Laser trimming cured Graphite/Epoxy (Gr/Ep) laminates with an acceptable heat affected zone (HAZ) has proven to be extremely difficult. The carbon fibers have a high thermal conductivity, and the material fibers and matrix do not simultaneously reach their vaporization temperatures. A new generation of solid state diode-pumped Nd:YAG lasers is being developed by a DARPA program called the Precision Laser Machining Consortium (PLM). The higher beam quality and pulsing techniques utilized by these lasers have been reported to reduce the HAZ of trimmed Gr/Ep laminates. The objective of this research was to evaluate the effect of these advanced laser features when cutting Gr/Ep. Cutting tests performed using high quality electrically pulsed Nd:YAG lasers have yielded smaller HAZ results compared to cuts with a continuous wave CO2 laser. By employing Q-switching modulation to an electrically pulsed beam even smaller HAZ results can be achieved. To effectively trim Gr/Ep laminates with an acceptable HAZ, the key is to minimize the amount of heat added to the cut edge. The combined use of high beam quality Nd:YAG lasers and pulsing techniques appears to be of benefit.
Laser trimming of graphite-epoxy laminates
1999
8 Seiten, 6 Quellen
Aufsatz (Konferenz)
Englisch