3D-characterization of micro balls with nanometer precision

纳米和微坐标测量机（CMMs）已经发展成为小型复杂零件的精确和可追溯测量。这些机器可实现的不确定度主要受探测球体形状的限制，它需要在几何上很好地表征。然而，目前还没有确定的技术来表征这种球体。因此，本项目的目的是研究、开发和比较半径小于300微米、不确定度为10纳米的微球的表征方法。为了减少复杂性，最初的研究仅限于测量一个大圆。这些研究导致了一种新策略的发展，该策略能够以高水平和垂直分辨率表征这些球体。它是基于一组原子力显微镜（AFM）表面扫描，并通过拼接算法进行评估。目前，这个程序可以表征一个大圆。在直径为120微米和300微米的球体上进行了初步实验，测量了平均半径，可重复性高达4纳米。在项目的下一阶段，该程序将扩展到一个完整球体的表征。此外，测量程序应针对重大影响进行优化，以减少可实现的不确定度。调查结束时为核实目的进行了比较测量。此外，将继续与使用不同物理相互作用的选定测量策略进行比较。

Nano and micro coordinate measuring machines (CMMs) have been developed for the precise and traceable measurement of small complex parts. The achievable uncertainty of these machines is mainly limited by the shape of the probing sphere, which needs to be geometrically well characterized. However, there is currently no established technique for the characterization of such spheres. It is, therefore, the objective of this project to investigate, develop and compare procedures for the characterization of micro spheres with radii below 300 µm and with an uncertainty of 10 nm.In order to reduce the complexity, the investigations were initially limited to the measurement of one great circle. These investigations led to the development of a new strategy, which enables the characterization of such spheres with a high lateral and vertical resolution. It is based on a set of atomic force microscope (AFM) surface scans, which are evaluated by a stitching algorithm.Currently, this procedure enables the characterization of one great circle. Initial experiments have been conducted on spheres with 120 µm and 300 µm diameters and the mean radius was measured with a repeatability of up to 4 nm. In the next phase of the project, this procedure is to be extended to the characterization of a full sphere. Additionally, the measurement procedure is to be optimized with regard to significant influences, in order to reduce the achievable uncertainty. The investigations conclude with comparative measurements for verification purposes. Additionally, comparisons with selected measurement strategies using different physical interactions will be continued.