Recent advances in 3D printing of biomaterials.

3D Printing promises to produce complex biomedical devices according to computer design using patient-specific anatomical data. Since its initial use as pre-surgical visualization models and tooling molds, 3D Printing has slowly evolved to create one-of-a-kind devices, implants, scaffolds for tissue engineering, diagnostic platforms, and drug delivery systems. Fueled by the recent explosion in public interest and access to affordable printers, there is renewed interest to combine stem cells with custom 3D scaffolds for personalized regenerative medicine. Before 3D Printing can be used routinely for the regeneration of complex tissues (e.g. bone, cartilage, muscles, vessels, nerves in the craniomaxillofacial complex), and complex organs with intricate 3D microarchitecture (e.g. liver, lymphoid organs), several technological limitations must be addressed. In this review, the major materials and technology advances within the last five years for each of the common 3D Printing technologies (Three Dimensional Printing, Fused Deposition Modeling, Selective Laser Sintering, Stereolithography, and 3D Plotting/Direct-Write/Bioprinting) are described. Examples are highlighted to illustrate progress of each technology in tissue engineering, and key limitations are identified to motivate future research and advance this fascinating field of advanced manufacturing

Mechanical Properties and Biological Responses of Bioactive Glass Ceramics Processed using Indirect SLS

This paper will report on research which aims to generate bone replacement components by processing bioactive glass-ceramic powders using indirect selective laser sintering. The indirect SLS route has been chosen as it offers the ability to tailor the shape of the implant to the implantation site, and two bioactive glass ceramic materials have been processed through this route: apatite-mullite and apatite-wollostanite. The results of bend tests, to investigate mechanical properties, and in vitro and in vivo experiments to investigate biological responses of the materials will be reported, and the suitability of completed components for implant will be assessed.Mechanical Engineerin

Design and Production of Complex Architectural Forms with Ceramic Elements

This paper describes a studio experiment developed with the aim of exploring the design and fabrication of complex architectural forms using ceramic elements. History has examples of double-sided curved forms built in ceramics. Such examples would not fulfill contemporary functional and aesthetic principles, neither would they be feasible or cost-effective considering current construction standards. There are recent examples of such forms built in other materials. These examples are difficult to emulate when ceramics is concerned, as they imply the fabrication of unique parts and sophisticated assembly techniques. Creating a double-curved surface in ceramics thus seems a difficult task. There are, however, advantages to such a formulation of design problems. They prompt the questioning of traditional wisdom, the rejection of accepted types, and the raising of interesting questions. What are the design strategies that should be followed when creating ceramic free-forms? What is the design media required to design them? And what are the techniques needed to fabricate and construct them? These are the questions investigated in the design project pursued jointly by students at an American and a Portuguese school, in collaboration with a professional research center and a ceramics factory. The students tested various possibilities, and in the process learned about state-of-art design and production techniques. The final projects are very expressive of their investigations and include a twisted glass tunnel, large-scale ceramic ‘bubbles,’ a rotated-tile wall, and a load-bearing wall

A Decision Support System Methodology For The Selection Of Rapid Prototyping Technologies For Investment-cast Gas Turbine Parts

In the power generation sector, more specifically, the gas turbine industry, competition has forced the lead time-to-market for product advancements to be more important than ever. For design engineers, this means that product design iterations and final product development must be completed within both critical time windows and budgetary constraints. Therefore, two areas that have received significant attention in the research and in practice are: (1) rapid prototyping technology development, and (2) rapid prototyping technology selection. Rapid prototyping technology selection is the focus of this research. In practice, selecting the rapid prototyping method that is acceptable for a specific design application is a daunting task. With technological advancements in both rapid prototyping and conventional machining methods, it is difficult for both a novice design engineer as well as an experienced design engineer to decide not only what rapid prototyping method could be applicable, but also if a rapid prototyping method would even be advantageous over a more conventional machining method and where in the manufacturing process any of these processes would be utilized. This research proposes an expert system that assists a design engineer through the decision process relating to the investment casting of a superalloy gas turbine engine component. Investment casting is a well-known technique for the production of many superalloy gas turbine parts such as gas turbine blades and vanes. In fact, investment-cast turbine blades remain the state of the art in gas turbine blade design. The proposed automated expert system allows the engineer to effectively assess rapid prototyping iii opportunities for desired gas turbine blade application. The system serves as a starting point in presenting an engineer with commercially-available state-of-the-art rapid prototyping options, brief explanations of each option and the advantages and disadvantages of each option. It is not intended to suggest an optimal solution as there is not only one unique answer. For instance, cost and time factors vary depending upon the individual needs of a company at any particular time as well as existing strategic partnerships with particular foundries and vendors. The performance of the proposed expert system is assessed using two real-world case studies. The first case study shows how the expert system can advise the design engineer when suggesting rapid manufacturing in place of investment casting. The second case study shows how rapid prototyping can be used for creating part patterns for use within the investment casting process. The results from these case studies are telling in that their implementations potentially result in an 82 to 94% reduction in design decision lead time and a 92 to 97% cost savings

Geometric Modeling of Cellular Materials for Additive Manufacturing in Biomedical Field: A Review

Advances in additive manufacturing technologies facilitate the fabrication of cellular materials that have tailored functional characteristics. The application of solid freeform fabrication techniques is especially exploited in designing scaffolds for tissue engineering. In this review, firstly, a classification of cellular materials from a geometric point of view is proposed; then, the main approaches on geometric modeling of cellular materials are discussed. Finally, an investigation on porous scaffolds fabricated by additive manufacturing technologies is pointed out. Perspectives in geometric modeling of scaffolds for tissue engineering are also proposed

Productive Frictions: Moving from Digital to Material Prototyping and Low-Volume Production for Design Research

In this paper we discuss the low-volume production of an interaction design research product known as the tilting bowl. The form of the tilting bowl was designed with 3D modeling tools and utilized digital fabrication for rapid prototyping. The final form was produced in a small number of glazed ceramic forms with embedded electronics and actuators. We focus on the lessons we learned from the challenges and design opportunities that arose in moving from digital processes to ceramic processes. We reflected on these lessons and developed thematic notions we refer to as frictions. These include shifting constraints, naïve expertise, manual automation, and dynamic materiality. The contributions of this paper are new design insights into the combination of digital and material processes for studio based prototyping and low-volume production and adds to the emerging relevance of digital fabrication, physical fabrication, and physical materials to interaction design and HCI research

Three-dimensional printed ceramics for concept modelling and bespoke production

Many ceramic manufacturing companies use 3D CAD software and 3D printing technologies to produce design concept models for evaluation, although the value to the design process is limited due to the type of materials that can be printed, conventional modelling and processing methods still need to be used to achieve a design concept model in a real material.A solution is desired that delivers a prototype that looks and feels like the final product and which can be fully tested for functionality glaze and decoration.In collaboration with Denby Pottery as the industrial partner this research project has refined and enhanced the 3D ceramic printing process already developed at the University of the West of England, and has enabled the production of concept models of new design ideas in a real ceramic material, printed directly from CAD data, fired, glazed and decorated