the outer diameter φ of the end mill 10 and the intended use, 1 It may be a book, or may be two, three, or a plurality of five or more (the upper limit is, for example, about 25).

The twist angle (angle of inclination with respect to the axis of the end mill 10) θ of the outer peripheral blade 15 is, for example, about 10 ° or more and 45 ° or less (further, the lower limit is 20 ° and the upper limit is 40 °).
Further, one or two or more (plurality) flanks 17 are formed on the outer peripheral blade 15, and the respective clearance angles are, for example, 1 ° or more and 10 ° or less (further, the lower limit is 3 ° and the upper limit is 7 °). ) Is set to about.

Further, as shown in FIGS. 1 and 2, a strengthening blade portion 18 is formed on the outer peripheral blade 15 located at the tip of the cutting blade portion 11 in the axial direction.
The reinforcing blade portion 18 is formed by extending a gash 19 forming the pair of bottom blades 13 and a gash 20 forming the pair of bottom blades 14 to the cutting edge position of the outer peripheral blade 15. (That is, the bottom blades 13 and 14 and the reinforcing blade portion 18 are continuous).
That is, the reinforcing blade portion 18 is a region where no conventional gash is formed, specifically, a region where the arc-shaped line that is the contour line of the gash 20 is substantially horizontal in FIG. 1 (in the radial direction). It is a blade portion formed in the outer end region).

Conventionally, the outer peripheral blade is formed by providing the above-mentioned groove on the outer peripheral portion of the cutting blade portion and further by providing a rake face, but here, normally, the gash for forming only the bottom blade is cut, It extends to the radial tip position of the blade portion (the blade tip position of the outer peripheral blade at the axial tip of the cutting blade portion).
Therefore, the rake angle of the rake face of the outer peripheral blade 15 can be made gentle as compared with the case where the gash is not extended, and wear and chipping can be suppressed.
At this time, a part of the rake face forming the bottom blades 13 and 14 becomes a part of the rake face of the outer peripheral blade 15, so that the rake angle of the rake face of the bottom blades 13 and 14 is across the width direction. The same (the rake angle of the rake face of the bottom blades 13 and 14 can be set to the same angle as the conventional one). The bottom blades 13 and 14 are also provided with a clearance angle of 1 or 2 or more (plural).

As shown in FIGS. 1 and 3, the blade edge of the strengthening blade portion 18 projects outward in the radial direction from the blade edge of the outer peripheral blade 15 excluding the reinforcing blade portion 18. For convenience of explanation, FIGS. 1 and 3 exaggerately show the protruding state of the blade edge of the reinforcing blade portion 18.
Of the reinforcing blade portion 18, the shape of the portion (including the blade tip) protruding outward in the radial direction from the outer diameter of the outer peripheral blade 15 excluding the reinforcing blade portion 18 is the front surface of the cutting blade portion 11 (gasch 19, 20). Seeing, it has a triangular shape. The outer diameter of the strengthening blade portion 18 gradually increases toward the axial center end of the cutting blade portion 11 (that is, the rotating cutting blade portion 11 has the axial center end of the cutting blade portion 11). Towards the reverse taper shape (conical shape)).

The dimension of the triangular portion of the reinforcing blade portion 18 is, for example, such that the protruding length R in the radial direction is about 0.003 to 0.02 times the outer diameter φ of the cutting blade portion 11 in the axial direction. The height H is about 0.003 to 0.05 times the outer diameter φ of the cutting blade portion 11, but it is not particularly limited and can be variously changed depending on the intended use of the end mill.
When the outer diameter φ of the end mill 10 is, for example, 3 mm, the protruding length R in the radial direction is about 0.01 to 0.05 mm (specifically 0.02 mm), and the height H in the axial direction. Can be set to about 0.01 to 0.1 mm (specifically, 0.05 mm).

  Further, the reinforcing blade portion is not limited to the above-described shape, and the outer diameter thereof may be the same as the outer diameter of the outer peripheral blade excluding the reinforcing blade portion. That is, the cutting edge of the above-mentioned strengthening blade portion 18 has a shape that does not protrude outward in the radial direction (a shape in which the radial projection length R is 0 (zero)).

In the manufacturing method of the end mill 10 described above, for example, in the front side region of the material formed into a cylindrical shape, first, the plurality of grooves 16 are formed with a predetermined twist angle θ, and the outer peripheral blade 15 is formed, The gash 19 and 20 are formed, and the bottom blades 13 and 14 are formed. At this time, since the gash 19 and 20 are extended to the cutting edge position of the outer peripheral blade 15, the reinforcing blade portion 18 can be formed on the outer peripheral blade 15.
In addition, since the blade edge of the strengthening blade portion 18 needs to be protruded outward in the radial direction from the blade edge of the outer peripheral blade 15 excluding the reinforcing blade portion 18, the material molded into the above-described columnar shape has a tip portion in the axial direction. The diameter of is larger than the diameter of other parts.

When using the end mill 10, the end mill 10 is rotated clockwise when viewed from the shank portion 12 side.
At this time, the tip portion in the axial direction of the end mill 10 can be prevented from being worn or chipped more than before by the strengthening blade portion 18 of the outer peripheral blade 15, and the period until rounding can be lengthened.
Therefore, the life can be extended as compared with the conventional one, and the efficiency of the cutting work can be improved.

Although the present invention has been described above with reference to the exemplary embodiments, the present invention is not limited to the configurations described in the above-described exemplary embodiments, and includes the matters described in the claims. It also includes other embodiments and modifications that are conceivable within the scope. For example, the case where the end mill of the present invention is configured by combining some or all of the above-described respective embodiments and modified examples is also included in the scope of rights of the present invention.
For example, the end mill can be used for roughing, finishing, or both roughing and finishing. In this case, the shape of the outer peripheral blade is changed as necessary.

Further, in the above-described embodiment, the case where the outer peripheral blade of the end mill is a right-handed right blade is described, but depending on the application, left-handed left blade, left-handed right-handed blade, left-handed right-handed blade Can also be In this case, the rotation direction of the end mill is also changed according to the arrangement of the blades (clockwise rotation or counterclockwise rotation when viewed from the shank portion side).
And in the said embodiment, although the case where the shape of the protrusion part of the strengthening blade part was made into the triangular shape was demonstrated, if the blade edge of the strengthening blade part is projected to the radial direction outer side, it will be limited to this shape. Instead, for example, it may be rectangular or square.

10: End mill, 11: Cutting blade portion, 12: Shank portion, 13, 14: Bottom blade, 15: Peripheral blade, 16: Groove, 17: Flank surface, 18: Reinforcing blade portion, 19, 20: Gash

Claims (2)

A bottom blade for plane cutting on the bottom portion, a peripheral blade spirally arranged on the outer peripheral portion, and a cutting blade portion respectively provided, and a shank portion integrally connected to the cutting blade portion in alignment with the axis. In an end mill having
The gash forming the bottom blade is extended to a blade tip position of the outer peripheral blade, and a reinforcing blade portion is formed on the outer peripheral blade positioned at a tip portion in the axial direction of the cutting blade portion, and the reinforcement The shape of the blade edge of the blade portion, which protrudes outward in the radial direction from the blade edge of the outer peripheral blade excluding the reinforcing blade portion, has a triangular shape when the cutting blade portion is viewed from the front , and the triangular shape radial projection length of the turned portions is 0.003 times to 0.02 times the outer diameter of the cutting edge portion, the height of the axial direction, 0 of the outer diameter of the cutting blade portion. An end mill characterized by being 003 times to 0.05 times.   The end mill according to claim 1, wherein the outer diameter of the reinforcing blade portion is gradually increased toward the tip of the cutting blade portion in the axial direction.

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