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US 7,207,111 B2Granted
Method of manufacturing an endodontic instrument
AssigneeOrmco Corporation
InventorsCarlos A. Aloise, Gary T. Garman
Life of this patent
Estimating the term…
Abstract
Method for manufacturing endodontic instruments having either helical or non-helical flutes with hard surfaces and resilient cutting edges by either an EDM or ECM process, wherein material is removed from the instrument blank in the desired flute pattern. The EDM or ECM process disintegrates the surface material, and as it cools, at least a portion of the removed material re-deposits onto the surface being machined to form a recast layer having a surface hardness that is at least about 15% greater than the hardness of the material forming the instrument blank.
Claims42
A method for forming an endodontic instrument comprising:
- providing an instrument blank with an initial diameter and made of a starting material having a first hardness;
- removing starting material from the instrument blank by a method selected from the group consisting of electrical discharge machining, wire electrical discharge machining, electrical discharge grinding and electrochemical machining to form a plurality of cutting edges and flutes having a non-directional surface finish,
- wherein at least about 25% of the initial diameter of the instrument blank is removed at a point of maximum metal removal, and
- redepositing at least a portion of the removed starting material on the cutting edges and flutes being formed to form a layer of recast material having a second hardness of at least about 15% greater than the first hardness.
1 more element
A method for forming an endodontic instrument comprising the steps of:
- forming a wire into an instrument blank with an initial diameter and made of a starting material initially having a first hardness;
- forming a first helical flute in the instrument blank by a method selected from the group consisting of electrical discharge machining, wire electrical discharge machining, electrical discharge grinding and electrochemical machining, including rotating the instrument blank about it's center longitudinal axis while advancing the instrument blank axially past an electrode without direct contact with the instrument blank to remove starting material therefrom and thereby form the first helical flute therein, wherein at least about 25% of the initial diameter of the instrument blank is removed at a point of maximum metal removal, and to redeposit at least a portion of the removed starting material on the flute being formed to form a layer of recast material having a non-directional surface finish and a second hardness at least about 15% greater than the first hardness;
- and
- rotatably indexing the instrument blank about the center longitudinal axis not more than 180 degrees and repeating the forming step to form a second helical flute having a non-directional surface finish and the second hardness at least about 15% greater than the first hardness.
1 more element
A method for forming an endodontic instrument comprising the steps of:
- forming a wire into an instrument blank with an initial diameter and made of a starting material initially having a first hardness;
- forming a first non-helical flute in the instrument blank by a method selected from the group consisting of electrical discharge machining, wire electrical discharge machining, electrical discharge grinding and electrochemical machining, including holding the instrument blank stationary about it's center longitudinal axis while advancing an electrode axially past the instrument blank without direct contact with the instrument blank to remove starting material therefrom and thereby form the first non-helical flute therein, wherein at least about 25% of the initial diameter of the instrument blank is removed at a point of maximum metal removal, and to redeposit at least a portion of the removed starting material on the flute being formed to form a layer of recast material having a non-directional surface finish and a second hardness at least about 15% greater than the first hardness;
- and
- rotatably indexing the instrument blank about the center longitudinal axis not more than 180 degrees and repeating the forming step to form a second non-helical flute extending in axial alignment with the first non-helical flute, the second non-helical flute having a non-directional surface finish and a second hardness at least about 15% greater than the first hardness.
1 more element
Dependencies are inferred from the claim text.