LASER ASSISTED MACHINING APPARATUS WITH DISTRIBUTED LASERS

• US 20120024827A1
• Filed: 09/08/2011
• Published: 02/02/2012
• Est. Priority Date: 09/07/2005
• Status: Active Grant

• Current Assignee: Purdue Research Foundation (The Trustees of Purdue University (d/b/a Purdue University))
• Original Assignee: Purdue Research Foundation (The Trustees of Purdue University (d/b/a Purdue University))
• Inventors: Shin, Yung
• Granted Patent: US 8,698,041 B2
• Time in Patent Office: Days
• US Class Current: 219/121.61
• CPC Class Codes: B23K 26/0823 Devices involving rotation of the workpiece
• CPC Class Codes: B23P 25/006 Heating the workpiece by laser during machining

Abstract

Laser assisted machining process and machine utilizing multiple distributed laser units that are strategically distributed around the workpiece being machined to simultaneously heat the workpiece, creating a desired temperature distribution for laser assisted machining. Sequential incremental heating from different directions and positions are used, resulting in longer tool life and shorter machining time.

Claims

1. A laser assisted machining apparatus, comprising:

a lathe having a workpiece holder that spins about a rotational axis and a cutting tool holder that moves along a path parallel to said rotational axis of said workpiece holder;

a first laser unit connected to said cutting tool holder so as to emit a first laser beam impinging upon a workpiece in said workpiece holder at a circumferential position about said rotational axis that is substantially ahead of that of a cutting tool in said tool holder;

a second laser unit connected to said cutting tool holder so as to emit a second laser beam impinging upon the workpiece

from an axial position behind the cutting tool relative to its travel direction along said path, and

at a circumferential position close to and ahead of that of the cutting tool and substantially behind that of the first laser beam on the workpiece; and

control means for independently controlling output of each of said first and second laser units.

2. The laser assisted machining apparatus of claim 1, wherein said second laser unit is arranged such that said second beam impinges substantially perpendicularly upon a chamfer formed on said workpiece by the cutting tool.

3. The laser assisted machining apparatus of claim 1, wherein the first beam impinges upon the workpiece at an axial position which is axially ahead of the cutting tool relative to its travel direction along said path.

4. The laser assisted machining apparatus of claim 1, wherein said circumferential position of the first laser beam is greater than 45 degrees circumferentially ahead of the cutting tool, and said circumferential position of the second laser beam is less than 15 degrees circumferentially ahead of the cutting tool.

5. A laser assisted machining apparatus utilizing multiple distributed lasers to assist a cutting tool in machining a rotating workpiece, comprising:

a cutting tool configured to cut material from the rotating workpiece, thereby creating a circumferential chamfer on the rotating workpiece; and

first and second laser units configured to sequentially, incrementally heat a small radially outer portion of the rotating workpiece prior to the cutting tool beginning to remove the small portion, the small portion including part of the chamfer surface, said first laser unit configured to preheat the small portion by directing a first laser beam onto its radially outermost surface when its circumferential position about the rotational axis of the rotating workpiece is substantially ahead of that of the cutting tool, said second laser unit configured to further heat the small portion by directing a second laser beam onto its chamfer surface at a high angle thereto when its circumferential position is in close proximity to that of the cutting tool.

6. The laser assisted machining apparatus of claim 5, wherein said first and second laser units are independently controlled to control temperature gradients within the workpiece.

7. A laser assisted machining apparatus utilizing multiple distributed lasers to assist a cutting tool in machining a rotating workpiece, comprising:

a first laser unit configured to heat the rotating workpiece with a first laser beam directed onto the workpiece at a first point

axially ahead of the cutting tool relative to the travel direction thereof, and

substantially circumferentially ahead of the cutting tool; and

a second laser unit configured to heat the rotating workpiece with a second laser beam directed onto the workpiece at a second point

axially even with the cutting tool and on a chamfer of the workpiece, and

circumferentially ahead of the cutting tool and substantially behind said first point;

whereby material on the rotating workpiece is sequentially heated by said first and second laser beams and then cut by said cutting tool;

wherein the power output of each of the laser units is independently controlled to control temperature gradients within the workpiece.

8. A laser assisted machining apparatus utilizing multiple distributed lasers to assist a cutting tool in machining a rotating workpiece, comprising:

a cutting tool configured to cut material from the rotating workpiece tool, thereby creating a chamfer on the rotating workpiece;

a first laser unit configured to heat the workpiece at a first point circumferentially ahead of the cutting tool; and

a second laser unit configured to heat the chamfer at a second point, circumferentially behind said first point and ahead of the cutting tool, thereby sequentially incrementally heating the rotating workpiece;

wherein said first laser unit comprises a higher-power laser than said second laser unit.

9. The laser assisted machining apparatus of claim 8, wherein said first and second laser units are independently controlled to control temperature gradients within the workpiece.