Heat transfer during pulsed laser cutting of thin sheets

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 0.10 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.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Mechanical Engineering

Department dc:contributor.department

Mechanical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1989

Author dc:creator

• Lindau, Jules Washington

Chair dc:contributor.committeechair

• Diller, Thomas E.

Committee members dc:contributor.committeemember

• Knight, Charles E.
• Vick, Brian L.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

etd-02062013-040225

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/40958