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Title: Development and implementation of adaptive slicing and selective hatching algorithms for FDM rapid prototyping
Other Titles: Ke bian ceng gao ji xuan ze xing gu hua suan fa zai FDM kuai su cheng xing xi tong zhi shi jian
可變層高及選擇性固化算法在 FDM 快速成型系統之實踐
Authors: But, Wing-chung (畢潁聰)
Department: Dept. of Manufacturing Engineering and Engineering Management
Degree: Master of Philosophy
Issue Date: 2002
Publisher: City University of Hong Kong
Subjects: CAD/CAM systems
Computer-aided design
Manufacturing processes -- Data processing
Rapid prototyping
Notes: 217 leaves : ill. ; 30 cm.
CityU Call Number: TS176.B87 2002
Includes bibliographical references (leaves 101-106)
Thesis (M.Phil.)--City University of Hong Kong, 2002
Type: Thesis
Abstract: This project focuses on the development and implementation of adaptive slicing and selective hatching algorithms for layered manufacturing. The main objective of adaptive slicing is for tackling the compromising issue of fast building speed and high surface accuracy in Rapid Prototyping (RP). The algorithm operates upon a NURBS (Non-Uniform Rational B-splines) based CAD surface model for avoiding possible problems in connection with the commonly used STL interface, which is different from most of the existing approaches based on the STL interface. A selective hatching strategy is also used for reducing the build time while maintaining the required part accuracy. The adaptive slicing algorithm is implemented in a CADICAM software environment, namely Unigraphics, and a stand-alone experimental software module has also been developed for selective hatching. The developed algorithms have been successfully implemented in a FDM Rapid Prototyping machine. The stand-alone experimental software module works collaboratively with the QuickSlice software of the machine developer, Stratasys Inc., and the final results are sent to the FDM machine for model production. Some case studies have been simulated to illustrate the efficiency of the developed approach and some test parts have been successfully built with the developed process on a FDM RP machine. Efficiency of the developed algorithms, specific technical parameters recommended for the FDM process and the analysis of the results obtained have also been studied cope with the intensive competition in the HK construction industry, change is needed in order to maintain and improve the quality performance in a construction organization under the IS0 9000 environment. Recent studies have shown that the I-1K construction industry is facing different difficulties in the IS0 9000 implementation. Since a successful IS0 9000 implementation involves a number of critical factors, and it is difficult for an organization to focus their effort on all these critical factors at the same time. It is therefore preferable to prioritize these elements according to their relative importance in the IS0 9000 implementation. The prioritization may help the organizations in their planning for the IS0 9000 implementation. There are, however, not many studies focus on this prioritization problem, in particular in the aspect of the HK construction industry. To this end, there is a need to determine and prioritize these factors in the implementation of IS0 9000 quality system in the HK construction industry. In this study, a number of hypotheses was first identified through literature review. Then, a postal survey was conducted to test these hypotheses. Factor analysis was then used to identify a number of factors from the variables in the questionnaire of the postal survey. Based on this finding and the literature review, a set of critical factors and sub-factors were formulated to build up a 2-level hierarchy of IS0 9000 implementation factors model. The factors were used in a series of interviews of a group of professional engineers from the local construction industry. The interview results were used to prioritize the critical factors and sub-factors in the IS0 9000 implementation in the HK construction industry. Analytic Hierarchy Process (AHP) was then used in this study to determine the relative priorities among these factors. Furthermore, case studies were conducted to examine the factors of higher priority to investigate how these factors affect the IS0 9000 implementation in the contractors. Three contractors with good quality practices in IS0 9000 were invited in the case studies. 'Their experiences can be treated as recommendations or suggestions for other local contractors in the planning of practices for IS0 9000 implementation. Results and findings of this study may provide some useful guidelines for the HK construction organizations planning for IS0 9000 implementation.
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