US 8,256,092 B1Granted

Method for helical boring

AssigneesMakino, Inc., AB Sandvik Coromant

InventorsDavid C. Woodruff, Nils David Oehlund, Gareth Wayne Mason

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Abstract

A tool may be used to form an engine cylinder bore in a compacted graphite iron workpiece using helical interpolation. The tool may be rotated about a first axis while orbiting about a second axis that is parallel to the first axis. While rotating and orbiting, the tool may be advanced into the workpiece. This helical interpolation may be used to successively engage cutting or honing elements of the tool with the workpiece. The elements may thereby be permitted to cool between each successive engagement, which may reduce wear on the tool. Various operating parameters associated with the process may have certain relationships that may be exploited in certain ways to obtain ideal results. For instance, a helical interpolation process may be used to perform an act of rough cutting on the workpiece and finish honing on the workpiece, without having to perform an intermediary step of semi-finish boring.

Claims34

Dependent claims

A method for working on a workpiece, the method comprising:

(a) providing a tool, wherein the tool defines a first axis extending longitudinally along the center of the tool, wherein the tool is rotatable about the first axis, wherein the tool has a periphery, a first diameter, and a selected number of cutting elements;
(b) providing a workpiece, wherein the workpiece has a bore having a second diameter and a bore length;
(c) rotating the tool about the first axis at a selected rate of rotation;
(d) moving the tool in an orbital motion about a second axis, wherein the second axis is separate from but parallel to the first axis, wherein the acts of rotating the tool and moving the tool in an orbital motion are performed contemporaneously, wherein each cutting element moves at a cutting element speed during the acts of rotating the tool and moving the tool in an orbital motion;
and
(e) advancing the tool into the bore of the workpiece at a selected linear rate of advancement to successively engage the cutting elements of the tool with the workpiece to enlarge the bore in the workpiece to a third diameter by cutting chips from the workpiece, wherein the third diameter is greater than the second diameter, wherein the tool continues to rotate about the first axis and orbit about the second axis during the act of advancing the tool, such that the tool is advanced at a helix angle, wherein the cutting elements are advanced at a selected peripheral linear feed rate during the act of advancing the tool;
wherein the linear rate of advancement is selected based at least in part on the rate of rotation.

4 more elements

A method for working on a workpiece, the method comprising:

(a) providing a first tool, wherein the first tool defines a first axis extending longitudinally along the center of the first tool, wherein the first tool is rotatable about the first axis, wherein the first tool has a periphery, a first diameter, and a plurality of cutting elements;
(b) providing a second tool, wherein the second tool defines a second axis extending longitudinally along the center of the second tool, wherein the second tool is rotatable about the second axis, wherein the second tool has a periphery, a second diameter, and a plurality of finish honing elements;
(c) providing a workpiece, wherein the workpiece is formed at least in part of compacted graphite iron;
(d) rotating the first tool about the first axis;
(e) moving the first tool in an orbital motion about a third axis, wherein the third axis is separate from but parallel to the first axis, wherein the acts of rotating the first tool and moving the tool in an orbital motion are performed contemporaneously;
(f) advancing the first tool into the bore of the workpiece in a first pass to successively engage the cutting elements of the first tool with the workpiece to form a bore in the workpiece, wherein the formed bore has a third diameter and a bore length, wherein the first tool continues to rotate about the first axis and orbit about the third axis during the act of advancing the first tool;
(g) rotating the second tool about the second axis;
(h) moving the second tool in an orbital motion about the third axis, wherein the third axis is separate from but parallel to the second axis, wherein the acts of rotating the first tool and moving the tool in an orbital motion are performed contemporaneously;
and
(i) advancing the second tool into the bore of the workpiece in a second pass to successively engage the finish honing elements of the second tool with the formed bore in the workpiece to finish hone the bore to a fourth diameter, wherein the second tool continues to rotate about the second axis and orbit about the third axis during the act of advancing the second tool;
wherein the method is performed without a semi-finish boring pass being performed between the first pass and the second pass.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/362,706Filed 30 Jan 2009 · us provisional application
Priority: 30 Jan 2008
Granted: 4 Sep 2012
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

B23C 3/02
Milling particular work; Special milling operations; Machines therefor: milling surfaces of revolution
B23B 41/12
Boring or drilling machines or devices specially adapted for particular work ; Accessories specially adapted therefor: for forming working…
B23C 2215/242
Components of internal combustion engines: combustion chambers
B23C 2220/52
Details of milling processes: orbital drilling, i.e. use of a milling cutter moved in a spiral path to produce a hole