Scaffolds in tissue engineering bone and cartilage.

https://cyberleninka.org/article/n/1018032.pdf

Polymer nanotechnology: Nanocomposites

Unlike conventional materials removal methods, additive manufacturing (AM) is based on a novel materials incremental manufacturing philosophy. Additive manufacturing implies layer by layer shaping and consolidation of powder feedstock to arbitrary configurations, normally using a computer controlled laser. The current development focus of AM is to produce complex shaped functional metallic components, including metals, alloys and metal matrix composites (MMCs), to meet demanding requirements from aerospace, defence, automotive and biomedical industries. Laser sintering (LS), laser melting (LM) and laser metal deposition (LMD) are presently regarded as the three most versatile AM processes. Laser based AM processes generally have a complex non-equilibrium physical and chemical metallurgical nature, which is material and process dependent. The influence of material characteristics and processing conditions on metallurgical mechanisms and resultant microstructural and mechanical properties of AM proc...

Laser additive manufacturing of metallic components: materials, processes and mechanisms

Additive manufacturing (AM) alias 3D printing translates computer-aided design (CAD) virtual 3D models into physical objects. By digital slicing of CAD, 3D scan, or tomography data, AM builds objects layer by layer without the need for molds or machining. AM enables decentralized fabrication of customized objects on demand by exploiting digital information storage and retrieval via the Internet. The ongoing transition from rapid prototyping to rapid manufacturing prompts new challenges for mechanical engineers and materials scientists alike. Because polymers are by far the most utilized class of materials for AM, this Review focuses on polymer processing and the development of polymers and advanced polymer systems specifically for AM. AM techniques covered include vat photopolymerization (stereolithography), powder bed fusion (SLS), material and binder jetting (inkjet and aerosol 3D printing), sheet lamination (LOM), extrusion (FDM, 3D dispensing, 3D fiber deposition, and 3D plotting), and 3D bioprinting....

Polymers for 3D Printing and Customized Additive Manufacturing

Additive manufacturing (AM) is poised to bring about a revolution in the way products are designed, manufactured, and distributed to end users. This technology has gained significant academic as well as industry interest due to its ability to create complex geometries with customizable material properties. AM has also inspired the development of the maker movement by democratizing design and manufacturing. Due to the rapid proliferation of a wide variety of technologies associated with AM, there is a lack of a comprehensive set of design principles, manufacturing guidelines, and standardization of best practices. These challenges are compounded by the fact that advancements in multiple technologies (for example materials processing, topology optimization) generate a "positive feedback loop" effect in advancing AM. In order to advance research interest and investment in AM technologies, some fundamental questions and trends about the dependencies existing in these avenues need highlighting. The goal of our review paper is to organize this body of knowledge surrounding AM, and present current barriers, findings, and future trends significantly to the researchers. We also discuss fundamental attributes of AM processes, evolution of the AM industry, and the affordances enabled by the emergence of AM in a variety of areas such as geometry processing, material design, and education. We conclude our paper by pointing out future directions such as the "print-it-all" paradigm, that have the potential to re-imagine current research and spawn completely new avenues for exploration. The fundamental attributes and challenges/barriers of Additive Manufacturing (AM).The evolution of research on AM with a focus on engineering capabilities.The affordances enabled by AM such as geometry, material and tools design.The developments in industry, intellectual property, and education-related aspects.The important future trends of AM technologies.

The status, challenges, and future of additive manufacturing in engineering

A Binary Interaction Model for Miscibility of Copolymers in Blends

/pdf/solid-freeform-fabrication-a-new-direction-in-manufacturing-4qiy9g5p1f.pdf

Solid Freeform Fabrication: A New Direction in Manufacturing

A technique is described which uses differential scanning calorimetry to estimate the glass transition of polymers containing a dissolved gas. The technique is simple and appears to give reliable results. The effects of CO2 sorption at pressures up to 25 atm were examined in detail for poly(methyl methacrylate) and its blends with poly(vinylidene fluoride). Less extensive results for polystyrene, polycarbonate, poly(vinyl chloride), and poly(ethylene terephthalate) are also given. Reductions in Tg of up to 50°C are observed. A theoretical relation by Chow predicts results in reasonable agreement with the experimental data. These findings are relevant to various applications such as membrane separation processes for gases.

Plasticization of glassy polymers by CO2

Solid Freeform Fabrication has been used to describe collectively a growing number of toolless manufacturing techniques. One of these process Selective Laser Sintering, in which a part is generated in layers from powder using a computer-controlled laser/scanning apparatus and power feed system. An overview of the basic principles of SLS machine operation is given. Two binding mechanisms are described for powder which becomes thermally activated by the scanning laser beam: viscous flow and melting of a low-melting-point phase in mixed powders of differing chemistries

Selective laser sintering of metals and ceramics

Selective laser sintering (SLS) is a new additive process for rapidly preparing prototype parts by selectively fusing portions of layers of polymer powder with a rastered, modulated, CO 2 laser beam. Layer to layer fusion is important for achieving good mechanics properties. Generally, the fusion depth is found to be a function of laser beam overlap on adjacent scans, scan speed, and intensity. It is also a function of the kinetic rates of powder sintering and of heat transfer. A one-dimensional model of the SLS thermal process is presented that can accurately predict, to within 20%, the effect of these process and material parameters on experimentally observed fusion depths in bisphenol-A polycarbonate powders

Joel W. Barlow

Papers

A Binary Interaction Model for Miscibility of Copolymers in Blends

Solid Freeform Fabrication: A New Direction in Manufacturing

Plasticization of glassy polymers by CO2

Selective laser sintering of metals and ceramics

Model of the selective laser sintering of bisphenol-A polycarbonate