# Statistical Tolerance Analysis--A Survey on Awareness, Use and Need in German Industry
###### Abstract  
The importance of geometric deviations of components for the aesthetic and functional quality of products has been undisputed for decades. So, it is not surprising that not only have numerous researchers devoted themselves to this field, but also commercial software tools for the analysis and optimization of tolerance specifications (currently already fully integrated in 3D-CAD systems) have been available for around 30 years. However, it is even more surprising that the well-founded specification of tolerances and their analysis using a so-called statistical tolerance analysis are only established in a few companies. There is thus a contradiction between the proclaimed relevance of tolerances and their actual consideration in everyday business life. Thus, the question of the significance of geometric deviations and tolerances as well as the use of statistical tolerance analysis arises. Therefore, a survey among 102 German companies was carried out. The results are presented and discussed in this paper.  
survey; tolerance analysis; German industry; tolerance engineering; GD&T  
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and holistic specification and analysis of tolerances are not a natural part of the company's philosophy. Rather, these are often understood as an arduous duty incumbent on the design engineer. Accordingly, the authors face the urgent question of how tolerance analysis in German companies is performed, focusing on three aspects:  
1. The relevance of geometric deviations and tolerances for companies and their products and processes;
2. The already established use of statistical tolerance analysis in companies;
3. The need for further development and research on statistical tolerance simulations.  
In order to answer these questions thoroughly, the authors conducted a representative survey of 102 German industrial companies. The survey was carried out in the late summer of 2012. The results of this survey are presented and discussed in this paper due to the self-imposed publication embargo of eight years on selected questions.  
The paper is structured as follows: Sections 2 and 3 will provide the foundation of the paper. Section 2 gives a general overview of the development of tolerance engineering from its early beginnings to date. The state of the art (Section 3) details existing surveys on certain aspects of tolerancing carried out in the last 30 years. The relevant information on the established survey, the procedure and the questionnaire are given in Section 4. Sections 5-7 then discuss the survey results-focusing on the three aspects of tolerancing-awareness of deviations and tolerances (Section 5), the current use and extent of statistical tolerance analysis (Section 6) and the need and potential of statistical tolerance simulations (Section 7). The paper concludes with a critical appraisal of the insights gained as well as the identification of an omnipresent dilemma that the tolerance community must strive to overcome (Section 8).  
In recent decades, various terms have become established for the discipline that encompasses all the methods and tools used in dealing with deviations and tolerances. The most common terms are \"geometric dimensioning and tolerancing (GD&T)\", \"dimensional management\", \"tolerance management\", \"geometry assurance\", \"tolerancing\" and \"tolerance engineering\". In this paper, we use the term \"tolerance engineering\", which is synonymous with all the others.