Die Erstellung von komplex geformtem Knochenersatz wurde durch den 3D-Pulverdruck unter Verwendung von Calciumphosphatmaterialien beschrieben. Gegenstand der vorliegenden Arbeit war deren Modifikation durch die Verwendung von Methacrylatkunststoffen. Ziel war es, durch die Infiltration von nicht resorbierbaren Kunststoffen, wie sie in kommerziell erhältlichen Knochenzementen verwendet werden, die mechanischen Eigenschaften der nicht gesinterten Keramikstrukturen zu verbessern. Getestet wurden verschiedene Methoden der Infiltration sowie der nachfolgenden Polymerisationsinitiierung durch chemische, thermische oder photochemische Aktivatoren. Daneben erfolgte der Druck von Tricalciumphosphat-Pulvern, die mit Polymethylmethacrylat Partikeln versetzt wurden und durch eine hydraulische Verfestigungsreaktion mit Phosphorsäure aushärten. Die erstellten Materialien wurden auf ihre Porosität, ihre mechanischen Eigenschaften sowie auf die Phasenzusammensetzung ihrer anorganischen Matrix und den Konversionsgrat ihrer organischen Komponente hin untersucht. Es gelang, die freie Porosität der Calciumphosphat-Matrix durch Verwendung von flüssigen, monomeren Kunststoffen zu füllen und diese durch eine thermische Initiierung der radikalischen Polymerisation vollständig zur Aushärtung zu bringen. Bei der Reaktion kommt es neben einer Polymerisationskontraktion im organischen Bestandteil der Kunststoffe zu einer Phasenumwandlung der Bruschitanteile der Calciumphosphat-Matrix. Proben, die mit einem flüssigen Bisphenol-A-Derivat versetzt wurden, zeigten eine Verdreifachung ihrer Festigkeit und erreichten maximale Druckfestigkeiten von 99 MPa, Biegefestigkeiten von 35 MPa und einen E-Modul von 18 GPa. Verglichen mit den biomechanischen Eigenschaften des physiologischen Hartgewebes liegen die Werte damit deutlich über denen von spongiösem und unter denen von kortikalem Knochen. Eine künftige Optimierung erscheint durch die Schaffung einer chemischen Verbundphase zwischen dem anorganischen Calciumphosphat-Gefüge und den Polymerbestandteilen als aussichtsreich. / The production of complex shaped bone graft was described by the 3D powder printing using calcium phosphate materials. The present work dealt with the modification of these materials by adding methylacrylate materials. The objective was to improve the mechanical properties of non-sintered ceramic structures by the infiltration of non-resorbable plastics such as used in commercialized bone cements. Different methods of infiltration as well as chemical, thermal or photochemical polymerization activators have been tested. In addition to that, tricalcium phosphate powders have been enriched by polymethylmethacrylate particles before being printed and cured by an hydraulic hardening reaction with phosphoric acid. The prepared materials have been tested for their porosity, their mechanical properties as well as for the phase composition of their inorganic matrix and the conversion rate of their organic components. It could be achieved to fill the open porosity of printed calcium phosphate matrix by using liquid, monomeric plastics and to cure them completely through a thermal initiation of radical polymerization. Besides the polymerization contraction in the organic component, the thermal treatment led to a phase transformation of the calcium phosphate brushite matrix. Samples, which were infiltrated with a liquid bisphenol-A derivative, showed a threefold increase of their strength and reached a maximum compressive strength of 99 MPa, a flexural strength of 35 MPa and a Young´s modulus of 18 GPa. Compared to biomechanical properties of physiological hard tissues, the levels were significantly higher than those of cancellous and lower than those of cortical bones. To further optimize, it seems promising to create a chemical bond between the inorganic phase of calcium phosphate microstructure and polymer components.

Fused Filament Fabrication (FFF) is a layer manufacturing process which can manufacture highly complex components from CAD files using a polymer extruder. RepRap is an open-source project to produce a rapid prototyping machine which can manufacture its own parts using the FFF process. This thesis focuses on the mechanical design of the ‘RepRap printer’ and documents how it was conceived, developed, tested, and finally used to make a set of its own parts. Self-manufacture was demonstrated by assembling this set of parts into a working copy of the original machine. The child machine went on to demonstrate replication without degeneracy by successfully manufacturing one of its own parts. A part count analysis of the child machine, not including the fasteners it needed in its early development phase, identified a self-manufacturing ratio of 48%. This proportion is relatively low because the design adopts modularity and redundancy principles to encourage development. Should the machine’s design be adapted to fully demonstrate self-manufacture, this ratio could rise to 67% in the near future. To increase the ratio further, the machine needs three new tool heads to print resin, conductive alloy, and flexible polymer. These developments are achievable in the mid-future and could increase the self manufactured parts ratio to 94%. As this machine is the first version of the RepRap printer, these results are encouraging. Parts which the RepRap printer is unlikely to make until the far-future include some of the electronic components, motors, conductive cable, solenoids and a heating element. However, a 94% self-manufacturing ratio will qualify it as an assisted self-replicating machine. As with natural self-reproducing organisms, the printer will benefit from geometric growth and evolution. The author discusses how, by trading power, computing, feedstock and assembly for manufacturing capability with human beings, the RepRap printer may become a household item, offering a radical alternative to the way our society manufactures and consumes.

Programvaruutveckling lider idag av stora problem och många av problemen är kopplade till hur krav samlas in och hanteras. Ett sätt att underlätta kravinsamlingen och att öka kommunikation med kund är att ta fram en prototyp, vilket är en konkret representation av programvaran som ska tas fram. När kravutvinningen har kommit tillräckligt långt kan denna prototyp användas som en del av en kravspecifikation. En vanlig form av kravspecifikation är ett dokument, men även en (exekverbar) prototyp kan vara en effektiv representation av programvaran som ska tas fram. I detta arbete undersöks det vilka problem som kan uppstå då en prototyp används som en del av en kravspecifikation. Problem identifieras i litteraturen och intervjuer utförs för att undersöka vilka problem som finns i praktiken. Det visar sig att flera av de problem som litteraturen tar upp inte ses som reella av de respondenter som tillfrågas. Vidare visar det sig att många problem som "borde" uppstå inte gör det på grund av att de tillfrågade organisationerna ofta tillämpar ett mer pragmatiskt än formellt arbetssätt.

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<p>Programvaruutveckling lider idag av stora problem och många av problemen är kopplade till hur krav samlas in och hanteras. Ett sätt att underlätta kravinsamlingen och att öka kommunikation med kund är att ta fram en prototyp, vilket är en konkret representation av programvaran som ska tas fram. När kravutvinningen har kommit tillräckligt långt kan denna prototyp användas som en del av en kravspecifikation. En vanlig form av kravspecifikation är ett dokument, men även en (exekverbar) prototyp kan vara en effektiv representation av programvaran som ska tas fram.</p><p>I detta arbete undersöks det vilka problem som kan uppstå då en prototyp används som en del av en kravspecifikation. Problem identifieras i litteraturen och intervjuer utförs för att undersöka vilka problem som finns i praktiken. Det visar sig att flera av de problem som litteraturen tar upp inte ses som reella av de respondenter som tillfrågas. Vidare visar det sig att många problem som "borde" uppstå inte gör det på grund av att de tillfrågade organisationerna ofta tillämpar ett mer pragmatiskt än formellt arbetssätt.</p>

No description available.

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nuSense is the result of a degree work on master level at Umeå Institute of Design exploring why wearable technology oftentimes tread a rather narrow path, with many different companies releasing essentially the same product with a new shell, and innovation being slow. Through research, interviews and user research, hardware prototyping and testing it became clear that developing for wearable technology is a very complicated task, for many reasons. Being able to build quick exploratory prototypes was nigh impossible if you do not have a grasp of hardware developing platforms and programming. Further, those outside the industry who just want to explore wearable technology lack a platform to do so easily, aside from buying ready-made solutions made to do one single prepackaged thing. Based on this a concept was developed to provide a platform to explore wearable technology, through modular building-blocks and an easy to grasp interface.

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.