某高精度星载主反射面天线制备工艺

Preparation Process of a High Precision Space-borne Main Reflector Antenna

为了提高星载碳纤维复合材料(CFRP)主反射面天线的型面精度和装配尺寸精度,重点从模具设计(采用复合材料与普通模具材料组合的方式)、模具热分布测试(降低固化过程中的残余应力)、背筋与反射面主体的胶接(采用最优参数控制)以及组合机加工(通过加工基准的转化来提高组合机加精度)等方面进行优化和控制。结果表明,主反射面型面均方根差(RMS)可达0.04 mm,对外接口及馈源安装面的平面度、位置度等装配精度满足设计要求。采用5mm厚复合材料上面板+6 mm厚Q235钢下面板设计的框架结构模具,面板之间的最大剪应变为0.097%,远远小于橡胶的剪切延伸率1.6%,在固化成型中能够缓冲面板之间的剪应力,并降低面板与产品之间的剪应力;对成型模具热分布进行测试,确定领先热电偶和滞后热电偶的最佳位置,避免了主反射面成型过程中温度不均匀对凹面型面精度的影响;背筋与反射面主体之间的装配间隙小于0.15 mm、胶层厚度0.1~0.2 mm、工装定位、固化过程中施加-0.02~-0.01 MPa压力为最优胶接工艺参数;通过旋转和平移将主反射面基准转移到成型模具基准孔,以基准转换后模具基准孔作为基准组合机加工,可以获得更好的装配精度。

In order to improve the profile accuracy and dimensional accuracy of the main reflector antenna of the on-board carbon fibre composite(CFRP),the optimisation and control were focused on the mould design by combining the composite material with common mould materials,the mould heat distribution test to reduce the residual stresses during the curing process,the gluing of the backstring with the main body of the reflector using the optimal parameter control,and the combined processing with improvement of the combined machining accuracy through the transformation of machining datums,and so on.The results show that the root mean square error(RMS) of the main reflective surface can reach 0.04 mm,and the flatness and position of the external interface and feeder mounting surface meet the design requirements.The frame structure mould designed by using 5 mm thick composite upper panel + 6 mm thick Q235 steel lower panel,the maximum shear strain between the panels is 0.097%,which is much smaller than the shear elongation of rubber 1.6%,and it can buffer the shear stress between the panels in the curing and moulding and reduce the shear stress between the panels and the product;the heat distribution of the moulding mould was tested to determine the optimum position of the leading thermocouples and the hysteretic thermocouples to avoid the thermal stresses.The optimal position of the leading thermocouple and lagging thermocouple is determined to avoid the influence of uneven temperature on the accuracy of concave surface profile during the moulding process of the main reflective surface;The assembly gap between the back rib and the main body of the reflective surface is less than 0.15 mm,the thickness of the adhesive layer is 0.1-0.2 mm,the tooling is positioned,and the pressure of-0.02--0.01 MPa is applied during the curing process as the optimal adhesive bonding process parameter;The benchmark of the main reflective surface is transferred to the benchmark hole of the moulding mould by rotation and translation.By rotating and translating the main reflective surface datum to the mould datum hole,and using the datum converted mould datum hole as the datum for combination machining,better assembly accuracy can be obtained.