Lee Moon G, Kim Gaeun, Lee Chan-Woo, Lee Soo-Hun, Jeon Yongho
Department of Mechanical Engineering, Ajou University, San 5, Woncheon-dong, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-749, South Korea.
Rev Sci Instrum. 2014 Apr;85(4):045104. doi: 10.1063/1.4869339.
Laser scanning systems have been used for material processing tasks such as welding, cutting, marking, and drilling. However, applications have been limited by the small range of motion and slow speed of the focusing unit, which carries the focusing optics. To overcome these limitations, a dynamic focusing system with a long travel range and high speed is needed. In this study, a dynamic focusing unit for a laser scanning system with a voice coil motor (VCM) mechanism is proposed to enable fast speed and a wide focusing range. The VCM has finer precision and higher speed than conventional step motors and a longer travel range than earlier lead zirconium titanate actuators. The system has a hollow configuration to provide a laser beam path. This also makes it compact and transmission-free and gives it low inertia. The VCM's magnetics are modeled using a permeance model. Its design parameters are determined by optimization using the Broyden-Fletcher-Goldfarb-Shanno method and a sequential quadratic programming algorithm. After the VCM is designed, the dynamic focusing unit is fabricated and assembled. The permeance model is verified by a magnetic finite element method simulation tool, Maxwell 2D and 3D, and by measurement data from a gauss meter. The performance is verified experimentally. The results show a resolution of 0.2 μm and travel range of 16 mm. These are better than those of conventional focusing systems; therefore, this focusing unit can be applied to laser scanning systems for good machining capability.
激光扫描系统已被用于焊接、切割、标记和钻孔等材料加工任务。然而，其应用受到承载聚焦光学器件的聚焦单元运动范围小和速度慢的限制。为了克服这些限制，需要一种具有长行程范围和高速的动态聚焦系统。在本研究中，提出了一种具有音圈电机（VCM）机构的激光扫描系统动态聚焦单元，以实现快速速度和宽聚焦范围。与传统步进电机相比，VCM具有更高的精度和速度，并且比早期的钛酸铅锆驱动器具有更长的行程范围。该系统具有中空结构，以提供激光束路径。这也使其紧凑且无传输，并具有低惯性。使用磁导模型对VCM的磁学特性进行建模。其设计参数通过使用布罗伊登-弗莱彻-戈德法布-肖诺方法和序列二次规划算法进行优化来确定。在设计VCM之后，制造并组装动态聚焦单元。通过磁有限元方法仿真工具Maxwell 2D和3D以及高斯计的测量数据验证磁导模型。通过实验验证性能。结果显示分辨率为0.2μm，行程范围为16mm。这些优于传统聚焦系统；因此，该聚焦单元可应用于激光扫描系统以获得良好的加工能力。
