薄施密特校正板的加工方法研究

针对薄板玻璃的刚度差，在研磨中容易产生变形这一特点，提出了一种新的加工方法。以加工薄施密特校正板（厚径比小于1／40）为例，用传统的上盘粘接固定工件进行加工，工件在下盘前的面形精度较好，但下盘后产生的变形使其面形精度下降，不能满足要求。采用真空模具法，吸附工件从而使工件固定产生预期的变形，面形精度易于控制，使加工非球面转变为加工平面，降低了加工难度，消除了工件在粘接过程中温度所引起的变形，降低了加工时的不均匀压应力，从而减少了变形，使得加工后的面形与加工过程中的面形接近，最终保证了工件的面形精度。

Study on Method for Manufacturing Thin Schmidt Corrector

Since the thin glass has poor rigidity and it is easy to deform in lapping,this paper puts forward a new method to reduce deformation.Taking the fabrication of thin Schmidt corrector,for example,technicians adopt the traditional surface adhesive method to fix the workpiece in lapping.Before the workpiece is taken off from the fixture,the surface accuracy is quite good.It can meet the requirement.But after being taken down from the fixture,the workpiece deforms,and its surface accuracy is reduced and could not meet the requirement.We adopt vacuum-mould method to fix the workpiece,which brings the workpiece deformation in expectant absorption and changes the process from machining aspheric surface to machining plane surface and removes workpiece deformation in adhering because of temperature change.Therefore the surface accuracy can be controlled easily and the difficulty of the machining process is reduced.In lapping we also try to reduce asymmetrical pressure on the workpiece,that reduces workpiece deformation in lapping and makes workpiece surface accurate.Thus workpiece surface accuracy is assured and the requirement is met.