KDP晶体飞切加工表面的微缺陷创成机理及其抑制方法研究

In our country, the engineering production of large-scale KDP crystals has suffered from the technical difficulty of micro surface defects for over ten years, i.e. the random appearance of pitting and scratching defects on the KDP crystal surface in diamond fly cutting, which heavily decreases the surface quality and finishing efficiency in mass production of KDP crystals. Therefore, aiming at the state of the art, the interaction effects of tool cutting edge and KDP crystal on the scale of a micrometer or a nanometer will be investigated firstly in this project. And subsequently, the formation mechanisms of micro surface defects of pitting and scratching on the finished KDP crystal surface will be explicated. Thirdly, the quantitative relationship between the quality of tool cutting edge, e.g. tool sharpness and chipping defects on cutting edge, and micro defects on the finished surface will be explored. Furthermore, the theoretical prediction model for the fly cut KDP crystal surface topography will be established, into which the effect of micro surface defects is integrated. Finally, some novelty methods related to tool geometries for controlling the micro surface defects will be proposed. The above works are desired to enable the achieving of micro defects free surface of large-scale KDP crystals as finished by single point diamond fly cutting to be easy and stable, which can act as a crucial technology to improve the level of optics manufacturing in laser-based nuclear fusion field.

我国大口径KDP晶体单点金刚石飞切加工表面的麻点和划痕微缺陷技术难题已困扰工程生产十多年，严重制约了KDP晶体批量加工质量和生产效率。针对国内技术现状，本项目将深入研究微纳尺度下金刚石刀具切削刃与KDP晶体相互作用机制，阐明KDP晶体单点金刚石飞切加工表面的麻点、划痕微缺陷形成机理，量化刀具切削刃质量与加工表面微缺陷的关系，建立耦合微缺陷作用的KDP晶体加工表面微观形貌理论预测模型，开创基于金刚石刀具特征参数的KDP晶体加工表面微缺陷控制方法，以此稳定大口径KDP晶体的单点金刚石飞切加工表面质量，为我国激光核聚变工程的光学加工技术发展提供关键技术支撑。

我国大口径KDP晶体单点金刚石飞切加工表面的麻点和划痕微缺陷技术难题已困扰工程生产十多年，严重制约了KDP晶体批量加工质量和生产效率。针对国内技术现状，本项目KDP晶体飞切加工的有限元仿真模型，深入研究了微纳尺度下金刚石刀具切削刃与KDP晶体相互作用机制，建立了KDP晶体直角切削和斜角切削的相对裂纹长度预测模型，阐明了KDP晶体单点金刚石飞切加工表面的麻点、划痕微缺陷形成机理，建立了耦合微缺陷作用的KDP晶体加工表面粗糙度理论预测模型，提出了基于金刚石刀具刀刃微缺陷控制的KDP晶体斜角飞切加工新方法，该方法采用新型微负倒棱刀具在-25°前角和15°刃倾角下，加工出了粗糙度Ra 1.36 nm的超光滑表面。本项目研究成果使无缺陷KDP晶体表面的加工变得更容易和稳定，将为我国激光核聚变工程的光学加工技术发展提供了关键技术支撑。