The article presents a generalized approach to the construction and use of mathematical models aimed at addressing process tasks of making precision instruments. Through the in-depth analysis of the instrument's design, the authors show how to set design parameters, the influence of which has been underestimated in the manufacturing process and design engineering. They introduce the algorithm of quantitative assessment of the impact of changes caused by the technological enhancement of the parts' design, on the device's functional features. They show an example of determining the spectrum of design parameters, determining their weight characteristics, and their impact on the instrument's functional features. The use of a set of critical parameters serves to accurately determine the parameters of a technological process, that condition these parameters. It is shown that the developed recommendations to enhance the technological processes help to reduce time spent on the instrument's manufacture and to increase the stability of their settings. The research is focused on a systematic approach to the production of precision instruments.