Cutters – for shaping – Comprising tool of specific chemical composition
Reexamination Certificate
2000-01-27
2001-11-13
Tsai, Henry (Department: 3322)
Cutters, for shaping
Comprising tool of specific chemical composition
C407S118000, C051S309000
Reexamination Certificate
active
06315502
ABSTRACT:
The invention relates to a cutter tool, having means, disposed in the region of the chip face, for preventing uncontrolled chip formation, which means are disposed at a certain spacing from a cutting edge at a layer of polycrystalline diamond (PKD) or polycrystalline boron tride (PKB), which is applied to a substrate body.
In chip-forming machining in particular of tough materials, such as nonferrous metals or plastics, the attempt is made to prevent the uncontrolled formation of long chips, because among other effects they can damage the machined surfaces. For that purpose, so-called chip breakers, which break the chips to a short length, and chip guide stages, which in a purposeful way divert the long chips away from the working region, are known. Since such means for preventing uncontrolled chip formation should be disposed as close as possible to the cutting edge if they are to operate effectively, the problem arises in cutting tools with cutting materials of polycrystalline diamond (PKD) or polycrystalline boron nitride (PKB) that the layer comprising these materials forms the chip face, and separate means cannot be reliably secured to that layer. The attempt is made to overcome this by soldering the cutting tools into a slit in a tool holder, but only a soldered connection between the substrate body and the slit is possible, while a narrow joint remains between the surface of the layer of PKD or PKB and the means for chip control. It turns out that chips can become stuck in this joint, and as a result on the one hand the tool carrier wears down rapidly, and on the other, damage to the surface of the workpiece material can occur.
The object of the invention is to create a cutting tool with a cutting material of PKD or PKB that makes it possible to have means for chip control without there being a joint toward the chip face in the vicinity of the cutting edge.
According to the invention, this object is attained in that the layer of PKD or PKB is recessed, in the region of the means for preventing uncontrolled chip formation, down to the substrate body, and the means for preventing uncontrolled chip formation are applied there directly to the substrate body.
The subsequent removal of the layer of PKD or PKB in the region of the recess, for instance by electroerosion, allows a precise approach to the cutting edge to a distance that would not be attainable in the production of the layer. Precise spacing of the means for preventing uncontrolled chip formation, of preferably about 0.3 to 1.5 mm, does not increase the risk of brittle breakage of the very vulnerable cutting materials.
A further advantage of the invention is that the cutting tool of the invention can be manufactured in a very economical way, and practically any means for chip control, in terms of their form, can be applied to the substrate body. Since these means are anchored on the substrate body in the vicinity of the cutting edge, a very firm hold of these means is also obtained, since in comparison to the formerly conventional versions, only a very short lever travel arm length exists between the engagement point of the chips and the anchoring point of the means for chip control on the substrate body. Because of the nearness of the anchoring point to the cutting edge, relatively tall chip breaking or chip guiding means can be made, if that should be desired.
The thickness of the layer of PKD or PKB is preferably about 0.3 to 1.5 mm. Such layer thicknesses can be attained by the known production processes for cutting tools; thin layer thicknesses offer the advantage that the electroerosion operation is less time-consuming and thus entails lower costs. It is especially favorable for the forming of the recess if the layer of PKD or PKB is applied to the substrate body by deposition of the cutting material in the vapor phase, because the coatings, for instance of diamond, that can be made in this way have only a slight layer thickness and are therefore especially easy to penetrate electroerosively in the machining process.
The cutting tool of the invention can be embodied as an insert for a holder or as an indexable cutter plate with a plurality of cutting edges.
The means for preventing uncontrolled chip formation can be surrounded on all sides by a remaining rib of the layer of PKD or PKB. In that case, the control means are secured solely to the substrate body of the cutting tool. Depending on the kind of use, it can also be expedient for the layer of PKD or PKB to be removed completely toward one edge of the holder, so that the control means can be soldered, welded or glued to both the substrate body of the cutting tool and to its holder, in order to achieve additional stability.
Preferably, the means for preventing uncontrolled chip formation, and/or the substrate body, comprise hard metal or high-alloy chromium tungsten tool steel (high-speed steel). It is especially ideal to make both parts of hard metal, since hard metal is especially resistant to damage from the chips, and this enables a good bond between the control means and the substrate body, for instance by soldering. On the other hand, steel parts can be better welded.
Depending on the area of use of the cutting tool and the material to be machined in chip-forming fashion, the means for preventing uncontrolled chip formation can be embodied as a chip guide stage for carrying away any developing chips, or as a chip breaker to shorten the chips to a harmless length.
In the embodiment as a chip breaker, the chip breaker expediently protrudes to from 0.5 to 3.0 mm above the layer of PKD and PKB and is beveled on its flank toward the cutting edge by about 40-50°. As an alternative to the beveling or in addition to it, the upper edge of the chip breaker, oriented toward the cutting edge, can be rounded with a radius of 0.5 mm, for example.
It is understood that the cutting tool of the invention, in all its possible embodiments, can be embodied as a drilling or milling tool or a lathe tool.
REFERENCES:
patent: 2870523 (1959-01-01), Richard
patent: 2955349 (1960-10-01), York
patent: 4159885 (1979-07-01), Schott
patent: 4189264 (1980-02-01), Kraemer
patent: 4414870 (1983-11-01), Peterson Jr. et al.
patent: 4561810 (1985-12-01), Ohno
patent: 4714385 (1987-12-01), Komanduri
patent: 4854784 (1989-08-01), Murray et al.
patent: 4856942 (1989-08-01), Bernadic et al.
patent: 5193948 (1993-03-01), Noggle
patent: 5215415 (1993-06-01), Fukuoka et al.
patent: 5246315 (1993-09-01), Hansson et al.
patent: 5302060 (1994-04-01), Nystrom et al.
patent: 5405711 (1995-04-01), Noggle
patent: 5772366 (1998-06-01), Wiman et al.
patent: 6146064 (2000-11-01), Floto
patent: 0 730 925 (1996-09-01), None
Jakob Lach GmbH & Co. KG
Larson & Taylor PLC
Tsai Henry
LandOfFree
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