Journal of Mechanical Engineering 57 (2011) 9

 

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Sustainability Assessment: Cryogenic Machining of Inconel 718

Authors - Franci Pušavec ‒ Janez Kopač

Abstract

This paper disseminates the foreground of sustainable cryogenic machining technology that has a high potential to cut production costs and improve competitiveness by reducing resource consumption and creating less waste. The sustainability issues on a shop floor level are pointed out via a life cycle assessment, concluding that the future of sustainable production is going to entail the use of cryogenic machining to reduce environmental burdens and health risks, while increasing machining performance and profitability. In addition, machining evaluation is covered by an experimental study undertaken to understand the likely impacts of the use of cryogenic technology on production costs. The case study refers to the machining of high-temperature Ni-alloy (Inconel 718). It is shown that tooling costs greatly contribute to the total production cost and that cryogenic machining offers a clean and a cost-effective route to improve sustainability performance in comparison to conventional machining.

Keywords - machining, sustainability, cryogenics, LCA, cost evaluation

Paper's information

Strojniški vestnik - Journal of Mechanical Engineering 57(2011)9, 637-647
DOI: 10.5545/sv-jme.2010.249

Sustainability Assessment: Cryogenic Machining of Inconel 718 (pdf)

 

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Length Variation of Toothed Belt during Exploitation

Authors - Blaza Stojanović ‒ Nenad Miloradović ‒ Nenad Marjanović ‒ Mirko Blagojević ‒ Lozica Ivanović

Abstract

Timing belt drives are a relatively new concept in power transmission, accepted nowadays in all areas of industry. Teeth, equally spaced on the inner side of timing belts, come into contact with the belt pulley’s teeth through their grooves. By this meshing, a connection between the belt and the belt pulley is achieved and torque is transmitted.
This paper reviews basic tribomechanical systems in timing belt drives, focusing on the analysis of the tribomechanical system “belt’s teeth - belt pulley’s teeth”. In addition, analysis of pitch variation and belt’s length variation during testing is conducted. Friction is the main cause of wear of the flanks of the belt’s teeth, which leads to an increase of pitch. Testing of the timing belt was conducted on a specially designed test bench and showed that the belt’s elongation is especially distinct in a period of running in.

Keywords - timing belt drives, belt pitch, friction, wear, tribology, tribomechanical systems

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 57(2011)9, 648-654
DOI:10.5545/sv-jme.2010.062

Length Variation of Toothed Belt during Exploitation (pdf)

 

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Signal Model-Based Fault Detection and Diagnosis for Induction Motors Using Features of Vibration Signal in Two-Dimension Domain

Authors - Van Tuan Do – Ui-Pil Chong

Abstract

In this paper, we propose an approach for vibration signal-based fault detection and diagnosis system applying for induction motors. The approach consists of two consecutive processes: fault detection process and fault diagnosis process. In the fault detection process, significant features from vibration signals are extracted through the scale invariant feature transform (SIFT) algorithm to generate the faulty symptoms. Consequently, the pattern classification technique using the faulty symptoms is applied to the fault diagnosis process. Hence, instead of analyzing the vibration signal to determine the induction motor faults, the vibration signal can be classified to the corresponding faulty category, which presents the induction motor fault. We also provide a framework for the pattern classification technique that is applicable to SIFT patterns. Moreover, a comparison with two other approaches in our previous work is also carried out. The testing results show that our proposed approach provides significantly high fault classification accuracy and a better performance than previous approaches.

Keywords - fault detection and diagnosis, SIFT, feature vector, texton dictionary, two-dimension domain, classification accuracy

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 57(2011)9, 655-666
DOI:10.5545/sv-jme.2010.162

Signal Model-Based Fault Detection and Diagnosis for Induction Motors Using Features of Vibration Signal in Two-Dimension Domain (pdf)

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FE-Modeling of Cold Rolling by In-Feed Method of Circular Grooves

Authors - Eduard Niţu – Monica Iordache – Luminiţa Marincei – Isabelle Charpentier –Gaël Le Coz – Gérard Ferron – Ion Ungureanu

Abstract

The methods of cold rolling of rods are widely used in manufacturing industries to obtain pieces with complex profiles. In this study, complex profiles with grooves have been formed by in-feed methods using two rolls. An experimental system was constructed to record the process parameters. The microhardness has been measured by the Vickers method in an axial section of the rolled piece. The process has also been simulated by means of finite element calculations using the Abaqus/Explicit code. The material behavior is described by using a 5-parameter strain-hardening law and by accounting for thermal effects at high strain-rates. Finally, a comparison is made between experimental and simulated results.

Keywords - groove profile, cold rolling, micro-hardness, finite element modeling

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 57(2011)9, 667-673
DOI:10.5545/sv-jme.2010.244

FE-Modeling of Cold Rolling by In-Feed Method of Circular Grooves (pdf)

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Surface Topography Modelling for Reduced Friction

Authors - Marko Sedlaček – Luis Miguel Silva Vilhena – Bojan Podgornik – Jože Vižintin

Abstract

The aim of the present research was to investigate the possibility to design contact surfaces with reduced friction using surface roughness and topography analysis. For this purpose, different 100Cr6 plate samples with different surface topography were prepared. Using different grades and combinations of grinding and polishing samples with similar Ra values, but different Rku and Rsk values were prepared. To evaluate influence of roughness parameters on friction and wear, dry and lubricated pin-on-disc tests were carried out under different contact conditions. Test results show that surfaces with high Rku and negative Rsk values results in reduced friction.
To investigate the effect of surface topography on surface roughness parameters and consequently on friction, real roughness profiles were virtually altered to achieve virtually textured surfaces. Using NIST SMATS softgauge for calculation of surface roughness parameters, virtually altered roughness profiles were investigated in terms of texture size, shape and spacing, and their influence on surface roughness parameters, especially on skewness and kurtosis. Lower diameter, higher spacing and wedge-shaped dimples were found to reflect in higher Rku and more negative Rsk parameters, which should lead to lower friction.

Keywords - surface topography, roughness parameters, friction, surface texturing

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 57(2011)9, 674-680
DOI:10.5545/sv-jme.2010.140

Surface Topography Modelling for Reduced Friction (pdf)

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Aspects of Using Tool Axis Inclination Angle

Authors - Marek Sadílek – Robert Čep – Igor Budak – Mirko Soković

Abstract

This contribution deals with the research and proposal to change a position of tool axis against milled surface during multi-axial milling. Our target is achieving an increase in milling efficiency (improvement of functional surface properties, increase in milling accuracy, increase in tool durability, decrease in energy load on a machine, and shortening of milling time). This research attempts to make production of shape planes more efficient. This concerns production of molds, impression dies, and other complicated parts in various engineering industries, primarily automotive and aircraft ones.

Keywords - tool axis inclination angle, ball-end milling, surface roughness, cutting forces

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 57(2011)9, 681-688
DOI:10.5545/sv-jme.2010.205

Aspects of Using Tool Axis Inclination Angle (pdf)

 

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Influence of Input Parameters on the Characteristics of the EDM Process

Authors - Mohammadreza Shabgard – Mirsadegh Seyedzavvar – Samad Nadimi Bavil Oliaei

Abstract
This paper presents the results of experimental studies carried out to conduct a comprehensive investigation on the influence of Electrical Discharge Machining (EDM) input parameters on the characteristics of the EDM process. The studied process characteristics included machining features, embracing material removal rate, tool wear ratio, and arithmetical mean roughness, as well surface integrity characteristics comprised of the thickness of white layer and the depth of heat affected zone of AISI H13 tool steel as workpiece. The experiments performed under the designed full factorial procedure, and the considered EDM input parameters included pulse on-time and pulse current. The results of this study could be utilized in the selection of optimum process parameters to achieve the desired EDM efficiency, surface roughness, and surface integrity when machining AISI H13 tool steel.

Keywords - electrical discharge machining, material removal rate, tool wear ratio, surface roughness, white layer thickness, depth of heat affected zone

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 57(2011)9, 689-696
DOI:10.5545/sv-jme.2011.035

Influence of Input Parameters on the Characteristics of the EDM Process (pdf)

 

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Application of Numerical Simulations in the Deep-Drawing Process and the Holding System with Segments’ Inserts

Authors - Mihael Volk – Blaž Nardin – Bojan Dolšak

Abstract
The demands for complicated products have increased dramatically over the last few years taking into consideration the utilisation of sheet metal, product quality and process conditions. For reliable product development and stable production process, the use of FEM is necessary.
One of the most significant parameters in the sheet metal forming process is the blank holding force. In the research work, the optimisation of the blank holding force was performed with the help of FEM analysis. For the optimisation the geometry and the structure of the blank holder was optimised. The best results were obtained with flexible, segmented blank holders, which enables wider technological window for good parts.

Keywords - Sheet metal forming, deep drawing, segmented holding system, finite elements methods (FEM), optimization

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 57(2011)9, 697-703
DOI:10.5545/sv-jme.2010.258

Application of Numerical Simulations in the Deep-Drawing Process and the Holding System with Segments’ Inserts (pdf)

 

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