动态优化刮刀速度的新型涂层工艺

为提高活塞式无扰动涂层工艺的涂层质量，针对高分辨率激光快速成形系统涂层工艺中存在的涂层厚度随制件高度增加而变厚的问题，提出在制作过程中动态优化刮刀速度的涂层方法。研究刮刀速度、制件高度对涂层厚度的影响。采用面响应法，建立涂层厚度误差关于制件高度及刮刀速度的数学模型。根据该模型，在制作过程中随制件高度的变化，动态优化刮刀速度，实现涂层厚度均匀化。验证试验结果表明：与普通涂层工艺相比，新型涂层工艺将涂层厚度偏差由27 μm降为6.9 μm，解决了涂层厚度随制件高度增加而变厚的问题，实现涂层厚度的均匀化，提高堆积方向的制作精度。该涂层工艺也可应用于普通光固化激光快速成形系统中，解决制作陷阱结构时涂层厚度随制件高度变厚问题，因此该工艺对于光固化快速成形技术中提高堆积方向制作精度具有重要意义。

NOVEL RECOATING PROCESS WITH DYNAMIC OPTIMIZED BLADE SPEED

In order to improve the recoating quality of piston recoating system and resolve the problem that resin layer thickness increases with the height of object during building process in high-resolution stereolithography system, a novel recoating process whose blade speed is dynamically optimized during building process is proposed. Experiments are carried out to investigate the influence of blade speed and object height on the thickness of resin layer. The mathematical model describing the relationship of recoating layer thickness with object height and blade speed is established with response surfaces methodology. Based on the mathematical model, blade speed is dynamically optimized according to the object height during building process, and then uniformity resin layers can be obtained. Verifying experiment results show that compared with current recoating process, the novel recoating process reduces the difference between maximum and minimum thickness of resin layer from 27 μm to 6.9 μm. Experiment results also indicate that the problem that the thickness of resin layer which increases with the height of objects is resolved, and the uniform resin layers have been obtained. As a result, fabricating accuracy of microstructures in building direction is improved. The methodology of the novel recoating process can be applied to current stereolithography system as a solution to the problem that the thickness of resin layer increases with the height of objects when fabricating objects with trapped volume, therefore the new recoating process has important significance for stereolithography system to improve building accuracy.