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Tissue loss and end-stage organ failure caused by disease or injury are two of the most costly problems encountered in modern medicine. To combat these problems, a relatively new field, called tissue engineering, has emerged. This field combines the medical and engineering fields in hopes of establishing an effective method to restore, maintain, or improve damaged tissue. In order to best replace the diseased tissue, many approaches to fabricating new tissue have focused on trying to replicate native tissue. The overall hypothesis of this dissertation is that a direct-write, BioAssembly Tool (BAT) can be utilized to fabricate viable constructs of cells and matrix that have a specified spatial organization and are truly three-dimensional (3D). The results of the studies within this dissertation demonstrate that the BAT can generate viable, spatially organized constructs comprised of cells and matrix by carefully controlling the environmental parameters of the system. A joint hypothesis associated with this dissertation is that 3D microscopy and image processing techniques can be combined to generate accurate representative stacks of images of the tissue within 3D, tissue engineered constructs. The results of the studies examining this hypothesis demonstrate that by taking into account the attenuation with depth in the imaged construct as well as by looking at the intensity and gradient of each voxel, accurate and reproducible thresholding can be achieved. Furthermore, this tool can be utilized to aid in the characterization of 3D tissue engineered constructs. Based on these studies, 3D microscopy and image processing shows promise in accurately representing the cellular volume within a tissue. More importantly, 3D, direct-write technology, specifically the BioAssembly Tool, could be used in the fabrication of viable, spatially organized constructs that can then be implanted into a patient to provide healthy tissue in the place of diseased or damaged tissue.

This thesis presents the development of a novel robotically effected plastic foam sculpting system for rapid prototyping and manufacturing purposes. The developed system is capable of rapidly sculpting physical objects out of expanded and extruded polystyrene using an electrically heated Nichrome sculpting tool. An overview of current conventional rapid prototyping systems indicated that the main disadvantages lie in the limited size of objects which can be built, the relatively long time involved to produce one part and the high cost of the systems and materials. An extensive literature and technology review was conducted on work which was similar to the novel system presented in this thesis. The literature provided many good ideas which could be applied. Two sections of experimental work were conducted. The first was aimed at simply proving the concept of robotically effected sculpting of plastic foams. A crude procedure was developed which proved to be rather tedious and manual, especially in terms of generating the tool paths. Qualitative observations of the cut surfaces were used to change the testing parameters to explore their effects and discover which parameters produced accurate and smooth sculpted surfaces. 12 tests were documented and proved that the sculpting of satisfactory surfaces was achievable. The second section of experimental work involved developing the aforementioned crude procedure to make it more automated, especially in terms of the tool path generation and optimisation step. An innovative five step procedure was developed which if followed can produce accurately sculpted artefacts using CAD models of the artefacts as the primary input. Two artefacts were successfully sculpted using the developed procedure. The first was a simple lofted surface; the CAD model of which was created in SolidWorks. The second artefact was a patient customised medical radiation therapy head and neck support; the CAD model of which was created by scanning the back of the author's head and neck with a 3D scanner. The sculpted support fitted the author perfectly. The implementation of the procedure in the two tests highlighted several points including the speed in which the whole process can be carried out. The time taken from the scanning of the authors head and neck with the 3D scanner through to the physical sculpted artefact, was a mere 80 minutes; of which only 13 minutes was consumed in the actual setup and sculpting step! This is extremely quick when compared to conventional rapid prototyping systems and CNC milling. Several areas of future work were outlined and included, tool and fixture design, automation and integration of the system procedure, tool pathing strategy for foam cutting and robot control system issues. The work presented in this thesis provides an excellent foundation for future development of the robotic foam sculpting system.

In the present work superplastic forming (SPF) is used as part of a process to create medical implants out of titanium. SPF is a forming process which offers many advantages over conventional forming processes. It allows for greater complexity in shape as well as the ability to work with difficult to form metals such as titanium which is a key metal in the biomedical field. SPF has been used extensively in the aerospace and automobile industry, however in recent years it has been shown to be a viable means in creating medical implants. The current process involves manipulating CT scans in order to create templates using rapid prototyping. These templates are then used to generate SPF molds out of investment material. Three different parts based on anatomical regions referenced from a model skull have been formed successfully. The parts formed are shown to be very accurate when compared against the skull model.

Thesis (Ph.D.)--University of Wollongong, 2005. / Typescript. Includes appendices. Bibliographical referennces: leaf 196-206.

Thesis (M.S. in Software Engineering)--Naval Postgraduate School, December 2008. / Thesis Advisor(s): Kolsch, Mathias. "December 2008." Description based on title screen as viewed on January 30, 2009. Includes bibliographical references (p. 51-52). Also available in print.

Thesis (M.S.)--Cleveland State University, 2008. / Abstract. Title from PDF t.p. (viewed on July 3, 2008). Includes bibliographical references (p.56-57). Available online via the OhioLINK ETD Center. Also available in print.

Universiẗat, Hochsch. für Wirtschafts-, Rechts- und Sozialwiss., Diss.--St. Gallen, 1997.

Thesis (Ph. D.)--Rutgers University, 2010. / "Graduate Program in Materials Science and Engineering." Includes bibliographical references (p. 173-184).

Thesis (M.S.)--University of Texas at El Paso, 2009. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.