К.V. Epifantsev

St. Petersburg State University of Aerospace Instrumentation, St. Petersburg, Russia;
epifancew@gmail.com

Al’manac of Modern Metrology № 1 (37) 2024, pages 91–101

Аbstract. The article discusses the results of comparing the measurement of a detail of the same configuration and mass on Mahr and Roundtest roundness instruments. The process of measuring shape defects is implemented in devices with ultra-precise sensors capable of detecting shape defects only during the rotation of the detail, which causes a number of difficulties in executing this algorithm because vector measurands rather than scalar ones are analysed. The self-compensation mechanism of the devices is also ar­ranged according to the principle of alignment, which is most important when aligning the table on which the detail is fixed. The main purpose of the work is to create an import-substituting device based on the analysis of the above-mentioned measurements. Modern types of roundness instruments play an extremely important role in asses­sing the quality of manufactured details that are rotary bodies (cylinders, shafts, gear couplings, bea­rings). When designing machines with high efficiency, the main driving force of which are rotary bodies, it is necessary to control the quality of these details with devices that would be able to detect the smallest flaws in the shape of long details, leading to the des­truc­tion of bearing assemblies and assemblies at high rota­tional speeds.
The self-calibration process in the devices takes place by introducing compen­sation coefficients due to additive or multiplicative corrections when detecting deviations of measurements from the standard (reference glass measure of roundness and calibra­tion of the force on the probe with a polyethylene film standard). At the same time, an amend­ment can be introduced every time before the start of the workflow in order to reduce the discrepancy in accuracy. In roundness instruments, an adjustment is introduced for each detail, which takes considerable time and reduces the number of possible controlled details per shift. On round meters, even of the modern digital type, the correction process is un­reasonably long (up to 7 minutes per 1 detail), unlike other devices, where the cor­rection is introduced once at the beginning of the working day and applies to the entire batch of details during the change of the operator of the QA gate. At the same time, the method of introducing corrections in the instrument-mathematical model is the know-how of many manufacturers, and it is this method that is a distinctive feature of the production of high-precision devices of this type. This issue is also discussed in detail in the article.

Keywords: quality management at the enterprise, roundness instruments, measu­rement of shape defects, corrections of the processes of centering alignment of a detail.

Full texts of articles are available only in Russian in printed issues of the magazine.