DOES HIGH BEAM QUALITY OF SOLID STATE LASERS ENHANCE LASER MATERIAL PROCESSING?

摘要

Lasers have been in use for material processing for decades as a flexible tool for different processes i.e. welding, cutting, drilling, surface modifications etc. Laser material processing offers a number of advantages over other processing technologies, i.e. high processing speeds, low heat input (minimal disruption to the parent material and coatings), low distortion of the parts, better cosmetic appearance and high flexibility. In the past, lamp pumped Nd: YAG lasers have been widely been used for a number micro and macro applications. Today, however, the parameter range of solid state lasers has increased significantly, especially after the emerging of fiber and disk lasers. The choice of a laser source for a specific application is no longer straightforward and obvious. Laser users are now faced with additional questions of laser beam quality and brightness. The main advantage of high beam quality is that the laser beam can be transported via a small diameter optical fiber, which translates to a small spot size at the workpiece. Laser sources with better beam quality are being made available at increasing power levels. However, choosing the optimum laser for an application may not be simply the selection of the highest beam quality at the required power level. This paper addresses this important issue --how the laser beam quality of solid state lasers affects the laser material processing performances by comparing welding and cutting data for thin and thick section of materials.