Study on a Ultra-precisely Joining Method using a Shrink Fitter

利用热装夹具实现了铝多面镜与碳化硅自作用气浮轴承的超精密连接。采用传统的连接方法，如紧定螺钉、弹簧等，电机发热不可避免地使多面镜镜面磨损。热装可以解决镜面因温度升高而变形的问题。与其他连接方法相比，收缩配合可以提供更好的轴定位。去年我们通过数值分析设计了收缩配合器的尺寸，其中镜面不会因电机产生的热量而翘曲超过100 nm。在此基础上进行了多面镜热装夹具的设计验证实验，在热装夹具的作用下，多面镜的镜面在超精密车床上被切割到100nm的平面度。这被称为二次切割。今年，为了省略二次切割，我们寻找了聚乙烯的最佳形状 关于我们 通过计算机模拟得到的平面镜。旋转中的多面镜的镜面通常在离心力的作用下向外变形约300nm。然而，人们认为多边形镜的特殊形状可以将这种变形保持在大约100 nm以下。因此，我们通过计算机模拟检查了大约30或40个形状，最终找到了2或3个最佳形状，这些形状可以将变形保持在容许量以下（提交给JSME）。此外，还研究了拟合曲面的不圆度对镜面变形的影响.制备六组试样，并测量每个试样的不圆度。基于测量的不圆度，计算了过盈配合后镜面的形状。在实验中，用ZYGO激光干涉仪测量了反射镜的面形，计算值与实测值吻合较好。因此，我们可以澄清不圆度的影响（将由JSME出版）。然而，也很明显，如果不圆度为0，则不能省略二次切削。少

A shrink fitter was used to join an aluminum polygon mirror and a SiC self-acting air bearing ultra-precisely. It is inevitable that mirror surfaces of the polygon mirror will de wearped by heat gensrated from a motor if conventional joining methods, such as set screws and springs, are taken. The shrink fitter can resolve the deformation problem of the mirror surfaces caused by the temperature rise. The shrinkage fit gives better shaft location than the other joining methods.Last year we designed dimensions of the shrink fitter by a numerical analysis, in which the mirror surfaces could not be warped over 100nm by the heat generated from the motor. Then the experiment were carried out to check the design of the shrink fitter.After joining by the shrink fitter, the mirror surfaces of the polygon mirror have to be cut by a ultra-precision lathe to a desirable flatness of 100nm. This is called secondary cut. This year, to omit the secondary cut, we have searched optimum shapes of the poly … More gon mirror through computer simulation. Usually the mirror surfaces of the polygon mirror in rotation are deformed outwaed to some 300nm by a centrifugal force. However it is thought that special shapes of the polygon mirror can keep this deformation below some 100nm. So we checked some 30 or 40 shapes through the computer simulation and finally found out 2 or 3 optimum shapes which could keep the deformation below tolerable amount (submitted to JSME). Furthermore the effect out-of-roundness ofothe fitting surfaces on the deformation of the mirror surfaces was investigated. Six sets of specimens were prepared and the out-of-roundness of each specimen was measured. The shapes of the mirror surfaces sfter the shrink fit were calculated based on the measured out-of-roundess. In the experiment, the mirror surfaces were measured by the laser interferometer, ZYGO.The calculated values were in good agreement with the measured ones. Thus we could clarify the effect of the out-of-roundness (to be published from JSME). However it was also clear that the secondary cut could not be omitted if the out-of-roundness was 0. Less