Reflections on the role of science in the evolution of dimensioning and tolerancing standards

Abstract

Dimensioning and tolerancing standards originated about 75 years ago in the form of various national and company standards that governed engineering draughting and documentation practices. They served the purpose of communicating to manufacturers what geometric variations designers could tolerate in a product without compromising the product’s intended function. These standards have evolved over time and are by now well entrenched in the engineering profession throughout the world. For several initial decades, this evolution was driven primarily by codification of best engineering practices without the benefit of any systematic scientific treatment. This trend encountered a major hurdle in early 1980s when the emergence of computer-aided design and manufacturing systems forced a drastic reexamination of these standards with a greater emphasis on mathematical formalism. Since then, scientific principles to explain past practices and to guide future evolution have emerged, and the role of science has now become more prominent in the development of these standards. This article describes some of the key scientific research results that have already had an impact, and the future scientific trends that are likely to have an influence, on these evolving standards.