Tula State University (Tula, Russia):

Protasyev V. B., Dr. Eng., Prof., e-mail: avprotasev@mail.ru
Plakhotnikova E. V., Dr. Eng., Associate Prof., e-mail: e_plahotnikova@mail.ru
Litvinova I. V., Cand. Econ, Associate Prof., e-mail: wivaw@rambler.ru

The article presents the author’s method of solving the actual problem of metallurgy and mechanical engineering – ensuring the quality of products. Quality assessment in production systems is proposed to be carried out by calculating the «signal/noise» criterion. This criterion determines the possibility of manufacture of products with the required quality and allows to assess the accuracy of production processes. It is shown that any characteristic of products cannot be constant, as, on the one hand, its nominal value changes in the favorable direction at improvement of production, and, on the other hand, there are always variations of this characteristic caused by destabilizing factors and changes of production conditions. The «signal/noise» criterion with sufficient completeness and objectivity characterizes the state of the production system, and development of the method of its measurement is currently a priority for the metallurgical complex and machine-building enterprises. The basis of the proposed technique is a mathematical model of the error balance, which allows to minimize the variation of the output characteristics and to establish the weight value of the parameters associated with the variation by finding a full differential. To assess the maximum achieved value of the output characteristic, it is proposed to use the equation of quality, taking into account the number and proportion of defects affecting the variation of the unit output characteristics of the product. An example of implementation of this technique for comparative analysis of companies engaged in manufacture of products from bar billets is given. The results of the analysis lead to the conclusion that at present time the measures are needed to correct the situation not only in terms of new technology, but also in the use of statistical control and, most importantly, in the training of personnel not only in managing bodies, but also in the workplace. It is noted that it is necessary to timely determine the index of equipment capabilities, its technical maintenance and service. A graphical interpretation of the «signal/noise» criterion is proposed, which made it possible to associate its value with the level of defects — the main parameter of the company’s activity, without losing sight of the place of this manufacturer in a number of competitors. It is possible to determine the weak links in production systems based on the provided methods, with reflection of this determination in documents, taking into account modern requirements to quality of products.
The results of this research are published with the financial support of Tula State University within the framework of the scientific project No. 2017-45ПУБЛ.

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