JP2008110472A - Radius end mill - Google Patents

Abstract

[Object] To ensure the sharpness and strength of a corner R blade in a radius end mill at the same time, improve chip disposal, and facilitate manufacture.
A chip discharge groove 4 is formed on the outer periphery of the front end portion of the end mill body 1 rotated about an axis O toward the rear end side, and the chip discharge groove 4 is twisted around the axis O in the end mill rotation direction T. An outer peripheral edge 7 is formed on the outer peripheral side ridge portion of the wall surface 5 facing the end mill rotation direction T, and a gash 8 is formed at the tip of the chip discharge groove 4, and the wall surface of the gash 8 facing the end mill rotation direction T A bottom blade 11 that is continuous from the outer peripheral blade 7 via a corner R blade 12 is formed at the tip side ridge of 9 and the wall surface 9 facing the end mill rotation direction T of the gash 8 is planar, and a chip discharge groove 4 intersects the corner R blade 12 with an intersecting ridge line L with the wall surface 5 facing the end mill rotation direction T.
[Selection] Figure 3

Description

  The present invention relates to a radius end mill in which an outer peripheral blade formed on the outer periphery of a tip end portion of an end mill body and a bottom blade formed on the distal end are continuous through a corner R blade having a substantially 1/4 arc shape.

As this type of radius end mill, for example, in Patent Document 1, when the bottom edge side of the corner R blade is the first cutting edge and the outer peripheral edge side is the second cutting edge, these cross sections are perpendicular to the axis of the end mill body. A radius end mill for high feed cutting has been proposed in which the rake face of the first and second cutting edges is curved in a convex shape, and a concave chip space in the bottom direction is formed continuously on the rake face of the second cutting edge. Yes. Patent Document 2 also proposes an end mill for processing a high-hardness material in which a rake face connected to a corner R blade is formed in a convex shape. Further, Patent Document 3 proposes that a gash with a gash angle of 45 degrees is formed at the tip of the chip discharge groove and the rake angle of the corner R blade is a negative angle in the radial direction and a positive angle in the axial direction Has been.
JP 2004-82275 A JP 7-246508 A JP-A-11-216609

  However, when the rake face connected to the corner R blade is formed in a convex shape like the radius end mills described in Patent Documents 1 and 2, the rake angle in the cross section perpendicular to the corner R blade becomes larger on the negative angle side and the edge angle is increased. Therefore, for high-feed cutting and high-hardness material processing, the corner R blade can maintain its strength to improve fracture resistance and prevent chipping. There is a problem that it becomes dull and causes an increase in cutting resistance. Further, it is difficult to accurately form the rake face of the arcuate corner R blade into a convex shape of a predetermined shape, and if the curved surface is uniformly curved, chips are generated without being divided. May cause clogging of chips.

  On the other hand, in the radius end mill described in Patent Document 3 in which the rake angle of the corner R blade is a negative angle in the radial direction and a positive angle in the axial direction, the corner R blade is not damaged or chipped even though the sharpness can be secured. Is likely to occur. In particular, when a curved surface such as a mold is cut three-dimensionally, the corner R blade is used over the entire length, whereas when the gash angle becomes 45 degrees as described above, the corner R Since the entire length of the blade is formed on the rake face formed by the gash, it is difficult to ensure the strength of the cutting edge of the portion that bites the work material. In addition, when the gash angle is large in this way, the larger the number of cutting edges, the more difficult the manufacture becomes because the grindstone interferes with the adjacent cutting edge when forming the gash, and furthermore, the rake face of the corner R edge Since the whole is formed by gash, the chips are also generated without being divided, and the chip disposability is impaired.

  The present invention has been made under such a background, and provides a radius end mill that can ensure the sharpness and strength of the corner R blade at the same time, improve chip disposal, and can be easily manufactured. The purpose is to do.

  In order to solve the above-described problems and achieve such an object, the present invention is configured to twist the rear end of the end mill body around the axis toward the rear end side toward the outer periphery of the front end of the end mill body rotated about the axis. A chip discharge groove is formed, an outer peripheral blade is formed on the outer peripheral side ridge portion of the wall surface facing the end mill rotation direction of the chip discharge groove, and a gash is formed at the tip of the chip discharge groove, A bottom blade that is continuous from the outer peripheral blade through a corner R blade is formed at the tip side ridge of the wall surface facing the end mill rotation direction of the gash, and the wall surface facing the end direction of the gasche end mill is planar. In addition, an intersecting ridge line with a wall surface facing the end mill rotation direction of the chip discharge groove intersects the corner R blade.

  Therefore, in the radius end mill configured as described above, the wall surface facing the rotation direction of the end of the gasche is flat, and the ridge line of the chip discharge groove with the wall surface facing the rotation direction of the end mill intersects the corner R blade. Therefore, on the tip side (bottom blade side) from the intersection of this intersecting ridge line and the corner R blade, the edge angle in the cross section perpendicular to the corner R blade is secured to maintain the cutting edge strength, It is possible to prevent the occurrence of chipping and chipping when biting the material. On the other hand, on the rear end side (outer peripheral blade side) with respect to the intersection point, the rake angle can be increased to the positive angle side to obtain a sharp sharpness, thereby reducing the cutting resistance.

  Further, since the gash only needs to be formed on the tip side so that the intersecting ridge line intersects the corner R blade, there is little possibility that the grindstone interferes with the adjacent cutting edge when forming the gash, and this gash end mill Since the wall surface facing the rotation direction is planar, the manufacturing itself is easy. Further, the rake face of the corner R blade is bent into a convex V-shaped cross section perpendicular to the intersecting ridge line through the intersecting ridge line, so that the chips generated by the corner R blade are moved along the intersecting ridge line. Therefore, it is possible to improve the chip disposability and prevent the occurrence of chip clogging.

  Here, in particular, when the curved surface of a mold is cut three-dimensionally, the entire corner R blade is used for cutting. Therefore, the position of the intersection of the corner R blade and the intersecting ridge line is the corner R blade. If it is positioned too close to the bottom blade on the tip side, the strength of the corner R blade cannot be maintained sufficiently, and conversely if it is positioned too close to the outer peripheral blade on the rear end side, increase in resistance cannot be prevented. At the same time, there is a possibility of causing interference of the grindstone during the formation of the gash. In any case, since the chip cutting effect by the intersecting ridgeline may be impaired, the intersection of the intersecting ridgeline and the corner R blade is from the end of the end mill body to the rear side in the axial direction. It is desirable that it is located within the range of 0.2 × R to 0.8 × R with respect to the radius R of the blade, and is located within the range of 0.3 × R to 0.6 × R. Is more desirable.

  On the other hand, for example, when grooving a work material, especially when forming a groove whose groove depth becomes gradually deeper in the extending direction of the groove, the end mill body is being sent out in the extending direction. It is also sent to the tip end side in the axial direction to perform so-called ramping groove machining. In such a case, the corner R blade is extremely small compared to the case where the curved surface of the mold described above is three-dimensionally cut. Since the part near the bottom edge is always close to the state of being cut into the work material, strength is required, but in the part from the part slightly away from the bottom edge to the outer peripheral edge, the flow of chips is rather reduced. In order not to interfere, it is desirable that the chip discharge groove is formed so as to continue to the wall surface facing the end mill rotation direction. Therefore, in such a case, the intersection between the intersecting ridge line and the corner R blade is located on the rear side in the axial direction from the front end of the end mill body so that it is located closer to the front end side of the end mill body than in the case of three-dimensional cutting. In addition, it is desirable to be within a range of 0.01 × R or more and less than 0.2 × R with respect to the radius R of the corner R blade, and within a range of 0.02 × R to 0.15 × R. It is more desirable to be located at.

  If the wall surface facing the end mill rotation direction of the gasche is a plane parallel to the axis, the strength of the corner rake angle of the bottom edge and the corner R edge on the bottom edge side with respect to the intersection point is reliably set to 0 °. In addition, the gash can be formed on the basis of the axis of the end mill body, which makes the manufacture easier.

  As described above, according to the present invention, the sharpness and strength of the corner R blade can be secured at the same time to reduce cutting resistance and to prevent the occurrence of chipping and chipping. Therefore, it is possible to provide a radius end mill that can improve chip disposal and can be easily manufactured.

  1 to 3 show an embodiment of the present invention. In the present embodiment, the end mill main body 1 is integrally formed of a hard material such as cemented carbide and has a substantially cylindrical shape centering on the axis O, and the base end portion (the right side portion in FIG. 1) is the shank portion 2. At the same time, the front end portion (left side portion in FIG. 1) is a cutting blade portion 3, and the outer periphery of the cutting blade portion 3 is an end mill at the time of cutting around the axis O from the front end of the end mill body 1 toward the rear end side. Chip discharge grooves 4 twisted to the rear side in the rotation direction T are formed at equal intervals in the circumferential direction in a plurality of strips (four strips in this embodiment).

  The wall surface 5 facing the end mill rotation direction T side of the chip discharge grooves 4 is formed in a concave curved surface shape recessed to the rear side in the end mill rotation direction T in the cross section orthogonal to the axis O. And the outer peripheral flank 6 of the cutting edge 3 are formed with an outer peripheral edge 7 that is helically twisted at the same twist angle as the chip discharge groove 4. It is considered as a rake face.

  On the other hand, a gash 8 is formed at the tip of the chip discharge groove 4 on the rear side in the end mill rotation direction T so as to cut out the tip edge of the wall surface 5 in the radial direction. The gash 8 is widened in the circumferential direction as shown in FIG. 2 from the center of the front end of the end mill body 1 toward the outer peripheral side, and on the rear end side in the axis O direction as shown in FIGS. It is a groove-like recess formed so as to be gradually deeper, and the wall surface 9 facing the end mill rotation direction T side is a flat surface, and the tip side ridge portion of the wall surface 9, that is, the wall surface 9 and the end mill body 1 tip A bottom blade 11 is formed at the intersecting ridge line portion with the formed tip flank 10.

  Accordingly, the wall surface 9 is the rake face of the bottom blade 11, and its axial rake angle is set to a negative angle side with respect to the torsion angle of the outer peripheral blade 7. In particular, in this embodiment, the wall surface 9 is as shown in FIG. The axial rake angle of the bottom blade 11 is 0 °. Further, when viewed from the front end side in the axis O direction, the bottom blade 11 extends linearly as shown in FIG. 2, and its radial rake angle is a negative angle, and further toward the inner peripheral side. A watermark angle is given so as to incline slightly toward the rear end side in the axis O direction.

  Further, the bottom blade 11 and the outer peripheral blade 7 are made continuous through the corner R blade 12 at the tip outer peripheral portion of the end mill body 1, and these continuous outer peripheral blade 7, corner R blade 12, and bottom blade 11 A cutting blade is configured. The corner R blade 12 is formed by forming a corner flank 13 having a convex curved surface at a corner portion where the outer peripheral flank 6 and the front flank 10 intersect with the outer peripheral blade 7 and the bottom blade 11 that are continuous with each other. The outer peripheral blade 7 and the bottom blade 11 are smoothly connected to each other, and when the rotation locus around the axis O is projected onto a plane including the axis O, it forms an approximately ¼ arc shape of the radius R. ing.

  The cross ridge line L between the wall surface 5 facing the end mill rotation direction T of the chip discharge groove 4 and the wall surface 9 facing the end mill rotation direction T of the gash 8 formed so as to cut out the wall surface 5 is shown in FIG. As shown in FIG. 1, the end mill body 1 extends to the outer peripheral side of the tip and crosses the corner R blade 12 at an intersection P. Here, the position of the intersection P where the intersecting ridge line L between the wall surfaces 5 and 9 facing the end mill rotation direction T side of the chip discharge groove 4 and the gash 8 intersects the corner R blade 12 is the tip of the end mill body 1, that is, the bottom A distance A from the position closest to the tip end side in the axis O direction on the blade 11 or the corner R blade 12 to the rear end side in the axis O direction is 0.2 × with respect to the radius R of the corner R blade 12. It arrange | positions so that it may become in the range of R-0.8 * R, and is arrange | positioned in the position of 0.5 * R in this embodiment.

  In the radius end mill configured as described above, the wall surface 9 facing the end mill rotation direction T side of the gash 8 is the rake face of the corner R blade 12 on the inner peripheral side of the tip from the intersection P of the corner R blade 12. The wall surface 5 facing the end mill rotation direction T side of the chip discharge groove 4 on the outer peripheral side of the rear end from the intersection point P is a rake face of the corner R blade 12, and the wall faces 5 and 9 which are the rake faces are the above-described cross ridge line L. Is bent into a convex V shape having an obtuse cross section. Since the wall surface 5 is a concave curved surface and the wall surface 9 is flat as described above, the intersecting ridge line L is convex on the tip side as shown in FIG. 3 when viewed from the end mill rotation direction T side. It will exhibit a convex curve.

  Therefore, according to the radius end mill having the above-described configuration, the wall surface 5 facing the end mill rotation direction T side of the chip discharge groove 4 is notched by the planar wall surface 9 of the gash 8 on the tip side from the intersection P. Thus, the cutting edge angle in the cross section perpendicular to the corner R blade 12 can be ensured to be larger than that of the rear end side and the cutting edge strength can be maintained. Chipping can be prevented. On the other hand, at the portion on the rear end side from the intersection P, the concave curved wall surface 5 is used as the rake face of the corner R blade 12 as it is, and the rake angle is larger on the positive side than the tip side. Therefore, in this portion, the corner R blade 12 can be given a sharper sharpness than the tip side, thereby reducing cutting resistance.

  Further, the gash 8 that cuts off the tip of the chip discharge groove 4 is such that the intersecting ridge line L of the wall surfaces 5 and 9 facing each other in the end mill rotation direction T intersects the corner R blade 12 on the tip side of the end mill body 1. As long as it is formed to a depth, when this gash 8 is formed with a grindstone, the grindstone hardly interferes with the cutting blade adjacent to the end mill rotation direction T side, and a large number of cutting blades are attached to the end mill body 1. Even if formed, it is easy to manufacture. In addition, the gash 8 may be formed so that the wall surface 9 is planar, and in the present embodiment, the wall surface 9 is a plane parallel to the axis O of the end mill body 1, so that the manufacturing is further simplified.

  Furthermore, the rake face of the corner R blade 12 is bent into a convex V shape in cross section via the intersecting ridge line L as described above, and is generated by the corner R blade 12 and rubs on the rake face. The chips flow out while being divided so as to be torn with the cross ridge line L as a boundary. Therefore, according to the radius end mill having the above-described configuration, in this corner R blade 12 which is frequently used especially when a curved surface of a die is three-dimensionally cut, chip disposal can be improved and chip clogging occurs. This makes it possible to perform smooth cutting processing.

  By the way, when the curved surface of the mold is three-dimensionally cut, the entire corner R blade 12 is used for cutting at a partial portion. Is excessively positioned on the bottom blade 11 side, conversely, in the corner R blade 12, the portion of the chip discharge groove 4 that uses the wall surface 5 as the rake face becomes too large, and the cutting edge strength is ensured to ensure that the cutting edge is not damaged. There is a risk that chipping cannot be reliably prevented. On the other hand, when the intersection point P is too close to the outer peripheral blade 7 side, the corner R blade 12 portion having the wall surface 9 of the gasche 8 as a rake face becomes too large, and the corner R blade 12 becomes dull and cut. Since the resistance may increase, the position of the intersection point P is determined such that the distance A from the front end of the end mill body 1 to the rear end side in the axis O direction is the radius R of the corner R blade 12 as in this embodiment. Therefore, it is desirable to be within a range of 0.2 × R to 0.8 × R, and it is more desirable to be within a range of 0.3 × R to 0.7 × R.

  Further, as in such a three-dimensional cutting, for example, the end mill main body 1 is compared with a case in which one of the entire range of the corner R blade 12 is partially used and the range to be used is changed. When performing ramping groove processing for extending a groove that gradually becomes deeper in the feed direction by feeding it in the feed direction intersecting with the axis O and also feeding it to the tip end side in the axis O direction, The range close to the bottom edge 11 on the tip side of the R edge 12 always cuts the bottom surface of this groove and is in a state of being cut into the work material. It is necessary to prevent chipping and chipping. On the other hand, in most of the corner R blades 12 on the outer peripheral blade 7 side from this range, since the groove processing is such that the feed direction side is closed, a smooth chip discharging property is required rather than the blade edge strength. That is, it is desirable that the corner R blade 12 is immediately connected to the wall surface 5 of the chip discharge groove 4 without passing through the wall surface 9 of the gash 8.

  Therefore, in such a case, the position of the intersection P between the intersecting ridge line L and the corner R blade 12 as in the radius end mill of another embodiment of the present invention schematically shown in FIG. The distance a from the end mill main body 1 tip to the intersection point P in the axis O direction rear end side is preferably 0.01 × R or more with respect to the radius R of the corner R blade 12. It is desirable that it be arranged so as to be within a range of less than × R. More preferably, the distance a is in the range of 0.02 × R to 0.15 × R. In the other embodiment schematically shown in FIG. 4, the same reference numerals are assigned to the parts common to the above-described one embodiment.

It is a side view which shows one Embodiment of this invention. It is the front view which looked at the embodiment shown in Drawing 1 from the axis line O direction tip side. It is an enlarged side view of the front-end | tip part of embodiment shown in FIG. It is the expanded side view which simplified the front-end | tip part which shows other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 End mill main body 3 Cutting edge part 4 Chip discharge groove 5 Wall surface which faces the end mill rotation direction T side of the chip discharge groove 4 7 Outer peripheral blade 8 Gash 9 Wall surface which faces the end mill rotation direction T side of Gash 8 11 Bottom blade 12 Corner R blade O End mill body 1 axis T End mill rotation direction L Intersection ridge line of walls 5 and 9 P Intersection ridge line L and corner R blade 12 intersection R Corner R blade radius A, a Axis O from end mill body 1 tip to intersection P Directional distance

Claims (4)

  A chip discharge groove that twists backward in the end mill rotation direction around the axis is formed on the outer periphery of the tip end portion of the end mill body rotated about the axis, and the outer periphery of the wall surface of the chip discharge groove facing the end mill rotation direction. An outer peripheral blade is formed on the side ridge, and a gash is formed at the tip of the chip discharge groove. From the outer peripheral blade to the tip side ridge of the wall surface facing the end mill rotation direction of the gash. A continuous bottom blade is formed via a corner R blade, and the wall surface facing the end mill rotation direction of the gasche is flat, and the cross ridge line with the wall surface of the chip discharge groove facing the end mill rotation direction is A radius end mill characterized in that it is crossed with the corner R blade.   The intersection of the intersecting ridge line and the corner R blade is within the range of 0.2 × R to 0.8 × R with respect to the radius R of the corner R blade from the end of the end mill body to the rear side in the axial direction. The radius end mill according to claim 1, wherein   The intersection of the intersecting ridge line and the corner R blade is in the range of 0.01 × R or more and less than 0.2 × R with respect to the radius R of the corner R blade from the end of the end mill body to the rear side in the axial direction. The radius end mill according to claim 1, wherein the radius end mill is located inside.   4. The radius end mill according to claim 1, wherein a wall surface facing the rotation direction of the end mill of the gasche is a plane parallel to the axis. 5.

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