JP6303650B2 - Roughing end mill - Google Patents

Description

  The present invention relates to a luffing end mill in which a wavy outer peripheral blade that is uneven in the radial direction of the end mill body as viewed from the end mill rotation direction is formed on the outer periphery of the end portion of the end mill body that is rotated about an axis.

  As such a luffing end mill, for example, in Patent Document 1, a plurality of blade grooves having a twist in the rotation direction are provided at one end of the shank, and a rotation locus centering on the rotation axis is a convex arc between the plurality of blade grooves. And a wavy roughing blade having a concave arc portion. In such a luffing end mill, a plurality of wavy luffing blades adjacent to each other in the circumferential direction of the end mill main body shift the phases of the waveforms, thereby cutting and generating chips to reduce cutting resistance.

JP 2008-137121 A

  However, even in such a luffing end mill, for example, when cutting a difficult-to-cut material such as a high-hardness work material or stainless steel, cutting resistance increases, and chatter vibration may occur in the end mill body. Further, when the cutting resistance is increased as described above, there is a possibility that damage such as a chipping may occur in the outer peripheral blade. And such damage becomes remarkable in the convex part of the unevenness | corrugation always used for cutting among the outer peripheral blades uneven | corrugated like a wave.

The present invention has been made under such a background, and even when cutting a high-hardness work material or difficult-to-cut material, it is possible to suppress the occurrence of chatter vibration and damage to the outer peripheral blade , and in particular, corrugated irregularities. An object of the present invention is to provide a roughing end mill capable of effectively suppressing damage to the convex portion of the outer peripheral blade.

In order to solve the above problems and achieve such an object, according to the present invention, an outer peripheral blade extending from the front end of the end mill main body to the rear end is formed on the outer periphery of the front end of the end mill main body rotated around the axis. The outer peripheral blade is formed in a corrugated shape that is uneven in the radial direction of the end mill body as viewed from the end mill rotation direction, and the outer peripheral flank that is connected to the rear side in the end mill rotation direction of the outer peripheral blade has a clearance angle. Is formed such that a margin portion of 0 ° or a first outer peripheral flank with a clearance angle of 3 ° or less intersects the outer peripheral blade, and the outer peripheral blade is an end mill. The convex portion that is uneven in the radial direction of the end mill body as viewed from the rotational direction is formed wider than the concave portion, and the concave portion is also located on a plane perpendicular to the axis. And is formed to have a width and a minimum width.

  In such a luffing end mill, a margin portion with a clearance angle of 0 ° or a first outer periphery clearance surface with a clearance angle of 3 ° or less intersects with the outer peripheral blade on the outer peripheral clearance surface continuous to the rear side in the end mill rotation direction of the outer peripheral blade. The blade angle between the rake face and the margin portion or the first outer peripheral flank can be increased at the cutting edge of the outer peripheral blade. For this reason, high rigidity and strength can be ensured in the outer peripheral blade, occurrence of chatter vibrations can be suppressed, and damage such as defects can be prevented.

  Here, if the clearance angle at the portion intersecting the outer peripheral blade of the outer peripheral flank is a negative angle smaller than 0 °, this intersecting portion interferes with the work material, leading to a significant increase in cutting resistance, The end mill body is bent, and the uncut portion on the processed surface increases. Further, even if the portion intersecting with the outer peripheral blade is the first outer peripheral flank, if the clearance angle is larger than 3 °, the outer peripheral blade cannot be sufficiently secured in rigidity and strength, and chatter vibration or Damage cannot be reliably prevented.

In the present invention, the margin portion or the first outer peripheral flank is formed wider than the concave portion in the convex portion where the outer peripheral blade is uneven in the radial direction of the end mill body when viewed from the end mill rotation direction. .

  In such a luffing end mill, since the marginal portion or the first outer peripheral flank is formed wider than the concave portion in the concave-convex convex portion that is always used for cutting among the peripheral blades that are wavyly concave-convex, this convex portion is particularly preferred. It is possible to sufficiently ensure the rigidity and strength of the portion, and to reliably prevent damage such as defects.

  Here, in the roughing end mill of a general right-handed twisted blade formed so that the outer peripheral blade is directed toward the rear end side of the end mill body toward the rear end side of the end mill body, one outer peripheral blade and the end mill rotational direction rear side When the phase of the waveform formed by these outer peripheral blades is less than ½ of the period of the waveform and the phase is sequentially shifted toward the tip side of the end mill body, The amount of cutting by the outer peripheral blade is the largest on the tip side of the end mill body than the position of the apex of the convex portion when viewed from the end mill rotation direction. Therefore, in such a case, the margin part or the first outer peripheral flank is also formed wider at the tip side of the end mill body than the position of the apex of the convex part when viewed from the end mill rotation direction. As a result, it is possible to effectively prevent a defect or the like in a portion where the cutting load is the largest.

  However, for example, in a roughing end mill in which the outer peripheral blades whose phase of the waveform is shifted by 1/2 cycle are alternately formed in the circumferential direction, the amount of cutting by the convex portion is also the largest at the apex position. In such a roughing end mill, the margin portion or the first outer peripheral flank is also formed at the widest position at the apex of the convex portion when viewed from the end mill rotation direction, thereby effectively preventing damage. be able to.

  As described above, according to the present invention, it is possible to ensure high rigidity and strength at the edge of the wavy outer peripheral blade, and even when cutting a hard material or difficult-to-cut material, chatter vibration is generated. Stable and efficient cutting can be performed while suppressing occurrence of damage and damage to the outer peripheral blade.

1 is a perspective view showing a first embodiment of the present invention. It is the enlarged front view which looked at embodiment shown in FIG. 1 from the front end side. It is a side view of embodiment shown in FIG. 1 is a view of the outer peripheral blade of the embodiment shown in FIG. 1 as viewed from the end mill rotation direction along a plane perpendicular to the axis of the end mill body, and (b) the end mill body along a plane perpendicular to the axis of the end mill body. It is the figure seen from the outer peripheral side. FIG. 1A is a view of the outer peripheral blade of the embodiment shown in FIG. 1 as viewed from the end mill rotation direction along a plane perpendicular to the twist line formed by the outer peripheral blade, and FIG. 1B is a plane perpendicular to the twist line formed by the outer peripheral blade. It is the figure seen from the outer peripheral side of the end mill main body along. FIG. 2 is a development view showing a cutting pattern according to the embodiment shown in FIG. 1, in which a rotation trajectory around the axis of a plurality of outer peripheral blades is shifted according to feed. The outer peripheral blade of the second embodiment of the present invention is (a) a view when viewed from the end mill rotation direction along a plane perpendicular to the axis of the end mill body, and (b) along a plane perpendicular to the axis of the end mill body. It is the figure seen from the outer peripheral side of the end mill main body. FIG. 7 is a view of the outer peripheral blade of the embodiment shown in FIG. 7 as viewed from the end mill rotation direction along a plane perpendicular to the twist line formed by the outer peripheral blade, and FIG. 7B is a plane perpendicular to the twist line formed by the outer peripheral blade. It is the figure seen from the outer peripheral side of the end mill main body along. FIG. 8 is a development view showing a cutting pattern according to the embodiment shown in FIG. 7, in which the rotation trajectory around the axis of the plurality of outer peripheral blades is shifted in accordance with the feed.

  1 to 6 show a first embodiment of the present invention. In this embodiment, the end mill main body 1 has a substantially cylindrical shape centered on the axis O with a hard material such as cemented carbide, and its rear end (upper right part in FIG. 1, upper part in FIG. 3) is a circle. The shank portion 2 remains in a columnar shape, and the tip portion (the lower left portion in FIG. 1 and the lower portion in FIG. 3) is a cutting blade portion 3. In such a luffing end mill, the shank portion 2 is gripped by the main spindle of the machine tool and rotated in the end mill rotation direction T around the axis O, and is usually fed in a direction perpendicular to the axis O to be cut into the work material. Process it.

  A chip discharge groove 4 extending from the front end of the end mill body 1 toward the rear end side is formed on the outer periphery of the cutting edge portion 3, and the outer peripheral side edge of the wall surface of the chip discharge groove 4 facing the end mill rotation direction T. The part is formed with an outer peripheral blade 6 having the wall surface as a rake face and the outer peripheral surface of the cutting edge part 3 intersecting the rake face as an outer peripheral flank face 5. In the present embodiment, four chip discharge grooves 4 are formed in the cutting blade portion 3 at intervals in the circumferential direction, and accordingly, the outer peripheral blade 6 is also formed at four intervals in the circumferential direction.

  As shown in FIG. 3, a gash 7 having a substantially V-shaped groove shape is formed at the tip of each chip discharge groove 4, and the tips of the wall surfaces of these gashes 7 facing the end mill rotation direction T are formed. At the edge, a bottom blade 8 having a rake face as the wall surface is formed so as to extend from the tip of each outer peripheral blade 6 to the inner peripheral side. The roughing end mill of the present embodiment is a radius type roughing end mill in which the bottom blade 8 intersects the outer peripheral blade 6 via a convex curved corner blade such as an arc. 2, the bottom blade 8 is a short bottom blade 8 extending from the tip of the outer peripheral blade 6 in the vicinity of the axis O (a bottom blade extending vertically in FIG. 2) to a position away from the axis O. 2 are formed alternately in the circumferential direction, and the distance from the long bottom blade 8 to the short bottom blade 8 adjacent to the end mill rotation direction T is from the short bottom blade 8. It is made larger than the space | interval to the long bottom blade 8 adjacent to the end mill rotation direction T.

  Each chip discharge groove 4 is formed to be twisted to the rear side in the end mill rotation direction T around the axis O as it goes from the front end to the rear end side of the end mill main body 1. 1 is formed in a spiral shape that twists toward the rear side in the end mill rotation direction T around the axis O as it goes from the front end to the rear end side. In the present embodiment, the helical twist angles formed by the four outer peripheral blades 6 are formed to be equal to each other. Therefore, the circumferential interval between the four outer peripheral blades 6 is equal to the outer peripheral blade connected to the long bottom blade 8. The distance from 6 to the outer peripheral blade 6 adjacent to the end mill rotation direction T is larger than the distance from the outer peripheral blade 6 connected to the short bottom blade 8 to the outer peripheral blade 6 adjacent to the end mill rotation direction T.

  On the other hand, the outer peripheral flank 5 of these outer peripheral blades 6 is formed so as to be uneven in the radial direction (inner and outer periphery of the end mill main body 1) from the front end to the rear end side of the end mill main body 1. As shown in FIG. 4A and FIG. 5A, the outer peripheral blade 6 is also formed in a wave shape that is uneven in the radial direction of the end mill body 1 when viewed from the end mill rotation direction T. In this embodiment, the waveform formed by the outer peripheral blade 6 has a constant period (a convex arc that is convex toward the outer peripheral side of the end mill body 1 and a concave arc that is concave toward the inner peripheral side when viewed from the end mill rotation direction T. The pitch is formed in a continuous shape.

  Further, in the four outer peripheral blades 6, the shape and size of the waveform formed by each outer peripheral blade 6, that is, the period and the amplitude are equal to each other, but the phase of this waveform is the peripheral blade 6 adjacent in the circumferential direction. Are shifted in the direction of the axis O. In the present embodiment, the phase is sequentially shifted to the front end side in the axis O direction by 1/4 of one cycle of the waveform between one outer peripheral blade 6 and the outer peripheral blade 6 adjacent to the rear side in the end mill rotation direction T. Yes.

  Further, a clearance angle is given to the outer peripheral flank 5 so as to go to the inner peripheral side of the end mill body 1 from the position slightly separated from the outer peripheral blade 6 toward the rear side in the end mill rotation direction T. The clearance angle of the outer peripheral flank 5 is larger than 3 °. On the other hand, a margin portion 9 is formed in a very narrow portion intersecting the outer peripheral edge 6 of the outer peripheral flank 5, and the clearance angle of the margin portion 9 is set to 0 °. It is set smaller than the clearance angle of the surface 5.

  Furthermore, the width of the margin portion 9 is formed wider than the concave portion in the convex portion where the outer peripheral blade 6 is uneven in the radial direction of the end mill body 1 when viewed from the end mill rotation direction T. That is, in the present embodiment, the width of the margin portion 9 is maximized at a portion where the outer peripheral blade 6 forms a convex arc on the outer peripheral side of the end mill body 1, and the outer peripheral blade 6 forms a concave arc on the inner peripheral side of the end mill main body 1. The width of the margin portion 9 is continuously increased or decreased so that the width of the margin portion 9 is minimized in the portion.

  In particular, in the first embodiment, the margin portion 9 is the position of the apex P on the outer peripheral side of the end mill body 1 of the convex portion (convex arc) when viewed from the end mill rotation direction T among the convex portions. The end mill body 1 is formed so as to be widest at a position slightly closer to the tip side. For example, in the roughing end mill in which the diameter of the outer peripheral blade 6 (the diameter of the circle formed by the apex P of the convex portion on the rotation locus around the axis O) is 10 mm, the width of the maximum margin portion 9 is as shown in FIG. The maximum width A in the direction along the plane Q perpendicular to the vertical axis is 0.185 mm, and is perpendicular to the twist line formed by the outer peripheral blade 6 (the twist line connecting the apexes P of one outer peripheral blade 6) as shown in FIG. The maximum width B in the direction along the plane R is 0.153 mm.

  In the present embodiment, the position where the width of the margin portion 9 is minimized is a position where the concave portion is recessed most on the inner peripheral side of the end mill body 1. As in the above, in a luffing end mill having a diameter of the outer peripheral blade 6 of 10 mm, the minimum width C on a plane perpendicular to the axis O as shown in FIG. 4 is 0.013 mm, and the twist made by the outer peripheral blade 6 as shown in FIG. The minimum width D on a plane perpendicular to the line is approximately 0 mm.

  Such a luffing end mill is rotated around the axis O as described above and fed in a direction perpendicular to the axis O, so that the outer peripheral blades 6 whose phases are shifted are sequentially cut as shown in FIG. The work material is cut (roughly processed) while generating cut chips cut into the material. At this time, in the luffing end mill having the above-described configuration, a margin portion 9 having a clearance angle smaller than that of the outer peripheral flank 5 is formed on the cutting edge side of the outer peripheral flank 5 continuous to the rear side in the end mill rotation direction T of the outer peripheral blade 6. The blade angle formed by the rake face and the margin portion 9 at the cutting edge of the outer peripheral blade 6 can be increased.

  For this reason, the rigidity of the outer peripheral blade 6 can be improved, and even when a difficult-to-cut material such as a high-hardness work material or stainless steel is cut, the chatter vibration is suppressed and stable. Cutting can be performed. Moreover, since the cutting edge strength of the outer peripheral blade 6 is improved, it is possible to prevent the outer peripheral blade 6 from being damaged such as a chip even when a large cutting load is applied, and the end mill life is extended to achieve efficient cutting. Can be performed.

  If the clearance angle of the portion corresponding to the margin portion 9 is a so-called negative angle smaller than 0 °, and this portion swells to the outer peripheral side with respect to the rotation locus around the axis O of the outer peripheral blade 6, This part interferes with the work surface of the work material, the cutting resistance increases remarkably, and the end mill main body 1 is bent to leave more parts left on the work surface. The portion corresponding to the margin portion 9 may be a first outer peripheral flank having a clearance angle of 3 ° or less. In this case, the first outer flank is connected to the rear side in the end mill rotation direction T. The outer peripheral flank 5 is a second outer flank that has a larger flank angle than the first outer flank. However, if the clearance angle of the first outer peripheral flank is larger than 3 °, the cutting edge rigidity and strength of the outer peripheral blade 6 cannot be sufficiently improved.

  Further, in the present embodiment, the margin portion 9 is formed so as to be wider than the concave portion in the convex portion of the outer peripheral blade 6 that is uneven in the radial direction of the end mill body 1 when viewed from the end mill rotation direction T. . Therefore, as shown in FIG. 6, it is possible to ensure sufficient rigidity and strength at the convex portion of the outer peripheral blade 6 that is always used for cutting regardless of the feed rate, and to obtain a high-hardness work material or difficult-to-cut material. It is possible to reliably prevent damage such as defects even when cutting.

  In addition, if the maximum width of the margin portion 9 which is the maximum in the convex portion is too small, the rigidity and strength of the outer peripheral blade 6 cannot be sufficiently secured, and conversely if too large, the cutting resistance increases. I will. For this reason, the maximum width A of the margin portion is 0.015 × d to 0.030 × d on the plane perpendicular to the axis O shown in FIG. It is desirable that the maximum width B on the plane perpendicular to the twist line formed by the outer peripheral blade 6 shown in FIG. 5 be in the range of 0.010 × d to 0.022 × d.

  Further, in the first embodiment, the four outer peripheral blades 6 having the same shape and the same corrugation are twisted around the axis O toward the rear side in the end mill rotation direction T from the front end to the rear end side of the end mill body 1. Are formed in a spiral shape, and one outer peripheral edge 6 and the outer peripheral edge 6 adjacent to the rear side in the end mill rotation direction T have phases that are sequentially set to the axis O by less than ¼ of one cycle of the waveform. It is shifted to the direction tip side.

  Therefore, in such a luffing end mill, the cutting amount (chip thickness) by the outer peripheral blade 6 is slightly more at the tip side of the end mill body 1 than the apex P of the convex portion of the outer peripheral blade 6 as shown in FIG. On the other hand, in the first embodiment, the margin portion 9 is formed to have the maximum widths A and B slightly on the tip side of the end mill main body 1 slightly from the apex P of the convex portion of the outer peripheral blade 6. Has been. Therefore, according to this embodiment, since the cutting amount is maximized, the marginal portion 9 where the cutting load is maximized is widened to improve rigidity and strength, thereby effectively damaging the outer peripheral blade 6. On the other hand, the width of the margin portion 9 can be narrowed at a portion where the cutting load does not increase so much that unnecessary increase in cutting resistance can be avoided.

  However, in the first embodiment, the four outer peripheral blades 6 in this way are each 1/4 of one cycle of the waveform with one outer peripheral blade 6 and the outer peripheral blade 6 adjacent to the rear side in the end mill rotation direction T. Since the phase is sequentially shifted toward the front end side in the axis O direction, the cutting amount is slightly larger at the front end side of the end mill body 1 than the apex P of the convex portion of the outer peripheral blade 6. For example, the phase of the waveform is just In the roughing end mill in which the outer peripheral blades 6 shifted by ½ cycle are alternately formed in the circumferential direction of the end mill main body 1, the cutting amount is the highest around the apex P of the convex portion of the outer peripheral blade 6 as shown in FIG. growing.

  Therefore, in such a case, as in the roughing end mill of the second embodiment of the present invention shown in FIGS. 7 and 8, the margin portion 9 is widest at the position of the vertex P of the convex portion. By forming, an increase in cutting resistance can be suppressed while effectively preventing damage to the outer peripheral blade 6. In this second embodiment, when the diameter of the outer peripheral blade 6 is 10 mm, the margin 9 has a maximum width A of 0.118 mm on the plane perpendicular to the axis O as shown in FIG. The small width C is 0.009 mm, the maximum width B on a plane perpendicular to the twist line formed by the outer peripheral blade 6 is 0.093 mm, and the minimum width D is 0.007 mm as shown in FIG.

DESCRIPTION OF SYMBOLS 1 End mill body 2 Shank part 3 Cutting edge part 4 Chip discharge groove 5 Outer peripheral flank 6 Outer peripheral blade 7 Gash 8 Bottom blade 9 Margin part (or 1st outer peripheral flank)
O End mill body 1 axis T End mill rotation direction

Claims (3)

An outer peripheral blade extending from the front end of the end mill main body to the rear end is formed on the outer periphery of the end mill main body rotated around the axis, and the outer peripheral blade extends in the radial direction of the end mill main body as viewed from the end mill rotation direction. The outer peripheral flank that is formed in a corrugated wave shape and continues to the rear side in the end mill rotation direction of the outer peripheral blade has a margin part with a flank angle of 0 ° or a first outer flank face with a flank angle of 3 ° or less. It is formed so as to intersect the outer peripheral blade,
The margin portion or the first outer peripheral flank is formed wider than the concave portion in the convex portion where the outer peripheral blade is uneven in the radial direction of the end mill body when viewed from the end mill rotation direction. roughing end mill, characterized in that minimum, and is formed with a width on the axis perpendicular to the plane. The margin portions or the first peripheral relief surface, claims, characterized in that it is the most widely formed at the tip side of the end mill body than the position of the apex of the convex portion when viewed from the end mill rotating direction The luffing end mill according to 1 . 2. The roughing end mill according to claim 1 , wherein the margin portion or the first outer peripheral flank is formed to be widest at a position of a vertex of the convex portion when viewed from an end mill rotation direction.

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