Research and Education in Mechanical Tolerancing and Dimensional Metrology

最近的国家研究发现，机械公差和计量标准和实践存在严重缺陷，大学、培训机构和工业界在这些方面的教学也存在严重缺陷。所有这些缺陷背后的中心问题是缺乏适当的机械公差的科学基础。从本质上讲，公差和计量学是从车间实践发展而来的，并作为特殊情况下的技术集合而被教授和应用。本项目致力于改善这一状况的四个相关研究方向：(1)为ANSI Y14.5公差标准的主要原则制定半正式的数学编码，最初是以专着和/或课程笔记的形式供工程专业学生使用；(2)用数学和计算技术分析形位公差累积的编码扩展(即一维公差叠加的推广)。这些技术在面向装配的设计中很重要；(3)将编码与计量实践联系起来，对尺寸和表面建模中的公开问题进行选择性研究；以及(4)功能公差方面的探索性研究(即控制空间变异性对设计人工制品性能的影响)。

Recent national studies have identified serious deficiencies in mechanical tolerancing and metrology standards and practices, and in the teaching of these in universities, training institutes, and industry. The central problem underlying all of these deficiencies is the lack of proper scientific foundations for mechanical tolerancing. In essence, tolerancing and metrology evolved from shop-floor practice, and are taught and applied as collections of special-case techniques. This project pursues four related lines of research to improve this situation: (1) development of a semi-formal mathematical codification for the main principles of the ANSI Y14.5 tolerancing standard, initially in the form of a monograph and/or course notes for engineering students; (2) extension of the codification with mathematical and computational techniques for analyzing the accumulation of geometric tolerances (i.e., generalization of one- dimension tolerance stacking). Such techniques are important in design for assembly; (3) linking of the codification to metrology practices, with selective research on open issues in dimensional and surface modeling; and (4) exploratory research in functional tolerancing (i.e., control of the effects of spatial variability on the performance of designed artifacts).