Title page for ETD etd-02062013-040225


Type of Document Master's Thesis
Author Lindau, Jules Washington
URN etd-02062013-040225
Title Heat transfer during pulsed laser cutting of thin sheets
Degree Master of Science
Department Mechanical Engineering
Advisory Committee
Advisor Name Title
Diller, Thomas E. Committee Chair
Knight, Charles Eugene Committee Member
Vick, Brian L. Committee Member
Keywords
  • Laser beam cutting
Date of Defense 1989-05-05
Availability restricted
Abstract

A numerical model of the temperature field during pulsed laser cutting of thin sheets (approximately 2.5 x l0-5 m) was developed. Cutting was simulated through removal of nodes from a finite difference scheme based on sensible heating to the phase change temperature and a single value of latent heat (melting or vaporization). The pulsed laser model predicts a heat-affected zone of less than 0.02 mm for pulsed laser cutting. For comparable cutting with a continuous power laser, a heat-affected zone between 0.05 and 0.l0 mm is predicted. Thermal stress levels were predicted to be an order of magnitude lower for pulsed laser cutting than for continuous power cutting. The stress levels predicted by the model also increased with cut speed. Experimentally, pulsed laser cutting yielded better cut quality, based on less cracking, than continuous power cutting. In addition, the cut quality deteriorated as the cutting speed was increased for the continuous power laser. Presently, application of pulsed laser cutting is limited by its low cutting speed, which is restricted by the energy density of the laser. The model predicts that increasing energy density will decrease the size of the heat-affected zone and increase the maximum cutting speed. Therefore, pulsed laser cutting at high speeds should be attainable without deterioration in cut quality.

Files
  Filename       Size       Approximate Download Time (Hours:Minutes:Seconds) 
 
 28.8 Modem   56K Modem   ISDN (64 Kb)   ISDN (128 Kb)   Higher-speed Access 
[VT] LD5655.V855_1989.L564.pdf 40.64 Mb 03:08:09 01:36:46 01:24:40 00:42:20 00:03:36
[BTD] next to an author's name indicates that all files or directories associated with their ETD are accessible from the Virginia Tech campus network only.

Browse All Available ETDs by ( Author | Department )

dla home
etds imagebase journals news ereserve special collections
virgnia tech home contact dla university libraries

If you have questions or technical problems, please Contact DLA.