SV-JME is indexed / abstracted in:

  • SCI-Expanded,
  • Compendex,
  • Inspec,
  • ProQuest-CSA,
  • SCOPUS,
  • TEMA, ...
The list of the remaining bases, in which SV-JME is indexed »

Editorial Office

University of Ljubljana
Faculty of Mechanical Engineering
Journal of Mechanical Engineering

Aškerčeva 6,

SI-1000 Ljubljana
Slovenia

P: +386 1 4771 137
E: info@sv-jme.eu



The journal is subsidized by Slovenian Research Agency.

 
ISSN: 0039-2480

Journal of Mechanical Engineering 63 (2017) 10

 

 

 


 

Manufacturing Space Homogeneity in Additive Manufacturing – Electron Beam Melting Case

Authors - Alexandre Piaget – Matthieu Museau* – Henri Paris


Abstract

This paper focuses on the manufacturing space homogeneity of the electron beam melting (EBM) technology. An Arcam AB A1 machine is used as tool for experimentations, with titanium (Ti-6Al-4V) as material. The objective of this study is to show the correlation between workpieces geometrical deformations and their position in the manufacturing space. Results show that the position on Z-axis does not affect quality, but there is a strong link in the Z-plane: significant defects appear near the manufacturing space boundaries. First manufactured layers are deformed in the vicinities of the manufacturing space edges. Up to 3 mm of material loss and 8mm of dimensional deformation are measured. Further analyses point that this phenomenon is particularly related to a sintering variation in the powder: there are up to 3 % density difference from the center to borders. To avoid the problem, reduction of the manufacturing space and a supporting strategy are proposed. Defects can also be removed by implementing thermal insulation on the machine or by modifying the beam operation.

Keywords -quality management, additive manufacturing, electron beam melting, manufacturing space homogeneity 

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 63(2017)10, 553-558, SI 81
DOI:10.5545/sv-jme.2017.4365

 

pdfManufacturing Space Homogeneity in Additive Manufacturing – Electron Beam Melting Case (.pdf 1.3MB)

 


  

Low Cost Printer for DLP Stereolithography

Authors - Joško Valentinčič* – Matej Peroša – Marko Jerman – Izidor Sabotin – Andrej Lebar


Abstract

A general research direction of stereolithography based on digital light processing (DLP) is to reduce the production time and to increase manufacturing accuracy. Compared to fused deposition modelling (FDM) machines, machines for DLP stereolithography are expensive and thus not available to a broad range of users as it is the case with FDM 3D printers. Comparing technologies, DLP stereolithography offers quicker and more accurate production. In this paper, performances of a low cost DLP stereolithographic printer is presented. Three main challenges are treated: an uneven illumination of commercial DLP projectors, a direction of illumination and a selection of optimal 3D printing parameters. Uneven illumination of DLP projector results in smaller usable working area and poor printing quality. The problem is solved by implementing an appropriate software mask, thus the product quality is not influenced by its position on a working table. The direction of illumination has a key role in DLP stereolithography. It is shown that constrained surface (illumination through a transparent bottom of the vat) gives better 3D printing accuracy compared to free surface (illumination of the photopolymer surface) stereolithography. To further improve the product quality, the optimal process parameters are determined. Using the Taguchi based surface response methodology optimal process parameters are defined and by using them, the deviation of the actual dimensions from the specified dimensions is less than 80 µm.

Keywords - DLP stereolithography, software mask, illumination, surface response method

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 63(2017)10, 559-566, SI 82
DOI:10.5545/sv-jme.2017.4591

 

pdfLow Cost Printer for DLP Stereolithography (.pdf 1.7MB)

 


 

Optimization of Hybrid Manufacturing for Surface Quality, Material Consumption and Productivity Improvement

Authors - Damir Grguraš* – Davorin Kramar


Abstract

This paper presents hybrid manufacturing process of 3D printing and milling. Fused deposition modeling (FDM) has been applied to improve product manufacturing performance, afterwards, milling was used to improve outer surface roughness. Today’s FDM systems rely on the use of standard nozzle size with a diameter of D1 = 0.4 mm. To achieve shorter production times a bigger nozzle size (diameter D2 = 1.1 mm) has been used in this research. Optimization of technological parameters of hybrid manufacturing was carried out according to the minimal time of production, a minimal final surface roughness and minimal usage of material. In addition, these results were compared with optimal results obtained with the standard nozzle size. Significantly shorter production time, without affecting surface quality, was achieved when using bigger nozzle size.

Keywords - hybrid manufacturing, fused deposition modeling, milling, PLA material, design of experiments – DOE, empirical modeling and optimization, response surface methodology – RSM

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 63(2017)10, 567-576, SI 83
DOI:10.5545/sv-jme.2016.4396

 

pdfOptimization of Hybrid Manufacturing for Surface Quality, Material Consumption and Productivity Improvement (.pdf 3.7MB)

 


 

Influence of Variously Modified Surface of Aluminium Alloy on the Effect of Pulsating Water Jet

Authors - Jiri Klich* – Dagmar Klichova – Vladimir Foldyna – Petr Hlavacek – Josef Foldyna


Abstract

Erosion effects of a pulsating water jet impinging the surface of aluminium alloy samples pre-treated by various techniques (rough and fine milling, planing and rolling) were studied. The influence of the initial surface topography on the final topography of the sample exposed to the pulsating water jet was investigated. Based on roughness parameter Ra erosion of surface layers was analysed and discussed in relation to the traversing speed of the jet. It was found that initial surface pre-treatment have a significant impact on the final topography of the surface affected subsequently by pulsating water jet. Surfaces, whose properties are significantly affected by the action of some machining processes (i.e. milling) show much greater resistance to pulsating water jet than unpaved surfaces (i.e. rolling) and surfaces have smaller roughness. While milled (rough or fine) or planed surface roughness has approximately the same increase of Ra parameter, only rolled surfaces are up to 150 times rougher after pulsating water jet treatment. This is due to the small hardening of the surface layers and reduced durability against pulsating water jet in comparison with others investigated techniques. The highest roughness was achieved on all pre-treated surfaces at the lowest speeds, because the pulsating water jet affects the surface for a longer time.

Keywords - pulsating water jet, surface topography, material erosion


Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 63(2017)10, 577-582, SI 84
DOI:10.5545/sv-jme.2017.4356

 

pdfInfluence of Variously Modified Surface of Aluminium Alloy on the Effect of Pulsating Water Jet (.pdf 1.5MB)




Effects of Continuous and Pulsating Water Jet on CNT/Concrete Composite

Authors - Vladimir Foldyna* – Josef Foldyna – Dagmar Klichova – Jiri Klich – Petr Hlavacek – Lenka Bodnarova – Tomas Jarolim – Katerina Mamulova Kutlakova

Abstract

This paper presents first results of the study of the resistance of carbon nanotube concrete composite (CNT/concrete composite) to the action of continuous and pulsating water jets. The experiments oriented at the determination of erosion effects of pulsating and continuous water jets impinging the surface of reference (concrete) and CNT/concrete composite samples were performed. Tested samples were characterized by X-ray powder diffraction and scanning electron microscope. Samples were exposed to pulsating and continuous water jets at various operating parameters. Erosion effects of pulsating and continuous jets were evaluated in terms of material removal rate. The possible influence of addition of CNTs to the concrete on its resistance to the action of continuous and pulsating water jets is discussed in the paper. The experiments proved that CNT/concrete composite exhibits higher resistance than reference concrete to the action of both pulsating and continuous water jet under the given testing conditions.

Keywords - pulsating and continuous water jet, CNT/concrete composite, material removal

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 63(2017)10, 583-589, SI 85
DOI:10.5545/sv-jme.2017.4357

 

pdfEffects of Continuous and Pulsating Water Jet on CNT/Concrete Composite (.pdf 1.5MB)




Automatable Splicing Method for Steel Cord Conveyor Belts – Evaluation of Water Jetting as a Preparation Process

Authors - David Zaremba* – Patrick Heitzmann – Ludger Overmeyer – Lennart Hillerns – Thomas Hassel

Abstract

The increased demand of mineral resources leads to worldwide application of incessantly longer conveying systems. The length between axes can amount to 15 km and more. Owing to manageable dimensions and weight, appropriate conveyor belts are produced in segments of up to 300 m. Final assembly takes place at the conveyor system, where the multitude of segments is connected to a long conveyor belt. An important point in assembly preparation is the stripping of the steel cords, which is mainly carried out manually using rudimentary techniques. The optimization potential is high, since the adoption of automatable and application-oriented preparation methods can minimize the conveyor downtime and improve the joint quality.
In this study, the application of the pure water jet is investigated, since this selective stripping method offers a lot of potential for automation and the creation of rough surfaces. The objective was to determine if an efficient, homogenous and selective removal of the rubber is possible without damaging the zinc coating of the steel cords. Following a parameter study, the generated kerf geometries and surfaces were investigated. The stripped steel cords and zinc coatings were analyzed through the preparation of micrographs. Concluding, an evaluation about the qualification of water jetting as an automatable method for joint and repair preparation is made.

Keywords - steel cord conveyor belt, splicing, repair preparation, automation, water jetting

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 63(2017)10, 590-596 , SI 86
DOI:10.5545/sv-jme.2017.4363

 

pdfAutomatable Splicing Method for Steel Cord Conveyor Belts – Evaluation of Water Jetting as a Preparation Process (.pdf 2.0MB)




Determining Focusing Nozzle Wear by Measuring AWJ Diameter

Authors - Miha Prijatelj – Marko Jerman – Henri Orbanić – Izidor Sabotin – Joško Valentinčič – Andrej Lebar*

Abstract

Abrasive water jet (AWJ) cutting is a versatile technology, but it is limited by relative poor accuracy. The main problem is the unknown diameter of the jet, as there is no device or instrument on the market that would enable a quick and easy measurement of it. With such an instrument the diameter could be regularly measured, nozzle wear monitored and noted offset adjusted. This would greatly improve the quality control of the process and the accuracy of the cut. This paper investigates the usage of a through-beam laser sensor for monitoring jet diameter and nozzle wear. Experiments were performed with five differently worn nozzles, with two different water pressures, with and without abrasive, at different standoff distances and with varying measuring times. Results show that the instrument is capable of monitoring the jet diameter and nozzle wear with an accuracy of ±0.03 mm, but it is very susceptible to the jet’s spray and abrasive sticking to the sensor’s screens. Jet diameter correlated better with the diameter of the focusing nozzle when taking measurements without the abrasive, at high water pressures and at a standoff distance of 1 mm.

Keywords - abrasive waterjet, nozzle diameter, jet diameter, nozzle wear

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 63(2017)10, 597-605, SI 87
DOI:10.5545/sv-jme.2017.4424

 

pdfDetermining Focusing Nozzle Wear by Measuring AWJ Diameter (.pdf 2.3MB)




Obtaining the Selected Surface Roughness by Means of Mathematical Model Based Parameter Optimization in Abrasive Waterjet Cutting

Authors - Andrzej Perec* – Frank Pude – Michael Kaufeld – Konrad Wegener

Abstract

The study on the effect of abrasive water jet machining process parameters on micro alloyed steel surface roughness was described. Taguchi method to predict machining parameters of due to minimum surface roughness was used. The influence of pressure, abrasive flow rate and traverse speed on the Rz and Rmax roughness parameters were presented. The optimum combination of processing parameters was established. Verified parameters were tested and the achieved results were compared to predicted values. This method allows limiting the amount of research needed to achieve the desired test results, thereby reducing the time as well as the cost required to carry them out. The Taguchi signal/noise (S/N) ratio enables the assessment of the relevance of the impact of various parameters on the process, which is still not well enough understood.

Keywords - mathematical model, continuous heating, Joule effect, dilatometry, AISI 304 stainless steel

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 63(2017)10, 606-613, SI 88
DOI:10.5545/sv-jme.2017.4463

 

pdfObtaining the Selected Surface Roughness by Means of Mathematical Model Based Parameter Optimization in Abrasive Waterjet Cutting (.pdf 1.8MB)



 


Leaflet SV-JME


 

 

Journal of Mechanical Engineering

in digital form


SV-JME-10-2017


SV-JME-9-2017


SV-JME-7-8-2017


SV-JME-6-2017

 

This web site uses cookies. By continuing to use website, you consent to install cookies on your device to access the site. More about cookies can be found here.