scholarly journals A study on extruded filament bonding in fused filament fabrication

2019 ◽  
Vol 25 (3) ◽  
pp. 555-565 ◽  
Author(s):  
Ana Elisa Costa ◽  
Alexandre Ferreira da Silva ◽  
Olga Sousa Carneiro
Keyword(s):  
Control Systems ◽  
Design Methodology ◽  
Mechanical Performance ◽  
Tensile Axis ◽  
Dimensional Accuracy ◽  
Fused Filament Fabrication ◽  
Bonding Quality ◽  
Content Type ◽  
Extrusion Rate ◽  
Forced Cooling

Purpose The performance of parts produced by fused filament fabrication is directly related to the printing conditions and to the rheological phenomena inherent to the process, specifically the bonding between adjacent extruded paths/raster. This paper aims to study the influence of a set of printing conditions and parameters, namely, envelope temperature, extrusion temperature, forced cooling and extrusion rate, on the parts performance. Design/methodology/approach The influence of these parameters is evaluated by printing a set of test specimens that are morphologically characterized and mechanically tested. At the morphological level, the external dimensions and the voids content of the printed specimens are evaluated. The bonding quality between adjacent extruded paths is assessed through the mechanical performance of test specimens, subjected to tensile loads. These specimens are printed with all raster oriented at 90º relative to the tensile axis. Findings The best performance, resulting from a compromise between surface quality, dimensional accuracy and mechanical performance, is achieved with a heated printing environment and with no use of forced cooling. In addition, for all the conditions tested, the highest dimensional accuracy is achieved in dimensions defined in the printing plane. Originality/value This work provides a relevant result as the majority of the current printers comes without enclosure or misses the heating and envelope temperature control systems, which proved to be one of the most influential process parameter.

Effect of nozzle diameter on mechanical and geometric performance of 3D printed carbon fibre-reinforced composites manufactured by fused filament fabrication

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jesús Miguel Chacón ◽  
Miguel Ángel Caminero ◽  
Pedro José Núñez ◽  
Eustaquio García-Plaza ◽  
Jean Paul Bécar
Keyword(s):  
Surface Roughness ◽  
Carbon Fibre ◽  
Mechanical Performance ◽  
Dimensional Accuracy ◽  
Nozzle Diameter ◽  
Fused Filament Fabrication ◽  
Manufacturing Costs ◽  
Content Type ◽  
3D Printed ◽  
Composite Samples

Purpose Fused filament fabrication (FFF) is one of the most popular additive manufacturing (AM) technologies due to its ability to build thermoplastic parts with complex geometries at low cost. The FFF technique has been mainly used for rapid prototyping owing to the poor mechanical and geometrical properties of pure thermoplastic parts. However, both the development of new fibre-reinforced filaments with improved mechanical properties, and more accurate composite 3D printers have broadened the scope of FFF applications to functional components. FFF is a complex process with a large number of parameters influencing product quality and mechanical properties, and the effects of the combined parameters are usually difficult to evaluate. An array of parameter combinations has been analysed for improving the mechanical performance of thermoplastic parts such as layer thickness, build orientation, raster angle, raster width, air gap, infill density and pattern, fibre volume fraction, fibre layer location, fibre orientation and feed rate. This study aims to assess the effects of nozzle diameter on the mechanical performance and the geometric properties of 3D printed short carbon fibre-reinforced composites processed by the FFF technique. Design methodology approach Tensile and three-point bending tests were performed to characterise the mechanical response of the 3D printed composite samples. The dimensional accuracy, the flatness error and surface roughness of the printed specimens were also evaluated. Moreover, manufacturing costs, which are related to printing time, were evaluated. Finally, scanning electron microscopy images of the printed samples were analysed to estimate the porosity as a function of the nozzle diameter and to justify the effect of nozzle diameter on dimensional accuracy and surface roughness. Findings The effect of nozzle diameter on the mechanical and geometric quality of 3D printed composite samples was significant. In addition, large nozzle diameters tended to increase mechanical performance and enhance surface roughness, with a reduction in manufacturing costs. In contrast, 3D printed composite samples with small nozzle diameter exhibited higher geometric accuracy. However, the effect of nozzle diameter on the flatness error and surface roughness was of slight significance. Finally, some print guidelines are included. Originality value The effect of nozzle diameter, which is directly related to product quality and manufacturing costs, has not been extensively studied. The presented study provides more information regarding the dependence of the mechanical, microstructural and geometric properties of short carbon fibre-reinforced nylon composite components on nozzle diameter.

Take-off control and characteristics of FanWing

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Lin Meng ◽  
Yang Gao ◽  
Yangyang Liu ◽  
Shengfang Lu
Keyword(s):  
Control System ◽  
Control Systems ◽  
Design Methodology ◽  
Control System Design ◽  
Control Methods ◽  
Force Analysis ◽  
Close Attention ◽  
Content Type ◽  
Vehicle Load ◽  
Practical Implications

Purpose As a short take-off and landing aircraft, FanWing has the capability of being driven under power a short distance from a parking space to the take-off area. The purpose of this paper is to design the take-off control system of FanWing and study the factors that influence the short take-off performance under control. Design/methodology/approach The force analysis of FanWing is studied in the take-off phase. Two take-off control methods are researched, and several factors that influence the short take-off performance are studied under control. Findings The elevator and fan wing control systems are designed. Although the vehicle load increases under the fan wing control, the fan wing control is not a recommended practice in the take-off phase for its sensitivity to the pitch angle command. The additional pitch-down moment has a significant influence on the control system and the short take-off performance that the barycenter variation of FanWing should be considered carefully. Practical implications The presented efforts provide a reference for the location of the center of gravity in designing FanWing. The traditional elevator control is more recommended than the fan wing control in the take-off phase. Originality/value This paper offers a valuable reference on the control system design of FanWing. It also proves that there is an additional pith-down moment that needs to be paid close attention to. Four factors that influence the short take-off performance are compared under control.

scholarly journals The use of rapid prototyping in the joining of fractured historical silver object

2018 ◽  
Vol 24 (3) ◽  
pp. 532-538 ◽  
Author(s):  
Maria Luiza Seixas ◽  
Paulo Santos Assis ◽  
João Cura D’Ars Figueiredo ◽  
Maria Aparecida Pinto ◽  
Daniella Gualberto Caldeira Paula
Keyword(s):  
Rapid Prototyping ◽  
Design Methodology ◽  
Mechanical Stability ◽  
Dimensional Accuracy ◽  
3D Modelling ◽  
Content Type ◽  
Minimal Impact ◽  
Speed Up ◽  
Elemental Chemical Analysis ◽  
Original Metal

Purpose This paper aims to present a proposal for the restoration of a silver crown by means of fitting pieces produced by the process of 3D modelling and rapid prototyping. It also analyses the benefits of this procedure in restoration of objects weakened by corrosive processes. Design/methodology/approach Elemental chemical analysis was carried out in the alloy used in the manufacture of the crown and the constructive and corrosive processes present were studied. Three fitting pieces were modelled and prototyped in wax casting by the stereolithography apparatus system aiming to restore the part and protect the original metal against impacts and external tensions which could speed up some deterioration processes. Findings The procedure presented in this paper has shown that formal and dimensional accuracy, only achieved by means of 3D technologies, made the restoration and mechanical stability of the crown possible without the use of adhesives or welding. Originality/value The proposed procedure is a new restoration alternative which causes minimal impact to the object and abides by the main standards for modern conservation. It is made with metal which is compatible with the original piece, retractable and easily identifiable.

Evaluation and prediction of material fatigue characteristics under impact loads: review and prospects

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xintian Liu ◽  
Que Wu ◽  
Shengchao Su ◽  
Yansong Wang
Keyword(s):  
Mechanical Properties ◽  
Design Methodology ◽  
Mechanical Performance ◽  
Impact Load ◽  
Impact Loads ◽  
Content Type ◽  
Material Fatigue ◽  
Mechanical Properties Of Materials ◽  
Fatigue Characteristics ◽  
Properties Of Materials

PurposeThe properties of materials under impact load are introduced in terms of metal, nonmetallic materials and composite materials. And the application of impact load research in biological fields is also mentioned. The current hot research topics and achievements in this field are summarized. In addition, some problems in theoretical modeling and testing of the mechanical properties of materials are discussed.Design/methodology/approachThe situation of materials under impact load is of great significance to show the mechanical performance. The performance of various materials under impact load is different, and there are many research methods. It is affected by some kinds of factors, such as the temperature, the gap and the speed of load.FindingsThe research on mechanical properties of materials under impact load has the characteristics as fellow. It is difficult to build the theoretical model, verify by experiment and analyze the data accumulation.Originality/valueThis review provides a reference for further study of material properties.

Effect of extrusion temperature on fused filament fabrication parts orthotropic behaviour

2019 ◽  
Vol 26 (4) ◽  
pp. 639-647
Author(s):  
Michele Angelo Attolico ◽  
Caterina Casavola ◽  
Alberto Cazzato ◽  
Vincenzo Moramarco ◽  
Gilda Renna
Keyword(s):  
Mechanical Properties ◽  
Morphological Characteristics ◽  
Single Layer ◽  
Acrylonitrile Butadiene Styrene ◽  
Surface Characteristics ◽  
Tensile Tests ◽  
Extrusion Temperature ◽  
Fused Filament Fabrication ◽  
Bonding Quality ◽  
Content Type

Purpose The purpose of this paper is to verify the effects of extrusion temperature on orthotropic behaviour of the mechanical properties of parts obtained by fused filament fabrication (FFF) under quasi-static tensile loads. Design/methodology/approach Tensile tests were performed on single layer specimens fabricated in polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS) to evaluate the mechanical properties at different extrusion temperatures and raster orientations (0°, 45° and 90°). Furthermore, a detailed study of morphological characteristics of the single layer samples cross-section and of the bonding quality among adjacent deposited filaments was performed by scanning electron microscopy to correlate the morphology of materials with mechanical behaviour. Findings The results show that the orthotropic behaviour of FFF-printed parts tends to reduce, while the mechanical properties improved with increase in extrusion temperature. Furthermore, the increase in extrusion temperature led to an improvement in inter-raster bonding quality and in the compactness and homogeneity of the parts. Originality/value The relation between the extrusion temperature, orthotropic behaviour and morphological surface characteristics of the single layer specimen obtained by FFF has not been previously reported.

Effects of ethical leadership and formal control systems on employee opportunistic behavior in China

2018 ◽  
Vol 25 (5) ◽  
pp. 1350-1362 ◽  
Author(s):  
Changsuk Ko ◽  
Mark H. Haney ◽  
Gukseong Lee
Keyword(s):  
Regression Analysis ◽  
Control Systems ◽  
Ethical Leadership ◽  
Interaction Effect ◽  
Design Methodology ◽  
Opportunistic Behavior ◽  
Direct Effects ◽  
Content Type ◽  
Formal Control ◽  
The Relationship

PurposeThe purpose of this paper is to explore how ethical leadership and formal control systems influence employee opportunistic behavior.Design/methodology/approachUsing survey data collected from Chinese employees (N=430), the authors conducted regression analysis to test hypothesized relationships between ethical leadership and formal control systems and employee opportunistic behavior. Both direct effects and an interaction effect were tested.FindingsThe authors found that both ethical leadership and formal control systems individually play significant roles in reducing employee opportunistic behavior. In addition, the results indicate that ethical leadership and formal control systems function as complements to jointly constrain employee opportunistic behaviors.Originality/valueThis study contributes to an understanding of the relationship between supervisors and followers in China by demonstrating the effects of ethical leadership and formal control systems on employee opportunistic behaviors, including an interesting interaction effect.

Observed effectiveness of the COSO 2013 framework

2019 ◽  
Vol 16 (1) ◽  
pp. 31-45
Author(s):  
Ifeoma Udeh
Keyword(s):  
Control Systems ◽  
Internal Control ◽  
Design Methodology ◽  
Control Process ◽  
Regression Analyses ◽  
Section 404 ◽  
Content Type ◽  
Sarbanes Oxley ◽  
Material Weaknesses ◽  
Practical Implications

Purpose This paper aims to examine the effectiveness of the Committee of Sponsoring Organization’s 2013 Framework, by investigating how the number of auditor-reported material weaknesses compares for Early-, Timely- and Late-adopters of the framework, and how the number of auditor-reported material weaknesses changed for Early- and Timely-adopters following their adoption of the framework. Design/methodology/approach The paper uses regression analyses based on a sample of US firms subject to Sarbanes-Oxley Act Section 404(b). Findings Timely-adopters of the 2013 Framework continued to exhibit fewer instances of auditor-reported material weaknesses than Late-adopters, even though they had a marginal increase in the number of auditor-reported material weaknesses, in the post-2013 Framework period. Practical implications The findings suggest that the effectiveness of the 2013 Framework may lie in the iterative nature of the internal control process, and as firms remedy deficiencies they or their auditors identify, they will continuously improve the effectiveness of their internal control systems. Originality/value Unlike existing literature, this paper uses data from the pre-2013 Framework, transition and post-2013 Framework periods to examine changes in the number of auditor-reported material weaknesses, thus differentiating between Early-, Timely- and Late-adopters of the 2013 Framework. It also shows the effect of adopting the 2013 Framework on the number of auditor-reported material weaknesses.

Controls amid the chaos

2017 ◽  
Vol 33 (4) ◽  
pp. 13-15
Keyword(s):  
Control Systems ◽  
Design Methodology ◽  
Reading Time ◽  
Management Control ◽  
Management Control Systems ◽  
Content Type ◽  
Digital Revolution ◽  
Time Dynamics ◽  
Pertinent Information ◽  
Practical Implications

Purpose This paper aims to review the latest management developments across the globe and pinpoint practical implications from cutting-edge research and case studies. Design/methodology/approach This briefing is prepared by an independent writer who adds their own impartial comments and places the articles in context. Findings Evolving industries, the digital revolution and the effect of the global economic crisis has entailed huge challenges for those seeking to implement management control systems. In her article “Organizations with changing structures: how to control?” (2016), author Eva Lechner pulls aside the curtains on a festival organizer and shows that while its time dynamics and culture are very different to most industries, the need for controls still apply, and they can be successfully applied as long as keen attention is paid to their consequences. Practical implications The paper provides strategic insights and practical thinking that have influenced some of the world’s leading organizations. Originality/value The briefing saves busy executives and researchers hours of reading time by selecting only the very best, most pertinent information and presenting it in a condensed and easy-to-digest format.

On the use of high viscosity polymers in the fused filament fabrication process

2017 ◽  
Vol 23 (4) ◽  
pp. 727-735 ◽  
Author(s):  
Muhammad Hussam Khaliq ◽  
Rui Gomes ◽  
Célio Fernandes ◽  
João Nóbrega ◽  
Olga Sousa Carneiro ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
High Viscosity ◽  
Polymer Processing ◽  
General Purpose ◽  
Good Choice ◽  
Fused Filament Fabrication ◽  
Content Type ◽  
Performance Requirements ◽  
Functional Prototype ◽  
The One

Purpose This work aims to provide additional insights regarding the practicability of using conventional materials in the fused filament fabrication (FFF) process. Design/methodology/approach Two different acrylonitryle butadiene styrene (ABS) grades are studied and compared, aiming to check to what extent the regular ABS developed for conventional polymer processing, with a different rheology than the one provided for the FFF process, can also be used in this process (FFF). Findings The rheological results show that a general-purpose ABS (ABS-GP) melt is much more viscous and elastic than ABS-FFF. It is clear that using ABS-GP as feedstock material in the FFF process results in poor coalescence and adhesion between the extruded filaments, which has a detrimental effect on the mechanical properties of the printed specimens. Despite its lower performance, ABS-GP can be a good choice if the objective is to produce an aesthetical prototype. If the objective is to produce a functional prototype or a final part, its mechanical performance requirements will dictate the choice. Originality/value This work provides insightful information regarding the use of high viscosity materials on the 3D printing process.

A survey on design and development of an unmanned aerial vehicle (quadcopter)

2016 ◽  
Vol 4 (2) ◽  
pp. 70-106 ◽  
Author(s):  
Deepak B B V L ◽  
Pritpal Singh
Keyword(s):  
Control Systems ◽  
Motion Control ◽  
Design Methodology ◽  
Dynamic Models ◽  
Control Strategies ◽  
Content Type ◽  
Military Applications ◽  
Previous Decade ◽  
Potential Applications ◽  
Aerial Vehicle

Purpose – In the previous decade, unmanned aerial vehicles (UAVs) have turned into a subject of enthusiasm for some exploration associations. UAVs are discovering applications in different regions going from military applications to activity reconnaissance. The purpose of this paper is to overview a particular sort of UAV called quadrotor or quadcopter. Design/methodology/approach – This paper includes the dynamic models of a quadrotor and the distinctive model-reliant and model-autonomous control systems and their correlation. Findings – In the present time, focus has moved to outlining autonomous quadrotors. Ultimately, the paper examines the potential applications of quadrotors and their part in multi-operators frameworks. Originality/value – This investigation deals with the review on various quadrotors, their applications and motion control strategies.

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