Wyniki wyszukiwania - Biblioteka Nauki

1

Analysis of power demand signal in laboratory rotary mixer

100%

Smyksy K. , Wrona R. , Ziółkowski E.

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tom Vol. 10, iss. 2

151--154

EN

The paper summarises the power measurement data for the main assemblies in a prototype turbine mixers for laboratory applications. Of particular interest are power demand signals in the paddle stirrer and the rotor. Tests were performed for the variable moisture content of the moulding sand containing bentonite. The process is described as dynamic and considered from the standpoint of automatics. Potential applications of the power demand signal are investigated in the context of the study of dynamics of the mixing processes, in terms of control of the water feeding to the moulding sand and for the purpose of evaluating the energy consumption.

2

Analysis and assessment of foundry moulding sand preparing process using the dynamic power measurement method

100%

Ziółkowski E. , Wrona R. , Smyksy K.

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tom Vol. 55, iss. 3

953-961

EN

Preparation of moulding sand is a key process, determining the final quality of casting products. Special requirements are imposed at stabilising and optimising the parameters of the moulding sand so that it should maintain its properties required for moulding. These requirements can be satisfied as long as specialised mixing systems are used to prepare and control the sand mixing processes. The key elements of the system include sand mixers supported by dedicated measuring equipment operating in accordance with the approved control methods. Methods employed to determine the key properties of sand mix include the methods applied in on-line mixing control systems. The author’s research to date has led to the development of a method whereby the sand quality indicator is defined by a dynamic power demand signal from the mixer system. This study provides the selected measurement data, showing power consumption by the driving units in a prototype turbine mixer, used in laboratory conditions. The experimental programme utilises a state-of-the-art microprocessor system for measuring the parameters having relevance to power consumption by the mixer drive. Measurement signals of power demand by a paddle stirrer and a rotor are analysed. Testing was done for variable moisture content in moulding sands containing different kind of bentonite and for variable mixer pan loads. The methodology is supported by measurements of sand properties by conventional methods. The complete set of data and interrelations holding between them is utilised to describe the investigated processes in terms of dynamic systems, in accordance with the rules of automation. Attention is given to practical applications of the power measurement method in the analysis of mixing dynamics, in control of water-feeding system and in evaluation of energy demand for the process. The proposed methodology enables the comprehensive evaluation and selection of constructional parameters of devices of sand preparation systems.

PL

Istotnym procesem w technologii wykonania odlewów, decydującym o ich jakości, jest sporządzanie masy formierskiej. Szczególne wymagania dotycza stabilizacji i optymalizacji parametrów masy, określających jej właściwości i przydatność do wykonania form odlewniczych. Spełnienie tych wymagań zależy od zastosowanych systemów sporządzania i sterowania procesem mieszania składników masy oraz konstrukcji zastosowanych mieszarek. Podstawowym układem w systemie są mieszarki mas oraz współpracujące oprzyrządowanie pomiarowe, działające według określonych metod badawczych. Spośród metod służących do określania istotnych właściwości mas formierskich, wyróżnia się metody stosowane w układach sterowania on-line zasadniczym procesem mieszania mas. Na podstawie autorskich badań zdefiniowano metodę, w której miernikiem oceny jakości masy jest dynamiczny sygnał poboru mocy przez układy mieszające masę. W artykule przedstawiono wybrane wyniki pomiaru poboru mocy przez zespoły napędu prototypowej, laboratoryjnej mieszarki wirnikowej. W badaniach wykorzystano nowoczesny mikroprocesorowy system do pomiarów zbiorów parametrów charakteryzujacych pobór mocy przez napęd mieszarki. Przeprowadzono analizę uzyskanych sygnałów pomiaru mocy napędu mieszadła łopatkowego oraz wirnika. Badania wykonano przy zmianie stopnia nawilżenia mieszanych mas formierskich z bentonitem (różne gatunki) oraz przy zmiennym napełnieniu misy mieszarki. Dopełnieniem metodyki badawczej były pomiary właściwosci masy metodami klasycznymi. Pełny zbiór danych i ich wzajemnych zależności posłużył do opisu badanych procesów w ujęciu systemów dynamicznych zgodnie z regułami automatyki. Zwrócono uwagę na praktyczne mozliwości wykorzystania sygnału poboru mocy: w analizie dynamiki procesu mieszania, w sterowaniu procesem dozowania wody do masy formierskiej oraz w ocenie energochłonności procesu. Zaproponowana metodyka umożliwia takze kompleksowa ocene i dobór parametrów konstrukcyjnych urządzeń systemów sporzadzania masy.

3

Wybrane zastosowania optymalizacji rozmytej w sterowaniu procesami odlewniczymi

100%

Ziółkowski E.

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tom R. 5, nr 17

393--398

PL

W artykule przedstawiono ogólny model matematyczny optymalizacji rozmytej oraz klasyfikację metod programowania matematycznego, które można wykorzystać w rozwiązywaniu zadań optymalizacji rozmytej. Przedstawiono także wybrane modele rozmytości parametrów dowolnego procesu technologicznego. Artykuł uzupełniono przykładami odlewniczych zastosowań optymalizacji rozmytej.

EN

The article presents a mathematical model of fuzzy optimization and a classification of the mathematical programming methods which can be used to solve the fuzzy optimization problems. The author has described selected fuzzy models of the technological processes parameters. The examples of the fuzzy optimization in foundry calculations have been included.

4

The sort of carburization and the quality of obtained cast iron

84%

Janerka K. , Bartocha D.

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tom Vol. 8, iss. 4

55-60

EN

In the production of cast iron, the pig iron's amount in charge material is more and more often limited, and replaced by steel scrap. That extorts the necessity of know-how the carburization and one is looking for carburizers, which ensure obtaining big carbon increment as quickly as possible with the high repeatability and the ones which ensure getting the adequate quality of cast iron. The object of presented research was definition of the influence of charge materials' sort on the structure, course of solidification, and the effectiveness of process. The cast iron melts, which are presented below, are made only on the basis of steel scrap with portion of graphitoidal, coke and anthracite carburizers, which were added to the charge in solid. In the article one compared the carburizers in respect of their structure, chemical constitution and the effectiveness obtained during the carburization of liquid metal. The melting of cast iron, based on the special pig iron, was carried out as well. The course of melts, chemical constitution of obtained cast iron and its structure were presented. The comparison between quality distribution and the volume fraction of graphite in classes of size for the individual melts were achieved and the TDA curves were inserted.

5

Contribution to the Assessment of the Data Acquisition Effectiveness in the Aspect of Gas Porosity Defects Prediction in Ductile Cast Iron Castings

84%

Ignaszak Z. , Sika R. , Rogalewicz M.

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tom Vol. 18, iss. 1

35--40

EN

The article presents an example of analysis of the influence of selected parameters deriving from data acquisition in foundries on the occurrence of Gas porosity defects (detected by Visual testing) in castings of ductile cast iron. The possibilities as well as related effectiveness of prediction of this kind of defects were assessed. The need to rationally limit the number of possible parameters affecting this kind of porosity was indicated. Authors also benefited from expert group's expertise in evaluating possible causes associated with the creation of the aforementioned defect. A ranking of these parameters was created and their impact on the occurrence of the defect was determined. The classic statistical tools were used. The possibility of unexpected links between parameters in case of uncritical use of these typical statistical tools was indicated. It was emphasized also that the acquisition realized in production conditions must be subject to a specific procedure ordering chronology and frequency of data measurements as well improving the casting quality control. Failure to meet these conditions will significantly affect the difficulties in implementing and correcting analysis results, from which INput/OUTput data is expected to be the basis for modelling for quality control.

6

Application of generalized finite difference method in numerical modelling of moving boundary problems

67%

Mochnacki B. , Lara S.

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tom Vol. 2, nr 1

129--143

EN

The application of generalized finite difference method for numerical modelling of thermal processes proceeding in the solidifying casting domain is presented. The solidification of pure metals and eutectic alloys is considered. In such case the solidification process takes place at the constant temperature (the Stefan problem). From the numerical point of view the solution of this task is very complex; in particular, in the case of 2D or 3D domains; and in literature one can find the procedures enabling to avoid the difficulties with the direct modelling of the problem discussed. The part of them consist in the substitution of the solidification point T* by the certain interval [T* - ΔT, T* + ΔT]. In this way the subdomain of artificial mushy zone is introduced and the fixed domain approach [1] can be used. On the stage of numerical algorithm construction and numerical simulation the generalized finite difference method is used. In the final part of the paper the examples of computations are shown.

7

A characteristic of design solutions for flask moulding lines

67%

Fedoryszyn A.

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2007

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tom Vol. 7, iss. 1

5-8

EN

Moulding machines used in manufacture of moulds from synthetic bentonite sands constitute basic equipment of mechanised stands, work centres, and production lines. In the present article, a short characteristic of this equipment was given, basing on the generally accepted criteria of classification taking into consideration novel design solutions and principles of cooperation between individual sub-assemblies. Moulding equipment offered by domestic producers was described with emphasis put on models representative of the distinguished classes and groups.