DEVELOPMENT OF ULTRA-PRECISION MACHINING SYSTEM FOR ASPHERIC MIRROR BASED ON ARC ENVELOPE GRINDING METHOD

本课题是基于“圆弧包络磨削法”的超精密磨削系统的开发。AEGM用于非球面陶瓷镜的磨削，可提高砂轮寿命和磨削性能，并显著降低总生产成本。我们的新仪器，利用AEGM的必要的仪器和控制系统已经设计和建造。刀具轨迹在一台超级计算机上计算，CNC程序生成和刀具轨迹补偿在与同一台超级计算机相连的PC机上进行。其次，对圆弧整形精度、砂轮设计、磨削工件表面粗糙度和形状精度进行了研究，研制了一种精密圆弧整形修整装置。该整形器用于圆形横截面轮廓的机上整形。对圆弧整形器的整形精度进行了检验，结果表明，其轮廓误差和半径误差均在（±）SY以内。[)0.5 mum和（]SY. 0.08mm。为了获得更好的形状精度，此外，我们研究了一种分辨率小于10 nm的在线形状测量仪。接下来，我们尝试了AEGM磨削试验与整形轮。利用该系统成功地磨削了直径为100 mm的玻璃和碳化硅非球面镜。第一次磨削后的形状误差（没有任何补偿）小于1.8 μ m，粗糙度为R<@D2max@>D2= 82 nm（R<@D2a@>D2= 10 nm）。所开发的基于AEGM的非球面陶瓷反射镜磨削系统具有良好的磨削性能。该系统不仅适用于外太空应用的大尺寸光学器件的制造，而且适用于微型器件的微尺寸光学器件的制造，这将在不久的将来得到广泛的应用。

This project deals with the development of an ultra-precise grinding system based on a new grinding technique called the "Arc Envelope Grinding Method (AEGM)". AEGM,which is used for grinding aspheric ceramic mirrors, increases both wheel life and grinding performance, and significantly decreases total production costs. The necessary instrumentation and control system of our new instrument that utilizes AEGM have been designed and built. The tool path was calculated on a supercomputer, and the CNC program generation and tool path compensation were performed on a PC linked to the same supercomputer. Next, arc truing accuracy, wheel design, surface roughness and form accuracy of the ground workpiece were investigated.We developed a precision truing and dressing device, called an "Arc Truer". The truer is for an on-machine truing of a round cross-sectional profile. An examination of truing accuracy of the Arc Truer revealed that profile and radius errors were within (]SY.+-。[)0.5 mum and (]SY.+-。[)0.08mm, respectively. To obtain better form accuracy, furthermore, we investigated an on-machine form-measuring instrument with resolution of less than 10 nm. Next, we tried the AEGM grinding tests with the trued wheel. Using this grinding system, aspheric mirrors of glass and silicon carbide, 100 mm in diameter, were successfully ground. The form error after the first grinding (without any compensation) was less than 1.8 mum, and the roughness was R<@D2max@>D2=82nm (R<@D2a@>D2=10nm). The AEGM-based system which we developed demonstrated excellent grinding performance of aspheric ceramic mirrors. This system is applicable for manufacturing not only large-scale optics for outer-space applications, but also micro-size optics for micro devices, which will be widely used in the near future.