Cristian-Vasile DoicinMihaela-Elena UlmeanuAllan E. W. RennieElena Lupeanu...
22页
查看更多>>摘要：Fused deposition modelling popularity is attributed to equipment affordability, materials availability and open-source software. Given the variety of optimisation combinations, process parameters can be elaborate. This paper provides methods for optimisation of mass calculation using multivariable regression analysis. Layer thickness, extrusion temperature and speed were considered independent variables for a two-level factorial experiment. DOE was used for 12 sets of programs and analysis (two stages) undertaken using Design-Expert V11 Software. In stage-1, four models were found to be significant. Stage-2 involved redesigning the remaining eight models, iteratively increasing the number of replicates and blocks. Adequacy of models was analysed, demonstrating that: model is significant, F-value is large, p < 0.05; lack of fit is insignificant; adequate precision >4.00; residuals are well behaved; R~2 is as close as possible to 1.00 or for models with multiple replicates, the adjusted R~2 and predicted R~2 differential <0.2. All models were validated through measured, calculated responses.
Alper EkinciAndrew A. JohnsonAndy GleadallXiaoxiao Han...
13页
查看更多>>摘要：Biodegradable polylactic acid-based polymers are the most common material that can be manufactured using material extrusion, one of the most widely known additive manufacturing methods. However, medical grade polymers are too expensive for degradation studies with common tensile specimens. Therefore, this paper aims to reduce the volume of the material used for manufacturing tensile specimens by introducing a new micro-X tensile specimen developed for steel. The tensile strength of micro-X tensile specimens were compared with the ASTM D1708 standard tensile specimens. Experimental results and statistical analysis showed that there was no significant difference in terms of tensile strength. Furthermore, the micro-X tensile specimen reduced the volume and as well as the cost to 1% in comparison to ASTM D638 type V standard tensile specimens.
查看更多>>摘要：The goal of the study is to analyse the post-printing characteristics of conductive tracks 3D-printed using material extrusion (ME) process with varying slicing strategies. Conductive track samples with constant width and varying heights between 0.4 mm and 0.8 mm were prepared using two different commercial conductive materials in a single, double and triple layer strategy. Post-printing functional analysis was done by measuring the resistance of samples at different lengths and comparing it to their corresponding counterparts fabricated with different slicing. Post-printing physical characterisation on selected samples was done by measuring the surface area of their cross sections using microscope images and their mass. The conclusions of the study were then transferred in a proposed set of design for additive manufacturing (DfAM) considerations that can be taken into account in the design and process planning phase when manufacturing conductive tracks or objects with such features using ME.
M. P. SreekanthSivakumar GanesanArivazhagan PugalendhiRajesh Ranganathan...
17页
查看更多>>摘要：Additive manufacturing (AM), a tool less manufacturing process has the advantage of saving material; however, this is not a wastage free manufacturing technology. In PolyJet technology, material wastage is more due to material replacement. This study concentrates on finding a solution to reduce the wastage of material and compare the mechanical properties of PolyJet-printed specimens in single-material (SM) mode and digital-material (DM) mode. In order to reduce the wastage, modified mixed tray strategy is proposed and it is validated by case example. Six different combinations of test specimens are derived from available three printing modes and two finish types of Objet260 Connex PolyJet. This research identified that the proposed technique is capable of saving material. Findings indicate that specimens printed by DM mode explicate low mechanical strength than SM mode. This study provides the awareness of the material replacement and increase the fidelity of the PolyJet-printed parts.
查看更多>>摘要：The UK is currently in the grip of a housing crisis, a recent report from the House of Lords stated that the shortage of affordable housing in Britain could jeopardise our standards of living for future generations. This paper aims to attempts to influence the problem of housing shortage by evaluating the potential of implementing fast building additive manufacturing (BAM) as a construction process. To validate the feasibility of BAM as a building process a variety of compressive and slump tests were conducted to assess the capabilities of concrete paste as a layer-by-layer build material. A structure was fabricated to represent a fused filament fabrication (FFF)-based BAM process; the tests determined that nozzle design limitation, the flowability of concrete and resistance to slump are key material characteristics in constructing house structural elements. Furthermore, the use of recyclable natural and steel wool fibres did not contribute to mixtures compressive strength but did significantly increase its flexural strength.
查看更多>>摘要：Generally, components tend to fail due to cyclic loading; therefore study of fatigue life of products is a critical issue. The purpose of this study is to develop a predictive model relating the process parameters with fatigue life of fused filament fabrication (FFF) technology-based 3D-printed parts. Test specimens are printed using a desktop FFF 3D printer to suit a laboratory-based fatigue testing machine. Response surface methodology-based central composite design method was used for the design of experiments to obtain a regression model for prediction of response. Lastly, genetic algorithm solver was used to optimise the predictive model results. Number of contours, layer thickness and raster width were found to have a significant effect while raster angle had very little effect on the fatigue life of FFF-based 3D printed parts. In addition, it was observed that there is a high significant interaction between layer thickness and raster width of the FFF specimens.
查看更多>>摘要：This present work investigates the computer vision and machine vision algorithms in the selective laser melting (SLM) process to additively manufacture the product. The proposed method provides a real-time layer-by-layer sequence monitoring feature during the layer deposition process. This real-time monitoring helps reduce waste by deciding on the termination or continuation of the production process. The method proposed and elucidated is monitoring by capturing the layer image after the laser melting process completes. A total of eight layers are simulated and analysed in the proposed work. The images are analysed using the greyscale pixel value algorithm. The present work results demonstrate the capability of greyscale pixel analysis to identify and quantify defects in the SLM processed layer. The analysis results show the feasibility and potential of exploiting bulk manufacturing quality control and inspection in an industrial environment.
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