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1
Content available remote Quality management in development of hard coatings on cutting tools
EN
Purpose: In this paper, an attempt is made to establish the general model of quality management also to the field of development and introducing of hard coatings on cutting tools. Design/methodology/approach: The conventional PVD and CVD methods have its limitations and that innovative processes are essential within the framework of an environmentally oriented quality management system. Meeting the requirements of ISO 9000 and ISO 14000 standards, the proposed model ensures the fulfilment of the basic requirements leading to the required quality of preparation processes and the quality of end products (hard coatings). Findings: One of the main pre-requisites for successful industrial production is the use of quality coated cutting tools with defined mechanical and technological properties. Therefore, for the development and introduction of new coated cutting tool (new combination of cutting material and hard coatings), it is necessary to carry out a number of studies with the purpose to optimize the coatings composition and processing procedures, and also to test new tools in working conditions. Research limitations/implications: The requirements from industry: produce faster, better, safety and more ecologically, force us to develop new effective tools and innovative technologies. This provides a technological challenge to the scientists and engineers and increases the importance of knowing several scientific disciplines. Practical implications: The quality of a company's product directly affects its competitive position, profitability and credibility in the market. Quality management system must undergo a process of continuous improvement, which extends from the deployment of preventive quality assurance methods to the application of closed loop quality circuits. Originality/value: Design of the original and structured model of quality management system for successful development, producing and involving of new coated tools in the practice.
2
Content available remote Case of temperature field and failure analysis of die-casting die
EN
Purpose: For economical production of aluminium and aluminium alloys die-castings it is important that the dies have a long working life. The replacement of a die is expensive in both: money and production time. Design/methodology/approach: Dies for aluminium alloys die-casting fail because of a great number of a different and simultaneously operating factors. Some of them may be controlled to some extent by the die-casting experts. Findings: In the process of the die-casting the primary source of loading is cyclic variation of the temperature; the influence of other loads is relatively insignificant. Research limitations/implications: Beside, the die design, the material selction and the process thermal stress fatigue course, which is the consequence of the working conditions, the inhomogeneous and to low initial temperature of the die, contribute to the cracks formation. Practical implications: In the experimental part of our work the failures on the working surface of the fixed half of the testing die for die-casting of aluminium alloys were observed with the use of non-destructive testing methods: such as thermographic analysis, penetrants and metallographic examination of polymeric replicas. Originality/value: It is clearly seen from the presented thermographs, that the required temperatures and homogeneity of the temperature field of the discussed case are not possible to reach without the changing both: the heating method and the die design. Therefore in the first stage a solution of the problem should be in changing of the position of heating and/or cooling channels, i.e. their closer shifting to the working surface of the die.
3
Content available remote Temperature field and failure analysis of die-casting die
EN
Purpose: Dies for aluminium alloys die-casting fail because of a great number of a different and simultaneously operating factors. Some of them may be controlled to some extent by the die-casting experts. Design/methodology/approach: In the experimental part of our work the failures on the working surface of the fixed half of the testing die for die-casting of aluminium alloys were observed with the use of non-destructive testing methods: such as thermographic analysis, penetrants, and metallographic examination of polymeric replicas. Findings: In the process of the die-casting the primary source of loading is cyclic variation of the temperature; the influence of other loads is relatively insignificant. Research limitations/implications: For economical production of aluminium and aluminium alloys diecastings it is important that the dies have a long working life. The replacement of a die is expensive in both: money and production time. Practical implications: Beside, the die design, the material selection and the process thermal stress fatigue course, which is the consequence of the working conditions, the inhomogeneous and to low initial temperature of the die, contribute to the cracks formation. Originality/value: It is clearly seen from the presented thermographs, that the required temperatures and homogeneity of the temperature field of the discussed case are not possible to reach without the changing both: the heating method and the die design. Therefore in the first stage a solution of the problem should be in changing of the position of heating and/or cooling channels, i.e. their closer shifting to the working surface of the die.
EN
Purpose: In European Union countries the legalisation forbids the production, processing and use of cadmium. By January 2008 at the latest, all articles and products containing cadmium will either have to be withdrawn from sale or an appropriate substitute for this heavy metal will have to be found. Design/methodology/approach: The present technology of production of fuses in Slovenian firm ETI Elektroelement, and the action thereof are adapted to the existing ecologically harmful alloy of tin and cadmium SnCd20, which ought to be replaced by one or more ecologically safe alloys with technological and application properties as similar as possible to the existing ones. Findings: In the frame of the presented investigation work we have found that practically all stated problems can be successfully solved by the low melting alloy of tin, bismuth and antimony named ETI-Sn-Bi-Sb. Research limitations/implications: Alloy ETI-Sn-Bi-Sb is ecologically safe, and by its technical and physical properties (melting point, conductivity, wettability) corresponds to the requirements of the use for fusible elements of low voltage fuses. Practical implications: Practical implications of our common work is in the introduction of new ecologically safe material for fusible elements, without cadmium in the existing technology of low voltage fuses. Originality/value: High value and originality and of our engineering work is confirmed by European Union patent and two Slovenian national patents for the ecologically safe low melting alloy named ETI-Sn-Bi-Sb, which received authors of this paper and Slovenian firm ETI Elektroelement.
EN
Purpose: The objective of the researches presented in the paper is to investigate, in laboratory conditions, the application possibilities of the proposed system for tool wear monitoring in hard turning, using modern tools and artificial intelligence (AI) methods. Design/methodology/approach: On the basic theoretical principles and the use of computing methods of simulation and neural network training, as well as the conducted experiments, have been directed to investigate the adequacy of the setting. Findings: The paper presents tool wear monitoring for hard turning for certain types of neural network configurations where there are preconditions for up building with dynamic neural networks. Research limitations/implications: Future researches should include the integration of the proposed system into CNC machine, instead of the current separate system, which would provide synchronization between the system and the machine, i.e. the appropriate reaction by the machine after determining excessive tool wear. Practical implications: Practical application of the conducted research is possible with certain restrictions and supplement of adequate number of experimental researches which would be directed towards certain combinations of machining materials and tools for which neural networks are trained. Originality/value: The contribution of the conducted research is observed in one possible view of the tool monitoring system model and it’s designing on modular principle, and principle building neural network.
PL
Przedstawiono wyniki badań strukturalnych oraz własności użytkowe narzędzi skrawających wykonanych z węglików spiekanych z naniesionymi w procesie PVD (katodowe odparowanie łukowe) cienkimi przeciwzużyciowymi powłokami typu TiN + gradient lub multi (Ti,Al,Si)N+TiN.
EN
Presented are the results obtained in structural tests and practical properties of the sintered carbide tools provided with fine film hard wearing TiN + gradient or multi (Ti,Al,Si)N+TiN coatings applied in PVD methods arc vaporation process.
PL
Przedstawiono wyniki badań struktury i własności tlenkowej ceramiki narzędziowej typu Al2O3+TiC niepokrytej i pokrytej jedno-, wielowarstwowymi, wieloskładnikowymi oraz gradientowymi powłokami przeciwzużyciowymi PVD i CVD. Zaprezentowano wyniki badań morfologii powierchni, struktury, składu chemicznego, składu fazowego, a także wyniki badań własności mechanicznych i użytkowych materiału pokrytego oraz materiały bez powłok.
EN
Presented are results of the tests carried out on structure and properties of the Al2O3+TiC oxide ceramic tools either non coated or coated with multi-layer, multi-component and gradient type hard wearing coatings types TiN, TiAlN, TiN+TiAlSiN+TiN, TiN+ multi TiAlSiN+TiN and TiN+TiAlSiN+AlSiTiN applied in CAE PVD cathodic arc vaporation process and also those coated with two layer TiCN+TiN and TiN+Al2O3 coatings applied in CVD process of chemical deposition of gas phase.
8
Content available remote Tin in free-cutting aluminium alloys.
EN
Free cutting aluminium alloys contain lead and bismuth which improve their machinability. Owing to the toxicity of lead there remains a tendency to replace it with other elements. The possibility of substituting lead in the AlCu5PbBi alloy (AA2011) with tin is described. Microstructural properties and machinability of tin containing alloys compared to the conventional alloy with lead are presented in this work.
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