Monolithic ceramic end mill
AssigneeKennametal Inc.
InventorsDanny R. Davis, Sean E. Landwehr, Russell L. Yeckley
Life of this patent
Estimating the term…
Abstract
End mills are disclosed which may be made monolithically of ceramic or other materials. The cutting portions of the end mills have lengths of cut that are no more than twice their cutting diameters and cores which are at least 0.7 times their cutting diameters. Their axial blades have cutting edges with negative radial rake and are separated by helical flutes. Their cutting ends have negative axial rake and are gashed ahead of center and have radial cutting edges with negative rake. Such end mills also have radiused corners and gashes transitioning from radial to axial at a flute. Methods of milling materials using such ceramic end mills are also disclosed.
Claims56
A monolithic end mill having a longitudinal axis, the end mill comprising:
- a shank portion extending along the longitudinal axis;
- and
- at least one cutting portion extending from the shank portion and including a cutting tip having a web, the cutting portion having a cutting diameter, an axial length of cut that is no more than twice the cutting diameter, a core diameter that is at least 0.7 times the cutting diameter, and a plurality of blades disposed at a helical angle from the longitudinal axis along the axial length of cut and extending at a radial angle onto the cutting tip to form a negative endrake across an axial cutting edge and terminating proximate to the web;
- wherein each of the blades of the plurality of blades is separated from one another by a flute and has a corner radius, a negative radial rake, and a negative axial rake;
- and
- wherein the cutting tip has a dish angle and a plurality of gashes, each of the gashes of the plurality of gashes having a gash angle and extending into one of the flutes and wherein the end mill is constructed from a ceramic.
A monolithic end mill having a longitudinal axis, the end mill comprising:
- a shank portion extending along the longitudinal axis;
- and
- at least one cutting portion extending from the shank portion and including a cutting tip having a web, the cutting portion having a cutting diameter, an axial length of cut that is no more than twice the cutting diameter, a core diameter that is at least 0.7 times the cutting diameter, and a plurality of blades disposed at a helical angle from the longitudinal axis of from about 39 to about 41 degrees along the axial length of cut and extending at a radial angle onto the cutting tip to form an endrake in the range of from about −1 to about −6 degrees and terminating proximate to the web;
- wherein each of the blades of the plurality of blades is separated from one another by a flute and has a corner radius in the range of from about 0.031 to about 0.4 times the cutting diameter, a negative radial rake in the range of from about 0 to about −4 tangential degrees, and a negative axial rake in the range of about −1 to about −3 degrees;
- and
- wherein the cutting tip has a dish angle in the range of from about 1.5 to about 3 degrees and a plurality of gashes, each of the gashes of the plurality of gashes having a gash angle in the range of from about 15 to about 30 degrees and extending into one of the flutes.
A method of machining an object comprising contacting the object with an end mill having a longitudinal axis, the end mill spinning at a preselected cutting speed around its longitudinal axis while the end mill is in contact with the object, the end mill including
- a shank portion extending along the longitudinal axis;
- and
- at least one cutting portion extending from the shank portion and including a cutting tip having a web, the cutting portion having a cutting diameter, an axial length of cut that is no more than twice the cutting diameter, a core diameter that is at least 0.7 times the cutting diameter, and a plurality of blades disposed at a helical angle from the longitudinal axis along the axial length of cut and extending at a radial angle onto the cutting tip to form a negative endrake across an axial cutting edge and terminating proximate to the web;
- wherein each of the blades of the plurality of blades is separated from one another by a flute and has a corner radius, a negative radial rake, and a negative axial rake;
- and
- wherein the cutting tip has a dish angle and a plurality of gashes, each of the gashes of the plurality of gashes having a gash angle and extending into one of the flutes and wherein the end mill is constructed from a ceramic.
A method of machining an object comprising contacting the object with an end mill having a longitudinal axis, the end mill spinning at a preselected cutting speed around its longitudinal axis while the end mill is in contact with the object, the end mill including
- at least one cutting portion extending from the shank portion and including a cutting tip having a web, the cutting portion having a cutting diameter, an axial length of cut that is no more than twice the cutting diameter, a core diameter that is at least 0.7 times the cutting diameter, and a plurality of blades disposed at a helical angle from the longitudinal axis of from about 39 to about 41 degrees along the axial length of cut and extending at a radial angle onto the cutting tip to form an endrake in the range of from about −1 to about −6 degrees and terminating proximate to the web;
- wherein each of the blades of the plurality of blades is separated from one another by a flute and has a corner radius in the range of from about 0.031 to about 0.4 times the cutting diameter, a negative radial rake in the range of from about 0 to about −4 tangential degrees, and a negative axial rake in the range of about −1 to about −3 degrees;
- and
- wherein the cutting tip has a dish angle in the range of from about 1.5 to about 3 degrees and a plurality of gashes, each of the gashes of the plurality of gashes having a gash angle in the range of from about 15 to about 30 degrees and extending into one of the flutes.
Dependencies are inferred from the claim text.