JP2017226048A - End mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an end mill having a longer service life than conventional ones and capable of improving the efficiency of cutting work.SOLUTION: An end mill 10 comprises: a cutting edge part 11 having plane cutting bottom blades 13 and 14 at the bottom and an outer peripheral blade 15 formed in a spiral shape on an outer periphery; and a shank part 12 integrally and concentrically connected with the cutting edge part 11. Gashes 19 and 20 forming the bottom blades 13 and 14 extends up to an edge position of the outer peripheral blade 15. A strengthened blade part 18 is formed in the outer peripheral blade 15 positioned in an axial tip of the cutting edge part 11. An edge of the strengthened blade part 18 projects radially outward relative to the edge of the outer peripheral blade 15 except the strengthened blade part 18, or an outer diameter of the outer peripheral blade in the strengthened blade part is the same as an outer diameter of the outer peripheral blade except the strengthening blade part.SELECTED DRAWING: Figure 1

Description

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

Conventionally, various end mills corresponding to the material are used for cutting the material.
These end mills include those for roughing that perform rough cutting and those for finishing. After using the end mill for roughing, the end mill for finishing is used to cut the material. . Note that the end mill includes a bottom blade for plane cutting formed by gash at the bottom of the substantially cylindrical cutting blade portion, and an outer peripheral blade arranged in a spiral shape on the outer periphery of the cutting blade portion. (For example, refer to Patent Document 1).

When using this end mill, the tip of the axial center, the corner where the bottom and outer peripheral blades are connected, is the part that comes into contact with the work material most and wears more severely than other parts. The part is rounded, and a right-angle plane cannot be formed on the workpiece.
For this reason, 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 it is replaced. It took time to reduce the efficiency of the cutting work.

JP 2011-20193 A

Therefore, like the end mill 80 shown in FIG. 4A, the gash 82 forming the bottom blade 81 is extended to the blade edge position of the outer blade 83, and the blade edge of the outer blade 83 positioned at the tip in the axial direction. It is conceivable 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 distal end in the axial direction is the tip. It becomes smaller than the outer diameter d2 of the outer peripheral blade 83 other than the portion. In this case, since a right-angle plane cannot be formed on the workpiece, this method is not conventionally used.
Further, as in the end mill 90 shown in FIG. 4B, the outer diameter d3 of the outer peripheral blade 92 located at the tip end portion in the axial direction is formed by extending the gash 91 to the intersection of the outer peripheral blade 92 and the bottom blade 93. Can be made the same as the outer diameter d4 of the outer peripheral blade 92 other than the tip. However, in this case, since the outer peripheral blade 92 located at the tip end in the axial direction has a sharp shape, it tends to be chipped when the workpiece is cut.

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

An end mill according to a first aspect of the present invention that meets the above object includes a cutting blade portion that includes a bottom blade for plane cutting at the bottom portion and an outer peripheral blade that is spirally disposed at the outer peripheral portion, and a shaft that is attached to the cutting blade portion. In an end mill having a shank portion integrally connected to each other,
The gash forming the bottom blade extends to the cutting edge position of the outer peripheral blade, the reinforcing blade portion is formed on the outer peripheral blade positioned at the axial center front portion of the cutting blade portion, and the strengthening The cutting edge of the blade portion protrudes radially outward from the cutting edge of the outer peripheral blade excluding the reinforced blade portion.

An end mill according to a second aspect of the present invention that meets the above-described object is a cutting blade portion that includes a bottom blade for plane cutting at the bottom portion and an outer peripheral blade that is spirally disposed at the outer peripheral portion. In an end mill having a shank portion integrally connected to each other,
The gash forming the bottom blade extends to the cutting edge position of the outer peripheral blade, the reinforcing blade portion is formed on the outer peripheral blade positioned at the axial center front portion of the cutting blade portion, and the strengthening 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 reinforced blade portion.

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

In the end mill according to the first invention, the gash forming the bottom blade is extended to the blade tip position of the outer blade, so the outer blade located in the axial direction tip portion of the cutting blade portion has the sharp edge described above. The reinforced blade portion has a shape different from the shape (see FIG. 4B). Thereby, at the time of use of an end mill (cutting of a material to be cut), wear and chipping at the axial direction front portion can be suppressed as compared with the conventional case.
Here, since the cutting edge of the reinforced blade portion protrudes radially outward from the cutting edge of the outer peripheral blade excluding the reinforced blade portion, the conventional end mill (that is, the outer periphery located at the axial center of the cutting blade portion) Compared with an end mill in which the cutting edge of the blade does not protrude radially outward, it is possible to lengthen the period until the end of the end mill in the axial center direction is rounded.
Therefore, by suppressing wear and chipping of the outer peripheral blade and prolonging the period until the end portion in the axial direction of the end mill is rounded, it is possible to achieve a longer life than before and improve the efficiency of the cutting work. it can.

In the end mill according to the second invention, the outer diameter of the outer peripheral blade in the reinforced blade portion is the same as the outer diameter of the outer peripheral blade excluding the reinforced blade portion. The cutting edge of the outer peripheral blade located at the front end in the axial direction of the cutting edge has the same shape as the end mill that does not protrude radially outward. However, since the gash forming the bottom blade extends to the cutting edge position of the outer cutting edge, the outer cutting edge positioned at the axial center of the cutting blade portion becomes the reinforced cutting portion.
Therefore, the wear and chipping of the tip portion in the axial center direction of the end mill can be suppressed, the life can be extended as compared with the conventional one, and the efficiency of the cutting work can be improved.

It is a front view of the end mill which concerns on one embodiment of this invention. It is a perspective view of the axial direction front side of the end mill. It is the top view seen from the axial center direction front side of the end mill. (A), (B) is a front view of the end mill which concerns on the reference examples 1 and 2, respectively.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for 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 with strong stickiness and hardness), a fiber reinforced plastic (particularly, a carbon fiber reinforced plastic). (CFRP)) and the like are used for cutting various materials (materials to be cut), and can have a longer life than conventional end mills and can improve the efficiency of cutting work. This will be described in detail below.

The end mill 10 includes a cutting blade portion 11 formed in a front side region of a material formed into a columnar shape, and a shank portion formed in the base side region thereof and integrally connected to the cutting blade portion 11 with its axis aligned. 12.
The end mill 10 has a structure in which the cutting blade portion 11 and the shank portion 12 are integrated (solid type), but is not limited to this structure. For example, the cutting blade portion and the shank portion of different materials are used. May be joined by friction welding, a cutting blade portion (chip) may be brazed to the shank portion (brazing type), or a blade tip exchange type (throw away type).

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 is a material to be cut. It can be appropriately selected depending on the material. In addition, as mentioned above, when manufacturing a cutting blade part and a shank part separately, at least a cutting blade part is comprised with an above-described material.
The length in the axial direction of the forming region of the cutting edge portion 11 of the end mill 10, that is, the blade length L can be variously changed depending on the use application of the end mill, and is not particularly limited, but, for example, 0.5 mm to 50 mm It is about the following (further, the lower limit is 1 mm and the upper limit is 10 mm).

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

The outer peripheral blade 15 is formed on the outer peripheral portion of the cutting blade portion 11 along a groove 16 formed in a spiral shape from the bottom blades 13, 14 toward the shank portion 12. 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 with the axis of the end mill 10 as the center. The number of the outer peripheral blades 15 (grooves 16) is four here, corresponding to the number of the bottom blades 13 and 14. For example, the number of the outer peripheral blades 15 (grooves 16) is 1 depending on the outer diameter φ of the end mill 10 and the use application. It may be a book, or may be 2, 3, or 5 or more (upper limit is, for example, about 25).

The twist angle (inclination angle with respect to the axis of the end mill 10) θ of the outer peripheral blade 15 is, for example, about 10 ° to 45 ° (further, the lower limit is 20 ° and the upper limit is 40 °).
In addition, one or two or more (plural) flank surfaces 17 are formed on the outer peripheral blade 15, and each flank angle is, for example, 1 ° to 10 ° (further, the lower limit is 3 ° and the upper limit is 7 °). ) Is set to about.

Further, as shown in FIG. 1 and FIG. 2, a reinforced blade portion 18 is formed on the outer peripheral blade 15 located at the axial center front portion of the cutting blade portion 11.
The reinforced blade portion 18 is formed by extending a gash 19 that forms a pair of bottom blades 13 and a gash 20 that forms a 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 reinforced blade portion 18 are continuous).
That is, the reinforced blade portion 18 is a region in which the gash is not formed in the related art, specifically, the region in which the arcuate line that is the outline of the gash 20 in FIG. This 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 providing a rake face, but here, normally, a gash for forming only the bottom blade is cut. It extends to the tip end position in the radial direction of the blade portion (the tip position of the outer peripheral blade at the tip portion in the axial direction of the cutting blade portion).
For this reason, the rake angle of the rake face of the outer peripheral blade 15 can be made gentle compared with the case where the gash is not extended, and wear and chipping can be suppressed.
At this time, since a part of the rake face forming the bottom blades 13 and 14 becomes a part of the rake face of the outer peripheral edge 15, the rake angle of the rake face of the bottom blades 13 and 14 extends in the width direction. (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 also have one or more (plural) clearance angles.

As shown in FIGS. 1 and 3, the blade edge of the reinforced blade portion 18 protrudes radially outward from the blade edge of the outer peripheral blade 15 excluding the reinforced blade portion 18. 1 and 3 exaggerate the protruding state of the cutting edge of the reinforced blade portion 18 for convenience of explanation.
The shape of the portion (including the cutting edge) of the reinforced blade portion 18 that protrudes radially outward from the outer diameter of the outer peripheral blade 15 excluding the reinforced blade portion 18 is the front of the cutting blade portion 11 (gash 19, 20). As seen, it has a triangular shape. The outer diameter of the reinforced blade portion 18 gradually increases toward the tip end in the axial direction of the cutting blade portion 11 (that is, the cutting blade portion 11 during rotation is the tip end in the axial direction of the cutting blade portion 11. It has a reverse taper shape (conical frustum shape).

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

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

In the manufacturing method of the end mill 10 shown above, for example, first, after forming the plurality of grooves 16 at a preset twist angle θ and forming the outer peripheral blade 15 in the front side region of the material formed into a columnar shape, The gashs 19 and 20 are formed, and the bottom blades 13 and 14 are formed. At this time, since the gashes 19 and 20 extend 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 it is necessary to make the blade edge of the reinforced blade portion 18 protrude radially outward from the blade edge of the outer peripheral blade 15 excluding the reinforced blade portion 18, the material formed in the above-described columnar shape is the tip portion in the axial direction. Is larger than the diameter of other parts.

When the end mill 10 is used, the end mill 10 is rotated clockwise as viewed from the shank portion 12 side.
At this time, the front end in the axial center direction of the end mill 10 can suppress wear and chipping as compared with the related art by the reinforced blade portion 18 of the outer peripheral blade 15 and can lengthen the period until roundness occurs.
Therefore, it is possible to extend the life compared to the conventional case and improve the efficiency of the cutting work.

As described above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the configuration described in the above embodiment, and the matters described in the scope of claims. Other embodiments and modifications conceivable within the scope are also included. For example, the case where the end mill of the present invention is configured by combining some or all of the above-described embodiments and modifications is also included in the scope of the right of the present invention.
For example, the end mill can be used for one that performs roughing, one that performs finishing, and one that performs 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 the right twist of the right blade has been described, but depending on the application, the left twist of the left blade, the left twist of the right blade, the right twist of the left blade It can also be. In this case, the rotation direction of the end mill is also changed according to the arrangement of the blades (right rotation or left rotation as viewed from the shank portion side).
And in the said embodiment, although the case where the shape of the protrusion part of the reinforcement | strengthening blade part was made into the triangular shape was demonstrated, if the blade edge | tip of a reinforcement | strengthening blade part protrudes to 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: Outer peripheral blade, 16: Groove, 17: Flank, 18: Reinforced blade portion, 19, 20: Gash

Claims (3)

A cutting blade portion provided with a bottom blade for plane cutting at the bottom portion and an outer peripheral blade spirally disposed at the outer peripheral portion, and a shank portion integrally connected to the cutting blade portion with its axis aligned In an end mill having
The gash forming the bottom blade extends to the cutting edge position of the outer peripheral blade, the reinforcing blade portion is formed on the outer peripheral blade positioned at the axial center front portion of the cutting blade portion, and the strengthening An end mill characterized in that a blade edge of the blade portion protrudes radially outward from a blade edge of the outer peripheral blade excluding the reinforced blade portion. A cutting blade portion provided with a bottom blade for plane cutting at the bottom portion and an outer peripheral blade spirally disposed at the outer peripheral portion, and a shank portion integrally connected to the cutting blade portion with its axis aligned In an end mill having
The gash forming the bottom blade extends to the cutting edge position of the outer peripheral blade, the reinforcing blade portion is formed on the outer peripheral blade positioned at the axial center front portion of the cutting blade portion, and the strengthening An end mill characterized in that an outer diameter of the outer peripheral blade in the blade portion is the same as an outer diameter of the outer peripheral blade excluding the reinforced blade portion.   2. The end mill according to claim 1, wherein an outer diameter of the reinforcing blade portion is gradually increased toward a tip end in an axial direction of the cutting blade portion.

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