Cutters – for shaping – Including tool having plural alternatively usable cutting edges
Reexamination Certificate
2002-06-12
2004-06-01
Fridie, Jr., Willmon (Department: 3722)
Cutters, for shaping
Including tool having plural alternatively usable cutting edges
C407S119000
Reexamination Certificate
active
06742970
ABSTRACT:
FIELD OF THE INVENTION
The invention pertains to a cutting tool for removing material from a workpiece wherein the cutting tool is held in a pocket of a tool holder. More specifically, the invention pertains to such a cutting tool that has a hard material cutting blank wherein the hard material comprises, for example, polycrystalline diamond (PCD) or polycrystalline cubic boron nitride (PcBN) or CVD diamond sheet. The cutting blank defines a cutting edge.
BACKGROUND OF THE INVENTION
In metal working (e.g., turning, milling, and boring applications) a cutting tool is received and held in a pocket of a tool holder to form a cutting assembly. In some cases, the cutting tool comprises a substrate that receives a cutting blank comprising either polycrystalline diamond or polycrystalline cubic boron nitride or CVD diamond sheet. The cutting blank defines the cutting edge.
In operation, the cutting edge contacts the workpiece and a part of the workpiece is generally removed in the form of a chip, a coil or a stringer of metal. At a point just prior to the metal being cut, i.e., at a point where the workpiece initially contacts the cutting edge, the workpiece material becomes compressed. This is especially the case with respect to a metal like either aluminum or an aluminum alloy.
At the time of being cut, the cut workpiece material is under compression and thereby tends to expand as it exits the cutting zone. The expansion of the workpiece material occurs so that the expanding workpiece rubs against the flank surface(s) that define (at least in part) the cutting edge. This contact between the workpiece material and the flank surface(s) causes abrasive wear and contributes to shortening the useful life of the cutting tool.
It thus becomes apparent that it would be desirable to provide a cutting tool that reduces the extent to which the workpiece material abrasively wears against the flank surface(s) upon exiting the cutting zone.
In the past, one style of cutting tool presented a substrate that held via brazing a cutting blank (e.g., comprising either PCD or PcBN). The cutting blank had flank surfaces that defined (at least in part) the cutting edge. The substrate had exposed flank surfaces and opposite flank surface(s). These flank surfaces were disposed at an angle with respect a vertical plane thereby defining a clearance angle. For these cutting tools, the clearance angle has been the same for each one of the flank surfaces of the substrate and the cutting blank. The disadvantage of this is that different tool holders are necessary to receive cutting tools that have different clearance angles.
For a number of reasons it would be desirable to provide cutting tools that exhibits different clearance angles and that can be received by the same tool holder.
SUMMARY OF THE INVENTION
In one form, the invention is a cutting tool for removing material from a workpiece wherein the cutting tool is held in a pocket of a tool holder. The cutting tool comprises a cutting tool substrate that has a rake substrate surface and a plurality of flank substrate surfaces. The cutting tool substrate contains a notch and the notch is at the intersection of a pair of adjacent flank substrate surfaces. The substrate has an opposite corner defined by the flank substrate surfaces that are opposite from the notch. The adjacent flank substrate surfaces are disposed at a substrate clearance angle with respect to the normal to the rake substrate surface. The opposite flank substrate surfaces are disposed at a substrate disposition angle with respect to the normal to the rake substrate surface. The opposite flank substrate surfaces contact a portion of the tool holder that at least in part defines the pocket. The cutting tool further includes a cutting blank that is received within the notch. The cutting blank has a rake blank surface and a pair of flank blank surfaces wherein a cutting edge is at the intersection of the rake blank surface and the flank blank surfaces. The flank blank surfaces are disposed at a cutting clearance angle with respect to the normal to the rake blank surface. The substrate clearance angle is equal to the cutting clearance angle. The cutting clearance angle is not equal to the substrate disposition angle.
In yet another form, the invention is a cutting tool assembly for removing material from a workpiece. The cutting tool assembly comprises a tool holder that contains a pocket wherein a rear surface and a bottom surface define the pocket, and a cutting tool is received within the pocket of the tool holder. The cutting tool comprises a cutting tool substrate that has a rake substrate surface and a plurality of flank substrate surfaces. The cutting tool substrate contains a notch and the notch is at the intersection of a pair of adjacent flank substrate surfaces. The substrate has an opposite corner defined by flank substrate surfaces that are opposite from the notch. The adjacent flank substrate surfaces are disposed at a substrate clearance angle with respect to the normal to the rake substrate surface. The opposite flank substrate surfaces are disposed at a substrate disposition angle with respect to the normal to the rake substrate surface. The opposite flank substrate surfaces contact a portion of the tool holder that at least in part defines the pocket. The cutting tool further includes a cutting blank received within the notch wherein the cutting blank has a rake blank surface and a pair of flank blank surfaces. A cutting edge is at the intersection of the rake blank surface and the flank blank surfaces. The flank blank surfaces are disposed at a cutting clearance angle with respect to the normal to the rake flank surface. The substrate clearance angle is equal to the cutting clearance angle. The cutting clearance angle is not equal to the substrate disposition angle.
In still another form thereof, the invention is a cutting tool for removing material from a workpiece wherein the cutting tool is held in a pocket of a tool holder. The cutting tool comprises a cutting tool substrate that has a rake substrate surface and a plurality of flank substrate surfaces including a pair of adjacent flank substrate surfaces. Each one of the adjacent flank substrate surfaces has a forward portion and a rearward portion. The cutting tool substrate contains a notch at the intersection of the forward portions of the adjacent flank substrate surfaces. The substrate has an opposite corner defined by opposite flank substrate surfaces that are opposite from the notch. The forward portions of the adjacent flank substrate surfaces are disposed at a substrate clearance angle with respect to the normal to the rake substrate surface. The rearward portions of the adjacent flank substrate surfaces and the opposite flank substrate surfaces are disposed at a disposition angle with respect to the normal to the rake substrate surface. The cutting tool further includes a cutting blank that is received within the notch wherein the cutting blank has a rake blank surface and a pair of flank blank surfaces. A cutting edge is at the intersection of the rake blank surface and the flank blank surfaces. The flank blank surfaces are disposed at a cutting clearance angle with respect to the normal to the rake blank surface. The substrate clearance angle is equal to the cutting clearance angle. The cutting clearance angle is not equal to the disposition angle.
In still another form thereof, the invention is a cutting tool for removing material from a workpiece wherein the cutting tool is held in a pocket of a tool holder. The cutting tool comprises a cutting tool substrate that has a rake substrate surface, adjacent flank substrate surfaces, and an opposite flank substrate surface. Each one of the adjacent flank substrate surfaces has a forward portion and a rearward portion. The cutting tool substrate contains a notch at the intersection of the forward portions of the adjacent flank substrate surfaces. The forward portions of the adjacent flank substrate surfaces are disposed at a substrate clearance angle with respect to t
Belsheim Stephen T.
Oles Edward J.
Fridie Jr. Willmon
Kennametal Inc.
Prizzi John J.
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