Metal boring with self-propelled rotary cutters
AssigneeRotary Technologies Corporation
InventorsHarry M. Weiss, Philip S. Szuba, Peter M. Beecherl, Gregory J. Kinsler
Life of this patent
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Abstract
A boring tool for use with compacted graphite iron materials includes at least one self-propelled rotating cutter insert. The insert is carried in a cartridge in which the insert is rotatable about is axis which is a secondary axis relative to a boring tool body in which the cartridge is mountable and which is rotatable about a primary axis. In the tool, the insert has its cutting point most distant from the tool axis that is the location at which axial and radial rake angles are defined to assure that the insert rotates during boring about its axis in the correct direction and at sufficient speed to assure cooling of the insert.
Claims21
A boring tool comprising a body rotatable about and advanceable along a primary axis during boring and carrying a round rotating cutting element mounted to the body for rotation about a secondary axis fixed relative to the primary axis, the cutting element having a circular cutting edge which bounds a cutting surface facing generally toward the direction of boring rotation of the body, the relation of the primary and secondary axes being defined so that, at a cutting location on the element located at the place of maximum distance of the cutting edge radially from the primary axis, the cutting surface has, relative to the primary axis, radial and axial rake angles defined in coordination with each other to assure rotation of the element, during boring operation of the tool, in a selected direction about the secondary axis.
A cutting member mount for a round rotatable cutter member useful in a boring tool having a body which is rotatable about and advanceable along a tool axis during boring, the mount including a base and an annular cutter member rotatably carried by the base for rotation about a cutter axis, the cutter member having a face extending substantially radially of the cutter axis and a peripheral cutting edge bounding the face, the mount including structural features by which the mount is rigidly connectable to the tool body in a predetermined relation to the body in which the cutter member face opens generally in the direction of boring rotation of the tool about its axis and the face has selected axial and radial angles of rake, relative to the tool axis, at a cutting location on the member at the place of maximum distance of the member cutting edge from the tool axis, the axial and radial rake angles having values which assure rotation of the member about the cutter axis in a selected direction during boring operation of the tool.
A method for machining a bore of specified diameter in a workpiece of specified material with a self-propelled rotating cutter element comprising the steps of defining, with reference to the properties of the workpiece material, first operating values for element cutting speed, depth of cut and axial feed rate;
- establishing for those first operating values of the relations of cutter element axial and radial rake angles to tangential, radial and axial cutting forces and cutter element angular velocity and torque;
- identifying cutter element rake angles for maximum torque in a desired direction about an axis of rotation of the cutter element;
- establishing cutter element bearing forces at the identified rake angles;
- providing a rotatable boring tool carrying a rotating cutter element having a cutting point spaced one-half the specified bore diameter radially from the tool axis of rotation and having at the cutting point the identified axial and radial rake angles;
- and operating the tool at an angular velocity productive of the defined cutting speed and at the defined axial feed rate to machine the bore in a workpiece of that specified material.
Dependencies are inferred from the claim text.