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LD2668 .T4 1946 S6 / Master of Science

by Li Kai Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves [112]-[113]). / Chapter chapter 1 --- INTRODUCTION --- p.1-1 / Chapter 1.1. --- Research objective --- p.1-1 / Chapter 1.2. --- Thesis organisation --- p.1-2 / Chapter chapter 2 --- BACKGROUND ON MOULD DESIGN --- p.2 1 / Chapter 2.1. --- Mould design process --- p.2-2 / Chapter 2.2. --- Basic structure of a simple two-piece mould --- p.2-4 / Chapter 2.3. --- Undercuts --- p.2-5 / Chapter 2.3.1. --- External undercut --- p.2-6 / Chapter 2.3.2. --- Internal undercut --- p.2-8 / Chapter chapter 3 --- RELATED WORKS --- p.3 1 / Chapter 3.1. --- Previous works --- p.3-1 / Chapter 3.2. --- Overview of the proposed approach --- p.3-2 / Chapter chapter 4 --- BACKGROUND THEORIES --- p.4 1 / Chapter 4.1. --- Mouldability of a part --- p.4-1 / Chapter 4.1.1. --- Mouldability with a simple 2-piece mould --- p.4-1 / Chapter 4.1.2. --- Mouldability with side core --- p.4-1 / Chapter 4.1.3. --- Mouldability with split core --- p.4-2 / Chapter 4.2. --- Solid sweep --- p.4-2 / Chapter 4.3. --- Application of solid sweep in mould design --- p.4-5 / Chapter 4.4. --- Spherical mapping and visibility mapping --- p.4-6 / Chapter 4.4.1. --- Spherical mapping --- p.4-6 / Chapter 4.4.2. --- Visibility mapping --- p.4-8 / Chapter chapter 5 --- DETERMINATION OF MAIN PARTING DIRECTION FOR SIMPLE 2-PIECE MOULD --- p.5 1 / Chapter 5.1. --- Extraction of possible main parting directions --- p.5-2 / Chapter 5.2. --- Main parting direction --- p.5-3 / Chapter 5.3. --- Ranking of main parting direction --- p.5-4 / Chapter 5.4. --- Calculation of projected area of a moulded part --- p.5-5 / Chapter 5.5. --- Creation of cavity solid --- p.5-8 / Chapter 5.6. --- Cleavage of cavity solid --- p.5-10 / Chapter 5.7. --- Undercut solid determination --- p.5-12 / Chapter 5.8. --- Difference in the application area of solid sweep and Visibility map --- p.5-13 / Chapter 5.9. --- Search strategy for parting direction of a 2-piece mould --- p.5-18 / Chapter chapter 6 --- DETERMINATION OF MAIN PARTING DIRECTION AND SIDE CORE --- p.6-1 / Chapter 6.1. --- Undercut evaluation --- p.6-2 / Chapter 6.2. --- Determination of main parting direction --- p.6-4 / Chapter 6.3. --- Determination of side core for a given main parting direction --- p.6-4 / Chapter 6.4. --- Search strategy for main parting direction and side core direction --- p.6-7 / Chapter 6.4.1. --- The search for single side core --- p.6-7 / Chapter 6.4.2. --- The search for multiple side cores --- p.6-9 / Chapter chapter 7 --- DETERMINATION OF SPLIT CORE DIRECTION --- p.7-1 / Chapter 7.1. --- Determination of split core direction --- p.7-1 / Chapter 7.2. --- Visibility check for split core --- p.7-3 / Chapter 7.3. --- Selection of split core --- p.7-3 / Chapter 7.4. --- Trajectory of split core --- p.7-5 / Chapter 7.4.1. --- Primary solid sweep --- p.7-5 / Chapter 7.4.2. --- Secondary solid sweep --- p.7-7 / Chapter 7.5. --- Interference check between split cores --- p.7-9 / Chapter 7.6. --- Search strategy for split core --- p.7-9 / Chapter chapter 8 --- HEURISTIC\DEPTH-FIRST SEARCH STRATEGY --- p.8-1 / Chapter 8.1. --- Side core determination --- p.8-1 / Chapter 8.2. --- Split core determination --- p.8-3 / Chapter chapter 9 --- EXPERIMENTAL RESULTS --- p.9-1 / Chapter chapter 10 --- COMPLEXITY ANALYSIS --- p.10-1 / Chapter 10.1. --- Determination of main parting direction and side cores --- p.10-2 / Chapter 10.2. --- Determination of side core directions --- p.10-5 / Chapter chapter 11 --- CONCLUSIONS --- p.11-1 / REFERENCES

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Investment casting has been an important form of metal casting for many years, but little is understood about the fluid flows that occur during mold filling. A key to quality castings is the understanding and control of the fluid flows that are present when the mold is filled with molten metal. It is thought that with a greater understanding of these flows, better control can be maintained and the end result will be a more efficient process that produces better parts. The subject of this thesis is the experimental study of the fluid mechanics of filling a small part mold. The experiments included tests on different downsprues, wells, runners, and chokes. The collected data were analyzed and the following recommendations were made: The shape of the downsprue, whether tapered or straight, does not seem to be important as long as the minimum area is small enough to provide the required choking. The use of a well has contributed to the smoothness of a flow, but its effect can be provided instead by chokes. Overflow chokes in the horizontal portions of the mold seem to be more effective than choking in the downsprue, but the use of both improves the flow. While runner extensions and underflow chokes might help to reduce impurities, they do little to help the smoothness of the flow. / Graduation date: 1991

Polydimethylsiloxane(PDMS) thin films have the advantages of flexible , good chemicophysical properties , low energetic surface that supports the vertical anchoring of liquid crystal molecules , could be fabricated easily by Replica Molding Method , low cost and good optically transparent. We study of the use of PDMS in flexible liquid crystal displays and the Electro-Optical properties of LC flexible cell. In experiment we use PDMS to fabricate vertical alignment layer , elastomer substrate and spacer to maintain the Electro-Optical properties in flexible displays.

Thesis (Ph. D.)--Lehigh University, 2001. / Includes vita. Includes bibliographical references (leaves 299-317).