The purpose of this paper is to present a new stereolithograhy (SL) process which could substantially improve the efficiency of building process through controlling the beam spot size and optimizing the process parameters dynamically.
In this process, the focus length of UV laser scanning head is changed by the dynamic focus mirror according to the building program. The beam spot in the resin surface varies with the focus length, and the laser power is adjusted accordingly to the changing spot in building process.
The study finds that the efficiency of building process has a close relationship with the beam spot size. The experiments showed that the larger the laser spot diameter was, the less the depth and the larger the width of the cured lines would be. Then the building program would adjust the UV laser power to compensate for the decreased curing depth caused by the enlarged beam spot. At last, the spot compensation was optimized for the new method that could keep the same building accuracy with the traditional SL process.
The variable beam spot process could improve the building efficiency by 30 percent without increasing the cost of system, and keep the same accuracy compared with the conventional SL process.
