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Peculiarities of methods of definition of optimal quality level of machine-building products
Section 5. Machinery construction
Aslanov Zabit Yunus, Azerbaijan State Economic University, Candidate of Technical Sciences, Associate Professor E-mail: aslanov.zabit@mail.ru Seydaliyev Ilham Mogomed, Azerbaijan State Economic University, Candidate of Technical Sciences, Associate Professor E-mail: ilham.seydaliyev@mail.ru
Peculiarities of methods of definition of optimal quality level of machine-building products
Abstract: The peculiarities of methods of definition of optimal quality level of machine building products are considered. The equations of regression for evaluation of competitiveness of the items of oil engineering with consideration of technical, exploitation and economic levels of quality were obtained using expert methods. The formulas for evaluation of optimal quality levels were determined and the formula for determination of integrated rating of the quality system was obtained.
Keywords: optimum quality level, competitiveness, machine-building products, expert methods, regression equation, integrated rating.
A selected method of evaluation plays crucial role when determining the optimal quality level of machinebuilding products. During the Soviet period, national economy approach was applied to evaluate the quality. Theoretical basis of measurement was created and various evaluation methods were developed, which was instrumental in creating applicable methods of quality evaluation of industrial products. Practical basis of all methods is formed by differential, complex and mixed methods [1, 183].
Differential method of evaluation of quality level of the product is performed on the basis ofdirect comparison of single indicators of product quality with the respective basic indicators. However, differential method does not allow comparing separate indicators against each other, comparing and assessing items of different types. Complex method of evaluation of quality level of the products involves the usage of a determining indicator of quality, i. e. characterizes the level ofquality with one indicator [2, 78]. Depending on the goal of evaluation, primary, integral or medium weighed indicator of product quality can be selected as a determining indicator.
Thus, differential and complex methods of evaluation of quality level of products do not always allow quite suc-
cessful solution of set tasks. It especially refers to evaluation of complicated machine-building products that have a big list of quality indicators. In these cases, single and complex quality indicators are applied simultaneously to evaluate the quality level of products.
In such case, a formula for evaluation of the quality level of machine-building products can look as follows:
*=z
j=1
A -Z(a ■ К)
1=1
BA г
j=i
where Т is a number for quality indicator groups; Г. g — quality level of j indicator group; H is a number for quality indicators in j group; A. is a parameter ofweightage of quality indicators of j group.
One can reduce the effect of linear dependence of k on P. by finding a more real dependence k=f (P,, P. 6a) and using interpolation polynomial
Pi kop = ao + aiPi + a2Pi +... + anP”,
where P . is a corrected assessment of the value of a
i kop
quality indicator; a is respective coefficients determined with the Lagrange interpolation formula; п is a degree at quality indicator.
It is especially important to correct the evaluations of numerical values of quality indicators, which have
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Section 5. Machinery construction
physical boundaries and limits of regulatory technical documents. The principle character of dependence of corrected evaluations for such indicators is shown in
Fig. 1
To receive an objective result of evaluation, it is required to define the dependence of P (t) of not only evaluated products, but also products of competitors. One can use the methods of forecast taking into consideration evolutional and possible radical tendencies of change of
Р [2,151]. Herewith, three methodical variants of usage of Р (t) are possible: comparison with Р (t) of competitors; comparison with average world Р (t); comparison with average Р (t) in the country.
The idea of methodical approach to consideration of the effect of time on Р or P£ can be presented graphically (Fig. 2). At the same time, the building of influence curves of P(t) is performed for all values t including in the interval of past (t2-tl) and future time (ts-t1).
Fig. 1. Character of dependences of quality indicators of machine-building products In the conditions of the market, it is required to the performance of evaluation of machine-building define not only quality, but also level of competitiveness products’ competitiveness. It prevents from considering
of machine-building products [4, 38-41]. However, the factors that significantly influence the results of a unified methodological base is almost absent in evaluation.
Fig. 2. Graphic method of evaluation of quality of machine-building products
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Investigation into a L-type gating system
It is proposed that regardless the used method, the basis of evaluation of quality and competitiveness of machine-building products should be the comparison of indicators of evaluated and rival products. To evaluate the quality systems (QS), it is proposed to use the theory of evaluation in accordance with which one should distinguish three elements: object, subject and a comparison base interacting with one another in the process of logical realization of evaluation algorithm [3, 24-30].
The analysis of methods of evaluation of QS, quality of products and competitiveness shows that all of them allow evaluating the object in absolute and comparative form. During the performance of QS evaluation, it is proposed to use rating methods. Herewith, the formula for evaluation of integrated rating of QS will look as follows:
P».=IB ■ P)=1 B, IB ■ P.)
j=i j=1L .=i
where Г is a number for parameter groups of QS rating;
B is the coefficient of weightage of j group (E B=i);
j=i
Pg. . is an integrated rating of j group; H is a number of parameters of rating in j group; P. is a numerical value of rating of i parameter of j group; B.. is a coefficient of weightage of i parameter of j group.
During the performance of rating evaluations in the comparative form, the integrated evaluation of QS can be done according to the formula:
В», ■ Kg)=E
b, m ■ k,. )
j=1 j=1 l >=1 _
where К is a relative integrated rating of j group of QS parameters; к is a relative rating of i parameter of j group.
On the basis of usage of expert methods, we obtained the equation ofregression to evaluate the competitiveness of products of oil machine-building:
К =0,333Г+0,067Г +0,267Г +0,200Г +0,133Г, where Г1 is a project technical level of quality; Г2 is a level of production quality; Г3 is an exploitation level of quality; Г4 is an economic level of quality; Г5 is a social-economic level of quality. Coefficients at Q,..., Г5 were defined as standardized depending on the obtained expert data of rank of each group.
Thus, the regression equation of competitiveness of oil machine-building products was obtained on the basis of analysis and by using expert methods. Typical dependences ofindicators ofquality level ofthe evaluated and rival products were revealed with the use of forecast methods. The graphic method of evaluation of quality of machine-building products was proposed on the basis of objective comparison of indicators of the evaluated and rival products.
References:
1. Mishin V.M. Quality management: Text book for universitites. - M.: YUNITI - DANA, 2005,463 p.
2. Mamedov N.M.; Aslanov Z.YU.; Seidaliev I.M. and others. Qualimetria and quality management: Textbook for universitites. - Baku: Elm, 2007, 325 p.
3. Aslanov Z.YU. Some aspects of evaluation of quality level and systems of quality of machine-building products // «Economy and society» The Institute of management and socio-economic development, 2013, №1/6 - P. 24-30.
4. Aslanov Z.YU. Peculiaritites of evaluation of level of qualty and competitiveness of machine-building products in Azerbaijan // Science and business: ways of development. Scientific and practical journal, 2013, №4 (22) - P. 38-41.
Vasenin Valery Ivanovich, Perm National Research Polytechnic University, associate professor, candidate of technical sciences, department "Materials, technologies and design of machinary"
E-mail: vaseninvaleriy@mail.ru Bogomjagkov Alexey Vasilievich, postgraduate student Sharov Konstantin Vladimirovich, postgraduate student
Investigation into a L-type gating system
Abstract: The results of theoretical and experimental study of gating system are given. A method of calculating the velocity and flow rate in each feeder and the entire system based on the number of concurrent feeders and diameters sprue and collector. A good agreement between the calculated and experimental data is presented.
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