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Laser-Assisted Machining Research
Objectives:

An ultimate objective is to provide alternative, economically attractive machining process capabilities with a complete physical understanding of the LAM processes and the development of a comprehensive thermo-mechanical model that will enable its commercial application to machine parts made of advanced materials such as ceramics, composites and high temperature alloys to precise specifications. Specific objectives of the research include:

  • Determine the [LAM] machinability improvement of ceramics including silicon nitride, zirconia and mullite, various metal matrix composites and high temperature alloys including titanium alloys, nickel-based alloys and hardened alloys.
  • Find operating conditions that globally optimize the processes, taking into account to:
    • maximize material removal rate
    • minimize sub-surface flaws
    • minimize surface roughness
    • minimize tool wear
  • Determine the material removal mechanisms for various workpiece materials.
  • Determine the tool wear mechanism and tool wear rate for representative LAM conditions.
  • Develop material constitutive models for various materials for stress, strain and strain rates representative of LAM.
  • Develop transient, three-dimensional model of the workpiece undergoing LAM, including internal radiation for semi-transparent materials.
  • Understand the underlying physics of LAM.
  • Develop guidelines to determine materials for which LAM is best suited.
  • Develop an economic analysis to determine conditions for which LAM is a feasible alternative to grinding or hard turning.

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Research Plan:

The study of laser-assisted machining at Purdue is based on the simultaneous experimental and numerical investigation of various processes including turning, milling and micromilling. The experiments and modeling share a symbiotic relationship, as certain parts of one relies on results from the other (Schematic). This allows the underlying physics to be determined while increasing the machining knowledge-base.

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 Achievements in LAM  

  Experimental results:

  • LAM has been successfully applied to machining of various ceramics such as silicon nitride, partially stabilized zirconia and mullite (as shown below).  A significant improvement of machinability has been achieved with long tool life up to 2 hours.

  • LAM has been successful in improving machinability of various difficult-to-machine alloys such as Inconel 718, Ti-6Al-4V, Waspaloy, Compacted Graphite Iron, stainless steel (P550), hardened steel, high Cr. steel, and metal matrix composites.  Typical improvement includes 30% reduction in specific cutting energy, 2-4 fold improvement in surface roughness, and 2-4 fold improvement of tool life.   It has been demonstrated that LAM does not adversely affect the subsurface integrity (no microstructural changes, no subsurface damage or cracks, compressive residual stresses).

  • LAM capabilities for micromachining have been successfully demonstrated for various materials, including titanium alloys, ceramics and ceramic-matrix composites.   In each case, a significant improvement of tool life, surface quality and cost savings has been demonstrated.

  Modeling results:

  • Three-dimensional transient numerical models have been developed to predict the workpiece temperature distributions during laser-assisted turning and milling operations.

  • Multi-scale, multi-phase finite element models have been developed to predict the LAM processes and subsurface damage.

Silicon Nitride
Silicon Nitride
Zirconia Ceramics
Partially Stabilized Zirconia
Mullite
Mullite
Thermal Model

Comparison between conventional machining and LAM of MMC

Conventional            LAM

Economic Analysis

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Numerical Modeling
3D Temperature Field
LAM Experiments
LAM of Silicon Nitride
SPONSORS

National Science Foundation
Caterpillar, Schlumberger, Lockheed Martin, Weir Minerals, Rolls Royce, Boeing, GE Aviation
Indiana 21st Century Research and Technology
DoD, NASA

 

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Purdue Seal MECHANICAL ENGINEERING
PURDUE UNIVERSITY

Last revised on Aug. 1, 2016 by Web Master

Copyright 2001 Dr. Y.C. Shin
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