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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Digital data processing and computational design for large area maskless photopolymerization

Rudraraju, Anirudh V. 12 January 2015 (has links)
Large Area Maskless Photopolymerization (LAMP) is a novel additive manufacturing technology currently being developed at Georgia Tech in collaboration with the University of Michigan at Ann Arbor and PCC Airfoils. It is intended for the fabrication of integrally cored ceramic molds for the investment casting of precision components such as high-pressure turbine blades. This dissertation addresses the digital data processing and computational design needs for this technology. Several data processing schemes like direct slicing, STL slicing, post-processing schemes like error checking, part placement and tiling etc. were developed in order to enable the basic functionality of the LAMP process. A detailed overview of these schemes and their implementation details are given in this dissertation. Several computational schemes to improve the quality and accuracy of parts produced through the LAMP process were also implemented. These include a novel volume deviation based adaptive slicing method to adaptively slice native CAD models, a gray scaling and dithering approach to reduce stair stepping effect on downward facing surfaces and a preliminary experimental study to characterize the side curing behavior of the LAMP photo-curable suspension for pre-build image compensation. The implementation details and a discussion of the results obtained using these schemes are given. A novel approach for addressing the “floating island” problem encountered in additive manufacturing was also developed. The need for supports specific to the kind of parts being built through LAMP is evaluated and a support generation strategy different from the previously reported approaches in the literature is presented. Finally, a few novel film cooling schemes that are extremely challenging to fabricate using existing manufacturing technologies but possible to fabricate using LAMP are chosen and analyzed for their cooling performance. It is shown that such novel schemes perform much better in cooling the blade surface than the conventionally implemented schemes and hence this final component of work gives a better appreciation of the impact LAMP technology has in disrupting the state of the art in turbine blade manufacturing and truly taking the blade designs to the next level.
92

The integration of rapid prototyping within industrial design practice

Evans, Mark January 2002 (has links)
Three-dimensional appearance models represent an essential outcome of industrial design practice, facilitating the origination, evaluation and specification of exterior form. As manufacturers face increasing pressure to reduce time scales for new product development, the production of such models using conventional fabrication techniques must be appraised. As a means of economically translating digital geometry into one-off components, rapid prototyping has the potential to contribute towards a reduction in lead times for the production of appearance models. The objective of this research is to propose a methodological approach for the effective integration of rapid prototyping within industrial design practice. The field and practice of industrial design is defined, the technology of rapid prototyping discussed, and their integration proposed through a draft computer-aided industrial design/rapid prototyping (CAID/RP) methodological approach. This is exposed to practitioner feedback, modified, and employed as a revised CAID/RP methodological approach during the industrial design of a nylon line trimmer. The product outcome is used to compare and contrast the production of an appearance model via rapid prototyping, an appearance prototype via rapid prototyping, and an appearance model via conventional fabrication techniques. Two issues arise from the use of the revised CAID/RP methodological approach: the production of stl files and the lack of physical interaction with product form. In addition, the emergence of rapid prototype sketch modelling systems following the line trimmer case study provides an opportunity for further enhancement. A strategy for the resolution of these issues is proposed, and their effectiveness evaluated through additional case studies. The resulting CAID/RP methodological approach is subject to validation through practitioner interviews and a normalised rating/weighting method. The positive feedback acknowledges the significance of the CAID/RP methodological approach through a reduction in product development lead times and enhancement of professional practice. The project makes a contribution to new knowledge and understanding in the area of professional practice through the definition and validation of operational paradigmatic change.
93

Development of a software procedure for Curved Layered Fused Deposition Modelling (CLFDM)

Huang, Bin January 2009 (has links)
Fused Deposition Modelling (FDM) is one of the most widely used Rapid Prototyping processes that uses the technique of depositing a semi-solid material in layers to build up a part and finds application in a variety of situations, be it making a mould for the rapid production of an industrial tool or the production of models for preoperative planning of complex cranial reconstructive surgery. When it comes to directly producing the end products, the process is still in its infancy, using inferior materials and flat layer deposition, bringing forth shortcomings such as poor surface quality, low strength for curved parts, and undesirably higher number of layers. Some of these shortcomings can be overcome if material deposition is modelled in curved layers as against the traditional flat-layer slicing and deposition. While the stair case effect can be significantly minimized, mechanical properties of the parts will also be enhanced due to continuity in fibres and the elimination of the inherent weakness between laminations. However, this being a fairly new idea, there are no existing facilities for practically implementing and experimentally testing this concept of Curved Layered Fused Deposition Modeling (CLFDM). The current research is to develop both hardware and software systems to build a working FDM system and implement CLFDM. The project involves the construction of an FDM system and then development of mathematical models for curved slicing. The numerical data generated from curved slicing algorithms is integrated with the hardware system for the practical implementation of CLFDM. Efficient curved slicing algorithms are developed and successfully used on the FDM system built for the practical implementation of CLFDM. Several case studies involving geometrical complications of increasing complexities have been successfully modelled and physically produced using CLFDM.
94

Development of a software procedure for Curved Layered Fused Deposition Modelling (CLFDM)

Huang, Bin January 2009 (has links)
Fused Deposition Modelling (FDM) is one of the most widely used Rapid Prototyping processes that uses the technique of depositing a semi-solid material in layers to build up a part and finds application in a variety of situations, be it making a mould for the rapid production of an industrial tool or the production of models for preoperative planning of complex cranial reconstructive surgery. When it comes to directly producing the end products, the process is still in its infancy, using inferior materials and flat layer deposition, bringing forth shortcomings such as poor surface quality, low strength for curved parts, and undesirably higher number of layers. Some of these shortcomings can be overcome if material deposition is modelled in curved layers as against the traditional flat-layer slicing and deposition. While the stair case effect can be significantly minimized, mechanical properties of the parts will also be enhanced due to continuity in fibres and the elimination of the inherent weakness between laminations. However, this being a fairly new idea, there are no existing facilities for practically implementing and experimentally testing this concept of Curved Layered Fused Deposition Modeling (CLFDM). The current research is to develop both hardware and software systems to build a working FDM system and implement CLFDM. The project involves the construction of an FDM system and then development of mathematical models for curved slicing. The numerical data generated from curved slicing algorithms is integrated with the hardware system for the practical implementation of CLFDM. Efficient curved slicing algorithms are developed and successfully used on the FDM system built for the practical implementation of CLFDM. Several case studies involving geometrical complications of increasing complexities have been successfully modelled and physically produced using CLFDM.
95

Development of a novel robotically effected plastic foam sculpting system for rapid prototyping and manufacturing : a thesis presented for the degree of masters in mechanical engineering in the University of Canterbury /

Posthuma, Anton. January 1900 (has links)
Thesis (M.E.)--University of Canterbury, 2007. / Typescript (photocopy). "May 2007." Includes bibliographical references (leaves 121-122). Also available via the World Wide Web.
96

Qualifizierung einer Prozesskette zum Laserstrahlsintern metallischer Bauteile

Niebling, Frank January 2005 (has links)
Zugl.: Erlangen, Nürnberg, Univ., Diss., 2005
97

Mechanical properties and microstructure study for direct metal deposition of titanium alloy and tool steel

Bao, Yaxin, January 2007 (has links) (PDF)
Thesis (M.S.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 29, 2007) Includes bibliographical references.
98

Automatisiertes Schichtverfahren für metallische Folien - System- und Prozesstechnik

Prechtl, Martin January 2006 (has links)
Zugl.: Erlangen, Nürnberg, Univ., Diss., 2006
99

Integration von sensorischen Komponenten in prototypische Bauteile

Šulc, Juraj January 2008 (has links)
Zugl.: Magdeburg, Univ., Diss., 2008
100

Rapid bone reconstruction using reverse engineering

Baksi, Stanley January 2007 (has links)
Zugl.: Magdeburg, Univ., Diss., 2007

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