ROTARY CUTTING TOOL WITH HONE EDGES

Abstract

A rotary cutting tool includes a shaft having and outer surface and having a longitudinal axis, a plurality of helical flutes formed in the shaft about the longitudinal axis, a plurality of helical cutting edges formed at an interface with the outer surface and a respective helical flute about the longitudinal axis, and a plurality of end cutting edges located on an axial distal end of a cutting portion of the shaft, the end cutting edges being contiguous with a corresponding one of the plurality of helical cutting edges and forming a corner in the transition between each of the end cutting edges and the corresponding one of the plurality of helical cutting edges. A hone edge extends along a portion of each of the end cutting edges, the associated corner and a portion of the corresponding one of the plurality of helical cutting edges.

Claims

1-19. (canceled)

20. A method of forming a rotary cutting tool comprising: providing a shaft having an outer surface and having a longitudinal axis forming a plurality of helical flutes in the shaft about the longitudinal axis defining a cutting portion, the remainder of the shaft defining a shank portion; forming a plurality of helical cutting edges at an interface with the outer surface and a respective helical flute about the longitudinal axis; forming a plurality of end cutting edges on an axial distal end of cutting portion of the shaft, the end cutting edges being contiguous with a corresponding one of the plurality of helical cutting edges and forming a corner in the transition between each of the end cutting edges and the corresponding one of the plurality of helical cutting edges; and engaging one of the plurality of helical cutting edges, the associated corner, and one of the plurality of end cutting edges with a filament brush to form a hone edge extending along a length of each of the one of the plurality of end cutting edges, the associated corner, and the corresponding one of the plurality of helical cutting edges.

21. The method of claim 20 further comprising, prior to forming the hone edges, securing the shaft in a chuck at the shank portion.

22. The method of claim 21 where the forming the hone edges includes rotating the shaft by the chuck.

23. The method of claim 20 where the filament brush is secured to a honing machine, and where in the forming the hone edges includes applying the filament brush of the honing machine to the length of the one of the plurality of helical cutting edges.

24. The method of claim 20 where the filament brush includes filaments flanged between two disks.

25. The Method of claim 20 where the filament brush is secured to a honing machine, and where in the forming the hone edges includes applying the filament brush of the honing machine to the length of the one of the plurality of end cutting edges.

26. The method of claim 25 where the honing machine includes filaments flanged between two disks.

27. The method of claim 20 where the hone edges are varying hone edges.

28. The method of claim 27 where the varying hone edges increase from the associated helical cutting edge toward the associated end cutting edge.

29. The method of claim 27 where there is increased honing on the corners as compared to the helical cutting edges.

30. The method of claim 20 where the forming hone edges is performed by a CNC machine.

31. The method of claim 20 where the filament brush engages the one of the plurality of helical cutting edges with a varying load the length of the one of the plurality of helical cutting edges.

32. The method of claim 20 where the filament brush engages one of the plurality of end cutting edges with a varying load the length of the one of the plurality of end cutting edges.

33. The method of claim 20 where the filament brush engages one of the plurality of helical cutting edges and the one of the plurality of end cutting edges with a varying load the length of the one of the plurality of helical cutting edges.

34. The method of claim 23 where the filament brush of the honing machine is applied to the length of the one of the plurality of helical cutting edges with a varying load.

35. The method of claim 25 where the filament brush of the honing machine is applied to the length of the one of the plurality of end cutting edges with a varying load.

36. The method of claim 20 where the filament brush is a diamond impregnated fiber brush.

37. The method of claim 23 further comprising: pivoting the filament brush of the hone machine 90 degrees about the corner; and where forming the hone edges includes applying the filament brush of the honing machine to the length of the one of the plurality of end cutting edges.

38. The method of claim 20 where the hone edge extending along the length of each of the one of the plurality end cutting edges, the associated corner, and the corresponding one of the plurality of helical cutting edges includes an edge radius, where the edge radius is variable along the hone edge length through the helical cutting edge, the corner, and the end cutting edge and where an axial angle and a radial angle of the contiguous hone edge are geometrically positive relative to rotating the shaft in a clock-wise rotational direction about the longitudinal axis.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 is a side view of a known end mill.

[0017] FIG. 2 is an enlarged portion of the end mill of FIG. 1.

[0018] FIG. 3 is a view similar to FIG. 2 except showing the end will after significant wear. and show new and used corners.

[0019] FIG. 4 is a tangential view of a portion of an end mill with corner radius.

[0020] FIG. 5 is a side of the portion of the end mill of FIG. 4.

[0021] FIG. 6 is a tangential view of a portion of an end mill with faced hook.

[0022] FIG. 7 is a side of the portion of the end mill of FIG. 4.

[0023] FIG. 8 is a tangential view of a portion of an end mill with B-Rad.

[0024] FIG. 9 is a side of the portion of the end mill of FIG. 4.

[0025] FIG. 10 is an enlarged front view of a portion of an end mill with hone edges.

[0026] FIG. 11 is a further enlarged portion of FIG. 10.

[0027] FIG. 12 is a tangential view the end mill of FIG. 10.

[0028] FIG. 13 is a side view of the end mill of FIG. 10.

[0029] FIG. 14 is an enlarged perspective view of the hone edge of the end mill of FIG. 10.

[0030] FIG. 15 is a schematic illustration of a first hone edge.

[0031] FIG. 16 is a schematic illustration of a second hone edge.

[0032] FIG. 17 is a schematic illustration of a third hone edge.

[0033] FIG. 18 is a schematic illustration of a fourth hone edge.

[0034] FIG. 19 is a schematic illustration of a fifth hone edge.

[0035] FIG. 20 is an enlarged view of a cutting edge of a conventional end mill after use.

[0036] FIG. 21 is an enlarged view of a cutting edge of an end mill with hone edge after use.

[0037] FIG. 22 is a front view of a portion of a CNC machine including a chuck holding a shaft.

[0038] FIG. 23 is a front view of another portion of the CNC machine of FIG. 22 including a machine brush.

[0039] FIG. 24 is a perspective view of the brush of FIG. 23.

[0040] FIG. 25 is another perspective view of the CNC machine of FIGS. 22-24 showing the machine in operation.

[0041] [Change line spacing to 1] FIG. 26 is a further perspective view of the CNC machine of FIGS. 22-24 showing the machine in further operation.

[0042] FIG. 27 shows an end mill with B-Rad.

[0043] FIG. 28 shows an end mill with hone edge.

DETAILED DESCRIPTION

[0044] There is shown in FIGS. 10-14, 21 and 28 an end mill rotary cutting tool 110. The tool 110 includes a shaft 112 having and an outer surface 114 and having a longitudinal axis X. The shaft 112 includes a shank portion 116, see FIG. 22, and cutting portion 118. A plurality of helical flutes 120 are formed in the shaft 112 in the cutting portion 118 about the longitudinal axis X.

[0045] A plurality of helical cutting edges 122 are formed at an interface with the outer surface 114 and a respective helical flute 120 about the longitudinal axis X. A plurality of end cutting edges 124 are located on an axial distal end 126 of the cutting portion 118 of the shaft 112. The end cutting edges 124 are contiguous with a corresponding one of the plurality of helical cutting edges 122 and form a corner 128 in the transition between each of the end cutting edges 124 and the corresponding one of the plurality of helical cutting edges 122.

[0046] A hone edge 130 extends along a portion of each of the end cutting edges 124, the associated corner 128 and a portion of the corresponding one of the plurality of helical cutting edges 122.

[0047] The hone edges 130 may all be varying hone edges, that is to say that the amount of honing may vary along the length of the edge. The varying hone edges 130 may, for example, increase from the associated helical cutting edge 122 toward the associated end cutting edge 124. There may be increased honing on the corners 128 as compared to the helical cutting edges 122 or as compared to the end cutting edges 124 or both. The hone edges 130 may be formed to all be geometrically positive.

[0048] The end mill of Claim 2 where the helix angle of the helical flutes varies along the longitudinal axis.

[0049] The rake angle of the helical cutting edges 122 may vary along the longitudinal axis X.

[0050] There is illustrated in FIGS. 15-19 a variety of hone edge with the thickness of the hone line 132 indicating the amount of honing by location.

[0051] In one embodiment, edges are rounded with a diamond impregnated fiber brush. Upon testing, see the method of corner strengthening has produced significant results. The corner radius stronger, as compared to other methods, and cutting force and torque were lower, and overall tool condition was better.

[0052] This method may include that the treatment size would not be consistent over the entire edge length. For example, it may vary so as to provide protection according to the load associated with a specific location on an end mill, or vary in any other way as desired. As an example, the axial edges may receive 0.001-0.002 (inch) radius, transitioning around the corner radius to 0.0003-0.0005 (inch) on the radial edges.

[0053] Listed are some of the benefits discovered provided by varying edge treatment as compared to other edge treatments: reduction of maximum force by 13.8% and torque by 11.5%, improvement of chip resistance at the corners over conventional protection methods, and improvement of chip resistance along the radial cutting edge.

[0054] In one embodiment this may be combine with varying helix and/or varying rake to create a tool where the combination of two or three work together. It is expected that the varying rake/varying helix will reduce vibration, while the varying hone may be able to withstand more vibration. It is expected that when combined these features will create a highly chip resistant design.

[0055] Illustrated is a test that compares a standard Z-Carb AP manufactured with a B-Rad, see FIGS. 20 and 27, to the identical product manufactured without a B-Rad, but with an axial edge treatment (hone) of 0.001 (inch), see FIGS. 21 and 28.

[0056] Profile cuts were made in 4140 and 316 stainless at Tool Wizard parameters. Parameters for Test 085-09 were duplicated, which was a test that had shown the comparison between a B-Rad and a conventional unprotected corner radius. In the 4140 profile test, the stockroom sample (T1) showed micro-chipping, as typically observed during a coating test. T2, without the B-Rad but with the axial hone, did not show this edge condition. Neither tool showed any notable corner radius area damage. In Test 2, profile milling in 316 stainless, the stockroom sample (T3) showed edge chipping which was not exhibited by T4, the non-B-Rad/axial honed tool. Neither tool showed any corner damage. Test 3 involved profile milling in 15-5 PH stainless and after milling 1600 inches both tools (T5 and T6) had identical wear and chipping and no corner radius area damage. Test 4 used the load cell to determine tool load while plunging. Each tool was plunged into the 4140 workpiece three times and the forces measured, recorded and averaged. Tool 8 with no B-Rad and the axial hone averaged 14 percent less maximum Z-axis force and 12 percent less maximum torque than the stockroom sample (T7).

[0057] In summary, in these tests, the stockroom samples showed edge damage equal to or worse than the axial honed tools, as well as generating more Z-axis force and torque while plunging. Overall, the preliminary results suggest the axial edge treatment is not detrimental to performance, and is likely beneficial to reduce corner damage as compared to the non-axial honed tools.

[0058] Below are Tables representing Test 1-Test 4 that illustrate four tests of stock sample compared to a honed sample.

[0059] [Remove shading from table]

TABLE-US-00001 MACHINE TOOL HOLDER COCLANTa 4140-alloy steel 28HRaa Haas VM3a Techniks ER-32 shorta S-373a Tool-Wizard-parameters-(Test-1)a SPEED FEE RADIAL WIDTH AXIAL DEPTH TOOLS TYPES 2.865-rpm/375 sfma 26.24 rpm/00229 250* (50% D)a 500 (D)a NOs DESCRIPTION MACHINE USAGE INSPECTION NOTES 1a ZAP1C05000_030TX .0003*a 640{circumflex over ()}a Varying micro chipping on cutting edges and corner rad stockroom samplea 2a Test sample without B-Rad, .0004*a 640{circumflex over ()}a Even and consistent wear on cutting edges and corner radi 001*axial hone,a indicates data missing or illegible when filed

[0060] [Remove shading from table]

TABLE-US-00002 WORKPIECEa MACHINE TOOL HOLDER COCLANTa 316-stainlessa Haas VM3a Techniks ER-32 shorta S-373a Tool-Wizard-parameters-(Test-2)a SPEED FEED RADIAL WIDTH AXIAL DEPTH TOOLS TYPES 3.025-rpm/396 sfma 21.78 rpm/0018 250* (50% D)a 400* (80% D)a NOs DESCRIPTION MACHINE USAGE INSPECTION NOTES 3a ZAP1C05000_030TX stockroom samplea 0003*a 640*a Varying edge damage with chipping .0044* to 007* on primary Corners/B-Rad intacta 4a Test sample without B-Rad .001* axial 0002*a 640*a 0008* edge wear even and consistent on cutting edges hone,a and corner radi indicates data missing or illegible when filed

[0061] [Remove shading from table]

TABLE-US-00003 WORKPIECEa 15-5PH-stainless MACHINE TOOL HOLDER COCLANTa 36/37 HRca Haas VM3a Techniks ER-32 shorta S-373a Parameters from test 085-09 (Test-3)a SPEED FEED RADIAL WIDTH AXIAL DEPTH TOOLS ;,TYPES 2.180-rpm/285 sfma 17.0 rpm/0019 250*a 125*a NOs DESCRIPTION MACHINE USAGE INSPECTION NOTES 5a ZAP1C05000_030TX stockroom 0002*a 1120*a .0025* wear no tool damage a samplea 1600*a .0032* wear each flude has a small-chip on edge No corner area damages 6a Test sample without B-Rad; 0004*a 1120*a 0025* wear no tool damage a .001*.axial hone,a 1600*a .0033* wear each flude has a small chip on edge No corner area damage a indicates data missing or illegible when filed

[0062] [Remove shading from table]

TABLE-US-00004 WORKPIECEa MACHINE TOOL HOLDER COCLANTa 4140 alloy steel 26HRca Haas VM3a Techniks ER-32 shorta S-373a Plunge in load cell (Test-4)a SPEED FEED RADIAL WIDTH AXIAL DEPTH TYPES 2.865-rpm/375 sfma 13.0 rpm/0045 500* (D)a 050*a TOOLS NOs DESCRIPTION MACHINE USAGE INSPECTION NOTES 7a ZAP1C05000_030TX stockroom samplea 0003*a 3 plungesa 328.14 lbs average maximum Z-axis load 69.1 average in lbs torquea 8a Test sample without B-Rad; .001*.axial 0003*a 3 plungesa 282.89 lbs average maximum Z-axis load 61.1 average hone,a in lbs torquea Comments Tool-B has approximately 14% less average Z-axis load and 12% less average torque requirement (maximum) a indicates data missing or illegible when filed

[0063] Below are Tables Tool 7 and Tool 8 that give the parameters for the stock sample and honed sample, Plunges 1-3.

[0064] [Remove shading from table]

TABLE-US-00005 Tool-7-stockroom sample Plunge-1a Plunge-2a Plunge-3a UNITS.fwdarw.lbs UNITS.fwdarw.lbs UNITS.fwdarw.lbs MEAN.fwdarw. 265.72 MEAN.fwdarw. 265.85 MEAN.fwdarw. 275.03 STD DEV .fwdarw. STD DEV .fwdarw. 54.32 STD DEV .fwdarw. 66.14 50.05 MINIMUM .fwdarw. MINIMUM .fwdarw. 117.05 MINIMUM .fwdarw. 70.62 104.80 MEDIAN .fwdarw. MEDIAN .fwdarw. 284.24 MEDIAN .fwdarw. 291.65 282.62 MAXIMUM .fwdarw. MAXIMUM .fwdarw. 315.67 MAXIMUM .fwdarw. 353.08 315.67 UNITS.fwdarw.inib UNITS.fwdarw.inib UNITS.fwdarw.inib MEAN.fwdarw. 52.211 MEAN.fwdarw. 50.895 MEAN.fwdarw. 50.236 STD DEV .fwdarw. STD DEV .fwdarw. 15.633 STD DEV .fwdarw. 15.741 11.651 MINIMUM .fwdarw. MINIMUM .fwdarw. 5.120 MINIMUM .fwdarw. 6.827 19.342 MEDIAN .fwdarw. MEDIAN .fwdarw. 54.327 MEDIAN .fwdarw. 52.716 54.233 MAXIMUM .fwdarw. MAXIMUM .fwdarw. 71.204 MAXIMUM .fwdarw. 69.687 66.274 indicates data missing or illegible when filed

[0065] [Remove shading from table]

TABLE-US-00006 Tool-8 without B-Rad and 001 axial edge prep/honea Plunge-1a Plunge-2a Plunge-3a UNITS .fwdarw.lbs UNITS .fwdarw.lbs UNITS .fwdarw.lbs MEAN .fwdarw. 238.00 MEAN .fwdarw. 244.21 MEAN .fwdarw. 248.13 STD DEV .fwdarw. STD DEV .fwdarw. 20.69 STD DEV .fwdarw. 38.18 15.09 MINIMUM .fwdarw. MINIMUM .fwdarw. 184.60 MINIMUM .fwdarw. 119.71 205.42 MEDIAN .fwdarw. MEDIAN .fwdarw. 247.55 MEDIAN .fwdarw. 253.56 239.90 MAXIMUM .fwdarw. MAXIMUM .fwdarw. 267.55 MAXIMUM .fwdarw. 319.92 261.21 UNITS .fwdarw.inib UNITS .fwdarw.inib UNITS .fwdarw.inib MEAN .fwdarw. 46.779 MEAN .fwdarw. 47.885 MEAN.fwdarw. 48.260 STD DEV .fwdarw. STD DEV .fwdarw. 7.835 STD DEV .fwdarw. 13.354 7.386 MINIMUM .fwdarw. MINIMUM .fwdarw. 20.964 MINIMUM .fwdarw. 7.433 22.394 MEDIAN .fwdarw. MEDIAN .fwdarw. 49.409 MEDIAN .fwdarw. 48.028 49.078 MAXIMUM .fwdarw. MAXIMUM .fwdarw. 57.938 MAXIMUM .fwdarw. 70.136 55.175

[0066] The developed method addresses the corner strength issue while also maintaining efficient shearing capability. By utilizing a CNC brush honing machine, method has been crafted to utilize brush wheel of the hone machine to produce a relatively wider, heavier hone at the axial end of the tool which diminishes in size as it proceeds down the radial side of the flutes.

[0067] By eliminating the faced hook and B-Rad, the shearing capability is improved and by adding the variable hone the corners are protected.

[0068] One method of forming a rotary cutting tool includes the steps of: [0069] providing a shaft having and outer surface and having a longitudinal axis; [0070] forming a plurality of helical flutes in the shaft about the longitudinal axis defining a cutting portion, the remainder of the shaft defining a shank portion; [0071] forming a plurality of helical cutting edges at an interface with the outer surface and a respective helical flute about the longitudinal axis; [0072] forming a plurality of end cutting edges on an axial distal end of cutting portion of the shaft, the end cutting edges being contiguous with a corresponding one of the plurality of helical cutting edges and forming a corner in the transition between each of the end cutting edges and the corresponding one of the plurality of helical cutting edges; and [0073] forming a hone edge extending along a portion of each of the end cutting edges, the associated corner and a portion of the corresponding one of the plurality of helical cutting edges.

[0074] Referring to FIGS. 22-26, the shaft may be secured in chuck at the shank portion and then rotated. A machining brush may be provided and applied to the helical cutting edges, the corners, and/or the end cutting edges to form hone edges, such as varying hone edges. The brush may include filaments flanged between two disks. This may be performed by a CNC machine.

[0075] While principles and modes of operation have been explained and illustrated with regard to particular embodiments, it must be understood, however, that this may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.