Patent Application
20150063931
The present invention pertains to an indexable drill assembly, as well as the drill body of the indexable drill assembly, useful for the drilling of holes in a workpiece. More specifically, the invention pertains to an indexable drill assembly, as well as the drill body of the indexable drill assembly, useful for the drilling of holes in a workpiece adapted to facilitate enhanced delivery of coolant adjacent the interface between the workpiece and each one of the outboard cutting insert and the inboard cutting insert (insert-chip interface) so as to provide cooling thereby diminishing tremendous heat and also providing lubrication at the insert-chip interface in a hole drilling operation.
Indexable drill assemblies useful for the drilling of holes in a workpiece generally include an outboard cutting insert and an inboard cutting insert wherein each cutting insert has a surface terminating at a cutting edge. The indexable drill further includes a tool holder formed with a seat adapted to receive the insert. Each cutting insert engages a workpiece to remove material, and in the process forms chips of the material. Excessive heat at the insert-chip interface can negatively impact upon (i.e., reduce or shorten) the useful tool life of each cutting insert.
For example, a chip generated from the workpiece can sometimes stick (e.g., through welding) to the surface of the cutting insert. The build up of chip material on the cutting insert in this fashion is an undesirable occurrence that can negatively impact upon the performance of the cutting insert, and hence, the overall drilling operation. A flow of coolant to the insert-chip interface will reduce the potential for such welding. It would therefore be desirable to reduce excessive heat at the insert-chip interface to eliminate or reduce build up of chip material.
As another example, in a chipforming drilling operation, there can occur instances in which the chips do not exit the region of the insert-chip interface when the chip sticks to the cutting insert. When a chip does not exit the region of the insert-chip interface, there is the potential that a chip can be re-cut. It is undesirable for the cutting insert to re-cut a chip already removed from the workpiece. A flow of coolant to the insert-chip interface will facilitate the evacuation of chips from the insert-chip interface thereby minimizing the potential that a chip will be re-cut during the drilling operation.
There is an appreciation that a shorter useful tool life increases operating costs and decreases overall production efficiency. Excessive heat at the insert-chip interface contribute to the welding of chip material and re-cutting of chips, both of which are detrimental to production efficiency. There are readily apparent advantages connected with decreasing the heat at the insert-chip interface wherein one way to decrease the temperature is to supply coolant to the insert-chip interface.
Heretofore, cutting inserts useful in material removal applications have provided for the delivery of coolant to the region of the insert-chip interface. The following patent documents are exemplary of some earlier efforts.
U.S. Pat. No. 6,123,488 to Kasperik et al. pertains to a cutting insert that contains a central aperture defined by an aperture wall. In the Kasperik et al. patent, the aperture wall contains protrusions that function to assist the operator to identify the specific cutting insert. U.S. Pat. No. 7,198,437 to Jonsson (also U.S. Reissue Pat. No. Re 42,644 E) discloses a round cutting insert-round shim assembly. The bottom surface of the cutting insert contains radial indexing portions and the top surface contains swirled chip breakers. U.S. Pat. No. 7,677,842 to Park shows a cutting insert that contains a central aperture defined by a wall. The wall has clearance portions that render the aperture non-circular.
United States Patent Application Publication No. US 2001/0027021 to Nelson et al. shows a round cutting insert that includes a base member having central aperture wherein a core member is in the central aperture. An interior coolant passage is defined between the core and the surface that defines the central aperture. United States Patent Application Publication No. US2009/0123244 to Beuttiker et al. pertains to a machine reamer that includes coolant flow passages around a screw (34) with the flow of coolant (apparently indicated by the arrows 78) in a coolant bore (66). See FIG. 1d.
U.S. Pat. No. 7,997,832 B2 to Prichard et al. discloses a cutting insert that contains interior coolant channels for delivery of coolant to the vicinity of the intersection of the cutting insert and the workpiece. In one embodiment, the cutting insert comprises a diverter plate that attaches to a milling insert body (e.g., see FIG. 7). In another embodiment, a milling insert body receives opposite rake plates (e.g., see FIG. 16). In still another embodiment, a milling insert body receives a milling rake plate (e.g., see FIGS. 19-22).
U.S. Pat. No. 7,125,207 to Craig et al. discloses a tool holder that carries cutting inserts. The tool holder contains an integral coolant channel. The integral coolant channel provides for the delivery of coolant to the cutting inserts. United States Patent Application Publication No. US 2011/0229277 A1 to Hoffer et al., and assigned to Kennametal Inc. (the assignee of the present invention) discloses a round cutting insert that includes distinct interior coolant passages that provide for the flow of coolant to the cutting edge of the insert. In one embodiment, the round cutting insert includes a base member that receives a core member. The distinct interior coolant passages are defined between the base member and the core member.
United States Patent Application Publication No. US2011/0020072 to Chen et al. shows a cutting insert and a cutting insert-shim assembly. The cutting insert contains a plurality of distinct coolant passages. The shim contains an opening that facilitates coolant flow to the cutting insert. United States Patent Application Publication No. US2010/00272529 to Rozzi et al. shows a rotary cutting tool in which there is coolant delivery to the pocket regions thereof. An integral cooling channel branches into a direct cooling channel in communication with a jet opening ad an indirect cooling channel that has an opening in the tool pocket. U.S. Pat. No. 6,595,727 B2 to Arvidsson shows a tool for chip-removing machining that provides coolant to a plurality of the cutting inserts via fluid-conducting grooves.
U.S. Pat. No. 5,346,335 to Harpaz et al. shows a cutting insert with a recessed portion. A through-going bore extends through the cutting insert including in the vicinity of the recessed portion. Coolant flows through the through-going bore to provide coolant to the cutting insert. Japanese Patent Application Publication JP 5-301104 (assigned to Sumitomo Electric Ind. Ltd.) shows a cutting insert that contains a plurality of interior cooling channels. United States Patent Application Publication No. US 2011/0020077 to Fouqyer shows a hollow clamping screw having an axial channel that carries lubricating fluid. The fluid apparently sprays on the cutting insert (e.g., see FIG. 9).
In one form thereof, the invention is an indexable drill assembly. The assembly includes a drill body, which has a head portion at the axial forward end thereof, and the head portion has an outboard pocket and an inboard pocket. The drill body further contains an outboard pocket coolant channel adjacent the outboard pocket, and an inboard pocket coolant channel adjacent the inboard pocket. The outboard pocket has a seating surface wherein the outboard pocket coolant channel opening at the seating surface. The drill body further contains an outboard retention screw aperture opening in the seating surface. The seating surface contains an outboard coolant ring surrounding the retention screw aperture wherein the outboard coolant ring is in fluid communication with the outboard pocket coolant channel. The inboard pocket has a seating surface wherein the inboard pocket coolant channel opening at the seating surface. The drill body further contains an inboard retention screw aperture opening in the seating surface. The seating surface contains an inboard coolant ring surrounding the inboard retention screw aperture wherein the inboard coolant ring is in fluid communication with the inboard pocket coolant channel. The assembly includes an indexable outboard cutting insert retained in the outboard pocket, and an indexable inboard cutting insert retained in the inboard pocket.
In yet another form thereof, the invention is an indexable drill assembly that includes a drill body, which has a head portion at the axial forward end thereof, and the head portion has an outboard pocket and an inboard pocket. The drill body further contains an outboard pocket coolant channel adjacent the outboard pocket, and an inboard pocket coolant channel adjacent the inboard pocket. The outboard pocket has a seating surface wherein the outboard pocket coolant channel opening at the seating surface. The drill body further contains an outboard retention screw aperture opening in the seating surface. The seating surface contains an outboard coolant ring surrounding the retention screw aperture wherein the outboard coolant ring is in fluid communication with the outboard pocket coolant channel. The inboard pocket has a seating surface wherein the inboard pocket coolant channel opening at the seating surface. The drill body further contains an inboard retention screw aperture opening in the seating surface. The seating surface contains an inboard coolant ring surrounding the inboard retention screw aperture wherein the inboard coolant ring is in fluid communication with the inboard pocket coolant channel. The assembly further includes an indexable outboard cutting insert that has an outboard primary coolant trough corresponding to each of at least a pair of adjacent discrete corners. The indexable outboard cutting insert is retained in the outboard pocket such that the outboard cutting insert is pulled-back toward the notch whereby less coolant flows through the outboard primary coolant trough corresponding to the discrete corners adjacent the notch of the outboard pocket. The assembly also includes an indexable inboard cutting insert that has an inboard primary coolant trough corresponding to each of at least a pair of adjacent discrete corners. The indexable inboard cutting insert is retained in the inboard pocket such that the inboard cutting insert is pulled-back toward the notch whereby less coolant flows through the inboard primary coolant trough corresponding to the discrete corners adjacent the notch of the inboard pocket.
In still another form thereof, the invention is a drill body which has a head portion at the axial forward end thereof, and the head portion has an outboard pocket and an inboard pocket. The drill body further contains an outboard pocket coolant channel adjacent the outboard pocket, and an inboard pocket coolant channel adjacent the inboard pocket. The outboard pocket has a seating surface wherein the outboard pocket coolant channel opening at the seating surface. The drill body further contains an outboard retention screw aperture opening in the seating surface. The seating surface contains an outboard coolant ring surrounding the retention screw aperture wherein the outboard coolant ring is in fluid communication with the outboard pocket coolant channel. The inboard pocket has a seating surface wherein the inboard pocket coolant channel opening at the seating surface. The drill body further contains an inboard retention screw aperture opening in the seating surface. The seating surface contains an inboard coolant ring surrounding the inboard retention screw aperture wherein the inboard coolant ring is in fluid communication with the inboard pocket coolant channel.
The following is a brief description of the drawings that form a part of this patent application:
As described hereinabove, the present invention pertains to an indexable drill assembly, as well as the drill body of the indexable drill assembly, useful for the drilling of holes in a workpiece. More specifically, the invention pertains to an indexable drill assembly, as well as the drill body of the indexable drill assembly, useful for the drilling of holes in a workpiece adapted to facilitate enhanced delivery of coolant adjacent (or proximate) the interface between the workpiece and each one of the outboard cutting insert and the inboard cutting insert (insert-chip interface) so as to provide cooling thereby diminishing tremendous heat and also providing lubrication at the insert-chip interface in a hole drilling operation. Delivery of coolant to the insert-chip interface is especially beneficial in drilling long-chipping materials, such as, for example, low carbon steel, stainless steel, and high temperature alloys.
Excessive heat at the insert-chip interface contribute to the welding of chip material and re-cutting of chips, both of which are detrimental to production efficiency. There is an appreciation that a shorter useful tool life increases operating costs and decreases overall production efficiency. It therefore becomes readily apparent that there are advantages connected with decreasing the heat due to high cutting temperatures at the insert-chip interface wherein one way to decrease the temperature is to supply coolant to the insert-chip interface.
Referring to the drawings,
The indexable drill assembly 40 includes an indexable drill body 42 that has a central longitudinal axis B-B. The indexable drill body 42 has an axial forward end 44 and an axial rearward end 46. The indexable drill body 42 has a head portion 48, which is at the axial forward end 44 of the indexable drill body 42, and a shank portion 52, which is at the axial rearward end 46 of the indexable drill body 42. The indexable drill body 42 has a helix portion 50 that is mediate between and contiguous with the head portion 48 and the shank portion 52. Helical flutes 51 extend in an axial orientation along most of the axial length of the helix portion 50. The helical flutes 51 facilitate the evacuation of chips generated during the drilling operation via the cutting inserts (130, 220) cutting the workpiece.
The indexable drill body 42 contains a body coolant channel 54, which is an interior channel, that runs along a portion of the axial length of the helix portion 50 and all of the axial length of the shank portion 52 of the indexable drill body 42. The body coolant channel 54 has an inlet 56 through which coolant (typically under pressure) enters from a coolant source 57. Coolant source 57 is shown in schematic fashion to be in communication with the body coolant channel 54 via inlet 56. The indexable drill body 42 further contains an outboard pocket coolant channel 70 that is in fluid communication with the body coolant channel 54. The outboard pocket coolant channel 70 has a receiving end 74 through which coolant enters from the body coolant channel 54 and a delivery end 72 (see
The indexable drill body 42 has an outboard pocket 58 defined by a pair of angularly disposed upstanding walls (60, 62) separated by a notch 64 and a seating surface 66. There is a retention screw aperture 76 in the seating surface 66 wherein there is a generally circular coolant ring 78 in the seating surface 66 adjacent to the retention screw aperture 76. As illustrated in
The indexable drill body 42 further has an inboard pocket 96 defined by an upstanding wall 98 and another upstanding wall 102 wherein a side notch 100 separates upstanding walls 98 and 102, and still another upstanding wall 106 wherein a central notch 104 separates the upstanding wall 102 from upstanding wall 106. A seating surface 108 further defines the inboard pocket 96. There is a retention screw aperture 120 in the seating surface 108 wherein there is a coolant ring 122 in the seating surface 108 adjacent to the retention screw aperture 120. As illustrated in
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The outboard cutting insert 130 contains four outboard primary coolant troughs 160, 162, 164 and 166 wherein each primary coolant trough corresponds to one of the discrete corners (150, 152, 154, 156), respectively. For the sake of brevity, a description of one primary coolant trough 160 will suffice for the description of the other three primary coolant troughs (162, 164, 166) since the four primary coolant troughs (160, 162, 164, 166) are substantially identical.
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The rake face 134 of the outboard cutting insert 130 contains two angular coolant troughs (180, 200) as described hereinafter. As described hereinafter, each angular coolant trough (180, 200) facilitates the delivery of coolant to the vicinity of the interface between the adjacent cutting edges (153, 157) of the outboard cutting insert 130 and the workpiece.
More specifically, the rake face 134 of the outboard cutting insert 130 contains a pair of radial innermost angular coolant troughs 180, each of which has a central longitudinal axis U-U, wherein a radial innermost angular coolant trough 180 is positioned on each side of the rake face section 174 of the primary coolant trough 160. The radial innermost coolant trough 180 is orientated so the axis U-U is generally perpendicular to the cutting edges. The radial innermost angular coolant troughs 180 are symmetric about a central longitudinal axis A-A (see
The rake face 134 of the outboard cutting insert 130 further contains a pair of radial outermost angular coolant troughs 200, each of which has a central longitudinal axis V-V, wherein a radial outermost angular coolant trough 200 is positioned on each side of the rake face section 174 of the primary coolant trough 160. The radial outermost coolant trough 200 is orientated so the axis V-V is generally perpendicular to the cutting edges. The radial outermost angular coolant troughs 200 are symmetrical about the longitudinal axis A-A of the primary coolant trough 160. The radial outermost angular coolant trough 200 has an entrance end 202 and an exit end 204 and an arcuate bottom surface 206. The entrance end 202 opens into the primary coolant trough 160 so as to directly receive coolant from the primary coolant trough 160. Coolant then travels the length of the radial outermost angular coolant trough 200 exiting via the exit end 204. The radial outermost angular coolant trough 200 has a depth that decreases in the radial outward direction which means that as the arcuate bottom surface 206 moves closer to the rake face 134 until it meets the rake face 134 at the exit end 204. The decrease in depth in the radial outward direction cause the coolant to exit the radial outermost angular coolant trough 200 in a generally upward orientation moving away from the rake face 134 and toward the vicinity of the outboard cutting insert 130-chip interface, which as illustrated in
The indexable drill assembly 40 further includes an indexable inboard cutting insert 220, which exhibits a trigon or trigonal geometry. The inboard cutting insert 220, as shown in
The rake face 224 intersects with the flank surfaces 226 to form three discrete inboard corners (240, 242, 244). Inboard cutting insert 220 has three cutting blades (generally designated as 241, 243, 245) wherein each of cutting blades (241, 243, 245) is formed by cutting edges (246a-248c). More specifically, cutting blade 241 is formed by cutting edges 246a and 248a, cutting blade 243 is formed by cutting edges 246b and 248b, and cutting blade 245 is formed by cutting edges 246c and 248c. As one skilled in the art can appreciate, the inboard cutting insert 220 can be indexed to different positions to present a different cutting location for engagement with the workpiece.
The inboard cutting insert 220 contains three primary coolant troughs 250, 252, 254 wherein each primary coolant trough corresponds to one of the discrete inboard corners (240, 242, 244), respectively. For the sake of brevity, a description of one primary coolant trough 250 will suffice for the description of the other two primary coolant troughs (252, 254) since the three primary coolant troughs (250, 252, 254) are substantially identical.
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The rake face 224 of the inboard cutting insert 220 contains two angular coolant troughs (260, 270) as described hereinafter. More specifically, the rake face 224 of the inboard cutting insert 220 contains a pair of radial innermost angular coolant troughs 260, each of which has a central longitudinal axis W-W, wherein a radial innermost angular coolant trough 260 is positioned on each side of the rake face section 258 of the primary coolant trough 250. The radial innermost coolant trough 260 is orientated so the axis W-W is generally perpendicular to the cutting edges. The radial innermost angular coolant trough 260 has an entrance end 262 and an exit end 264 and an arcuate surface 266. The entrance end 262 opens directly into the mouth 236 so as to directly receive coolant from the mouth 236. Coolant then travels along the length of the radial innermost angular coolant trough 260 exiting via the exit end 264. Each radial innermost angular coolant trough 260 has a depth that decreases in the radial outward direction. The decrease in depth in the radial outward direction causes the coolant to exit the radial innermost angular coolant trough 260 in a generally upward orientation moving away from the rake face 224 and toward the vicinity of the inboard cutting insert 220-chip interface. As shown in
The rake face 224 of the inboard cutting insert 220 further contains a radial outermost angular coolant trough 270, which has a central longitudinal axis X-X, positioned on each side of the rake face section 258 of the primary coolant trough 250. The radial outermost coolant trough 270 is orientated so the axis X-X is generally perpendicular to the cutting edges. The radial outermost angular coolant trough 270 has an entrance end 272 and an exit end 274 and an arcuate surface 276. The radial outermost angular coolant trough 270 has an entrance end 272 and an exit end 274 and an arcuate bottom surface 276. The entrance end 272 opens into the primary coolant trough 250 so as to directly receive coolant from the primary coolant trough 250. Coolant then travels the length of the radial outermost angular coolant trough 270 exiting via the exit end 274. The radial outermost angular coolant trough 270 has a depth that decreases in the radial outward direction. The decrease in depth in the radial outward direction causes the coolant to exit the radial outermost angular coolant trough 270 in a generally upward orientation moving away from the rake face 224 and toward the vicinity of the inboard cutting insert 220-chip interface, which is illustrated in
Coolant is supplied, typically under pressure, to the body coolant channel 54 whereby the coolant flows into each one of the outboard pocket coolant channel 70 and the inboard pocket coolant channel 114. Coolant enters the outboard pocket body coolant channel 70 via the receiving end 74 and exits through the delivery end 72 into the vicinity of the outboard pocket 58 so as to flow into the outboard cutting insert 130 as described hereinafter. Coolant in the inboard pocket coolant channel 114 enters via the receiving end 118 and exits through the delivery end 116 into the vicinity of the inboard pocket 96 so as to flow into the inboard cutting insert 220 as described hereinafter.
In reference to the flow of coolant into the outboard cutting insert 130 and referring to
Referring to primary coolant trough 160 (which applied to the other primary coolant troughs 162, 164, 166), coolants flows into the primary coolant trough 160 so as to pass through the aperture section 170. Some of the coolant then impinges on the rearward facing surface 294 of the head portion 292 and is directed to pass through the mouth section 172 and then flow into the rake face section 174 of the primary coolant trough 160. Further, some of the coolant flows into the entrance end 182 of each one of the radial innermost angular coolant troughs 180 and out of the exit end 184 thereof. Some of the coolant flows into the entrance end 202 of each of the radial outermost angular coolant troughs 200 and out of the exit end 204 thereof. Some of the coolant flows completely through the primary coolant trough 160 exiting at the exit end 176 thereof. As described hereinabove, the coolant exiting the rake face section 174 and the radial innermost angular coolant trough 180 and the radial outermost angular coolant trough 200 travels in a direction generally away from the rake face 134.
The outboard retention screw 280 exerts a so-called “pull back” on the outboard cutting insert 130 so as to pull the outboard cutting insert 130 into the outward pocket 58. Thus, the volume of coolant entering those primary coolant troughs is greater for the primary coolant troughs farther away from the notch 64 that separates the upstanding walls 60 and 62 as compared to the primary coolant troughs closer to the notch 64. More specifically, the outboard retention screw 280 provides for a “pull back” feature upon complete tightening into the retention screw aperture 76. The outboard retention screw 280 accomplishes this feature by a difference in the orientation of the longitudinal axis of the threaded portion 286 as compared to the longitudinal axis of the remainder of the outboard retention screw 280. This feature is shown and described in issued U.S. Pat. No. 8,454,274 to Chen et al. (assigned to the assignee of the present patent application), which is hereby incorporated by reference herein. This difference in coolant volume flow is shown in
In reference to the flow of coolant into the inboard cutting insert 220 and referring to
Referring to primary coolant trough 250 (which applied to the other primary coolant troughs 252, 254), coolant flows into the primary coolant trough 250 so as to pass through the aperture section 256. Some of the coolant then impinges on the rearward facing surface 320 of the head portion 318 of the inboard retention screw 306 and is directed to pass through the mouth section 257 and then flow into the rake face surface section 258 of the primary coolant trough 250. Coolant flows out of the rake face section 258 at the exit end 259. Further, some of the coolant flows into the entrance end 262 of each one of the radial innermost angular coolant troughs 260 and out of the exit end 264 thereof. Some of the coolant flows into the entrance end 272 of each of the radial outermost angular coolant troughs 270 and out of the exit end 274 thereof. Some of the coolant flows completely through the primary coolant trough 250 exiting at the exit end 259 thereof. As described hereinabove, the coolant exiting the rake face section 258 and the radial innermost angular coolant trough 260 and the radial outermost angular coolant trough 270 travels in an upward direction away from the rake face 224.
The inboard retention screw 306 exerts a so-called “pull back” on the inboard cutting insert 220 so as to pull the inboard cutting insert 220 into the inboard pocket 96. Thus, the volume of coolant entering the primary coolant troughs is greater for the primary coolant troughs farther away from the central notch 104 that separates the upstanding walls 102 and 106. More specifically, the inboard retention screw 306 provides for a “pull back” feature upon complete tightening into the retention screw aperture 120. The outboard retention screw 306 accomplishes this feature by a difference in the orientation of the longitudinal axis of the threaded portion 312 as compared to the longitudinal axis of the remainder of the inboard retention screw 306. This feature is shown and described in issued U.S. Pat. No. 8,454,274 to Chen et al. (assigned to the assignee of the present patent application) which is hereby incorporated by reference herein. This difference in coolant volume flow is shown in
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The indexable cutting insert 344 contains four primary coolant troughs (380, 382, 384 and 386) wherein each primary coolant trough (380, 382, 384 and 386) corresponds to one of the discrete corners (364, 366, 368, 370), respectively. For the sake of brevity, a description of one primary coolant trough 380 will suffice for the description of the other three primary coolant troughs (382, 384, 386) since the four primary coolant troughs (380, 382, 384 and 386) are substantially identical. Primary coolant trough 380 has a central longitudinal axis Z-Z.
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The rake face 348 of the indexable cutting insert 344 contains angular coolant troughs 396 as described hereinafter. Each angular radial coolant trough 396, which has a central longitudinal axis Y-Y, facilitates the delivery of coolant to the vicinity of the interface between the adjacent cutting edges (374, 376) of the indexable cutting insert 344 and the workpiece. The angular coolant trough 396 is orientated so the axis Y-Y is generally perpendicular to the cutting edges.
More specifically, the rake face 348 of the indexable cutting insert 344 contains a pair of angular coolant troughs 396 positioned on each side of the rake face section 174 of the primary coolant trough 382. The angular coolant trough 396 is symmetric about a central longitudinal axis Z-Z through the primary coolant trough 382. The angular coolant troughs 396 each have an entrance end 398 and an exit end 400 and an arcuate surface 402. The entrance end 398 opens into the mouth 360 so as to receive coolant from the mouth 360. Coolant then travels along the length of the angular coolant trough 396 exiting via the exit end 400. The angular coolant trough 396 has a depth that decreases in the radial outward direction. The decrease in depth in the radial outward direction cause the coolant to exit the angular coolant trough 396 in a generally upward orientation moving away from the rake face 348 and toward the vicinity of the indexable cutting insert 344-chip interface, which is in the vicinity of the cutting edges 372, 378. The coolant exiting the rake face section 392 and the radial angular coolant trough 396 travels in an upward direction away from the rake face 348.
The present invention provides an indexable drill useful for the drilling of holes in a workpiece adapted to facilitate enhanced delivery of coolant adjacent the interface between the workpiece and each one of the outboard cutting insert and the inboard cutting insert (insert-chip interface) so as to diminish excessive heat at the insert-chip interface in a hole drilling operation. By diminishing the heat, the present invention is able to reduce excessive heat at the insert-chip interface to eliminate or reduce build up of chip material. By diminishing the heat, the present invention will facilitate the evacuation of chips from the insert-chip interface thereby minimizing the potential that a chip will be re-cut during the drilling operation.
The patents and other documents identified herein are hereby incorporated by reference herein. Other embodiments of the invention will be apparent to those skilled in the art from a consideration of the specification or a practice of the invention disclosed herein. It is intended that the specification and examples are illustrative only and are not intended to be limiting on the scope of the invention. The true scope and spirit of the invention is indicated by the following claims.
