WO2014057783A1 - ボールエンドミル及びインサート - Google Patents
ボールエンドミル及びインサート Download PDFInfo
- Publication number
- WO2014057783A1 WO2014057783A1 PCT/JP2013/075286 JP2013075286W WO2014057783A1 WO 2014057783 A1 WO2014057783 A1 WO 2014057783A1 JP 2013075286 W JP2013075286 W JP 2013075286W WO 2014057783 A1 WO2014057783 A1 WO 2014057783A1
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- WIPO (PCT)
- Prior art keywords
- rake angle
- radial
- angle
- cutting edge
- arc
- Prior art date
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23C—MILLING
- B23C5/00—Milling-cutters
- B23C5/02—Milling-cutters characterised by the shape of the cutter
- B23C5/10—Shank-type cutters, i.e. with an integral shaft
- B23C5/1009—Ball nose end mills
- B23C5/1027—Ball nose end mills with one or more removable cutting inserts
- B23C5/1036—Ball nose end mills with one or more removable cutting inserts having a single cutting insert, the cutting edges of which subtend 180 degrees
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23C—MILLING
- B23C2200/00—Details of milling cutting inserts
- B23C2200/20—Top or side views of the cutting edge
- B23C2200/203—Curved cutting edges
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23C—MILLING
- B23C2200/00—Details of milling cutting inserts
- B23C2200/28—Angles
- B23C2200/286—Positive cutting angles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23C—MILLING
- B23C2210/00—Details of milling cutters
- B23C2210/04—Angles
- B23C2210/0407—Cutting angles
- B23C2210/0414—Cutting angles different
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23C—MILLING
- B23C2210/00—Details of milling cutters
- B23C2210/04—Angles
- B23C2210/0407—Cutting angles
- B23C2210/0442—Cutting angles positive
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T407/00—Cutters, for shaping
- Y10T407/19—Rotary cutting tool
- Y10T407/1906—Rotary cutting tool including holder [i.e., head] having seat for inserted tool
- Y10T407/1908—Face or end mill
- Y10T407/1924—Specified tool shape
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T407/00—Cutters, for shaping
- Y10T407/23—Cutters, for shaping including tool having plural alternatively usable cutting edges
- Y10T407/235—Cutters, for shaping including tool having plural alternatively usable cutting edges with integral chip breaker, guide or deflector
Definitions
- the present invention relates to an integral or index-replaceable ball end mill suitable for three-dimensional finishing of a work material, and an insert mounted on the index-replaceable ball end mill.
- a ball end mill is used to perform three-dimensional processing including a flat surface and a curved surface on a work material such as a mold.
- a work material such as a mold.
- the rake angle of the arc-shaped cutting edge of the ball end mill is important. Therefore, various proposals have conventionally been made regarding the rake angle of the arc-shaped cutting edge.
- JP 10-80815 sets the rake angle to -2 ° to -20 ° in order to strengthen the cutting edge strength in the vicinity of the outer peripheral cutting edge, and 0 ° in order to improve the chip dischargeability in the vicinity of the axial center.
- a ball end mill suitable for three-dimensional curved surface processing such as a mold set at ⁇ 10 °. Specifically, an example is described in which the rake angle near the leading edge is + 3 ° and the rake angle near the peripheral cutting edge is -10 °. However, since the rake angle at the most projecting position of the cutting edge is negative, there is a problem that the machinability is inferior in high precision finish cutting of the work material.
- JP-A 2008-110437 has a ball blade and an outer peripheral blade, and the rake angle of the ball blade in the normal direction is -10 to -15 ° at R10 °, -5 to +3 at R50 ° to R70 °.
- a CBN ball end mill is proposed which has a peak and an R90 ° of -10 ° to 0 °, thereby suppressing chipping of the entire ball blade to provide a long life.
- a specific example of the normal direction rake angle of the ball blade is a peak at -10 ° at R10 °, at 0 ° at R60 °, and at -5 ° at R90 °, gradually positive direction from R10 ° to R60 ° It changes and gradually changes in the negative direction from R 60 ° to R 90 °.
- this ball end mill has a peak in the normal direction rake angle in the range of R50 ° to R70 °, and since the normal direction rake angle is larger on the negative side in R10 ° than R90 °, There is a problem that the machinability in high precision finish cutting is inferior.
- JP-A-8-118133 has a curvilinear cutting edge as a ball end mill for cutting a relatively soft work material such as wood, non-ferrous metal, etc. smoothly and with high accuracy
- the rake angle of the cutting edge is the tip ( Ball with 10-30 ° at the bottom edge) and 20-40 ° at the outer circumference
- the corner has a middle rake angle that changes continuously from the rake angle of the bottom edge and the rake angle of the outer circumference
- An example of the rake angle is 10 ° at the tip and 20 ° at the outer periphery, and another example is 20 ° at the tip and 30 ° at the outer periphery.
- the rake angle of the cutting edge of this ball end mill is (a) the outer periphery is larger than the tip, and (b) the rake angle of the corner is intermediate the rake angles of the tip and the outer periphery Therefore, it can not be used as a ball end mill for finishing a workpiece with high hardness (Rockwell hardness: 40 HRC or more) such as a mold.
- the central blade of the ball blade is formed by rake faces, the relief angle of the ball blade is smaller than the relief angle of the central blade, and the normal direction of the ball blade is from the center to the outer peripheral direction.
- the ball end mill has been proposed to gradually increase to the positive side, thereby improving the strength and chip dischargeability.
- the normal direction rake angle of the central blade of the ball blade is -45 °, and it gradually increases from the center to the outer circumferential direction to -10 ° on the positive side.
- this ball end mill has a large negative angle of rake angle in the normal direction of the center blade, there is a problem that it is inferior in machinability in high precision finish cutting of a work material.
- Japanese Utility Model Publication No. 62-12503 is a ball end mill having an S-shaped ball blade in a tip view, and the rake angle of the normal direction of the ball blade is negative at the rotation axis, and the rake angle on the outer peripheral side is gradually Proposed a positive and increased ball end mill.
- the rake angle of the ball edge is gradually and positively increased from the rotation axis to the outer peripheral side in order to improve the chip discharge performance and the strength of the cutting edge.
- the machinability in finish cutting is inferior.
- Japanese Patent Application Laid-Open No. 2004-291096 is an indexable tip having a twisted arc-shaped cutting edge, and the thickness of the tip body at a position orthogonal to the rotation axis is 0.5 D to 0.9 D [D is a flat plate portion of the tip body Thickness (mm). And the radiation angle at the most convex point in the rotational direction is set to 40 to 70 °.
- Japanese Patent Application Laid-Open No. 2004-291096 does not disclose any change according to the radiation angle of the rake angle of the indexable tip.
- the indexable tip does not have an outer peripheral cutting edge having a twisting shape coupled to the rear end of the arcuate cutting edge. Therefore, it is not suitable for three-dimensional finishing of a work material having a standing wall with good surface roughness.
- a first object of the present invention is to insert an insert to be attached to an integral or indexable ball end mill capable of three-dimensional finishing of a work material having a standing wall surface with good surface roughness, and an indexable ball end mill To provide.
- a second object of the present invention is to provide an integral or index-replaceable ball end mill which prevents chips from getting caught in the gap between a cutting edge and a work material, and an insert mounted on the index-replaceable ball end mill. It is.
- a third object of the present invention is to provide an integral or index-replaceable ball end mill in which cutting resistance and its amplitude are reduced to suppress vibration, and an insert mounted on the index-replaceable ball end mill.
- the ball end mill according to the present invention has an arc-shaped cutting edge which is curved in an S-shape in a front view and extends from the foremost end to the outermost circumference point and a twist shape smoothly connected to the arc-shaped cutting edge.
- An outer peripheral cutting edge having a radius of curvature, and a convex curved surface rake face forward in the rotational direction of the circular arc cutting edge,
- the radial direction rake angle of the arc-shaped cutting edge is ⁇ ⁇ ⁇ ⁇ (where ⁇ is a radial direction rake angle at a radial angle of 5 °, ⁇ is a radial direction rake angle at a radial angle of 90 °, ⁇ Is the radial direction rake angle at the most convex point in the rotational direction of the arc-shaped cutting edge).
- the maximum value of the radial rake angle of the arc-shaped cutting edge is within the range of a radial angle of 12 to 40 °, and the radial rake angle decreases continuously from the most convex point in the rotational direction to the outermost point It is characterized by
- the insert according to the present invention has an arc-shaped cutting edge which is curved in an S-shape in front view and extends from the tip to the outermost periphery point, an outer peripheral cutting edge having a twist shape smoothly connected to the arc-shaped cutting edge, A convex curved surface rake face in the direction of rotation of the arc-shaped cutting edge,
- the radial direction rake angle of the arc-shaped cutting edge is ⁇ ⁇ ⁇ ⁇ (where ⁇ is a radial direction rake angle at a radial angle of 5 °, ⁇ is a radial direction rake angle at a radial angle of 90 °, ⁇ Is the radial direction rake angle at the most convex point in the rotational direction of the arc-shaped cutting edge).
- the maximum value of the radial rake angle of the arc-shaped cutting edge is within the range of a radial angle of 12 to 40 °, and the radial rake angle decreases continuously from the most convex point in the rotational direction to the outermost point
- the radial rake angle ⁇ is preferably conformal.
- the radial direction rake angle ⁇ is preferably a conformal angle of 0 ° or more.
- the difference between the radial rake angle ⁇ and the radial rake angle ⁇ is preferably 2 to 6 °.
- the difference between the radial rake angle ⁇ and the radial rake angle ⁇ is preferably 0 to 2 °.
- the difference between the radial rake angle ⁇ and the radial rake angle ⁇ is preferably 2 to 6 °.
- the difference between the maximum value of the radial rake angle and the radial rake angle ⁇ is preferably 0.1 to 1.0 °.
- the radial rake angles ⁇ , ⁇ and ⁇ preferably satisfy the conditions of 2 ° ⁇ ⁇ ⁇ 10 °, 0 ° ⁇ ⁇ ⁇ 6 ° and 3 ° ⁇ ⁇ ⁇ 14 °, respectively.
- the most convex point in the rotational direction of the arc-shaped cutting edge be located at a position where the radiation angle is 30 to 47 °.
- the radial direction rake angle of the arc-shaped cutting edge is ⁇ 1 ⁇ 2, where ⁇ 1 is the radial direction rake angle within the range from the most convex point in the rotational direction to the outermost point, and ⁇ 2 is the most convex in the rotational direction It is preferable to satisfy the relationship of the radial direction rake angle in the range from the point to the forefront.
- the axial rake angle on the arcuate cutting edge is negative in the range from the tip to the most convex point in the rotational direction, and in the range from the most convex point in the rotational direction to the outermost point. It is preferably positive.
- the thickness T S (mm) of the insert at the outermost peripheral point S preferably satisfies the condition of 0.4 T ⁇ T S ⁇ 0.5 T with respect to the thickness T (mm) of the flat plate portion of the insert.
- An intersection angle ⁇ 1 of the line connecting the rear end point R of the outer peripheral cutting edge and the most convex point Q in the rotational direction and the rotation axis is 15 to 30 °, and the outermost peripheral point S and the rear end point R Is preferably smaller than an intersection angle .delta.2 between the line connecting the two and the rotation axis.
- the outer peripheral cutting edge has a length of 0.2 T to 0.5 T, where T is the thickness (mm) of the flat portion of the insert. It is preferable to satisfy the condition of
- the indexable ball end mill according to the present invention is characterized in that the insert is fixed to a slit provided at a hemispherical tip of an end mill body.
- the integral or indexable ball end mill and insert of the present invention cover the entire area of the arc-shaped cutting edge.
- Cutting resistance is small, and chip dischargeability is good. Therefore, generation
- the axial rake angle of the arc-shaped cutting edge is negative from the cutting edge P to the most convex point Q in the rotational direction, 0 ° at the most convex point Q in the rotational direction, and positive from the most convex point Q in the rotational direction to the outermost point S Then, the arc-shaped cutting edge first contacts the work material at the most convex point Q in the rotational direction, and then the contact area with the work material reaches both the forefront P and the outermost circumference point S by rotation of the cutting edge. Since it spreads, cutting resistance is reduced.
- Cutting resistance can be reduced even if the axial direction rake angle is negative, by continuously increasing the radial direction rake angle of the arc-shaped cutting edge from the leading edge P to the most convex point Q in the rotational direction.
- the second effect is to improve the chipping resistance and chipping resistance of the cutting edge, avoid deterioration of the cutting edge, and achieve a long life.
- the third effect is that not only the cutting resistance is reduced, but also the chatter vibration is suppressed by the reduction of the amplitude, and the machined surface roughness of the work material surface can be improved.
- FIG. 1 is a perspective view showing a blade insertable ball end mill according to an embodiment of the present invention.
- FIG. 7 is a front view showing the tip end of the indexable ball end mill of FIG. 1 in a state in which the insert is not attached.
- FIG. 7 is a side view showing the tip portion of the indexable ball end mill of FIG. 1 in a state in which the insert is not attached.
- FIG. 7 is a side view showing the tip end of the indexable ball end mill of FIG. 1 in a state in which the insert is not attached from the direction orthogonal to FIG. 3.
- FIG. 1 is a perspective view of an insert according to an embodiment of the present invention. It is a top view which shows the insert of FIG. It is a front view which shows the insert of FIG.
- FIG. 5 is a schematic view showing the relationship between a radial rake angle and a radiation angle for the arc-shaped cutting edge of the insert of the present invention.
- it is a graph showing the relationship between the radial direction rake angle and the radiation angle.
- It is a side view which shows the relationship between an axial direction rake angle and a radiation angle about the circular arc-shaped cutting edge of the insert of this invention.
- it is a graph showing the relationship between the axial rake angle and the radiation angle.
- FIG. 5 is a side view of an insert according to an embodiment of the present invention.
- FIG. 1 It is a front view which shows the blade-tip-exchange-type ball end mill of FIG. It is a side view which shows the front-end
- the integral ball end mill is an integrated one of an end mill body and an insert having a cutting edge, and the shape itself is not different from that of the indexable ball end mill. Accordingly, the following description of the indexable ball end mill and insert also applies to the integral ball end mill.
- FIG. 1 to FIG. 4 show an indexable ball end mill 1 according to an embodiment of the present invention
- FIG. 5 shows an insert attached to the indexable ball end mill 1.
- the indexable ball end mill 1 comprises an end mill body 2 that rotates about a rotation axis L, a shank portion 3 integrally connected to the rear end of the end mill body 2, and a tip of the end mill body 2.
- a hemispherical tip 4 integrally connected via a tapered portion 7.
- the hemispherical tip 4 has a slit 8 extending in a direction (radial direction) perpendicular to the axis of rotation L to receive the insert 5 and to fix the insert 5.
- a screw hole 10 (the center line of which intersects the rotation axis L) which penetrates the hemispherical tip 4 in the direction orthogonal to the slit 8.
- a clamp screw 6 for detachably fixing the insert 5 is screwed into the screw hole 10.
- the end mill body 2, the shank 3 and the hemispherical tip 4 are made of an alloy tool steel such as SKD 61, for example.
- the slit 8 has two inner surfaces 8 a and 8 b extending in parallel with the rotation axis L as a center, and a bottom surface 8 c.
- the hemispherical tip 4 is radially divided by the slit 8 to form a pair of tip halves 4a and 4b.
- the insert 5 is a flat plate having a thickness T having a pair of parallel and flat side surfaces 51a1 and 51a2, and an arc surface connecting the pair of side surfaces 51a1 and 51a2 And a triangular portion 52 integrally connected to the rear end of the semicircular portion 51.
- the semicircular portion 51 includes first flanks 51b1 and 51b2 and second flanks 51c1 and 51c2 forming end faces connecting the pair of side faces 51a1 and 51a2, and convexly curved rake faces 51e1 and 51e2.
- the arc-shaped cutting edges 51d1 and 51d2 formed along the ridges of the first flanks 51b1 and 51b2 and the rake surfaces 51e1 and 51e2, and the arc-shaped cutting edges 51d1 and 51d2 smoothly at a point S And a through hole 51p for inserting a clamp screw 6 having a center located at the arc center point O of the arc-shaped cutting edges 51d1 and 51d2.
- the arc center point O is located at the midpoint of the center line of the through hole 51p (the midpoint in the thickness direction of the insert 5).
- a point S is a point where a straight line M passing through the arc center point O and orthogonal to the rotation axis L1 intersects the cutting edge, and is the outermost peripheral point of each of the arc-shaped cutting edges 51d1 and 51d2. That is, the outer diameter of each of the arc-shaped cutting edges 51d1 and 51d2 is maximum at the point S.
- a point at which the arc-shaped cutting edges 51d1 and 51d2 intersect is the forefront P intersecting the central axis (rotational axis) L1 of the insert 5.
- the rotation axis L1 passes through the tip P of the insert 5 and the arc center point O.
- the rotation axis L 1 of the insert 5 coincides with the rotation axis L of the end mill body 2
- the tip P of the insert 5 is located on the rotation axis L of the end mill body 2.
- the triangular portion 52 has a pair of parallel flat triangular side surfaces 52a1 and 52a2 and inclined bottom surfaces 52b1 and 52b2 connecting the triangular side surfaces 52a1 and 52a2.
- the inclined bottom surfaces 52b1 and 52b2 are the bottom surface 8c of the slit 8.
- each of the arc-shaped cutting edges 51d1 and 51d2 is convex in the forward direction of the rotational direction R of the indexable ball end mill 1, and viewed from the front, approximately S about the foremost end P It is shaped like a letter.
- the most convex position of the arc-shaped cutting edges 51d1 and 51d2 in the rotational direction R is at the point Q. Therefore, the point Q is called "the most convex point in the rotational direction".
- K shown in FIG. 6A is a straight line connecting the arc center point O and the most convex point Q in the rotational direction.
- the outer peripheral cutting edges 51k1 and 51k2 having a twist shape are linear in parallel to the rotation axis L1 in the plan view of FIG. 6A, and are inclined with respect to the rotation axis L1 in the side view of FIG. Therefore, when the insert 5 attached to the slit 8 rotates, the rotation loci of the pair of outer peripheral cutting edges 51k1 and 51k2 are cylindrical.
- the outer peripheral cutting edges 51k1 and 51k2 having the twist shape function to finish the standing wall surface with a good surface roughness, particularly when processing the corner portion of the work material.
- the pair of outer peripheral cutting edges have a circular arc shape in the radial direction, it is effective for reducing the cutting resistance, but a stepped portion by cutting remains on the machined surface, and the surface roughness is reduced.
- the outer peripheral cutting edges 51k1 and 51k2 are positioned on the cylindrical surface [the linear shape in FIG. 6 (a)], the cutting edge of the insert 5 can be repeatedly re-polished.
- the outer peripheral cutting edge is in the shape of a circular arc in the radial direction, the outer diameter of the cutting edge is reduced due to regrinding, so regrinding can not be performed.
- (A) Condition of Rake Angle of Arc-Shaped Cutting Edge There are a radial direction rake angle and an axial rake angle at the rake angles of the arc-shaped cutting edges 51 d 1, 51 d 2.
- the “radial direction rake angle” is the angle of the rake surfaces 51e1 and 51e2 with respect to a straight line (radial straight line) radially extending from the arc center point O toward the arc-shaped cutting edges 51d1 and 51d2, and “normal direction rake angle” I sometimes call it.
- the “axial direction rake angle” is an angle formed by the tangent of the arc-shaped cutting edges 51d1 and 51d2 with the rotation axis L1 on the side surface of the insert 5 shown in FIG.
- Radial direction rake angle In the positive radial direction rake angle, as shown in FIG. 7, the rake surface 51e1 is positioned behind the straight line connecting the arc center point O and the arc-shaped cutting edge 51d1 in the rotational direction R ( Direction of rotation R inclined forward)). The opposite is true for negative radial rake angles.
- FIG. 7 shows that, for one cutting edge 51d1, 5 °, 15 °, 30 °, 45 °, 60 °, 75 ° from the rotation axis L1 between the forefront P of the arc-shaped cutting edge 51d1 and the rear end point S, respectively.
- a rake angle at a position shifted by a radiation angle of 90 ° is the inclination angle of the rake surface 51e1 at the position P5 ° with respect to the straight line connecting the arc center point O and the point P5 ° of the arc-shaped cutting edge 51d1.
- the radial rake angles at radiation angles of 5 °, 15 °, 30 °, 45 °, 60 °, 75 ° and 90 ° are + 7.0 °, + 7.5 °, +7.5, respectively. °, + 7.0 °, + 6.0 °, + 4.5 ° and + 3.0 °.
- Figure 8 shows the relationship between the radial rake angle and emission angle shown in FIG. 7 by the curve F 1.
- the radial rake angle ⁇ at the most convex point Q in the rotational direction is the same as or larger than the radial rake angle ⁇ near the leading edge P.
- the radiation angle is an angle that the radiation straight line makes with the rotation axis L1.
- the radial direction rake angle ⁇ at a position where the radiation angle is 5 ° from the leading edge P is used as the vicinity of the leading edge P.
- the above relationship is expressed by the following equation. ⁇ ⁇ ⁇ ⁇
- the reason for setting ⁇ ⁇ is that the cutting resistance in the vicinity of the leading end P of the arc-shaped cutting edge 51d1 is reduced to improve the biting property to the work material and the outermost circumference point S of the arc-shaped cutting edge 51d1 In the above, it is to ensure sufficient cutting edge strength to increase the thickness of chips.
- the reason for making the radial direction rake angle ⁇ at the most convex point Q in the rotational direction more than the rake angle ⁇ in the vicinity of the leading edge P is the cutting of the arc-shaped cutting edge of the most convex point Q in the rotational direction which contacts the workpiece first. This is to reduce the resistance and to improve the biting property to the work material.
- the radiation angle at the most convex point Q in the rotational direction is preferably in the range of 30 to 47 °.
- the axial rake angle (axial rake) becomes negative in the range from the forefront P of the arc-shaped cutting edge 51d1 to the most convex point Q in the rotational direction.
- the area is shortened, which is effective in reducing cutting resistance by chip thinning.
- the region where the axial rake becomes positive can be made longer in the range from the most convex point Q in the rotational direction to the point R, which is effective in improving chip discharge performance. That is, the chips are discharged diagonally above the workpiece processing surface outside the tangent of the tool rotation path (the chips are separated from the cutting edge well), and the chips bite into the gap between the cutting edge and the work material It is possible to avoid problems.
- the radiation angle at the most convex point Q in the rotational direction exceeds 47 °, the most convex point Q in the rotational direction is too far from the cutting edge P, and the arc-shaped cutting edge receives the collision with the work material at the most convex point Q in the rotational direction. Not only the impact increases, but also the chips become thick, and the chip dischargeability decreases.
- the radiation angle at the most convex point Q in the rotational direction is less than 30 °, the absolute value of the negative value at the axial rake angle connecting from the leading edge P to the most convex point Q in the rotational direction becomes large, At the same time, the chip dischargeability near the rotation center of the cutting edge is deteriorated.
- the radiation angle at the most convex point Q in the rotational direction is more preferably in the range of 35 to 40 °.
- the difference between the radial rake angle ⁇ and the radial rake angle ⁇ is preferably 2 to 6 °.
- the difference between the radial rake angle ⁇ and the radial rake angle ⁇ is preferably 0 to 2 °.
- the difference between the radial rake angle ⁇ and the radial rake angle ⁇ is preferably 2 to 6 °.
- the difference between the maximum value of the radial rake angle and the radial rake angle ⁇ is preferably 0.1 to 1.0 °.
- the radial rake angle increases relatively largely from the vicinity of the leading edge P to the maximum value, and gradually decreases from the maximum value to the outermost point S through the most convex point Q in the rotation direction. It will change along.
- the radial rake angle ⁇ is preferably conformal.
- the other radial rake angles ⁇ and ⁇ may be negative.
- the cutting resistance is small and chatter vibration is also small, so the radial direction rake angle ⁇ , in order to make the machinability to the machinable materials better. It is preferable that ⁇ and ⁇ be all conformal.
- the radial direction rake angle is a conformal angle, the chipping resistance of the cutting edge is reduced, but in the finishing process, there is no problem of chipping resistance because the amount of cutting is small.
- the cutting resistance is large, so to increase the cutting edge strength, the radial rake angle ⁇ , the radial rake angle ⁇ , and the radial rake angle ⁇ It is preferable to do.
- the radial direction rake angle ⁇ be close to 0 ° even at a negative angle in order to improve the biting property to the work material.
- radial direction rake angles ⁇ , ⁇ and ⁇ satisfy the relationship of ⁇ ⁇ ⁇ ⁇ , and ⁇ 6 ° ⁇ ⁇ ⁇ ⁇ 0.5 °, ⁇ It is preferable to satisfy the conditions of 10 ° ⁇ ⁇ ⁇ ⁇ 2 ° and ⁇ 6 ° ⁇ ⁇ ⁇ ⁇ 0.5 °.
- the entire arc-shaped cutting edge is strengthened, and the fracture resistance of the cutting edge in cutting of high hardness work material having Rockwell hardness of 45 HRC or more Is improved.
- the radial direction rake angle is negative angle, cutting resistance of the cutting edge is increased and chip dischargeability is reduced, but in finishing of high hardness work material, the cutting amount is smaller than roughing and semi-finishing, so cutting The increase in resistance is small, and there is no problem with chip dischargeability.
- the cutting resistance at the leading edge P and the vicinity thereof is not excessively increased, and the corrosion resistance to the high hardness work material is favorably maintained.
- Hardness The cutting edge strength required for finish machining of the work material can be secured.
- ⁇ > ⁇ 0.5 ° since the strength of the cutting edge at the leading edge P is insufficient, a defect of the cutting edge or the like occurs.
- ⁇ ⁇ -6 ° cutting resistance of the arc-shaped cutting edge at the leading edge P and its vicinity becomes excessive, and wear of the cutting edge, welding of chips, deterioration of machined surface properties of work material, etc. Will occur.
- the maximum value of the radial rake angle of the arc-shaped cutting edge lies between 12 and 40 °, preferably between 15 and 30 °.
- the position of the point where the arc-shaped cutting edge is most convex forward in the rotational direction R (the most convex point in the rotational direction) Q has a radiation angle in the range of 30 to 47 °. This makes it possible to widen the region where the axial rake angle of the arc-shaped cutting edge forming an S-shape in a front view is positive (can narrow the negative region), and sufficient strength of the arc-shaped cutting edge is obtained even if the cutting resistance is high. Can be secured. In addition, when the area in which the axial direction rake angle is positive is wide, it is possible to satisfactorily discharge chips while sufficiently securing the strength of the arc-shaped cutting edge.
- the range having the radial direction rake angle ⁇ 1 corresponds to the positive range of the axial direction rake angle
- the radial direction rake angle ⁇ 2 is
- the range corresponds to a range in which the axial direction rake angle is negative.
- the axial rake angle also changes according to the radiation angle.
- the axial rake angles at radiation angles of 15 °, 30 °, 45 °, 60 ° and 75 ° are -48.409 °, -18.257 °, 0 °, +12. 069 ° and 19.38 °.
- the axial rake angle on the arc-shaped cutting edge is negative in the range from the leading edge P to just before the most convex point Q in the rotational direction, and is 0 at the most convex point Q in the rotational direction. It is preferable to be positive in the range beyond the outermost point S. In the range from the forefront P to the most convex point Q in the rotation direction, the negative axial direction rake angle gradually increases in the positive direction, and the range from the most convex point Q in the rotational direction to the outermost point S is a positive axis The direction rake angle gradually increases. As shown in FIG. 10, the axial rake angle near the leading edge P is preferably about -70 ° to -80 °, and the axial rake angle at the outermost peripheral point S is preferably about + 20 °.
- the axial direction rake angle of the outermost peripheral point S By setting the axial direction rake angle of the outermost peripheral point S to about + 20 °, chips are discharged in a direction perpendicular to the tangent of the tool rotation trajectory, and chip discharge performance is improved. On the other hand, if the axial rake angle in the vicinity of the outermost peripheral point S is smaller than + 20 °, the chip discharging property is reduced, and if larger than + 20 °, the cutting edge becomes too thin to secure rigidity.
- the radial rake angle and the axial rake angle of the arc-shaped cutting edge are measured using a non-contact three-dimensional digitizer or the like. Also, the above description of the radial rake angle and the axial rake angle applies to any of the arc-shaped cutting edges 51d1 and 51d2.
- an angle ⁇ 1 at which the line segment N connecting the most convex point Q in the rotational direction of the arc-shaped cutting edge 51d1 and the rear end point R of the outer peripheral cutting edge 51k1 intersects the rotation axis L1 is It is preferable that a line segment H connecting the outermost peripheral point S of the arcuate cutting edge 51d1 and the rear end point R of the outer peripheral cutting edge 51k1 be smaller than an angle ⁇ 2 intersecting the straight line L2 parallel to the rotation axis L1. That is, it is preferable that ⁇ 1 ⁇ 2.
- the inclination angle ⁇ 1 of the line segment N preferably satisfies the condition of 15 to 30 °.
- the chip discharge direction substantially overlaps the tangential direction of the rotation path of the tool, and the tool advances so as to follow the chip. There is a problem that it bites into the gap. This defect appears particularly in corner processing in contour processing.
- the inclination angle ⁇ 1 of the line segment N exceeds 30 °, not only the outer peripheral cutting edge having a twist shape can not be made sufficiently long, but also the thickness of the outer peripheral cutting edge becomes thin, and the strength of the cutting edge decreases. Furthermore, the amplitude of cutting resistance becomes large and chatter vibration occurs at the time of cutting, and the surface roughness of the work material is deteriorated. More preferably, ⁇ 1 is 20-30 °.
- the length F (mm) of the outer peripheral cutting edge 51k1 (line segment H) satisfies the condition of 0.2 T ⁇ F ⁇ 0.5 T. If F is less than 0.2 T, the outer peripheral cutting edge 51k1 is too short, and the number of regrinding is small. On the other hand, if F is more than 0.5 T, the outer peripheral cutting edge 51k1 is too long for necessary, and the cutting resistance rises sharply, causing the occurrence of chattering vibration during cutting.
- the thickness T S (mm) of the insert 5 at the outermost peripheral point S preferably satisfies the condition of 0.4 T ⁇ T S ⁇ 0.5 T.
- T S is the stiffness of the cutting edge is less than 0.4 T is too low.
- T S is more preferably 0.45 T ⁇ 0.49 T.
- the insert 5 of such a shape can be formed of, for example, a cemented carbide containing tungsten carbide (WC) and cobalt (Co).
- WC tungsten carbide
- Co cobalt
- Insert WC base cemented carbide insert 5 can be manufactured, for example, according to the following procedure. First, granulated powder composed of a mixture of tungsten carbide powder, cobalt powder and, if necessary, an additive added thereto is molded by a powder molding method or the like. At the time of molding, screw insertion holes are also formed. The shaped bodies are produced larger by an amount of 20 to 30% of sintering shrinkage. The compact is sintered at about 1300-1400 ° C.
- the obtained sintered body is subjected to three-dimensional polishing processing by NC control to form arc-shaped cutting edges 51d1 and 51d2, outer peripheral cutting edges 51k1 and 51k2 having a twist shape, and inclined bottom surfaces 52b1 and 52b2.
- NC control processing using a thin disk-like diamond rotary grindstone or the like is performed.
- a film which imparts wear resistance and heat resistance is formed by the PVD method on the surface of the obtained insert 5 excluding the screw insertion hole.
- the film is made of, for example, Ti—Al based nitride, Ti—Si based nitride, Ti—B based nitride, or the like.
- the life of the indexable ball end mill can be extended.
- FIG. 12, FIG. 13 and FIG. 14 show the indexable ball end mill 1 in which the insert 5 is fixed to the slit 8 of the end mill body 2 by the clamp screw 6.
- both side surfaces 51a1 and 51a2 of the insert 5 are in close contact with both inner surfaces 8a and 8b of the slit 8, and the inclined bottom surfaces 52b1 and 52b2 of the insert 5 and the bottom surface 8c of the slit 8 Since it adheres, insert 5 is positioned with high accuracy.
- the cutting edge P of the insert 5 slightly protrudes from the slit 8 along the rotation axis L, and further includes a pair of arc-shaped cutting edges 51d1 and 51d2 and a pair of outer peripheral cutting edges 51k1 and 51k2, and first and second cutting edges
- the flanks 51 b 1, 51 b 2, 51 c 1, 51 c 2 also slightly protrude from the slit 8.
- the thickness T (mm) of the insert 5 preferably satisfies the condition of 0.2 D to 0.5 D with respect to the outer diameter D (mm) of the end mill. As a result, the blade groove can be made sufficiently deep while sufficiently securing the strength of the arc-shaped cutting edge.
- the indexable ball end mill 1 equipped with one insert 5 having a pair of cutting edges corresponds to a two-edged ball end mill.
- Solid Type Ball End Mill The present invention is not limited to the indexable ball end mill, but can be applied to an integral (solid type) ball end mill. Solid-type ball end mills are not different from indexable ball end mills except that the insert is essentially integral with the end mill tip. However, with regard to the radial rake angle and the axial rake angle of the arc-shaped cutting edge, the solid ball end mill preferably has the following features.
- Example 1 A cemented carbide insert with a T diameter of 30 mm, a shank diameter of 32 mm, a total length of 250 mm, and a neck length of 180 mm and a cemented carbide insert attached to the slit at the tip of the shank end mill body
- Three types of inserts 1 to 3 having the arc-shaped cutting edge with a radius of 15 mm and the outer peripheral cutting edge having a twist shape of 3.0 mm in length and having the outer shape shown in FIGS. 5 and 6 were produced.
- the radial rake angle and the axial rake angle of the arc-shaped cutting edge at each radiation angle were measured by a non-contact three-dimensional digitizer.
- the radial rake angle and axial rake angle at each radiation angle are shown in Table 1.
- the radial direction rake angles at the outermost circumference point S (radiation angle 90 °) of inserts 1 to 3 were 0 °, + 3.0 ° and + 6.0 °, respectively.
- the cutting conditions of the work material are as follows. Processing method: Dry cutting (air blow) Cutting speed (Vc): 754 m / min Speed: 8000 rpm Feeding speed (Vf): 7500 mm / min Feeding amount per blade (fz): 0.47 mm / tooth Radial cut amount ae: 0.15 mm and 0.3 mm in two ways Pick feed (pf): 0.5 mm Tool overhang (OH): 180 mm
- the surface roughness Ry of the machined surface when the radial direction incision amount ae is 0.15 mm and 0.3 mm is shown in the optical micrograph (18 ⁇ ) of FIG.
- FIG. 15 shows the surface roughness Ry when the processing distance of the wall surface of the work material reaches 5 m.
- the target of surface roughness Ry of the finished surface of the mold for molding an automobile outer plate is 10 ⁇ m or less, but the target for cutting with a radial cut amount ae of 0.15 mm and 0.3 mm
- the following surface roughness Ry was achieved.
- the surface roughness of the machined surface was better when the radial cut amount ae was 0.15 mm.
- the surface roughness Ry of the machined surface by the indexable ball end mill equipped with the insert 2 with the radial direction rake angle ⁇ set to + 3.0 ° is 4.3 ⁇ m, diameter for cutting with a radial direction cut amount ae of 0.3 mm It was 4.4 ⁇ m in cutting with a direction cut amount ae of 0.3 mm, which was smaller than when other inserts 1 and 3 were used. From this, it can be said that it is preferable to set the radial direction rake angle ⁇ to about 3 ° in finish cutting of the inclined wall surface of the work material made of FCD 700 assuming a mold for molding an automobile outer plate.
- Example 2 In the same end mill body as in Example 1, the radial rake angles at radiation angles of 5 °, 30 °, 45 °, 60 °, 85 ° and 90 ° are + 1.0 °, + 1.5 °, + 1.0 °, 0 °, respectively.
- the same insert as in Example 1 is attached except that it is -2.5 ° and -3.0 °, and the wall surface of the hard work material made of SKD11 with Rockwell hardness of 60 HRC is cut at the inclination angle of 85 ° under the following conditions did.
- the surface roughness Ry of the obtained machined surface was 2 to 3 ⁇ m, and it was found that even a hard work material can be cut with high finishing accuracy.
- Example 3 In the same end mill body as in Example 1, the radial rake angles at radiation angles of 5 °, 30 °, 45 °, 60 °, 85 ° and 90 ° are -2.5 °, -2.0 °, -2.5 °, -3.5, respectively.
- the same insert as in Example 1 is attached except that the angle is -6.0 ° and -6.5 °, and the wall surface of the hard work material made of SKD11 with Rockwell hardness 60 HRC is cut under the condition of 85 ° processed.
- the surface roughness Ry of the obtained machined surface was 2 to 3 ⁇ m, and it was found that even a hard work material can be cut with high finishing accuracy.
- Inserts of Example 4 and Comparative Examples 1 and 2 were attached to the slit at the tip of the shank end mill body of 30 mm diameter, 32 mm shank diameter, 220 mm overall length, and 120 mm neck length.
- an indexable ball end mill was obtained.
- Each of the indexable ball end mills was mounted on the spindle of a milling machine, one-piece cutting was performed under the following cutting conditions, and the dynamic change of the cutting resistance was measured by a cutting dynamometer (manufactured by Kistler).
- the shapes of cutting forces and chips are shown in Table 3, and dynamic changes in cutting forces are shown in FIGS. 16 to 18 as component forces of cutting forces in the X-axis, Y-axis and Z-axis directions, respectively.
- the Y axis is the tool feed direction
- the X axis is the direction orthogonal to the Y axis (the tangential direction of rotation)
- the Z axis is the rotation axis direction.
- Work material S50C (Hardness, 220 HB) Processing method: Dry piece cutting (air blow) Cutting speed (Vc): 200 m / min Speed: 2122 rpm Feeding speed (Vf): 849 mm / min Feeding amount per blade (fz): 0.2 mm Radial cut amount ae: 0.5 mm Depth of cut: 15 mm Tool overhang (OH): 180 mm
- the dynamic change of the cutting resistance was smaller in Example 4 than in Comparative Examples 1 and 2.
- the cutting resistance (100 kgf) in the X-axis direction in Example 4 satisfied the target.
- the cutting resistance of Example 4 was 60% lower than that of Comparative Example 2 (250 kgf).
- FIGS. 19 to 21 show chips discharged by cutting in Example 4 and Comparative Examples 1 and 2.
- FIG. The chips in Example 4 were more twisted than the chips in Comparative Examples 1 and 2. This is because the region where the axial rake angle (axial rake) of the arc-shaped cutting edge is positive is wide and the twist angle is large. Further, it can be understood from the chip shape that the chip generation direction is obliquely above the processing surface. That is, in Example 4, the problem that the chips bit into the gap between the cutting edge and the work material was prevented. On the other hand, in the inserts of Comparative Examples 1 and 2, the chips were caught in the gap between the cutting edge and the work material.
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Abstract
Description
前記円弧状切れ刃の放射方向すくい角がβ<α≦γ(ただし、αは放射角度が5°における放射方向すくい角であり、βは放射角度が90°における放射方向すくい角であり、γは前記円弧状切れ刃の回転方向最凸点における放射方向すくい角である。)の条件を満たし、
前記円弧状切れ刃の放射方向すくい角の最大値が12~40°の放射角度の範囲内にあり、かつ
前記放射方向すくい角が前記回転方向最凸点から前記最外周点にかけて連続的に減少することを特徴とする。
前記円弧状切れ刃の放射方向すくい角がβ<α≦γ(ただし、αは放射角度が5°における放射方向すくい角であり、βは放射角度が90°における放射方向すくい角であり、γは前記円弧状切れ刃の回転方向最凸点における放射方向すくい角である。)の条件を満たし、
前記円弧状切れ刃の放射方向すくい角の最大値が12~40°の放射角度の範囲内にあり、かつ
前記放射方向すくい角が前記回転方向最凸点から前記最外周点にかけて連続的に減少することを特徴とするインサート。
第二の効果は、切れ刃の耐欠損性、耐チッピング性の向上を図り、切れ刃の劣化を回避して、長寿命化を図ることができる。
第三の効果は、切削抵抗が低減されるだけでなく、その振幅の低減によりビビリ振動が抑えられ、被削材表面の加工面粗さを向上させることができる。
図1~図4は本発明の一実施形態による刃先交換式ボールエンドミル1を示し、図5はその刃先交換式ボールエンドミル1に装着するインサートを示す。図1に示すように、刃先交換式ボールエンドミル1は、回転軸線Lを中心として回転するエンドミル本体2と、エンドミル本体2の後端に一体的に連結するシャンク部3と、エンドミル本体2の先端にテーパ部7を介して一体的に連結する半球状先端部4とを具備する。図2及び図3に示すように、半球状先端部4は、インサート5を受承するように回転軸線Lと直交する方向(半径方向)に延在するスリット8と、インサート5を固定するために半球状先端部4をスリット8と直交する方向に貫通するネジ穴10(その中心線は回転軸線Lと交差する)とを具備する。ネジ穴10にはインサート5を着脱自在に固定するクランプネジ6が螺合する。エンドミル本体2、シャンク部3及び半球状先端部4は、例えばSKD61等の合金工具鋼からなる。
図5及び図6に示すように、インサート5は、一対の平行かつ平坦な側面51a1,51a2を有する厚さTの平板状で、一対の側面51a1,51a2を連結する円弧面を有する半円状部51と、半円状部51の後端部に一体的に連結する三角形状部52とからなる。
円弧状切れ刃51d1,51d2のすくい角には、放射方向すくい角と軸方向すくい角がある。「放射方向すくい角」は、円弧中心点Oから円弧状切れ刃51d1,51d2に向かって放射状に延びる直線(放射直線)に対するすくい面51e1,51e2の角度であり、「法線方向すくい角」と呼ぶこともある。また「軸方向すくい角」は、図9に示すインサート5の側面において、円弧状切れ刃51d1,51d2の接線が回転軸線L1となす角度である。
正の放射方向すくい角では、図7に示すように、すくい面51e1は、円弧中心点Oと円弧状切れ刃51d1とを結ぶ直線より回転方向R後方に位置する(回転方向R前方に傾斜している)。負の放射方向すくい角では、その逆である。
β<α≦γ
本発明のインサートでは、軸方向すくい角も放射角度に応じて変化する。一方の切れ刃51d1について図9に示す例では、15°、30°、45°、60°及び75°の放射角度における軸方向すくい角はそれぞれ-48.409°、-18.257°、0°、+12.069°及び19.38°である。
図11に示すように、円弧状切れ刃51d1の回転方向最凸点Qと外周切れ刃51k1の後端点Rとを結ぶ線分Nが回転軸線L1と交差する角度δ1は、円弧状切れ刃51d1の最外周点Sと外周切れ刃51k1の後端点Rとを結ぶ線分Hが回転軸線L1と平行な直線L2と交差する角度δ2より小さいのが好ましい。すなわち、δ1<δ2であるのが好ましい。これにより、円弧状切れ刃51d1と被削材との接触時の衝撃を緩和し、切れ刃の耐欠損性及び耐チッピング性を高めることができる。逆に、δ1≧δ2であると、円弧状切れ刃51d1と被削材との接触時の衝撃が大きくなり、円弧状切れ刃51d1の耐欠損性及び耐チッピング性が低下する。
WC基超硬合金製のインサート5は、例えば次の手順より製造することができる。まず、炭化タングステン粉末とコバルト粉末と、必要に応じて添加物を加えた混合物からなる造粒粉を、粉末成形法等により成形する。成形時にネジ挿通穴も形成する。成形体は20~30%の焼結収縮の分だけ大きく製造する。成形体を約1300~1400℃で焼結する。
図12、図13及び図14は、エンドミル本体2のスリット8にインサート5をクランプネジ6で固定した刃先交換式ボールエンドミル1を示す。スリット8にインサート5をクランプネジ6で固定すると、インサート5の両側面51a1,51a2がスリット8の両内面8a,8bに密着するとともに、インサート5の傾斜底面52b1,52b2がスリット8の底面8cと密着するので、インサート5は高精度で位置決めされる。
本発明は刃先交換式ボールエンドミルに限定されず、一体的な(ソリッド型の)ボールエンドミルにも適用できる。ソリッド型のボールエンドミルは、基本的にインサートがエンドミル先端部と一体的である以外、刃先交換式ボールエンドミルと異なることはない。ただし、円弧状切れ刃の放射方向すくい角及び軸方向すくい角について、ソリッド型のボールエンドミルは以下の特徴を具備するのが好ましい。
刃先径30 mm、シャンク径32 mm、全長250 mm、及び首下長さ180 mmのシャンクタイプのエンドミル本体の先端部のスリットに装着する超硬合金製のインサートとして、7.2 mmの厚さTを有し、半径15 mmの円弧状切れ刃及び長さ3.0 mmのねじれ形状を有する外周切れ刃を有し、図5及び図6に示す外形を有する3種類のインサート1~3を作製した。各インサートについて、各放射角度における円弧状切れ刃の放射方向すくい角及び軸方向すくい角を非接触式三次元デジタイザにより測定した。各放射角度における放射方向すくい角及び軸方向すくい角を表1に示す。インサート1~3の最外周点S(放射角度90°)における放射方向すくい角はそれぞれ0°、+3.0°及び+6.0°とした。
加工方法: 乾式切削(エアーブロー)
切削速度(Vc): 754 m/分
回転数: 8000 rpm
送り速度(Vf): 7500 mm/分
1刃当たりの送り量(fz): 0.47 mm/tooth
径方向切込み量ae: 0.15 mm及び0.3 mmの二通り
ピックフィード(pf): 0.5 mm
工具突き出し量(OH): 180 mm
実施例1と同じエンドミル本体に、放射角度が5°、30°、45°、60°、85°及び90°における放射方向すくい角がそれぞれ+1.0°、+1.5°、+1.0°、0°、-2.5°及び-3.0°である以外実施例1と同じインサートを装着し、ロックウェル硬さが60 HRCのSKD11からなる硬質被削材の傾斜角85°の壁面を以下の条件で切削加工した。得られた加工面の表面粗さRyは2~3μmであり、硬質の被削材でも高い仕上げ精度で切削加工できることが分った。
加工方法: 乾式切削(エアーブロー)
切削速度(Vc): 400 m/分
回転数: 4244 rpm
送り速度(Vf): 2550 mm/分
1刃当たりの送り量(fz): 0.3 mm/tooth
径方向切込み量ae: 0.1 mm
ピックフィード(pf): 0.3 mm
工具突き出し量(OH): 120 mm
実施例1と同じエンドミル本体に、放射角度が5°、30°、45°、60°、85°及び90°における放射方向すくい角がそれぞれ-2.5°、-2.0°、-2.5°、-3.5°、-6.0°及び-6.5°である以外実施例1と同じインサートを装着し、ロックウェル硬さが60 HRCのSKD11からなる硬質被削材の傾斜角85°の壁面を以下の条件で切削加工した。得られた加工面の表面粗さRyは2~3μmであり、硬質の被削材でも高い仕上げ精度で切削加工できることが分った。
加工方法: 乾式切削(エアーブロー)
切削速度(Vc): 400 m/分
回転数: 4244 rpm
送り速度(Vf): 2550 mm/分
1刃当たりの送り量(fz): 0.3 mm/tooth
径方向切込み量ae: 0.1 mm
ピックフィード(pf): 0.3 mm
工具突き出し量(OH): 120 mm
表2に示すパラメータ以外実施例1と同じ形状の超硬合金製インサートを製造した。
(2) インサートの厚さ。
(3) 回転方向最凸点Qにおける放射角度。
被削材: S50C(硬さ、220 HB)
加工方法: 乾式片削り加工(エアーブロー)
切削速度(Vc): 200 m/分
回転数: 2122 rpm
送り速度(Vf): 849 mm/分
1刃当たりの送り量(fz): 0.2 mm
径方向切込み量ae: 0.5 mm
切込み量: 15 mm
工具突き出し量(OH): 180 mm
Claims (20)
- エンドミル本体の先端部に、正面視でS字状に湾曲して最先端から最外周点まで延びる円弧状切れ刃と、前記円弧状切れ刃になめらかに連結するねじれ形状を有する外周切れ刃と、前記円弧状切れ刃の回転方向前方の凸曲面状すくい面とを有するボールエンドミルであって、
前記円弧状切れ刃の放射方向すくい角がβ<α≦γ(ただし、αは放射角度が5°における放射方向すくい角であり、βは放射角度が90°における放射方向すくい角であり、γは前記円弧状切れ刃の回転方向最凸点における放射方向すくい角である。)の条件を満たし、
前記円弧状切れ刃の放射方向すくい角の最大値が12~40°の放射角度の範囲内にあり、かつ
前記放射方向すくい角が前記回転方向最凸点から前記最外周点にかけて連続的に減少することを特徴とするボールエンドミル。 - 請求項1に記載のボールエンドミルにおいて、前記放射方向すくい角γが正角であることを特徴とするボールエンドミル。
- 請求項1又は2に記載のボールエンドミルにおいて、前記放射方向すくい角βが0°以上の正角であることを特徴とするボールエンドミル。
- 請求項1~3のいずれかに記載のボールエンドミルにおいて、前記放射方向すくい角αと前記放射方向すくい角βとの差が2~6°であり、前記放射方向すくい角γと前記放射方向すくい角αとの差が0~2°であり、前記放射方向すくい角γと前記放射方向すくい角βとの差が2~6°であり、前記放射方向すくい角の最大値と前記放射方向すくい角γとの差が0.1~1.0°であることを特徴とするボールエンドミル。
- 請求項1~4のいずれかに記載のボールエンドミルにおいて、前記放射方向すくい角α、β及びγがそれぞれ2°≦α≦10°、0°≦β≦6°、及び3°≦γ≦14°の条件を満たすことを特徴とするボールエンドミル。
- 請求項1~5のいずれかに記載のボールエンドミルにおいて、前記放射角度が30~47°となる位置に前記円弧状切れ刃の回転方向最凸点があることを特徴とするボールエンドミル。
- 請求項1~6のいずれかに記載のボールエンドミルにおいて、前記円弧状切れ刃の放射方向すくい角がθ1<θ2(ただし、θ1は前記回転方向最凸点から前記最外周点までの範囲内における放射方向すくい角であり、θ2は前記回転方向最凸点から前記最先端までの範囲内における放射方向すくい角である。)の関係を満たすことを特徴とするボールエンドミル。
- 請求項1~7のいずれかに記載のボールエンドミルにおいて、前記円弧状切れ刃上の軸方向すくい角が、前記最先端から前記回転方向最凸点までの範囲内では負であり、前記回転方向最凸点を超えて前記最外周点までの範囲内では正であることを特徴とするボールエンドミル。
- 正面視でS字状に湾曲して最先端から最外周点まで延びる円弧状切れ刃と、前記円弧状切れ刃になめらかに連結するねじれ形状を有する外周切れ刃と、前記円弧状切れ刃の回転方向前方の凸曲面状すくい面とを有するインサートであって、
前記円弧状切れ刃の放射方向すくい角がβ<α≦γ(ただし、αは放射角度が5°における放射方向すくい角であり、βは放射角度が90°における放射方向すくい角であり、γは前記円弧状切れ刃の回転方向最凸点における放射方向すくい角である。)の条件を満たし、
前記円弧状切れ刃の放射方向すくい角の最大値が12~40°の放射角度の範囲内にあり、かつ
前記放射方向すくい角が前記回転方向最凸点から前記最外周点にかけて連続的に減少することを特徴とするインサート。 - 請求項9に記載のインサートにおいて、前記放射方向すくい角γが正角であることを特徴とするインサート。
- 請求項9又は10に記載のインサートにおいて、前記放射方向すくい角βが0°以上の正角であることを特徴とするインサート。
- 請求項8~11のいずれかに記載のインサートにおいて、前記放射方向すくい角αと前記放射方向すくい角βとの差が2~6°であり、前記放射方向すくい角γと前記放射方向すくい角αとの差が0~2°であり、前記放射方向すくい角γと前記放射方向すくい角βとの差が2~6°であり、前記放射方向すくい角の最大値と前記放射方向すくい角γとの差が0.1~1.0°であることを特徴とするインサート。
- 請求項8~12のいずれかに記載のインサートにおいて、前記放射方向すくい角α、β及びγがそれぞれ2°≦α≦10°、0°≦β≦6°、及び3°≦γ≦14°の条件を満たすことを特徴とするインサート。
- 請求項8~13のいずれかに記載のインサートにおいて、前記放射角度が30~47°となる位置に前記円弧状切れ刃の回転方向最凸点があることを特徴とするインサート。
- 請求項8~14のいずれかに記載のインサートにおいて、前記円弧状切れ刃の放射方向すくい角がθ1<θ2(ただし、θ1は前記回転方向最凸点から前記最外周点までの範囲内における放射方向すくい角であり、θ2は前記回転方向最凸点から前記最先端までの範囲内における放射方向すくい角である。)の関係を満たすことを特徴とするインサート。
- 請求項8~15のいずれかに記載のインサートにおいて、前記円弧状切れ刃上の軸方向すくい角が、前記最先端から前記回転方向最凸点までの範囲内では負であり、前記回転方向最凸点を超えて前記最外周点までの範囲内では正であることを特徴とするインサート。
- 請求項8~16のいずれかに記載のインサートにおいて、前記インサートの平板部の厚さT(mm)に対して前記最外周点Sにおける前記インサートの厚さTS(mm)が0.4 T≦TS<0.5 Tの条件を満たすことを特徴とするインサート。
- 請求項8~17のいずれかに記載のインサートにおいて、前記外周切れ刃の後端点Rと前記回転方向最凸点Qとを結ぶ線分と前記回転軸線との交差角δ1が15~30°であり、かつ前記最外周点Sと前記後端点Rとを結ぶ線分と前記回転軸線との交差角δ2より小さいことを特徴とするインサート。
- 請求項8~18のいずれかに記載のインサートにおいて、前記外周切れ刃の長さが0.2 T~0.5 T[ただし、Tは前記インサートの平板部の厚さ(mm)である。]の条件を満たすことを特徴とするインサート。
- 請求項8~19のいずれかに記載のインサートが、エンドミル本体の半球状先端部に設けられたスリットに固定されていることを特徴とする刃先交換式ボールエンドミル。
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EP13845106.7A EP2907608B1 (en) | 2012-10-10 | 2013-09-19 | Ball end mill and insert |
CN201380052334.7A CN104703737B (zh) | 2012-10-10 | 2013-09-19 | 球头立铣刀以及镶刀 |
JP2014506654A JP5614511B2 (ja) | 2012-10-10 | 2013-09-19 | ボールエンドミル及びインサート |
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EP2907608B1 (en) | 2020-09-02 |
US9868161B2 (en) | 2018-01-16 |
MY177341A (en) | 2020-09-12 |
EP2907608A1 (en) | 2015-08-19 |
KR20150055118A (ko) | 2015-05-20 |
IN2015DN02461A (ja) | 2015-09-04 |
JPWO2014057783A1 (ja) | 2016-09-05 |
CN104703737B (zh) | 2017-05-24 |
EP2907608A4 (en) | 2016-06-01 |
CN104703737A (zh) | 2015-06-10 |
KR101534120B1 (ko) | 2015-07-09 |
US20150258617A1 (en) | 2015-09-17 |
JP5614511B2 (ja) | 2014-10-29 |
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