Additive manufacturing introduces a new design paradigm that allows the fabrication of geometrically complex parts that cannot be produced by traditional manufacturing and assembly methods. Using a cellular heat exchanger as a motivational example, this thesis investigates the creation of a hybrid manufacturing approach that combines selective laser sintering with an electroforming process to produce complex, hollow, metal geometries. The developed process uses electroless nickel plating on laser sintered parts that then undergo a flash burnout procedure to remove the polymer, leaving a complex, hollow, metal part. The resulting geometries cannot be produced directly with other additive manufacturing systems. Copper electroplating and electroless nickel plating are investigated as metal coating methods. Several parametric parts are tested while developing a manufacturing process. Copper electroplating is determined to be too dependent on the geometry of the part, with large changes in plate thickness between the exterior and interior of the tested parts. Even in relatively basic cellular structures, electroplating does not plate the interior of the part. Two phases of electroless nickel plating combined with a flash burnout procedure produce the desired geometry. The tested part has a density of 3.16g/cm3 and withstands pressures up to 25MPa. The cellular part produced has a nickel plate thickness of 800µm and consists of 35% nickel and 65% air (empty space). Detailed procedures are included for the electroplating and electroless plating processes developed. / Master of Science

I investigated two unique processes developed throughout this body of work. The first technique is the cracking and lifting of an electroformed layer from a core vessel form. The second process, that I named “crunch-raising”, is used to form vessels. General data is gathered through research of traditional metalsmithing processes. Using an individualized approach, new data is gathered through extensive experimentation to develop a knowledge base because specific reference information does not currently exist. I find that an electroformed layer can be lifted from a core form with extreme torch heat to reveal the underlining vessel. I also find that the “crunch-raising” technique leaves a rippled texture in the surface of a vessel as it is being formed. I conclude that the project is successful. It is quite significant in that it has given me a personal vocabulary to define my current work.

This study presents a novel concept to integrated nebulizer nozzle plate for FD-ESI (Fused-droplet Electrospary Ionization Mass Spectrometry) using modified LIGA process. This fabrication technique can reduce the production cost of current nozzle plate. It comprises of multi-exposure and single develop (MESD) process, the extra-hard Ni-Co (Nickel-Cobalt) electroforming and thin-wall plastic microinjection molding. The template of nozzle plate is patterned using dry film and MESD process. Later, the template is transferred into metal Ni-Co mold by electroplating. In this study, the technique of extra-hard Ni-Co alloy electroplating process with Hardness of Vickers over (HV) 550 is developed. Then with the stiffness of Ni-Co mold, it can withstand high injection speed. Thin-wall microinjection molding process with short cycle time to fabricate nozzle plate can be finished. Liquid crystal polymer (LCP) is used for thin-wall microinjection molding process. In order to make efficiently atomization, we used ANSYS to optimize PZT actuator. Besides, the work of nebulizer with FD-ESI was demonstrated in this study. a novel design of nozzle plate.

Abstract The conventional hydrophilic electrode used to spray the catalyst on the level-off carbon layer and the utilization of catalysts can only be reacted between the gas and the catalyst; however, the internal catalyst of the proton exchange membrane cannot be reacted. In order to increase the reaction of the catalyst, the hydrophobic pillared micro structures (HPMS) are made on the carbon layer, so that the gas can reach the catalyst in the internal membrane so that a reaction on large surface between the gas and the catalyst can be achieved. It is easier to build the gas channel in the internal HPMS than the structures of the carbon layer. As a result, more gas can be sent to the internal catalyst thus enlarging the reaction zone and more reactions between the gas and the catalyst is then achieved. The carbon powder is sprayed in the conventional HPMS in the deposition process. The HPMS are formed after the gravity process while the powder is passing the metal netmask and the manufacturing time is long. The experimental design uses electroforming to make the micro porous structure so that the hydrophobic carbon layer can be stamped thereby forming the HPMS. It has been proven that the time for the manufacturing process can be shortened if the micro structured metal template is applied. The micro structured metal template is used to stamp the small and large HPMS on the side electrode of the cathode, the stamping HPMS pressure was 500kg/cm2. With the same catalyst quantity the surface of the small HPMS was raised 63% and its performance was up to 55%; the surface of the large HPMS was raised 30% and its performance was up to 30%. The catalyst quantity of the cathode was reduced from 0.5mg/cm2 to 0.25 mg/cm2 and its performance remains the same. The experiment¡¦s results indicate that the reaction of the catalyst was only on the surface between the gas and the catalyst. Either small or large HPMS or after reducing the catalyst quantity can all raise the performance of the fuel cell as well as economize the catalyst. And by two kind of different size dimension microstructure metal template manufacture small or large HPMS, the electrode power density all may achieve 720mW/cm2 and 595mW/cm2.

To survive in today's manufacturing environments companies must push the standards of accuracy and speed to the highest levels possible. Electro Discharge Machining (EDM) has been used for over 50 years and recent developments have seen the use of EDM become much more viable. The goal of this research is to produce and evaluate electrodes produced by different manufacturing methods. The use of electroforming and spray-metal deposition has only recently become viable methods of producing usable rapid tooling components. The speed and accuracy as well as the cost of manufacture play a vital role in the tool and mould manufacturing process. Electroforming and spray-metal deposition offer an alternate option to traditional machining of electrodes. Electroforming is one method of producing electrodes for EDM. The fact that electroforming can be used to produce multiple electrodes simultaneously gives it the advantage of saving on costs when multiple electrodes are needed. Spray-metal deposition offers another alternative that is much cheaper and relatively faster to manufacture. The used of these non-traditional manufacturing methods in this research are compared to the performance of traditional solid electrodes in terms of machining time, material removal rate, tool wear rates and surface roughness at several standard machining settings. The results of this research are presented in this thesis along with conclusions and comments on the performance of the different methods of electrode manufacture. The major findings of the research include the solid electrodes performed better than the electroformed electrodes in Material Removal Rate (MRR), Tool Wear Rate (TWR), and Surface Roughness (Ra) at all machine settings. However it was found that the production cost of the solid electrodes was six times that of the electroformed electrodes. The production of spray metal electrodes was unsuccessful. The electrode shell walls were not an even thickness and the backing material broke through the shell making them unusable. It is concluded that with further refinements and research, electroforming and spray metal processes will become an extremely competitive method in electrode manufacture and other rapid tooling processes.

Thesis (Ph. D.)--University of Massachusetts Amherst, 2009. / Includes bibliographical references (p. 153-161). Print copy also available.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2006. / Bibliography: leaves 83-91. Also available online.

Doctorat en Sciences / info:eu-repo/semantics/nonPublished

At best anger is problematic for most of us and especially an issue for women (and other discriminated groups). True a collaborative craft project focusing on silver objects, I investigate female anger and how it is perceived. Also, how the prevention of acting it out silences our need for change. I use the aesthetics of magic to reference the judging of women acting outside of set rules, and also as a tactic of female liberation.

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