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Improving the quality level in the automotive industry

Pacana Andrzej, Czerwińska Karolina

Production Engineering Archives

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2020

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Vol. 26, Iss. 4

162--166

EN

Currently, effective quality management of manufactured products is a factor determining the development of manufacturing companies. However, the identification of the source of non-compliance and the analysis of its causes are sometimes underestimated and are not followed by appropriate methodologies. The study aimed to streamline and improve the production process of aluminium pistons for passenger cars by solving the problem related to a significant number of non-compliant products. The analysis of types of nonconformities identified through penetration testing was performed. The use of histogram, brainstorming session and Pareto-Lorenz diagram was proposed, which allowed identifying the causes of the problem. The presented solution shows the practical effectiveness of a sequence of selected instruments to solve production problems. The proposed sequence of methods can be implied in other qualitative analyses in different companies.

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Complex criterion of dimensional stability discussed on the example of piston silumins

Czekaj E., Sobczak J., Saja K.

Journal of KONES

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2008

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Vol. 15, No. 2

41-50

EN

The article discusses the use of a quality polygon method in complex evaluation of the dimensional stability of a newly developed AK12 E piston silumin of the Lo-Ex (Low-Expansion) type with around-eutectic silicon content. According to PN-EN 1706:2001, the reference material was standard aluminium piston alloy designated as EN AC-48000 (EN AC-AlSi12CuNiMg). It is an analogue of the well-known and commonly used in production of pistons AK12 alloy according to PN-76/H-88027, withdrawn now from use. Basing on the analysis of Polish and foreign reference literature and on the authors' own knowledge and experience, five parameters of the reversible and irreversible (permanent) dimensional changes in AK12 E and AK12 S alloys (designations adopted for standard alloys) were chosen. The obtained quantitative evaluations, referred to individual parameters, enabled the values of complex (synthetic) parameters of the dimensional stability to be finally determined. From the numerical and geometrical analysis it follows that AK12 E alloy offers the dimensional stability definitely superior to that of AK12 S, but this is on the cost of the tensile strength Rm reduced at room temperature. The obtained experimental results and computations were checked on pistons during the stand engine tests.

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Optymalizacja składu chemicznego siluminów tłokowych typu eutektycznego pod względem stabilności wymiarowej i właściwości mechanicznych

Lech Z., Czekaj E.

Biuletyn Instytutu Odlewnictwa

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2001

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R. 4, nr specjal

3-11

PL

Na przykładzie siluminów tłokowych przedstawiono najistotniejsze aspekty związane z praktyczną realizacją idei syntezy złożonych (wieloskładnikowych) stopów odlewniczych, w stosunku do których stawianych jest szereg wymagań. Jest to tzw. wielokryterialna (wieloparametryczna) optymalizacja w przestrzeni n-wymiarowej. Pokazano, jak za pomocą wykorzystania zarówno ścisłych, a także nie do końca sformalizowanych procedur - dotyczących matematycznego modelowania i optymalizacji - dochodzić możemy do nowych, praktycznie ważnych inżynierskich rozwiązań w stosunkowo złożonych sytuacjach - z jakimi możemy mieć do czynienia w odlewnictwie. Wynik pracy stanowi opracowanie nowego aluminiowego stopu tłokowego - typu stopowy silumin eutektyczny - o podwyższonych parametrach stabilności wymiarowej, jak też optymalizacja składu chemicznego stopu AK12, w zakresach dopuszczalnych przez PN-76/H-88027 stężeń dodatków stopowych, ze względu na szeroko rozumianą stabilność wymiarową w warunkach eksploatacji oraz podstawowe właściwości mechaniczne.

EN

Taking piston silumins as an example, the most important aspects of practical execution of the synthesis of complex (multi-component) cast alloys, in respect of which numerous requirements are imposed, have been presented. This is the, so called, multi-criterial (multi-parameter) optimisation within n-dimensional space. It has been demonstrated how by application of both precise scientific methods as well as stil not fully formalised procedures of mathematical modelling and optimisation, one can reach new, important in engineering practice, solutions of relatively complex situtations which can occur in foundry engineering practice. The output of the study is development of a new aluminium piston alloy. This is a eutectic silumin of the improved parameters of dimensional stability. Another output of the study is optimisation of the chemical composition of an AK12 alloy within the range of alloying elements, concentration specified by Polish Standard PN-76/H-88027, to achieve dimensional stability under performance conditions and improved basic mechanical properties, both understood in a broad meaning of this word.