PARTIALLY HARDENED ROTARY TOOL AND CORRESPONDING PRODUCTION METHOD

Abstract

A rotary tool for machining workpieces, comprising at least one main body with a clamping segment, a tool head comprising a cutting region, and at least one coolant channel for feeding a cooling and lubricating fluid into the cutting region. At least one partial surface section of the cutting region forms a hardened region, which covers and/or defines the coolant channel and is surface-hardened. A method for producing a rotary tool.

Claims

1. A rotary tool for machining workpieces, comprising a main body with a clamping segment and a tool head comprising a cutting region with at least one cutting edge, the tool head further comprising at least one coolant channel for feeding a cooling and lubricating fluid into the cutting region, at least a partial surface section of the cutting region forming a hardened region that covers and/or defines the coolant channel and is surface-hardened.

2. The rotary tool according to claim 1, wherein an essentially round or elliptical hardened region is formed concentrically around a cooling channel outlet nozzle on an end face or lateral face, of the cutting region.

3. The rotary tool according to claim 1, wherein the rotary tool comprises an essentially elongate and strip-shaped hardened region, which follows the coolant channel in the interior of the tool head and covers the coolant channel.

4. The rotary tool according to claim 1, wherein the hardened region is formed by selectively austenitizing the outer layer of a surface material in the cutting region.

5. The rotary tool according to claim 4, wherein the austenitizing of the outer layer is realized by means of laser beam hardening, electron beam hardening, ion beam hardening or induction hardening.

6. A method for producing a rotary tool according to claim 1, wherein at least one partial surface section of the cutting region of the tool head is, during or after the production of the rotary tool from a main body, subjected to a selective surface hardening process, in which a surface section that covers and/or defines a coolant channel of the rotary tool is surface-hardened in order to form the at least one hardened region.

7. The method according to claim 6, wherein a case hardening process in the form of laser beam hardening, electron beam hardening, ion beam hardening or induction hardening is used for carrying out the partial surface hardening step.

8. The method according to claim 6, wherein the rotary tool to be partially surface-hardened is moved relative to a selective hardening device in order to thereby austenitize the partial surface area into the hardened region.

9. The rotary tool according to claim 1, wherein an essentially round or elliptical hardened region is formed concentrically around a cooling channel outlet nozzle in a flute of the cutting region.

10. The rotary tool according to claim 1, wherein an essentially elongate and strip-shaped hardened region, which follows the coolant channel in the interior of the tool head and covers the coolant channel is formed along a flute.

Description

DRAWINGS

[0016] Other advantages can be gathered from the following description of the drawings. These drawings show exemplary embodiments of the invention. The drawings, the description and the claims contain numerous characteristics in combination. For practical purposes, however, a person skilled in the art will also consider these characteristics individually and form other sensible combinations thereof.

[0017] In the drawings:

[0018] FIG. 1 schematically shows a tool head according to an exemplary embodiment of an inventive rotary tool with hardened regions;

[0019] FIG. 2 shows a perspective view of another exemplary embodiment of a rotary tool with hardened regions;

[0020] FIG. 3 shows a top view of an end face of a tool region of another exemplary embodiment of a rotary tool;

[0021] FIG. 4 shows a perspective view of an exemplary embodiment of a rotary tool with partially hardened surface areas;

[0022] FIG. 5 shows a perspective view of a deep hole rotary tool according to an exemplary embodiment of the invention;

[0023] FIG. 6 shows another deep hole rotary tool according to an exemplary embodiment of the invention; and

[0024] FIG. 7 shows a perspective view of another exemplary embodiment of a rotary tool according to the invention.

[0025] In these figures, identical or similar components are identified by the same reference symbols.

[0026] FIG. 1 shows a tool head 12 of a rotary tool 10. The tool head 12 comprises two primary cutting edges 14a and 14b, which are connected to one another by a cross edge 16. A flute 20 extends between the two primary cutting edges 14a, 14b and separates the flanks of the cutting edges 14a, 14b from one another. The flute 20 is defined by secondary cutting edges of the cutting phase 22a, 22b. Outlet regions of coolant channels 24a (drawn with broken lines) and 24b, which branch off a main coolant channel extending along the axis of the rotary tool 10, are respectively recessed into the flute surfaces. The first flank in the concentric surface area around the outlets 24a, 24b is respectively realized in the form of a hardened region 26a and 26b with a locally hardened surface in order to prevent the relatively thin material wall between the surface area and the respective coolant channel 24a, 24b from fracturing under high thermal and mechanical stress. The respective hardened region 26a, 26b can be selectively heated, for example by means of a laser hardening process, and subsequently quenched in order to increase its hardness in comparison with the remaining regions of the tool head 12.

[0027] FIG. 2 shows a perspective view of another drilling tool 40 that is realized in the form of a reaming tool. The tool head 42 of the reaming tool 40 comprises two primary cutting edges 46a and 46b for reaming a sunk bottom of a workpiece. Outlet regions of coolant channels 52a and 52b are respectively arranged on the end face 44 in order to cool the primary cutting edge 46 and to remove chips. The hardened regions 54 are respectively arranged concentrically around the outlet regions 52a and 52b in order to prevent the relatively thin material wall from fracturing under high mechanical and thermal stress. The coolant channels 52a and 52b are routed along the wall formed by a helicoidal flute 50. A secondary cutting edge 48 along the flank of the outer walls of the reaming tool 40 serves for reaming a drill hole and for polishing the workpiece surface within the recess being produced.

[0028] FIG. 3 shows a tool head 62 of a PCD drilling tool 60. Two PCD edges 68a and 68b, which respectively border on flutes 70a and 70b, are arranged on the point section 64 of the tool head 62. Several coolant channel outlets 66a-66f are arranged on the end face 74 and can discharge a lubricating and cooling fluid in different directions of the end face 74 in order to thereby achieve an effective chip transport via the flutes 70 and to cool the tool head 62. Groups of three coolant channel outlets 66a, 66b, 66c and 66e, 66d, 66f are respectively combined within common hardened regions 72a and 72b, which are defined concentrically around the outlets 66 and respectively reinforce the surface area around the outlets 66 of the coolant channel in order to thereby increase the sturdiness of the PCD tool head 62. The regions 72 around the coolant channels 66, which are reinforced by means of case hardening, prevent fracturing under high thermal and mechanical stress.

[0029] FIG. 4 shows another exemplary embodiment of a drilling tool 80 in the form of a perspective view. The drilling tool 80 comprises a clamping segment 82 in the form of a shaft and a tool head 84, which carries several cutting edges 96 and a coiled bezel 92 that forms the periphery of a flute 98. The cutting edges 96 are arranged on an end face 94 of the tool head 84. Two coolant channels 88a, 88b feature contoured outlets on the end face 94. The outlets are separated from the circumferential surface of the tool head 84 by webs 86. Elliptical hardened regions 90 are arranged concentrically around the outlets of the coolant channels 88a, 88b. Additional strip-shaped hardened regions, which are drawn with broken lines, are provided along the flute 98 and define the relatively thin material wall between the respective coolant channel 88a, 88b and the flute surface 98.

[0030] FIGS. 5 and 6 show two different embodiments of deep hole drills 100 and 120. Each deep hole drill 100, 120 features a clamping segment 136 in the form of a hollow shaft and a respective tool head 102 and 122. Each tool head 102, 122 comprises a bezel cutting edge 112, 134 and respectively features a coolant channel outlet 106 or several coolant outlet nozzles 128, which supply cooling fluid for cooling the tool head and for removing chips from respective head cutting edges 116 and 138, on its end face 104, 124. Chips are removed in respective flutes 110 and 132 that can be flushed with the lubricating and cooling fluid. On the peripheral edge of the end face 104, the deep hole drill 100 features stabilizing webs 108a and 108b on its surface area. A not-shown inlet of the coolant channel is provided in the hollow shaft 136 of the deep hole drill 120 on the clamping end. Hardened regions 114 and 130a, 130b are respectively arranged on the end faces 104, 124 of the tool heads 102, 122, which comprise the coolant channel outlet nozzles 128 of the respective coolant channels 106 and 128, and cover the corresponding end face 104, 124 and at least a strip-shaped region of the respective flutes 110 and 132. A deep hole is additionally cut out and widened by means of respective bezel cutting edges 112 and 134 that define the flutes 110, 132.

[0031] FIG. 7 ultimately shows a perspective view of another exemplary embodiment of a rotary tool 150 with a partially hardened surface area for protecting a coolant channel 164. The rotary tool 150 comprises a main body 152, which has an axis 168 and forms a clamping segment 154 in the form of a shaft and a tool head 156. A head cutting edge 158, as well as a flute 160, is provided in the tool head 156. The flute 160 is defined by a bezel cutting edge 162. An outlet of a coolant channel 164 is located in the flute 160, wherein said outlet is surrounded by an elongate, strip-shaped hardened region 166 that reinforces the wall between the flute 160 and the coolant channel 164 in order to increase the sturdiness of the rotary tool 150.

[0032] Significant wear of a drilling tool can occur, in particular, in the processing of aluminum materials with a higher silicone content such that undesirable fracturing of a cooling channel wall can occur. In order to prevent such fractures, the regions of the tool head that cover the coolant channel can be hardened by means of a selective surface hardening process, particularly laser beam hardening. A selective hardening process has the advantage that selected regions can be hardened in order to thereby flexibly protect partial surface areas of the tool head against mechanical wear. Especially laser beam hardening, as well as electron beam hardening and ion beam hardening, or even an inductive hardening process may be used in this case.

LIST OF REFERENCE SYMBOLS

[0033] 10 Rotary tool [0034] 12 Tool head [0035] 14 Primary cutting edge [0036] 16 Cross edge [0037] 18 End face [0038] 20 Flute [0039] 22 Secondary cutting edge [0040] 24 Coolant channel [0041] 26 Hardened region [0042] 28 [0043] 30 [0044] 32 [0045] 34 [0046] 36 [0047] 38 [0048] 40 Reaming tool [0049] 42 Tool head [0050] 44 End face [0051] 46 Primary cutting edge [0052] 48 Secondary cutting edge/cutting bezel [0053] 50 Flute [0054] 52 Cooling channel [0055] 54 Hardened region [0056] 56 [0057] 58 [0058] 60 PCD drilling tool [0059] 62 Tool head [0060] 64 Point section [0061] 66 Cooling channel [0062] 68 PCD edges [0063] 70 Flute [0064] 72 Hardened region [0065] 74 End face [0066] 76 [0067] 78 [0068] 80 Drilling tool [0069] 82 Shaft, clamping segment [0070] 84 Tool head [0071] 86 Web [0072] 88 Coolant channel with contoured outlet [0073] 90 Hardened region [0074] 92 Bezel [0075] 94 End face [0076] 96 Cutting edge [0077] 98 Flute [0078] 100 Deep hole drill [0079] 102 Tool head [0080] 104 End face [0081] 106 Cooling channel [0082] 108 Web [0083] 110 Flute [0084] 112 Bezel cutting edge [0085] 114 Hardened region [0086] 116 Head cutting edge [0087] 118 [0088] 120 Deep hole drill [0089] 122 Tool head [0090] 124 End face [0091] 128 Coolant outlet nozzle [0092] 130 Hardened region [0093] 132 Flute [0094] 134 Bezel cutting edge [0095] 136 Hollow shaft [0096] 138 Head cutting edge [0097] 140 [0098] 142 [0099] 144 [0100] 146 [0101] 148 [0102] 150 Drilling tool [0103] 152 Main body [0104] 154 Shaft, clamping segment [0105] 156 Tool head [0106] 158 Head cutting edge [0107] 160 Flute [0108] 162 Bezel cutting edge [0109] 164 Coolant channel [0110] 166 Hardened region [0111] 168 Tool axis