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Gibson I.,National University of Singapore | Gibson I.,Center for Rapid and Sustainable Product Development
23rd Annual International Solid Freeform Fabrication Symposium - An Additive Manufacturing Conference, SFF 2012

The paraphrase of John F Kennedy's famous words is for 2 purposes. Firstly it is to acknowledge that there are some people who have considered that it is a major part of their life's work to promote Additive Manufacturing (AM) technology as primarily a selfless act. AM comprises an outstanding range of technology that should be brought to public attention as a true revolution in how we design and manufacture products. The second purpose is to show that technology development is only one part of this promotion process and that there are other ways in which we can get involved. This paper describes the author's journey over the (approximately) 20 years since he was introduced to what was then called Rapid Prototyping (RP). It is not a catalogue of research and development projects but rather a list of activities that he has been involved in to help promote and support AM technology over these years. It will describe the conferences, activities, associations and publications that have been created to allow academics and professionals to describe and discuss their work amongst themselves and to the larger society. Source

Mota C.,University of Pisa | Puppi D.,University of Pisa | Gazzarri M.,University of Pisa | Bartolo P.,Center for Rapid and Sustainable Product Development | Chiellini F.,University of Pisa
Polymer International

In the last decade, the melt-electrospinning technique has gained attention for the production of highly porous microfibrous tissue engineering scaffolds. The possibility of processing polymers without the use of organic solvents is one of the main advantages over solution electrospinning. In this study, computer-controlled melt-electrospinning of a commercial poly(ε{lunate}-caprolactone) and of two batches with different molecular weights of a three-arm star poly(ε{lunate}-caprolactone) by means of a screw-extruder-based additive manufacturing system is reported. Experimental parameters such as processing temperature, extrusion flow rate and applied voltage were studied and optimized in order to obtain non-woven meshes with uniform fibre morphology. Applying the optimized parameters, three-dimensional scaffolds were produced using a layer-by-layer approach (0-90° lay-down pattern). © 2013 Society of Chemical Industry. Source

Mitchell G.R.,Center for Rapid and Sustainable Product Development | Ahn K.-H.,University of Reading | Davis F.J.,University of Reading
Virtual and Physical Prototyping

We review the process of electrospinning and how this new technique for generating a rich morphology of nano and micro scale fibres sits alongside established procedures for rapid manufacturing. We introduce the key elements of electrospinning and how these influence the nature and distribution of the fibres produced. We describe the range of polymers available for electrospinning and the limitations to the use of these materials. Using this base we review the potential approaches to using electrospinning as part of a broader rapid manufacturing system and the possible applications for such a hybrid system. © 2011 Taylor & Francis. Source

Mota C.,University of Pisa | Puppi D.,University of Pisa | Dinucci D.,University of Pisa | Errico C.,University of Pisa | And 2 more authors.

This research activity was aimed at the development of dual-scale scaffolds consisting of three-dimensional constructs of aligned poly(ε-caprolactone) (PCL) microfilaments and electrospun poly(lactic-co-glycolic acid) (PLGA) fibers. PCL constructs composed by layers of parallel microsized filaments (0/90o lay-down pattern), with a diameter of around 365 μm and interfilament distance of around 191 μm, were produced using a melt extrusion-based additive manufacturing technique. PLGA electrospun fibers with a diameter of around 1 μm were collected on top of the PCL constructs with different thicknesses, showing a certain degree of alignment. Cell culture experiments employing the MC3T3 murine preosteoblast cell line showed good cell viability and adhesion on the dual-scale scaffolds. In particular, the influence of electrospun fibers on cell morphology and behavior was evident, as well as in creating a structural bridging for cell colonization in the interfilament gap. © 2011 by the authors. Source

Almeida H.D.A.,Center for Rapid and Sustainable Product Development | da Silva Bartolo P.J.,Center for Rapid and Sustainable Product Development
Medical Engineering and Physics

Advanced additive techniques are now being developed to fabricate scaffolds with controlled architecture for tissue engineering. These techniques combine computer-aided design (CAD) with computer-aided manufacturing (CAM) tools to produce three-dimensional structures layer by layer in a multitude of materials. Actual prediction of the effective mechanical properties of scaffolds produced by additive technologies, is very important for tissue engineering applications. A novel computer based technique for scaffold design is topological optimisation. Topological optimisation is a form of " shape" optimisation, usually referred to as " layout" optimisation. The goal of topological optimisation is to find the best use of material for a body that is subjected to either a single load or a multiple load distribution. This paper proposes a topological optimisation scheme in order to obtain the ideal topological architectures of scaffolds, maximising its mechanical behaviour. © 2010 IPEM. Source

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