WO2023119614A1 - エンドミル - Google Patents

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Publication number
WO2023119614A1
WO2023119614A1 PCT/JP2021/048138 JP2021048138W WO2023119614A1 WO 2023119614 A1 WO2023119614 A1 WO 2023119614A1 JP 2021048138 W JP2021048138 W JP 2021048138W WO 2023119614 A1 WO2023119614 A1 WO 2023119614A1
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WO
WIPO (PCT)
Prior art keywords
groove
end mill
tool
cutting
rear end
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2021/048138
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English (en)
French (fr)
Japanese (ja)
Inventor
格 伊東
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
OSG Corp
Original Assignee
OSG Corp
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Filing date
Publication date
Application filed by OSG Corp filed Critical OSG Corp
Priority to EP21969047.6A priority Critical patent/EP4454794A4/en
Priority to PCT/JP2021/048138 priority patent/WO2023119614A1/ja
Priority to JP2023568982A priority patent/JP7703048B2/ja
Priority to CN202180102470.7A priority patent/CN117980100A/zh
Priority to US18/707,172 priority patent/US20250033127A1/en
Publication of WO2023119614A1 publication Critical patent/WO2023119614A1/ja
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23C—MILLING
    • B23C2210/00—Details of milling cutters
    • B23C2210/04—Angles
    • B23C2210/0485—Helix angles
    • B23C2210/0492—Helix angles different
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23C—MILLING
    • B23C2210/00—Details of milling cutters
    • B23C2210/40—Flutes, i.e. chip conveying grooves
    • B23C2210/402—Flutes, i.e. chip conveying grooves of variable depth
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23C—MILLING
    • B23C2210/00—Details of milling cutters
    • B23C2210/40—Flutes, i.e. chip conveying grooves
    • B23C2210/402—Flutes, i.e. chip conveying grooves of variable depth
    • B23C2210/405—Flutes, i.e. chip conveying grooves of variable depth having decreasing depth in the direction of the shank from the tip of the tool

Definitions

  • the present invention relates to end mills.
  • Roughing end mills used for heavy cutting and rough cutting are required to store and discharge a large amount of generated chips. For that reason, it is important to secure a sufficient chip room. Increasing the chip room reduces the cross-sectional area of the tool. When the cross-sectional area of the tool is reduced, the tool cannot withstand the bending stress during cutting, which may cause breakage.
  • the groove of the taper end mill disclosed in Patent Document 1 is provided so that the groove bottom radius becomes smaller from the shank side toward the tip side of the tool.
  • the groove bottom radius is the distance between the groove bottom and the axis.
  • the groove bottom radius changes linearly at a predetermined slope angle in the axial direction.
  • the slope angle changes at a predetermined change point so that the tip side of the tool is smaller than the shank side.
  • the core thickness is small on the tip side of the tool where the taper angle is small. As a result, a chip room can be secured on the tip side of the tool where cutting is mainly performed.
  • the core thickness increases at a large rate of change toward the shank side. Therefore, the taper end mill can ensure strength and rigidity.
  • An object of the present invention is to provide an end mill that can improve machining efficiency.
  • An end mill is an end mill in which cutting edges are provided along a plurality of twisted grooves twisted about an axis, wherein the groove bottoms of the twisted grooves extend from the tip of the tool toward the rear end of the tool.
  • a linear portion extending linearly in parallel with the axis to a position separated by the length of the outer diameter;
  • a gradient portion that linearly inclines toward the direction outer side, a rear end of the linear portion and a front end of the gradient portion are connected, and a gradient portion extends radially outward from the linear portion side toward the gradient portion side.
  • an R-shaped portion curved in an arc, and the rake angle of the cutting edge is constant over the entire circumference of the cutting edge.
  • the groove bottom of the twisted groove of this mode has a straight portion, it is possible to sufficiently secure the chip accommodation capacity. Furthermore, the groove bottom of the twisted groove has an inclined portion on the rear end side. The inclined portion linearly inclines radially outward from the straight portion side toward the rear end side. As a result, since the groove bottom radius increases toward the rear end side, the rigidity on the rear end side can be improved. Furthermore, an R-shaped portion is provided between the straight portion and the inclined portion. The R-shaped portion curves radially outward in an arc shape from the straight portion side to the slope portion side. As a result, the entire R-shaped portion can receive the stress applied between the straight portion and the sloped portion while the workpiece is being cut.
  • the rigidity of the whole tool can be improved.
  • the rake angle is constant over the entire circumference of the cutting edge, so cutting performance for the workpiece can be ensured.
  • the end mill can process the workpiece with a high depth of cut and a high feed rate, thereby improving the processing efficiency.
  • the plurality of twisted grooves of the end mill of this aspect are unequal divisions in which groove division angles of two twisted grooves adjacent in the circumferential direction are different from each other in a front view of the tip of the tool.
  • An unequal lead in which the twist angles of the two twist grooves are different from each other may also be used.
  • the end mill can suppress self-excited vibration that occurs during cutting of the workpiece.
  • the plurality of twisted grooves of the end mill of this aspect alternately include first grooves and second grooves having different groove division angles in the circumferential direction, and the first groove division angle of the first groove is equal to that of the second groove. and the width of the first groove on the tool tip side is narrower than the groove width of the second groove on the tool tip side, and the first groove is on the tool tip side
  • the groove width may be gradually widened from the tip side toward the rear end side, and the groove width of the second groove may be gradually narrowed from the tool tip side toward the rear end side.
  • the first slope angle of the slope portion of the first groove of the end mill of this aspect and the second slope angle of the slope portion of the second groove may be different from each other.
  • the end mill can achieve both improved chip discharge performance and improved rigidity.
  • the tip of the tool of the end mill of this aspect may be hemispherical, and the cutting edge may be provided with a nick at least on the tip side of the tool.
  • the end mill can improve chip discharge performance and reduce contact friction with the workpiece.
  • the value of the radius R of the R-shaped portion of the end mill of this aspect may be within the range of 50 to 90 mm.
  • the curved shape of the R-shaped portion can be favorably formed, so that the rigidity can be improved.
  • the R-shaped portion can be formed by moving the grindstone along an arc track. You may form a R-shaped part by the processing method which transfers .
  • FIG. 1 is a perspective view of an end mill 1;
  • FIG. 2 is a side view of the end mill 1;
  • FIG. 3 is a cross-sectional view taken along line II of FIG. 2; 3 is an image diagram of a cross section along the axis O of the end mill 1.
  • FIG. FIG. 4 is a developed view of twisted grooves 5 to 8; It is a figure which compared the shape of the 1st groove
  • 4 is a graph showing the results of Test 1; 4 is a table showing the results of Test 2; 10 is a graph showing the results of Test 3-1; 10 is a graph showing the results of Test 3-2; 7 is a table showing lengths of straight portions, radii R of rounded portions, ⁇ 5, and ⁇ 6 of seven types of end mills. 4 is a table showing the results of Test 4; 4 is a graph showing the results of Test 4;
  • the configuration of a roughing ball end mill 1 (hereinafter referred to as end mill 1) will be described with reference to FIGS.
  • the end mill 1 is mainly used for heavy cutting and rough cutting.
  • the end mill 1 integrally includes a shank 2 and a blade portion 3 on the axis O.
  • the shank 2 is provided on the rear end side of the end mill 1 and the blade portion 3 is provided on the front end side of the end mill 1 .
  • the shank 2 is a round bar and is attached to the spindle of a machine tool (not shown). The machine tool rotates the end mill 1 clockwise around the axis O (see arrow T in FIGS.
  • the end mill 1 cuts grooves in the work.
  • the base material of the end mill 1 is HSS, it is not limited to this, and a hard film may be coated with, for example, cemented carbide.
  • the end mill 1 has a tool length of 80 mm, a tool diameter of 10 mm, a shank 2 length of 57.6 mm, and a blade portion 3 length of 22.4 mm.
  • the blade part 3 is rod-shaped and connected to the shank 2 on the axis O, and a hemispherical ball part 30 is provided at its tip.
  • Four twisted grooves 5 to 8 are provided around the axis O on the outer peripheral surface of the blade portion 3 .
  • the twisted grooves 5 to 8 are twisted to the right when viewed from the shank 2 side, and have unequal divisions and unequal leads as will be described later.
  • a peripheral cutting edge 11 is provided along one opening edge of each of the twisted grooves 5-8. Therefore, four outer peripheral cutting edges 11 are provided on the outer peripheral surface of the blade portion 3 .
  • the rake angle of the peripheral cutting edge 11 is constant over the entire circumference, and is, for example, 6°.
  • a large number of nicks 15 are provided on the peripheral cutting edge 11 .
  • the nick 15 extends parallel to the direction crossing the axis O. As shown in FIG.
  • the ball portion 30 is provided with four bottom cutting edges 12 .
  • the four bottom cutting edges 12 are connected to the corresponding four outer peripheral cutting edges 11, respectively.
  • the rake angle of the bottom cutting edge 12 is also constant over the entire circumference like the peripheral cutting edge 11, and is 6° as an example.
  • Two nicks 16 are provided on each of the four bottom cutting edges 12 .
  • the nick 16 also extends parallel to the direction intersecting the axis O. As shown in FIG. Chips cut out by the peripheral cutting edge 11 and the bottom cutting edge 12 are separated by the nicks 15 and 16 and discharged to the shank 2 side through the twisted grooves 5 to 8 together with the coolant. Therefore, the chip discharge performance is improved, so that the end mill 1 can perform cutting with high efficiency.
  • the twisted grooves 5 and 7 face each other across the axis O, and the twisted grooves 6 and 8 sandwich the axis O. facing each other.
  • the twisted grooves 5 and 7 are defined as the first grooves 21 and the twisted grooves 6 and 8 are defined as the second grooves 22 . Since the groove division angle ⁇ 1 of the first groove 21 and the groove division angle ⁇ 2 of the B groove are different from each other, the twisted grooves 5 to 8 are unequal divisions.
  • the groove division angle ⁇ 1 is 81° and the groove division angle ⁇ 2 is 99°. Since the twisted grooves 5 to 8 are unevenly divided, the four outer peripheral cutting edges 11 are unevenly arranged in the circumferential direction. As an example, the four peripheral cutting edges 11 are arranged at positions of 0°, 81°, 180°, and 261°. As a result, periodic self-excited vibration does not occur during cutting, and chattering is less likely to occur even when the cutting load is high. Furthermore, since chips are scattered and discharged, it is possible to prevent clogging of the twisted grooves 5 to 8 with chips during cutting.
  • the twist angle ⁇ 3 of the first groove 21 and the twist angle ⁇ 4 of the second groove 22 are different from each other, so the twist grooves 5 to 8 have unequal leads.
  • the twist angles ⁇ 3 and ⁇ 4 are twist angles with respect to the axis O. As shown in FIG. As an example, the twist angle ⁇ 3 is 40° and the twist angle ⁇ 4 is 42°. In this embodiment, the twist angle ⁇ 4 of the second grooves 22 is greater than the twist angle ⁇ 3 of the first grooves 21 .
  • the width of each of the first groove 21 and the second groove 22 will be described with reference to FIG.
  • the width of the groove means the length in the direction orthogonal to the length direction of the groove.
  • the two first grooves 21 and the two second grooves 22 are arranged alternately in the circumferential direction on the outer peripheral surface of the blade portion 3 .
  • the groove division angle ⁇ 1 of the first grooves 21 is smaller than the groove division angle ⁇ 2 of the second grooves 22 (see FIG. 3). Therefore, on the tip side (left side in FIG. 4) of the blade portion 3, the width of the first groove 21 is narrower than the width of the second groove 22, and the width of the second groove 22 is equal to the width of the first groove 21. It's wider than that.
  • the width of the first groove 21 gradually increases toward the shank 2 side, and the width of the second groove 22 gradually decreases toward the shank 2 side, contrary to the first groove 21 . Therefore, on the shank 2 side of the blade portion 3, the width of the first groove 21 is wider than the width of the second groove 22, and the width of the second groove 22 is narrower than the width of the first groove 21. .
  • FIG. 5 is a cross-sectional view along the axis O of the end mill 1.
  • the first groove 21 and the second groove 22 are arranged along the axis O. It is an image diagram extended parallel to.
  • the groove bottom of the first groove 21 includes a linear portion 41, an R-shaped portion 42, an inclined portion 43, and a raised portion 44 in order from the tool tip side toward the shank 2 side.
  • the linear portion 41 is provided on the tip side of the blade portion 3 and is a portion that extends parallel to the axis O from the tip side of the tool to the outer diameter Dc.
  • the outer diameter Dc is the tool diameter (diameter) of the end mill, and is 10 mm as an example.
  • An enlarged diameter portion 40 is provided on the tip side of the tool.
  • the enlarged diameter portion 40 is tapered from the tip of the tool toward the shank 2 side, or enlarged in diameter in a curved shape based on this, and is connected to the front end of the straight portion 41 .
  • the length of the expanded diameter portion 40 may be designed according to the tool diameter.
  • the groove bottom diameter ratio of the straight portion 41 is 53%.
  • the groove bottom diameter ratio is the ratio of the groove bottom diameter to the tool diameter.
  • a large chip room 61 is formed in a portion of the first groove 21 corresponding to the straight portion 41 .
  • the sloped portion 43 is a sloped portion provided closer to the shank 2 than the intermediate portion in the length direction of the blade portion 3 and linearly sloped so that the groove bottom diameter increases toward the shank 2 side.
  • An example of the slope angle ⁇ 5 of the slope portion 43 with respect to the axis O is 5°.
  • the R-shaped portion 42 is a portion that smoothly connects the rear end of the straight portion 41 and the front end of the inclined portion 43 in an arc shape.
  • the R-shaped portion 42 is curved in an arc shape so that the groove bottom diameter gradually increases from the rear end of the straight portion 41 toward the front end of the sloped portion 43 .
  • the groove bottom diameter ratio at the rear end of the R-shaped portion 42 is 55%.
  • the gently arcuate R-shaped portion 42 can be formed by applying a grindstone to the base material of the tool rotating at high speed or by moving the tool along an arcuate trajectory.
  • the raised portion 44 is a portion that is rounded up from the rear end of the inclined portion 43 toward the surface of the tool.
  • the groove bottom of the second groove 22 like the groove bottom of the first groove 21, also has an enlarged diameter portion 50, a linear portion 51, and an R-shaped portion in this order from the tool tip side toward the shank 2 side.
  • a portion 52 , an inclined portion 53 , and a rounded portion 54 are provided.
  • a large chip room 62 is formed in a portion of the second groove 22 corresponding to the straight portion 51 .
  • the slope angle ⁇ 6 of the slope portion 43 with respect to the axis O is 3°. Although the slope angles ⁇ 5 and ⁇ 6 of this embodiment are different from each other, they may be the same.
  • the chip discharge performance and rigidity when cutting a workpiece with the end mill 1 will be described.
  • the depth of cut is normally less than the outer diameter Dc, so the end mill 1 is required to have a large capacity to accommodate chips.
  • large chip rooms 61 and 62 are provided in portions corresponding to the straight portions 41 and 51, respectively. Since the chip rooms 61 and 62 can accommodate large chips generated on the tip side of the tool, they can be discharged to the shank 2 side. Thereby, the end mill 1 can prevent chips from clogging the first groove 21 and the second groove 22 .
  • the groove bottom radii of the straight portions 41 and 51 of the first groove 21 and the second groove 22 become smaller, but the groove bottom radii of the sloped portions 43 and 53 gradually increase toward the shank 2 side.
  • the end mill 1 can improve the rigidity on the shank 2 side compared to an end mill in which the linear portions 41 and 51 of the first groove 21 and the second groove 22 are extended to the shank 2 side. Therefore, the end mill 1 can improve the rigidity of the blade portion 3 on the shank 2 side while improving the chip discharging performance of the first groove 21 and the second groove 22 .
  • the end mill 1 does not directly connect the straight portions 41, 51 and the sloped portions 43, 53, but indirectly connects them via the R-shaped portions 42, 52. If the straight portions 41, 51 and the sloped portions 43, 53 are directly connected, the groove bottom radius changes abruptly at the connecting portion between the straight portions 41, 51 and the sloped portions 43, 53. In this case, since a large load is applied to the connection portion where the groove bottom radius changes rapidly during cutting of the workpiece, there is a possibility of breakage at the connection portion. Since the end mill 1 smoothly connects the straight portions 41, 51 and the sloped portions 43, 53 by the arc-shaped R-shaped portions 42, 52, the groove bottom radius from the straight portions 41, 51 toward the sloped portions 43, 53 gradually increases. As a result, the load is applied to the entire R-shaped portions 42 and 52 in a distributed manner during cutting of the workpiece, so breakage can be effectively prevented.
  • the processing of the R-shaped portions 42 and 52 is performed by bringing a circular grindstone into contact with the base material rotating at high speed.
  • the size of the radius R (R dimension) at this time is preferably 50 (mm) to 90 (mm).
  • the size of R is greater than 90 (mm)
  • the rounded portions 42, 52 extend toward the shank 2, so the front ends of the sloped portions 43, 53 move toward the shank 2, reducing rigidity. put away.
  • the size of the R is smaller than 50 (mm)
  • the rounded portions 42 and 52 are slightly curved, so stress concentration is likely to occur, and chips can smoothly flow into the first grooves 21.
  • the rake angle of the outer peripheral cutting edge 11 is constant (for example, 6°) at any position.
  • the sharpness of the workpiece can be improved, and the cutting resistance can be reduced.
  • the chip shape is stabilized, clogging of chips in the first groove 21 and the second groove 22 can be prevented.
  • the slope angle ⁇ 5 of the slope portion 43 of the first groove 21 having a large width on the shank 2 side is larger than the slope angle ⁇ 6 of the slope portion 53 of the second groove 22 having a narrow width on the shank 2 side.
  • Test 1 was conducted to verify the effects of the groove bottom shapes of the first groove 21 and the second groove 22 .
  • the end mill 1 of the present invention and end mills 101 to 104 of comparison were examined for tool life when cutting a workpiece.
  • the tool life was determined by cutting endurance length (m).
  • the cutting endurance length was defined as the length when Vb (peripheral flank wear width) was 0.5 mm or when it was broken.
  • the end mills 101 to 104 are obtained by changing the groove bottom shapes of the first groove 21 and the second groove 22, respectively.
  • FIG. 6 only the groove bottom shape of the first groove 21 will be described for the sake of clarity.
  • the end mill 101 is obtained by extending the straight part 41 of the end mill 1 to the shank 2 side and rounding it up with a rounding part 44 .
  • the end mill 102 is obtained by shallowing the groove bottom of the linear portion 41 of the end mill 101 .
  • the end mill 103 is obtained by making the groove bottom of the linear portion 41 of the end mill 102 shallower.
  • the end mill 104 is obtained by deforming the groove bottom into a zigzag shape.
  • Each of the end mills 1, 101 to 104 has a tool diameter of 10 mm and four blades.
  • the groove bottom diameter ratio at each position of the end mills 1, 101 to 104 will be explained. As shown in FIG. 7, for each of the end mills 1, 101 to 104, the groove bottom diameter ratio was measured at four points 7 mm, 10 mm, 15 mm, and 20 mm away from the tip of the tool. The groove bottom diameter ratio indicates the ratio (%) of the groove bottom diameter to the tool diameter. In end mill 1, the groove bottom diameter ratio at the 7 mm point was 53%, the groove bottom diameter ratio at the 10 mm point was 53%, the groove bottom diameter ratio at the 15 mm point was 55%, and the groove bottom diameter ratio at the 20 mm point was 58%. .
  • the 7 mm point corresponds to the position on the tip side of the linear portion 41
  • the 10 mm point corresponds to the position of the rear end of the linear portion 41
  • the 15 mm point corresponds to the position of the starting end of the slope portion 43
  • the 20 mm point corresponds to It corresponds to a position on the rear end side of the lengthwise intermediate portion of the inclined portion 43 .
  • the groove bottom diameter ratio was 53% at each of the 7 mm point, 10 mm point, 15 mm point, and 20 mm point.
  • the groove bottom diameter ratio was 57% at the 7 mm point, 10 mm point, 15 mm point, and 20 mm point.
  • the groove bottom diameter ratio was 58% at the 7 mm point, 10 mm point, 15 mm point, and 20 mm point.
  • the groove bottom diameter ratio at the 7 mm point is 53%
  • the groove bottom diameter ratio at the 10 mm point is 44.67%
  • the groove bottom diameter ratio at the 15 mm point is 56.33%
  • the groove bottom diameter ratio at the 20 mm point is 58. %Met.
  • the rake angles of the outer peripheral cutting edges 11 of the end mills 1, 101 to 104 were all set to 6°.
  • the cutting speed was 80 m/min
  • the rotational speed was 2547 min ⁇ 1
  • the feed rate was 1019 mm/min
  • the axial depth of cut was 10 mm
  • the width was 10 mm.
  • the feed speed means the speed at which the table on which the workpiece is fixed is moved relative to the tool mounted on the spindle of the machine tool (not shown).
  • the durable cutting length (m) of the end mill 1 which is the product of the present invention, was 120.8.
  • the end mill 101 had a durable cutting length (m) of 0.1 and was broken during cutting of the workpiece.
  • the end mill 102 had a durable cutting length (m) of 34 and was broken during cutting of the workpiece.
  • the end mill 103 had a cutting endurance length (m) of 0.1 and was broken during cutting of the workpiece.
  • the end mill 104 had a durable cutting length (m) of 58 and was broken during cutting of the workpiece. Considering these results, in the end mill 101, since the linear portion 41 extends to the shank 2 side, it is considered that the rigidity of the shank 2 side was lowered and the breakage occurred.
  • the end mill 102 had a larger groove bottom diameter ratio than the end mill 101, and thus had slightly improved rigidity.
  • the groove bottom diameter ratio was further increased and the chip room was narrowed, chips were clogged in the first groove 21, resulting in breakage.
  • End mill 104 had a longer cutting endurance length (m) than end mills 101 to 103, but was significantly shorter than end mill 1. Since the bottom of the groove is zigzag, it is thought that chips were caught on the bottom of the groove and clogged, resulting in breakage.
  • the end mill 1 which is the product of the present invention, had the longest cutting endurance length (m). rice field.
  • Test 2 was conducted to verify the effects of unequal division and unequal leads.
  • Test 2 the maximum depth of cut into the work was examined for the end mill 1, which is the product of the present invention, and the end mill, which is the comparative product, with equal division and equal lead.
  • the tool diameter of each of the present invention product and the comparative product is 10 mm, and the number of blades is 4.
  • the maximum depth of cut of the product of the present invention was larger than the maximum depth of cut of the comparative product. I found out.
  • Test 3 was conducted to verify the effect of keeping the rake angle constant.
  • end mill 1 which is the product of the present invention
  • an end mill whose rake angle varies according to the slope of the groove bottom were prepared as comparison products, and the maximum value of cutting force (N) when the depth of cut was changed. and averaged.
  • the configuration of the comparative product is the same as that of the product of the present invention except that the rake angle varies according to the slope of the groove bottom.
  • Both the tool diameters of the present invention product and the comparative product are ⁇ 20 (R10) mm.
  • Pre-hardened steel (40HRC) was used for the work.
  • the cutting speed was 100 m/min
  • the rotation speed was 1590 min ⁇ 1
  • the feed speed was 450 mm/min
  • the groove was cut with a width of 10 mm.
  • the cutting resistance (N) was measured when the axial cutting depth AP was changed from 0.3D to 1.0D, and the maximum and average values were examined. Note that D is the tool diameter.
  • the maximum value of AP 0.6D
  • the value was 2182
  • the maximum value of the cutting resistance of the product of the present invention showed a tendency to increase as the depth of cut increased, similar to the change in the maximum value of the comparative product.
  • the slope of the rise was greatly reduced especially after the depth of cut of 0.5D, and the difference increased as the depth of cut increased.
  • the maximum value of AP 0.6D
  • the value was 2062
  • the average value of the cutting resistance of the products of the present invention also tended to increase as the depth of cut increased, similar to the change in the average value of the comparative products.
  • the average value of the cutting resistance of the product of the present invention compared to the change in the average value of the comparative product, the slope of the increase at a cutting depth of 0.5D or later is greatly reduced, and as the cutting depth increases The difference has grown.
  • the maximum and average values of the cutting resistance of the products of the present invention increased as the depth of cut increased, but they were lower than the rising slope of the maximum and average values of the cutting resistance of the comparative products. Therefore, it was found that the constant rake angle of the peripheral cutting edge 11 reduces the cutting resistance to the workpiece.
  • Test 4 was conducted in order to verify the inclination angles ⁇ 5 and ⁇ 6 of the first groove 21 and the second groove 22 and the curved shape of the R-shaped portions 42 and 52 .
  • 7 types of end mills A to G were prepared, and the tool life of each was examined by cutting the workpiece.
  • End mills A and B are products of the present invention
  • end mills C to G are comparative products.
  • the length (mm) of the straight portions 41 and 51 of the first groove 21 and the second groove 22, the size of the R of the R-shaped portions 42 and 52, and the slope angle of the slope portion 43 .theta.5 and the slope angle .theta.6 of the slope portion 53 are defined respectively.
  • the length (mm) of the straight portions 41 and 51 is the length from the tip of the tool to the rear end of each of the straight portions 41 and 51 (hereinafter collectively referred to as straight portions).
  • the straight portions 41 and 51 have the same length.
  • the length of the straight portion is 10 mm
  • the size of the R-shaped portion is 75 mm
  • the slope angle ⁇ 5 is 3°
  • the slope angle ⁇ 6 is 3°
  • the straight portion has a length of 10 mm
  • the radius of the rounded portion is 75 mm
  • the slope angle ⁇ 5 is 5°
  • the slope angle ⁇ 6 is 3°.
  • the only difference between end mills A and B is the slope angle ⁇ 5.
  • the straight portion has a length of 10 mm
  • the radius of the rounded portion is 10 mm
  • the inclination angle ⁇ 5 is 3°
  • the inclination angle ⁇ 6 is 3°.
  • the straight portion has a length of 10 mm, the radius of the rounded portion is 30 mm, the inclination angle ⁇ 5 is 3°, and the inclination angle ⁇ 6 is 3°.
  • the straight portion has a length of 10 mm, the radius of the rounded portion is 50 mm, the inclination angle ⁇ 5 is 3°, and the inclination angle ⁇ 6 is 3°.
  • the straight portion has a length of 10 mm, the radius of the rounded portion is 90 mm, the inclination angle ⁇ 5 is 3°, and the inclination angle ⁇ 6 is 3°.
  • the straight portion has a length of 10 mm, the radius of the rounded portion is 100 mm, the inclination angle ⁇ 5 is 3°, and the inclination angle ⁇ 6 is 3°.
  • the tool diameter of each of the end mills A to G is 10 mm, and the number of teeth is four.
  • Cutting conditions will be explained.
  • Stainless steel (SUS304) was used for the work.
  • the cutting speed was 80 m/min
  • the rotation speed was 2547 min ⁇ 1
  • the feed rate was 1019 mm/min
  • the groove width was 10 mm
  • the axial depth of cut was 10 mm.
  • the tool life when grooving a workpiece under these cutting conditions was investigated. As in Test 1, the tool life was determined by cutting endurance length (m).
  • the cutting endurance length was defined as the length when Vb (peripheral flank wear width) was 0.5 mm or when it was broken.
  • the conversion values are calculated for each of the other end mills, and these conversion values and the cutting endurance length are determined.
  • the condition of the tool was comprehensively evaluated in three stages of ⁇ , ⁇ , and ⁇ .
  • an end mill with a conversion value of 70 to 100% was rated as ⁇
  • an end mill with a conversion value of 40 to 70% was rated as ⁇
  • an end mill with a conversion value of 0 to 39% was rated as x.
  • End mill A has a cutting endurance length of 120.8
  • end mill B has a cutting endurance length of 131.5
  • end mill C has a cutting endurance length of 2.4
  • end mill D has a cutting endurance length of 13.3
  • end mill E. was 95.2
  • the end mill F had a cutting endurance length of 102.3
  • the end mill G had a cutting endurance length of 37.6. From these results, the cutting endurance length of end mill B was the longest. Therefore, if the cutting endurance length of end mill B is 100.0%, the conversion value of end mill A is 91.9%, the conversion value of end mill C is 1.8%, and the conversion value of end mill D is 10.1%.
  • the conversion value of the end mill E was 72.4%
  • the conversion value of the end mill F was 77.8%
  • the conversion value of the end mill G was 28.6%.
  • the reason why the end mills A, B, E, and F were judged to be the cutting endurance length was wear, and the end mills C, D, and G were broken.
  • both end mills A and B were evaluated as O, and it was found that the groove bottom shape of each of the first groove 21 and the second groove 22 could improve chip discharge performance and ensure rigidity. rice field.
  • the tool life of the end mill B was longer than that of the end mills A and B, it was found that setting the slope angles ⁇ 5 and ⁇ 6 different from each other rather than making them the same would extend the tool life.
  • the end mills A, C to G have different R values of the R-shaped portions. As the value of R increases, the arc of the R-shaped portion (R-shaped portion) curves gently and greatly.
  • the evaluation of the end mills A, E, and F was ⁇ , and the evaluation of the other end mills C, D, and G was x. That is, the end mill E with an R value of 50 (mm), the end mill A with an R value of 75 (mm), and the end mill F with an R value of 90 (mm) did not break and reached the tool life due to wear.
  • the curved shape of the R-shaped portion becomes steep, so that the load tends to be concentrated. Therefore, it is considered that the end mills C and D having small R values are likely to break at the R-shaped portion. Conversely, if the value of R is large, the R-shaped portion becomes nearly straight, so that the groove bottom diameter hardly changes from the straight portion and the rigidity cannot be improved. Therefore, in this case as well, it is considered that the R-shaped portion is likely to break.
  • the entire R-shaped portion can receive the load applied between the straight portion and the sloped portion, and the durability is improved. can be improved.
  • the peripheral cutting edge 11 and the bottom cutting edge 12 are examples of the "cutting edge” of the present invention.
  • the groove dividing angle ⁇ 1 is an example of the "first groove dividing angle” in the present invention
  • the groove dividing angle ⁇ 2 is an example of the “second groove dividing angle” in the present invention.
  • the slope angle ⁇ 5 is an example of the "first slope angle” in the present invention
  • the slope angle ⁇ 6 is an example of the "second slope angle” in the present invention.
  • the end mill 1 of the present embodiment is a roughing machine for heavy cutting and rough cutting in which the outer cutting edge 11 and the bottom cutting edge 12 are provided along the twisted grooves 5 to 8 twisted around the axis O. It is an end mill.
  • Each groove bottom of the twisted grooves 5 to 8 has a linear portion 41 (51), an R-shaped portion 42 (52), and an inclined portion 43 (53).
  • the linear portion 41 extends linearly in parallel with the axis O from the front end of the tool to a position separated by the length of the outer diameter of the tool toward the rear end side.
  • the sloped portion 43 is provided closer to the rear end than the straight portion 41 and linearly slopes outward in the radial direction from the straight portion 41 toward the rear end.
  • the R-shaped portion 42 connects the rear end of the straight portion 41 and the front end of the sloped portion 43 , and curves radially outward in an arc shape from the straight portion 41 side toward the sloped portion 43 side.
  • the rake angle between the outer peripheral cutting edge 11 and the bottom cutting edge 12 is constant over the entire circumference.
  • the groove bottoms of the twisted grooves 5 to 8 are provided with the linear portions 41, it is possible to ensure a sufficient chip accommodation capacity. Furthermore, since the sloped portion 43 is provided on the rear end side, the groove bottom radius increases toward the rear end side, so that the rigidity on the rear end side can be improved. Furthermore, since the R-shaped portion 42 is provided between the straight portion and the sloped portion, the stress applied between the straight portion 41 and the sloped portion 43 is distributed and received by the entirety of the R-shaped portion 42 during cutting of the workpiece. be able to. Thereby, the end mill 1 can improve the rigidity of the whole tool.
  • the end mill 1 is capable of machining a workpiece with a high depth of cut and a high feed, so that machining efficiency in heavy cutting and rough cutting can be improved.
  • the end mill 1 is for heavy cutting and rough cutting, but may be for normal cutting or finishing.
  • the end mill 1 has four twisted grooves 5 to 8, but the number of twisted grooves may be plural, for example, two or four or more.
  • the end mill 1 has unequal divisions and unequal leads, but may be unequal divisions and equal leads, unequal divisions and equal leads, and equal divisions and unequal leads.
  • the twisted grooves 5 to 8 are right-handed, but may be left-handed.
  • the rake angle between the peripheral cutting edge 11 and the bottom cutting edge 12 is constant, it may not be constant, and may vary according to the slopes of the groove bottoms of the twisted grooves 5 to 8, for example.
  • the number of nicks 16 provided on the bottom cutting edge 12 should be at least one, and may be two or more.
  • the number of nicks 15 provided on the outer peripheral cutting edge 11 is also not limited.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Milling Processes (AREA)
PCT/JP2021/048138 2021-12-24 2021-12-24 エンドミル Ceased WO2023119614A1 (ja)

Priority Applications (5)

Application Number Priority Date Filing Date Title
EP21969047.6A EP4454794A4 (en) 2021-12-24 2021-12-24 End mill
PCT/JP2021/048138 WO2023119614A1 (ja) 2021-12-24 2021-12-24 エンドミル
JP2023568982A JP7703048B2 (ja) 2021-12-24 2021-12-24 エンドミル
CN202180102470.7A CN117980100A (zh) 2021-12-24 2021-12-24 立铣刀
US18/707,172 US20250033127A1 (en) 2021-12-24 2021-12-24 End mill

Applications Claiming Priority (1)

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PCT/JP2021/048138 WO2023119614A1 (ja) 2021-12-24 2021-12-24 エンドミル

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US20240217009A1 (en) * 2021-05-07 2024-07-04 Kyocera Sgs Precision Tools, Inc. High feed circle segment cutter
CN120480267B (zh) * 2025-07-17 2025-10-03 株洲钻石切削刀具股份有限公司 一种铣磨钻头

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WO2010102605A1 (de) * 2009-03-07 2010-09-16 Gühring Ohg Schaftfräser
US20130315681A1 (en) * 2011-02-15 2013-11-28 Vladimir Volokh Rotary cutter
JP2013248727A (ja) * 2012-05-01 2013-12-12 Kobe Steel Ltd 切削工具およびその設計方法
WO2019244361A1 (ja) 2018-06-22 2019-12-26 オーエスジー株式会社 テーパエンドミル

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CH675842A5 (en) * 1990-01-18 1990-11-15 Tungstentools S A Twist drill with variable depth helix - has core with different diameter sections proportionate to spiral diameter and with specified conicity
JP3036343B2 (ja) * 1993-10-29 2000-04-24 日立ツール株式会社 エンドミル
EP2871014A3 (en) * 2005-10-03 2015-08-12 Mitsubishi Materials Corporation Method of boring pilot hole
KR101746483B1 (ko) * 2011-06-17 2017-06-13 미츠비시 히타치 쓰루 가부시키가이샤 다날 엔드밀

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Publication number Priority date Publication date Assignee Title
WO2010102605A1 (de) * 2009-03-07 2010-09-16 Gühring Ohg Schaftfräser
US20130315681A1 (en) * 2011-02-15 2013-11-28 Vladimir Volokh Rotary cutter
JP2013248727A (ja) * 2012-05-01 2013-12-12 Kobe Steel Ltd 切削工具およびその設計方法
WO2019244361A1 (ja) 2018-06-22 2019-12-26 オーエスジー株式会社 テーパエンドミル

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Title
See also references of EP4454794A4

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US20250033127A1 (en) 2025-01-30
JP7703048B2 (ja) 2025-07-04
EP4454794A1 (en) 2024-10-30
EP4454794A4 (en) 2025-11-19
CN117980100A (zh) 2024-05-03
JPWO2023119614A1 (https=) 2023-06-29

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