| 大尺寸SIC空间反射镜离子束加工热效应分析与抑制 |
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| 引用本文： | 许艳军,赵宇宸,沙巍,齐光. 大尺寸SIC空间反射镜离子束加工热效应分析与抑制[J]. 红外与激光工程, 2014, 43(8): 2556-2561 |
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| 作者姓名： | 许艳军 赵宇宸 沙巍 齐光 |
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| 作者单位： | 1.中国科学院长春光学精密机械与物理研究所,吉林 长春 130033; |
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| 基金项目： | 国家863计划(863-2-5-1-13B) |
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| 摘 要： | 离子束加工中从离子源射出的高速离子撞击光学反射镜表面，离子的动能转化成热能以及中和灯丝的热辐射作用，使反射镜温度急剧升高。反射镜温升过快，会导致柔性连接结构胶结部位发生不可逆的非线性变化，并且热膨胀使实际加工位置和理想加工位置发生偏移，增加了加工误差，因此需要对加工过程中产生的热效应进行抑制。提出了通过规划加工路径和增强散热的方法，增强加工过程的散热，控制反射镜的温度。针对600 mm260 mm的某主反射镜，对增强散热前后不同加工路径的离子束加工进行了研究和有限元分析。分析表明:加工路径的选择、增强散热对反射镜的温度分布有较大影响，增强散热前，采用横栅格加工路径，反射镜最高温度为35.8 ℃，对应全口径PV=/5，采用分区纵栅格加工路径，反射镜最高温度则达到52 ℃，PV=/10。增强散热后，不同加工路径离子束加工中，反射镜温度均有所下降，采用横向栅格加工路径反射镜温度最高为28.2 ℃，对应全口径PV=/20，采用分区纵栅格加工路径反射镜温度最高为41 ℃，PV=/7。通过对比，最终采用增强散热的横栅格加工路径的加工方式。对优选的加工路径进行了试验验证，试验结果与仿真结果一致。结果表明:优化加工路径，增强散热措施能够抑制离子束加工的热效应，为离子束加工热效应抑制提供理论基础。
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| 关 键 词： | 空间反射镜 离子束加工 热效应 抑制 |
| 收稿时间： | 2013-12-05 |
Analysis and suppression of thermal effects of ion beam processing for large-size SIC space mirror |
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| Affiliation: | 1.Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,China;2.University of Chinese Academy of Sciences,Beijing 100049,China |
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| Abstract: | The high-speed ion emits from the ion source during the ion beam processing impacts the optical mirror surface, thermal energy deposited inside the mirror which comes from kinetic energy and radiation of filament, makes the mirror temperature rise sharply. When the temperature of the mirror rises sharply, it could make cement of flexible components change irreversibly and nonlinearly, and the actual machining position is not the ideal position due to expansion, so it is necessary to suppress the thermal effect. A method of machining path planning and heat conduction enhancement was proposed to control the temperature of the mirror. For a primary mirror of 600 mm260 mm, research and finite element analysis were carried out for ion beam processing with different processing paths before and after heat conduction enhancement, which shows that the path selection and heat conduction enhancement have serious effects to the mirror. Before heat conduction enhancement, the maximum temperature of the mirror was 35.8 ℃, PV=/5 when horizontal grid-shape machining path was used, and the maximum temperature of the mirror was 52 ℃, PV=/10 when vertical grid-shaped machining path was used. After heat conduction enhancement, the temperature of mirror about all machining path declined, the maximum temperature of the mirror was 28.2 ℃, PV=/20, when horizontal grid-shape machining path was used and increasing the heat conduction path, the maximum temperature of the mirror was 52 ℃, PV=/10, when vertical grid-shaped machining path was used. By contrast, the method of horizontal grid-shape machining path was used and the heat conduction path was increased finally. The optimal path was tested experimentally. The results agree with the simulational result，and it shows that optimizing the processing path and enhancing heat conduction measures can suppress the thermal effect of ion beam processing. This research provides theoretical basis for the thermal effects suppression of ion beam processing. |
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