JPH067855Y2 - End mill - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention is of a throw-away type which is suitable for grooving or stepping various work materials such as copper, stainless steel and cast iron. It is about end mills.

[Prior Art] In recent years, when performing groove processing or step processing on a material to be cut,
BACKGROUND ART Various throw-away type end mills in which a throw-away tip (hereinafter, abbreviated as a tip) having a plurality of cutting edges along the axial direction of the tool body is detachably mounted are being used.

FIG. 10 shows a conventional end mill of this type,
Reference numeral 1 in the figure shows the end mill body of this end mill.

The end mill body 1 has a substantially cylindrical appearance that is rotated around the axis O, and a plurality of tip mounting seats 2 ... Draw a spiral with a small twist angle in the direction of the axis O on the outer circumference of the tip end portion. It is arranged in this way. The chip mounting seats 2 ... Are formed at positions separated from each other by a predetermined distance. Further, in the end mill main body 1, a plurality of rows (two rows are shown in the drawing) of spiral rows formed by the tip mounting seats 2 are formed at equal intervals in the circumferential direction. The chip mounting seats 2 in each row are arranged so as to be located between the chip mounting seats 2 and 2 in mutually adjacent rows.

And on the tip mounting seat 2 of this end mill body 1,
Each of the rectangular plate-shaped chips 3 is detachably mounted. Here, in each tip 3, the cutting edge 4 formed on the ridge portion is located on the outer peripheral side of the end mill main body 1, and the rake surface 5 formed on the side surface thereof is clamped in the rotation direction of the end mill main body 1. It is attached to the chip mounting seat 2 with a screw 6. In addition, reference numeral 7 in the drawing denotes a tip forming a bottom blade in which the cutting edge 8 adjacent to the cutting edge 4 is attached toward the tip side of the end mill main body 1 at the most distal end of the end mill main body 1. It is shown.

In the above conventional end mill having the above configuration,
With the movement of the end mill body 1 which is fed in the direction of the axis O or in a direction orthogonal to the axis O while rotating, the side edges 9 of the work material W and the bottom edge are formed by the cutting edges 4 of the tips 3 ... The bottom surface 10 of the work piece W is cut by the cutting blade 8 of the tip 7 attached to the tip portion. In this case, a row of chips 3 ...
The portion left uncut between the ... Is cut by the chips 3 mounted at the corresponding positions in the adjacent rows.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional end mill, the part left after cutting with one row of chips 3 ... Adjacent rows of chips 3 ...
Since it is configured to be cut by, two rows of chips 3 are required to cut the side surface 9 of the work material W. That is, it is difficult to perform high-feed cutting because the number of cutting edges 4 ... Which are substantially involved in cutting on the same circumference is smaller than the number of rows of formed chips 3. Since the impact applied to the chip 3 is large, the chip 3 is apt to be chipped or chipped, resulting in a short tool life.

Further, since the cutting edge 8 has a small axial rake angle, the cutting resistance is large, and moreover, it is necessary to form a large number of rows of chips 3 on the end mill main body 1. Therefore, it is difficult to design the end mill having a small diameter. There was a problem that was.

[Object of the Invention] The present invention has been made in view of the above circumstances, and has a large number of chips substantially involved in cutting on the same circumference.
Further, it is an object of the present invention to provide a throw-away type end mill having a small cutting resistance and a long tool life.

[Means for Solving Problems] The present invention is provided on the outer circumference of an end mill body having a substantially cylindrical shape.
A plurality of tip mounting seats are arranged so as to draw a spiral along the axial direction of the end mill body, and each of these tip mounting seats has a square plate-shaped throw-away tip with a rake face along the cutting edge of the end mill body. In an end mill mounted in the direction of rotation, the tip mounting seat has the spiral drawn by them at 50 ° to the axis.
The throw-away tip is arranged at a position inclined by 70 °, and the throw-away tip is placed in each tip mounting seat, and each rake face is oriented in the same direction as the direction in which the spiral is inclined with respect to the axis. While being mounted with a small angle of inclination of 25 ° to 35 ° with respect to the axis,
The side surface on the rear end side of the throw-away tip and the side surface on the tip side of the adjacent throw-away tip face each other, and are arranged so as to have a portion where they overlap.

[Operation] In the end mill having the above-described configuration, the tip is mounted on each tip mounting seat, and the rake face of the tip is oriented in the same direction as the helix formed by the row of these tips with respect to the axis. Since the chips are mounted so as to be inclined at a smaller angle, the leading and trailing ends of the cutting blades of a row of chips can be axially overlapped with the leading and trailing ends of the cutting blades of the adjacent chips in the rotation path. Therefore, it is possible to increase the number of cutting edges that are substantially involved in cutting on the same circumference. The rake face of the tip should be 2
Since an axial rake angle is provided by inclining it by 5 ° to 35 °, the impact applied to this tip can be reduced. As a result, the cutting resistance of the chip can be reduced, and the chipping and chipping of the chip can be prevented. Furthermore, the side surface of the tip rear end side, and the side surface of the tip side of the adjacent chip is arranged so as to face each other, the chips generated by the rear end of the cutting edge of the chip, Without being disturbed by the tip side of the adjacent tip that overlaps the rear end of the cutting edge of this tip,
By discharging smoothly, the trailing edge of the cutting edge of the tip overlapping with the tip of the cutting edge of the adjacent tip can reliably contribute to cutting, and the mounting space for each tip can be reduced. Thus, even a small diameter end mill can be easily manufactured.

[Embodiment] FIGS. 1 to 6 show an example of the end mill of the present invention.

1 to 3, reference numeral 11 in the drawings denotes an end mill body of this end mill having a substantially cylindrical shape.
On the outer periphery of the tip portion of the end mill body 11, four recessed groove-shaped chip pockets 12 ... Which are spirally twisted leftward along the axial direction are formed at equal intervals in the circumferential direction. ing. Further, a plurality (7 in the figure) of chip mounting seats 13 facing the chip pocket 12 are spirally drawn as a whole on the outer periphery of each end pocket of the end mill body 11 located on the rear side in the rotational direction. Are arranged at a slight distance from each other.

As shown in FIG. 3, the tip pocket 12 and the tip mounting seat 13 have spirals drawn by 50 ° to 70 ° with respect to the axis O of the end mill body 11.
It is arranged so as to be inclined by an angle A ₁ within the range.

Here, the reason why the inclination angle of the spiral is 50 ° to 70 ° is that when the inclination angle is less than 50 °, the cutting edges of the chips 14 in a row overlap in the direction of the axis O in the rotation locus as described later. Since the length that can be made is small and the axial rake angle of the cutting edge becomes small, it is not possible to obtain a sufficient cutting resistance reduction effect. On the other hand, when the inclination angle exceeds 70 °, the tip mounting seat becomes larger. This is because 13 and the chip pocket 12 adjacent thereto interfere with each other, which makes the design difficult, and also causes a decrease in the tool rigidity of the end mill body 11 itself, which both become inconvenient.

Then, the chips 14 are attached to the chip mounting seats 13 ...
... is attached.

As shown in FIGS. 4 to 6, the tip 14 has a plate shape with a substantially square appearance, and the upper and lower surfaces thereof are respectively flanks 1.
5 and 15, and the pair of opposing side surfaces are rake surfaces 16 and 16, respectively. Further, a cutting edge 17 is provided on the ridge portion where each of the flanks 15 and the rake face 16 intersect.
Are formed. The flank 15 is formed with a plurality of (three in the drawing) V-shaped groove portions 18 having a V-shaped cross section, which divide the cutting blades 17 into saw-tooth shapes. This groove 18
Is formed on the flank 15 from the position where the cutting edge 17 is divided into a predetermined length in a direction inclined with respect to the cutting edge 17.

As shown in FIGS. 1 to 3 and FIG. 6, the tip 14 having the above-mentioned configuration is such that one of the flanks 15 is brought into contact with each tip mounting seat 13 of the end mill main body 11 to cut it. The rake face 16 along the blade 17 faces the tip pocket 12 in the direction of rotation of the end mill body 11 and is detachably attached by a clamp screw 19.

Here, as shown in FIG. 3, the tip 14 has its rake face 16 in the same direction as the inclination direction of the spiral with respect to the axis O by an angle A _{2 that} is 25 ° to 35 ° smaller than the inclination angle of the spiral. It is installed at an angle. In other words, the tip 14 is attached with a negative axial rake angle A ₂ of 25 ° to 35 °. As a result, the tip 14 has the cutting edge 17
Of the cutting edge 17 of the tip 14 and the rear end portion 17b of the cutting edge 17 adjacent to each other are mounted so as to overlap each other in the direction of the axis O with a length indicated by T ₁ in the drawing.
Further, the side surface on the rear end side of the chip 14 and the adjacent chip 1
4 and the side surface on the front end side are arranged to face each other.

Further, on the tip end surface of the end mill body 11, chips 20 forming the bottom blade of the end mill are provided at positions symmetrical with respect to the axis O. Each chip 2
Each of the reference numerals 0 has a substantially diamond-shaped appearance, and the flank 21 is directed toward the tip side of the end mill body 11 and the flank 2
The cutting blade 22 along 1 is located on the tip end side, and the cutting blade 23 adjacent to the cutting blade 22 is located on the outer peripheral side.

As shown in FIG. 3, this tip 20 is mounted with a positive axial rake angle A ₃ of about 10 ° attached to a cutting edge 23 on the outer peripheral side. 17a of the cutting edge 17 of the chip 14 adjacent to
Are overlapped with each other in the direction of the axis O in the rotational loci of each other by a length indicated by T ₂ in the drawing.

In such an end mill, along with the movement of the end mill main body 11 which is fed while rotating around the axis O, the cutting edges 17 of the tips 14 and the side surfaces of the work material, and the cutting edges 22 of the tips 20 are used. The bottom surface of the work material is cut.

In such an end mill, however, the spirals drawn by the tips 14 forming a spiral row along the axis O direction of the end mill main body 11 are 50 ° to 70 ° with respect to the axis O. Of the tip mounting seat 13 and the rake face 16 of the tip mounting seat 13 in the same direction as the inclination direction with respect to the axis O of the spiral, which is 25 ° to 35 ° smaller than the inclination angle of the spiral. Since it was mounted with only a tilt, the front and rear ends 1 of the cutting blades 17 of the row of chips 14
7a and 17b can be overlapped with each other in the direction of the axis O in the rotation locus.

Therefore, one side of the chip 14 can cut the side surface of the work material, and thus the number of cutting edges substantially involved in cutting on the same circumference can be greatly increased as compared with the conventional one. Therefore, high feed cutting can be performed. Further, as a result of the increase in the number of cutting edges involved in cutting on the same circumference, it is possible to reduce the number of rows of the tips 14 ... in the circumferential direction, so that it is particularly easy to design an end mill having a small diameter. Becomes Further, the cutting edge 1
7 the rear end 17b of the cutting edge 17 of the adjacent cutting edge 17a
Since it can be cut with, the rear end portion 1 of the cutting blade 17
The so-called lack of relief of the flank 15 in 7b can be eliminated. Moreover, since the side surface on the rear end side of the chip 14 and the side surface on the front end side of the adjacent chip 14 are arranged so as to face each other, the cutting generated by the rear end portion 17b of the cutting blade 17 of the chip 14 is performed. The scrap is this chip 14
Of the cutting edge 17 overlaps with the tip end 17a of the cutting edge 17 of the adjacent tip 14 by being smoothly discharged without being disturbed by the tip end side of the adjacent tip 14 overlapping with the rear end 17b of the cutting edge 17. The rear end portion 17b of the cutting edge 17 of the chip 14 can surely contribute to the cutting, and the mounting space of each chip 14 can be reduced,
Even a small-diameter end mill can be easily manufactured.

Further, since the rake face 16 of the tip 14 is inclined by 25 ° to 35 ° with respect to the axis O which is the axial rake angle, the impact applied to the cutting edge 17 of the tip 14 can be reduced. Therefore, the cutting resistance of the tip 14 can be reduced, and the chipping and chipping can be prevented.

Moreover, in this end mill, the tip 20
Is attached to the cutting edge 23 forming the bottom edge thereof with a positive axial rake angle A ₃ , so that the back force is reduced, and in combination with the reduction of the cutting resistance of the tip 14, the end mill It is possible to significantly reduce the cutting force as a whole. Further, since the chips 14 having the grooves 18 formed on the flanks 15 are used, the chip discharging performance is also improved.

In the above embodiment, the chips 14 ... Are arranged so as to draw a so-called left-handed helix, and
The rake face 16 of No. 4 was mounted in the same direction as the direction in which the spiral is inclined with respect to the axis line, that is, with a negative axial rake angle, but the present invention is not limited to this, and FIGS.
As shown in the figure, the tips 25 are arranged in the end mill main body 26 so as to draw a spiral with a twist angle A ₄ of the same amount as that of the tips 14 and a so-called right-handed helix. By inclining the rake face 27 in the same direction as the spiral at an inclination angle A ₅ similar to the inclination angle A ₂ , the same operational effect can be obtained even if the rake face 27 is attached with a positive axial rake angle A _5. You can

Further, in the above-mentioned embodiment, the chips 14 in which the groove portions 18 that divide the cutting edge 17 are formed on the flank 15 are mounted, but the invention is not limited to this, and for example, those used for finish cutting or light cutting. For such a groove 18
A tip having no ... may be mounted, and the overlapping amounts T ₁ and T _{2 of the} cutting edge 17 are also the inclination angle A of the spiral.
₁ , it is possible to arbitrarily select the axial rake angle A ₂ and the chip interval.

[Effects of the Invention] As described above, according to the present invention, a plurality of tip mounting seats are arranged on the outer periphery of a substantially cylindrical end mill body so as to draw a spiral along the axial direction of the end mill body.
In an end mill in which each of the tip mounting seats has a square plate-shaped throw-away tip mounted so that the rake face along the cutting edge is oriented in the rotation direction of the end mill body, the tip mounting seats are formed by the spirals drawn by them. A direction in which the throw-away tip is placed on each of the tip mounting seats and each of the rake faces is inclined with respect to the axis by arranging the throw-away tip at an angle of 50 ° to 70 ° with respect to the axis. While being mounted in the same direction as the helix with an angle smaller by 25 ° to 35 ° than the angle of inclination with respect to the axis, the side surface on the rear end side of the throw-away tip and the side surface on the tip side of the adjacent throw-away tip. Are arranged so as to face each other and have an overlapping portion.

Therefore, according to this end mill, by setting the inclination angle of the spiral to 50 ° to 70 °, if the inclination angle is less than 50 °, the cutting blades of a row of chips are overlapped in the axial direction in the rotation trajectory. The length you get is small,
Moreover, the axial rake angle of the cutting edge becomes small, so that a sufficient effect of reducing the cutting resistance cannot be obtained, and when the inclination angle exceeds 70 °, the tip mounting seat and the tip pocket adjacent to the tip mounting seat. Can interfere with each other and its design is not difficult, and in addition, it is possible to solve the problem that the tool rigidity of the end mill body itself is reduced, and all sides of the work material are cut with a row of chips that draw a spiral. Therefore, it is possible to increase the number of chips that are substantially involved in cutting on the same circumference, so that high feed cutting can be performed. Further, as a result of providing the tip with a large axial rake angle, its cutting resistance can be reduced, and furthermore, the impact received during cutting is mitigated, so that chipping of the cutting edge and chipping can be prevented. Moreover, since the side surface on the rear end side of the chip and the side surface on the front end side of the adjacent chip are arranged so as to face each other, the chips generated by the rear end portion of the cutting edge of the chip, The tip of the adjacent tip that overlaps with the rear end of the cutting edge of this tip is discharged smoothly without being disturbed by the tip side of the tip of the cutting edge of the adjacent tip. The rear end portion of the blade can surely contribute to cutting, and the mounting space for each tip can be reduced, so that an end mill having a small diameter can be easily manufactured.

[Brief description of drawings]

1 to 6 show an embodiment of the end mill of the present invention. FIG. 1 is a front view, FIG. 2 is a bottom view, FIG. 3 is a developed view of FIG. 1, and FIG. A front view showing a throw-away tip mounted on the end mill of this example, FIG. 5 is a side view of the same, FIG. 6 is a sectional view taken along line VI-VI of FIG. 1, and FIGS.
FIG. 7 shows another embodiment of the present invention. FIG. 7 is a front view, FIG. 8 is a bottom view, FIG. 9 is a developed view of FIG.
The figure is a front view showing a conventional end mill. 11 ... End mill main body, 12 ... Chip pocket, 13 ... Chip mounting seat, 14,20 ... Chip (throw-away tip) 16 ... Cake face, 17,22,23 ... Cut blade, 25 ... Chip , 26 ...... mill body, 27 ...... rake _{face, A 1, A 2, A} 3, A 4, A 5 angle of inclination with respect to ...... axis, O ...... axis.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takanobu Saito 1-27-20 Nishi-Shinagawa, Shinagawa-ku, Tokyo Mitsubishi Metals Co., Ltd. Tokyo Works (56) Bibliography Sho 60-29416 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. An outer periphery of a substantially cylindrical end mill body,
A plurality of tip mounting seats are arranged so as to draw a spiral along the axial direction of the end mill body, and each of these tip mounting seats has a square plate-shaped throw-away tip with a rake face along the cutting edge of the end mill body. In an end mill mounted in the direction of rotation, the tip mounting seat has the spiral drawn by them at 50 ° to the axis.
The throw-away tip is arranged at a position inclined by 70 °, and the throw-away tip is placed in each tip mounting seat, and each rake face is oriented in the same direction as the direction in which the spiral is inclined with respect to the axis. The side surface on the rear end side of the throw-away tip and the side surface on the tip side of the adjacent throw-away tip face each other and are mounted while inclining at an angle smaller than the inclination angle with respect to the axis by 25 ° to 35 °. The end mill is characterized in that it is arranged with overlapping portions.