The Use of Additive Manufacturing Techniques in the Construction of Model-Scale Propellers

2013 ◽  
Author(s):  
Matthew Garvin ◽  
Mohammed Islam ◽  
David Molyneux ◽  
Paul Herrington
Keyword(s):  
Additive Manufacturing ◽  
Computer Aided Design ◽  
Open Water ◽  
Cost Effective ◽  
Design Tool ◽  
Efficient Manner ◽  
Model Scale ◽  
Order Of Magnitude ◽  
Manufacturing Techniques ◽  
Open Water Performance

Historically, it has been expensive for model test basins to supply custom model-scale propellers for ship propulsion experiments, due to the high cost of traditional propeller fabrication methods. This paper presents a new method of manufacturing model propellers in a cost effective and time efficient manner. A new computer aided design tool has been developed to quickly develop propeller geometry, which can then be built using additive manufacturing processes. These processes reduce the cost of manufacturing propellers by an order of magnitude compared to machined metal propellers. The results of a study comparing propeller open water and self-propulsion experiments using traditional metal propellers to newly developed plastic propellers are presented. This study also includes an evaluation of the effect of surface roughness on the open water performance coefficients. The measured propulsive performance coefficients of the plastic propellers were within 2% of that of geometrically similar metal propellers with the same blade roughness.

Development of 3D Finite Element Model for Predicting Process-Induced Defects in Additive Manufacturing by Selective Laser Melting (SLM)

2016 ◽  
Author(s):  
Bilal Hussain ◽  
A. Sherif El-Gizawy
Keyword(s):  
Additive Manufacturing ◽  
Laser Beam ◽  
Selective Laser Melting ◽  
Thermal Stresses ◽  
Cost Effective ◽  
Element Model ◽  
Laser Melting ◽  
Two Phase ◽  
Free Process ◽  
Manufacturing Techniques

Selective Laser Melting (SLM) is one of the important Additive Manufacturing techniques for building functional products. Nevertheless, the absence of accurate models for predicting the SLM process behavior, delays development of cost effective and defects free process. This work presents a coupled thermo-mechanical numerical model to capture the two phase (solid-liquid) solidification melting phenomena that occur in the process. The proposed model will also predict the evolvement of process-induced properties and defects particularly residual stresses caused by temperature gradient and thermal stresses. CO2 or Nd:YAG laser beam can be used as a heat source with a Gaussian distribution for the laser beam energy.

scholarly journals Design for Additive Manufacturing: Optimization of Piping Network in Compact System With Enhanced Path-Finding Approach

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Pei Cao ◽  
Zhaoyan Fan ◽  
Robert X. Gao ◽  
J. Tang
Keyword(s):  
Additive Manufacturing ◽  
Video Game ◽  
Optimal Path ◽  
Computational Cost ◽  
Design Tool ◽  
Computational Time ◽  
Path Finding ◽  
Network Systems ◽  
Efficient Manner ◽  
Visibility Graphs

This research aims at unleashing the potential of additive manufacturing technology in industrial design that can produce structures/devices with irregular component geometries to reduce sizes/weights. We explore, by means of path-finding, the length minimization of freeform hydraulic piping network in compact space under given constraints. Previous studies on path-finding have mainly focused on enhancing computational efficiency due to the need to produce rapid results in such as navigation and video-game applications. In this research, we develop a new Focal Any-Angle A* approach that combines the merits of grid-based method and visibility graph-based method. Specifically, we formulate pruned visibility graphs preserving only the useful portion of the vertices and then find the optimal path based on the candidate vertices using A*. The reduced visibility graphs enable us to outperform approximations and maintain the optimality of exact algorithms in a more efficient manner. The algorithm proposed is compared to the traditional A* on Grids, Theta* and A* on visibility graphs in terms of path length, number of nodes evaluated, as well as computational time. As demonstrated and validated through case studies, the proposed method is capable of finding the shortest path with tractable computational cost, which provides a viable design tool for the additive manufacturing of piping network systems.

scholarly journals Evaluating additive manufacturing for the production of custom head supports: A comparison against a commercial head support under static loading conditions

2020 ◽  
Vol 234 (5) ◽  
pp. 458-467
Author(s):  
Jonathan D Howard ◽  
Dominic Eggbeer ◽  
Peter Dorrington ◽  
Feras Korkees ◽  
Lorna H Tasker
Keyword(s):  
Additive Manufacturing ◽  
Static Loading ◽  
Computer Aided Design ◽  
Rear Surface ◽  
Cost Effective ◽  
Lateral Force ◽  
Maximum Displacement ◽  
Wheelchair Users ◽  
Continuous Filament ◽  
Aided Design

The provision of wheelchair seating accessories, such as head supports, is often limited to the use of commercial products. Additive manufacturing has the potential to produce custom seating components, but there are very few examples of published work. This article reports a method of utilising 3D scanning, computer-aided design and additive manufacturing for the fabrication of a custom head support for a wheelchair. Three custom head supports, of the same shape, were manufactured in nylon using a continuous filament fabrication machine. The custom head supports were tested against an equivalent and widely used commercial head support using ISO 16840-3:2014. The head supports were statically loaded in two configurations, one modelling a posterior force on the inner rear surface and the other modelling a lateral force on the side. The posterior force resulted in failure of the supporting bracketry before the custom head support. A similar magnitude of forces was applied laterally for the custom and commercial head support. When the load was removed, the custom recovered to its original shape while the commercial sustained plastic deformation. The addition of a joint in the head support increased the maximum displacement, 128.6 mm compared to 71.7 mm, and the use of carbon fibre resulted in the head support sustaining a higher force at larger displacements, increase in 30 N. Based on the deformation and recovery characteristics, the results indicate that additive manufacturing could be an appropriate method to produce lighter weight, highly customised, cost-effective and safe head supports for wheelchair users.

Labelling additively manufactured parts by microstructural gradation – advanced copy-proof design

2016 ◽  
Vol 22 (4) ◽  
pp. 630-635 ◽  
Author(s):  
Thomas Niendorf ◽  
Florian Brenne ◽  
Mirko Schaper ◽  
Andre Riemer ◽  
Stefan Leuders ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Additive Manufacturing ◽  
Eddy Current ◽  
Computer Aided Design ◽  
Current Method ◽  
Eddy Current Method ◽  
Content Type ◽  
Current Technique ◽  
Manufacturing Techniques ◽  
Electro Magnetic

Purpose As additive manufacturing techniques, such as selective laser melting, allow for straightforward production of parts on basis of simple computer-aided design files only, unauthorized replication can be facilitated. Thus, identification and tracking of individual parts are increasingly vital in light of globalized competition. This paper aims to overcome the susceptibility of additive manufacturing techniques for product piracy by establishing a method for introducing and reading out product identification markers not visible by naked-eye inspection. Design/methodology/approach Lasers of different nominal power were used for altering the solidification mechanisms during processing in distinct areas of the samples. The resulting local microstructural characteristics and mechanical properties, respectively, were determined by scanning electron microscopy and hardness measurements. The applicability of an advanced eddy current technique for reading out local differences in electro-magnetic properties was examined. Findings The findings show that distinct microstructural features are obtained in dependence of the locally applied laser power. These features manifest themselves not only in terms of grain morphology, texture and hardness but also induce changes in the local electro-magnetic properties. The inscribed pattern can be non-destructively visualized by using an advanced eddy current technique. Originality/value Conventional copy protection basically consists in supplementary labelling or surface modification. In the present study, a new method is proposed for additively manufactured parts, overcoming the drawbacks of the former methods through process-induced microstructure manipulation. Slight alterations in the electro-magnetic material properties can be detected by advanced eddy current method allowing for identification of arbitrary and inimitable component information in additively manufactured parts.

Mastering Manufacturing: Exploring the Influence of Engineering Designers’ Prior Experience When Using Design for Additive Manufacturing

2021 ◽  
Author(s):  
Rohan Prabhu ◽  
Timothy W. Simpson ◽  
Scarlett R. Miller ◽  
Nicholas A. Meisel
Keyword(s):  
Additive Manufacturing ◽  
Computer Aided Design ◽  
Early Stage ◽  
Prior Experience ◽  
Educational Interventions ◽  
Design For Manufacturing ◽  
Current Standard ◽  
Manufacturing Techniques ◽  
Aided Design ◽  
Am Processes

Abstract Additive manufacturing (AM) processes present designers with unique capabilities while imposing several process limitations. Designers must leverage the capabilities of AM — through opportunistic design for AM (DfAM) — and accommodate AM limitations — through restrictive DfAM — to successfully employ AM in engineering design. These opportunistic and restrictive DfAM techniques starkly contrast the traditional, limitation-based design for manufacturing techniques — the current standard for design for manufacturing (DfM). Therefore, designers must transition from a restrictive DfM mindset towards a ‘dual’ design mindset — using opportunistic and restrictive DfAM concepts. Designers’ prior experience, especially with a partial set of DfM and DfAM techniques could inhibit their ability to transition towards a dual DfAM approach. On the other hand, experienced designers’ auxiliary skills (e.g., with computer-aided design) could help them successfully use DfAM in their solutions. Researchers have investigated the influence of prior experience on designers’ use of DfAM tools in design; however, a majority of this work focuses on early-stage ideation. Little research has studied the influence of prior experience on designers’ DfAM use in the later design stages, especially in formal DfAM educational interventions, and we aim to explore this research gap. From our results, we see that experienced designers report higher baseline self-efficacy with restrictive DfAM but not with opportunistic DfAM. We also see that experienced designers demonstrate a greater use of certain DfAM concepts (e.g., part and assembly complexity) in their designs. These findings suggest that introducing designers to opportunistic DfAM early could help develop a dual design mindset; however, having more engineering experience might be necessary for them to implement this knowledge into their designs.

scholarly journals Improving the fidelity of aerodynamic probes using additive manufacturing

2016 ◽  
Vol 22 (1) ◽  
pp. 200-206 ◽  
Author(s):  
Ishaq Jarallah ◽  
Vasudevan P Kanjirakkad
Keyword(s):  
Additive Manufacturing ◽  
Computer Aided Design ◽  
Design Methodology ◽  
Cost Effective ◽  
Flow Measurements ◽  
Content Type ◽  
Support Materials ◽  
Cost Effective Method ◽  
Computer Aided ◽  
Individual Calibration

Purpose – This paper aims to offer the aerodynamic testing community a new procedure for manufacturing high-quality aerodynamic probes suitable for 3D flow measurements with consistent geometry and calibration by taking advantage of the additive manufacturing technology. Design/methodology/approach – The design methodology combines the advantages and flexibilities of computer aided design (CAD)/computer aided manufacturing (CAM) along with the use of computational fluid dynamics to design and analyse suitable probe shapes prior to manufacturing via rapid prototyping. Findings – A viable procedure to design and possibly batch manufacture geometrically accurate pneumatic probes with consistent calibration is shown to be possible through this work. Multi-jet modelling prototyping methods with wax-based support materials are found to be a cost-effective method when clean and long sub-millimetre pressure channels are to be cut. Originality/value – Utilisation of the geometry consistency that is made possible by 3D printing technology for the design and development of pneumatic probes is described. It is suggested that the technique could lead to batch production of identical probes, thus avoiding precious time of a skilled labourer and elaborate individual calibration requirement.

Computer-Aided Design and Additive Manufacturing of Custom Silicone Prosthetic Finger

2020 ◽  
Author(s):  
Lei Chen ◽  
Jeffery Plott ◽  
Matthew Hildner ◽  
Lillian Mei ◽  
Albert Shih ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Social Life ◽  
Computer Aided Design ◽  
Wait Time ◽  
Cost Effective ◽  
Thin Wall ◽  
Silicone Injection ◽  
Computer Aided ◽  
Prosthetic Finger ◽  
Aided Design

Abstract Finger and partial finger amputations are one of the most frequently encountered forms of partial hand loss. Most of these amputees can benefit from prosthetic fingers, which should be both functional and aesthetic, to enhance rehabilitation by permitting a more normal professional and social life. Custom prosthetic fingers perform better than off-the-shelf ones due to better fit, comfort, and match to the patients’ physical characteristics. The conventional fabrication process for custom prosthetic fingers uses multiple impressions and molds combined with silicone injection molding to create the final shape. This process has not seen significant changes for decades and comes with a high cost and long wait time, stopping the prosthesis from benefitting the patient in a cost-effective, timely, and lifelike functional way. This study developed a new manufacturing approach for custom prosthetic fingers based on an additive manufactured custom thin-wall mold. The approach was based on optical 3D scanning of the amputees’ fingers and computer-aided design of custom finger prosthetic geometry and the corresponding thin-wall mold. Preliminary clinical study on an amputee patient shows the feasibility of this new custom molding approach and future work will clinically evaluate the performance of the prosthetic fingers created via the computer-aided design and additive manufacturing approach.

A review of biomaterials scaffold fabrication in additive manufacturing for tissue engineering

2019 ◽  
Vol 34 (6) ◽  
pp. 415-435 ◽  
Author(s):  
Tang Mei Shick ◽  
Aini Zuhra Abdul Kadir ◽  
Nor Hasrul Akhmal Ngadiman ◽  
Azanizawati Ma’aram
Keyword(s):  
Tissue Engineering ◽  
Additive Manufacturing ◽  
Material Properties ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Scaffold Fabrication ◽  
Manufacturing Techniques ◽  
Manufacturing Technologies

The current developments in three-dimensional printing also referred as “additive manufacturing” have transformed the scenarios for modern manufacturing and engineering design processes which show greatest advantages for the fabrication of complex structures such as scaffold for tissue engineering. This review aims to introduce additive manufacturing techniques in tissue engineering, types of biomaterials used in scaffold fabrication, as well as in vitro and in vivo evaluations. Biomaterials and fabrication methods could critically affect the outcomes of scaffold mechanical properties, design architectures, and cell proliferations. In addition, an ideal scaffold aids the efficiency of cell proliferation and allows the movements of cell nutrient inside the human body with their specific material properties. This article provides comprehensive review that covers broad range of all the biomaterial types using various additive manufacturing technologies. The data were extracted from 2008 to 2018 mostly from Google Scholar, ScienceDirect, and Scopus using keywords such as “Additive Manufacturing,” “3D Printing,” “Tissue Engineering,” “Biomaterial” and “Scaffold.” A 10 years research in this area was found to be mostly focused toward obtaining an ideal scaffold by investigating the fabrication strategies, biomaterials compatibility, scaffold design effectiveness through computer-aided design modeling, and optimum printing machine parameters identification. As a conclusion, this ideal scaffold fabrication can be obtained with the combination of different materials that could enhance the material properties which performed well in optimum additive manufacturing condition. Yet, there are still many challenges from the printing methods, bioprinting and cell culturing that needs to be discovered and investigated in the future.

A new methodology for design and manufacturing of a customized silicone partial foot prosthesis using indirect additive manufacturing

2019 ◽  
Vol 42 (11) ◽  
pp. 645-657 ◽  
Author(s):  
Osama Abdelaal ◽  
Saied Darwish ◽  
Khaled Abd Elmougoud ◽  
Saleh Aldahash
Keyword(s):  
Additive Manufacturing ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Design Data ◽  
Three Dimensional Objects ◽  
Design And Manufacturing ◽  
Manufacturing Procedure ◽  
Manufacturing Techniques ◽  
Aided Design ◽  
Partial Foot Amputation

The production of customized prostheses for the foot and ankle still relies on slow and laborious steps of the traditional plaster molding fabrication techniques. Additive manufacturing techniques where three-dimensional objects can be constructed directly based on the object’s computer-aided-design data in a layerwise manner has opened the door to new opportunities for manufacturing of novel and personalized medical devices. The purpose of the present study was to develop a new methodology for design and manufacturing of a customized silicone partial foot prosthesis via an indirect additive manufacturing process. Furthermore, the biomechanics of gait of a subject with partial foot amputation wearing the custom silicone foot prosthesis manufactured by the indirect additive manufacturing was characterized, in comparison with a matched healthy participant. This study has confirmed the possibility of producing silicone partial foot prosthesis by indirect additive manufacturing procedure. The amputated subject reported total comfort using the custom prosthesis during walking, as well as cosmetic advantages. The prosthesis restored the foot geometry and normalized many of gait characteristics. The findings presented here contribute to introduce a proper understanding of biomechanics of walking after wearing silicone partial foot prosthesis and are useful for prosthetists and rehabilitation therapists when treating patients after partial foot amputation.

scholarly journals μSmartScope – Towards a low-cost microscopic medical device for cervical cancer screening using additive manufacturing and optimization

2021 ◽  
pp. 146442072110227
Author(s):  
Pedro Brandão ◽  
Paulo T Silva ◽  
Marco Parente ◽  
Luís Rosado
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Medical Device ◽  
Low Cost ◽  
Weight Ratio ◽  
Cost Effective ◽  
Automated Analysis ◽  
Tensile Tests ◽  
Design Tool ◽  
Manufacturing Technologies

Developing a low-cost medical device requires numerous stages of prototyping, where using traditional manufacturing technologies can increase development costs. The current study presents the development of a critical component for a low-cost microscope whose goal is to confer an inexpensive solution for automated analysis of microscopic smears. A novel design methodology was developed to optimize the achieved solution. During the exploration of this methodology, it is asked: how can an additive-manufactured prototype be cost-effective for accurate examination of cervical cytology smears? To understand the effect on cost and tensile strength that infill density and perimeter wall count, tensile tests were conducted. These results combined with the developed methodology achieved the most cost-effective solution. To achieve this, topology optimization was used to improve the stiffness-per-weight ratio of different parts. Finally, design for additive manufacturing and topology optimization was proven as an effective design tool.

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