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J. Jersák and S. Simon

Abstract

The Technical University of Liberec and Brandenburg University of Technology Cottbus-Senftenberg investigated the influence of cooling lubricants on the surface roughness and energy efficiency of cutting machine tools. After summarizing the achieved experimental results, the authors conclude that cooling lubricants extensively influence the cutting temperature, cutting forces and energy consumption. Also, it is recognizable that cooling lubricants affect the cutting tools lifetime and the workpiece surface quality as well. Furthermore, costs of these cooling lubricants and the related environmental burden need to be considered. A current trend is to reduce the amount of lubricants that are used, e.g., when the Minimum Quantity Lubrication (MQL) technique is applied. The lubricant or process liquid is thereby transported by the compressed air in the form of an aerosol to the contact area between the tool and workpiece. The cutting process was monitored during testing by the three following techniques: lubricant-free cutting, cutting with the use of a lubricant with the MQL technique, and only utilizing finish-turning and finish-face milling. The research allowed the authors to monitor the cutting power and mark the achieved surface quality in relation to the electrical power consumption of the cutting machine. In conclusions, the coherence between energy efficiency of the cutting machine and the workpiece surface quality regarding the used cooling lubricant is described.

Open access

B. Srivathsa and D.K. Das

.G. and Hutchinson J.W. (2000): The ratcheting of compressed thermally grown oxide on ductile substrate. – Acta Mat., vol.48, pp.2593-2601. Helminiak M.A. (1998): Factors effecting the lifetime of thermal barrier coatings. – Mech. of Mat., vol.26, pp.91-110. Hsueh C.H. and Fuller E.R. (2000): Analytical modeling of oxide thickness effects on residual stresses in thermal barrier coatings. – Scripta Materialia, vol.42, pp.781–787. Hutchinson J.W. (2001): Delamination of compressed multilayers on curved Substrates. – J. Mech. Phys. Solids, vol.49

Open access

Koudelka Libor

Abstract

In the first quarter of the last century hydraulic power plants were equipped with high-speed Francis turbines even in the situation when a contemporary project manager would suggest Kaplan turbine. The reason is simple. Mr. Kaplan patented his turbine only in 1912 [1], https://en.wikipedia.org/wiki/Viktor_Kaplan . Those high-speed Francis turbines have just reached their lifetime. Mainly runners need repair. Our customers’ respond is that even renowned firms refuse to deliver runners with better parameters. Offer is to replace whole turbine with Kaplan or to make a copy of the existing runner. This paper presents experience and results of such a high-speed runner design. The runner substituted the one of Prokopa & sons from 1939 in powerhouse and mill at Křemže stream. Virtual prototyping technique has been used.

Open access

Peter Šlesar and Roland Jančo

- Strojnícky časopis 2017 (67), No. 2, pp. 77 - 84. [7] F. Trebuňa, F. Šimčák, Elasticity, strength and plasticity in mechanical engineering. Edition of scientific and special publications - Faculty of Mech. Eng. TU in Kosice, Emilena, Košice 2005. ISBN 80-8073-276-0. [8] F. Trebuňa, F. Šimčák, J. Bocko, and M. Pástor, Analysis of the Causes of Casting Pedestal Failures and the Measures for Increasing Their Residual Lifetime, Engineering Failure Analysis 2013 (29), 27 - 37.

Open access

Miroslav Pástor, Peter Frankovský, Martin Hagara and Pavol Lengvarský

REFERENCES [1] F. Trebuňa, F. Šimčák. Stability of the Mechanical System Elements (in Slovak), Košice, 2004 [2] F. Trebuňa, F. Šimčák, J. Bocko, M. Pástor. Analysis of the Causes of Casting Pedestal Failures and the Measures for Increasing Their Residual Lifetime. Engineering Failure Analysis 2013 (29), 27 – 37. [3] F. Trebuňa, et al. Final Report on the Examination of the Anchor Threaded Joints of the ZPO 2 Casting Pedestal (in Slovak). Košice 2014 . [4] Y. Nashwan. Experimental Strain Investigation of Bolt Torque Effect in

Open access

Miroslav Pástor, Peter Čarák and Imrich Gömöry

Causes of Casting Pedestal Failures and the Measures for Increasing Their Residual Lifetime”, Engineering Failure Analysis 29, pp. 27 – 37, 2013 . [12] Trebuňa, F., Šimčák, F., Pástor, M., Šarga, P. “Residual stress analysis in containers for transport of radioactive materials”, Applied Mechanics and Materials 732, pp. 28 – 31, 2015 . DOI: 10.4028/ www.scientific.net/AMM.732.28 [13] Hagara, M., Trebuňa, F., Pástor, M., Huňady, R., Lengvarský, P. “Analysis of the aspects of residual stresses quantification performed by 3D DIC combined with standardized

Open access

Valentin Gornoava, Gheorghe Ion Gheorghe and Liliana-Laura Badita

Abstract

The main objectives of the present project are to study and to improve mechanical properties of different systems from mechatronic and biomedical domains, in order to increase their functionality and life span. This is why nanostructured thin films (e.g. Al, Cr, Ti, Ti/Al multilayers) were deposited on different steel substrates, used in mechatronic and biomedical applications. By the characterization of coated surfaces of the products used in various fields such as medicine, mechatronics, electronics, etc. depends their proper operation, durability and reliability. This is the main reason why, we studied new types of layers and multilayers using Atomic Force Microscopy and scratch tests. The main result of the realized tests is that all studied nanostructured thin films offer the possibility of increasing the lifetime of substrates, being an important factor for proper functional operation, durability and reliability of the final systems in which they are used.

Open access

Liliana-Laura Badita, Gheorghe Gheorghe, Vasile Bratu, Valentin Gornoava, Marian Vocurek, Aurel Zapciu and Iulian Sorin Munteanu

Abstract

Taking into account the importance of mechatronic applications, researches regarding the possibility to improve the lifetime of mechatronic components were made. Nanostructured metallic thin films (Ti, Cr, Al and Ti/Al multilayer) were deposited on different types of steel substrates, because nanomaterials have exceptional properties in relation to the common materials. In this paper a part of the results obtained after mechanical and topographic characterization of the thin films are presented. Cr is the deposited thin film showing the highest hardness on the surface of steel substrate type OSC. After the scratch tests realized, Ti layer presented the best adhesion on all types of steel substrates used in experiments. The results of these researches could be extremely useful for engineers in the mechatronic field.

Open access

Mihai-Constantin Balaşa, Ştefan Cuculici, Cosmin Panţu, Simona Mihai, Alexis-Daniel Negrea, Mihai-Octavian Zdrafcu, Dorin-Dacian Leţ, Viviana Filip and Ştefan Cristea

Abstract

Designing orthopedic implants with a long lifespan is essential for improving patients’ quality of life. It is necessary to develop new products with a high degree of personalization for the human body. Physicians and engineers analyzed the geometry and behavior of healthy joints’ motion under specific load conditions as well as the behavior over time and lifetime of orthopedic implants fitted to patients to improve their quality. The paper presents the way in which three-dimensional modeling techniques using specialized software (Catia, SolidWorks) can be combined with reverse engineering techniques (3D scanning) to optimize the design of orthopedic implants. The design of an implant consists of its three-dimensional modeling, as well as simulation of its integration into the human body, in order to analyze its behavior during motion. Therefore, it is necessary not only to 3D model the parts that make up the implant itself, but also to 3D model the bone to which the implant will be fitted. The paper highlights the complementarity of the classic modeling techniques with the reverse engineering techniques, which is necessary because the design of the parts that make up the implant itself can be achieved by specialized software modeling techniques, while the bones, having complex geometries, are better suited to 3D Modeling by scanning.

Open access

Herbert Danninger

Abstract

Traditionally, powder metallurgy has been based on two major industrial sectors – ferrous precision parts and hardmetals. Both of them relied heavily on the automotive industry, with focus on internal combustion engines. Today, there is an increasing trend towards alternative drivetrain systems, and powder metallurgy faces the challenge to find new applications to replace those lost with the decrease of classical internal combustion drives. In this presentation it is shown that the main strength of powder metallurgy lies in its enormous flexibility regarding materials, geometries, processing and properties. This enables PM to adapt itself to changing requirements in a changing industrial environment. Examples given are PM parts in alternative drivetrain systems, new alloying concepts and processing routes offering distinct advantages. With hardmetals, innovative microstructures as well as sophisticated coatings offer increased lifetime, applications ranging from metalworking to rockdrilling and concrete cutting. A particularly wide area is found in functional materials which range from components for high power switches to such for fuel cells. Soft and hard magnets are accessible by PM with particularly good properties, PM having in part exclusivity in that respect, such as for NdFeB superhard magnets as well as soft magnetic composites (SMCs). Metal injection moulding (MIM) is gaining further ground, e.g. in the medical area which is a fast-growing field, due to demographic effects. Finally, most additive manufacturing techniques are powder based, and here, the knowledge in powder handling and processing available in the PM community is essential for obtaining stable processes and reliable products. Conclusively it can be stated that PM is on the way to fully exploit its potential far beyond its traditional areas of applications.