基于节能理念的LED光源快速成型系统

 LED-SL是采用大功率UV-LED作为固化光源的新型快速成型系统。其基本原理是LED发出的紫外光通过聚焦镜汇聚到树脂液面,该聚焦镜在机械式x-y工作台的驱动下,在树脂液面进行扫描,使液态光敏树脂固化。通过与激光和汞灯光源的比较,阐述了UV-LED固化光源的优势。由于机械式工作台的运动学特性,在扫描固化线时,光束总是在其起始端从静止开始加速,在中段保持匀速运动,到达终点时又减速到静止状态。由于加速和减速段的曝光量大于中间段,使得固化单线两头粗中间细,形成骨形误差。采用功率匹配的能量控制方式以消除骨形误差。功率匹配是指动态调整光束功率,使得扫描过程中光功率始终与扫描速度成正比。实验结果表明功率匹配方式能有效提高成型精度。UV-LED、激光、高压汞灯3种固化光源能耗的实验表明,UV-LED的光固化能耗仅为激光的0.86%,汞灯的0.1%,从而证明了LED-SL突出的节能优势。

Energy-conserving Stereolithography System with UV-LED Light Source

An inexpensive stereolithography (SL) system with high power UV-LED curing light source, the LED-SL, is developed. The working principle of the UV-LED light based SL system (LED-SL) and its characteristics are discussed. The divergent UV light emitted from the LED is focused on the resin surface by a set of focusing lens. Controlled by the computer, the workbench drives the scanner to move along X-Y plane, and polymerizes the liquid resin according to the current cross-section of a layered part. The advantages of UV-LED light source are analyzed. Because of the kinematic behavior of the mechanical scanning workbench, the exposure at the ends of a single cured line is much greater than that in the middle segment, and hence bone-shaped errors would occur, which means that the ends of a cured line have larger sizes than the middle segment. The power matching scanning method is used to improve the accuracy of a cured line, dynamically adjusting the beam power to ensure that the power is proportional to the scanning speed. The experimental results indicate that the power matching method can effectively improve the building accuracy. The SL energy consumption of UV-LED, laser and UV lamp sources are experimentally compared, and the results show that the energy consumption of UV-LED is merely 0.86% of laser and 0.1% of UV lamp, an outstanding energy conservation performance of the LED-SL.