For the past 40 years, metal additive manufacturing (AM) technologies with the capability of fabricating highly complex metal components with virtually no geometrical limitations, have enabled new opportunities in product designs and performance, while reducing total cost and shortening lead time, improving material efficiency and creating more sustainable products. A significant attention and interest of manufacturing industry lies on where metal AM can replace or improve production capability of traditional manufacturing (TM). Currently, the inherent difference between metal AM and TM leads to two separate manufacturing regions: metal AM is best suited for producing complex parts in small quantities while TM dominates high volume production. While metal AM processes are capable of providing individually designed products with a high level of details, TM processes with their fast, precise, and efficient production in combination with the long-established, quality assured, and widely implemented manufacturing techniques makes the competition incredibly difficult for AM when it comes to high volume production.As metal AM field evolves with an increasing demand in highly complex and customizable products, there is a critical need to fill in the gap in terms of production speed between metal AM and TM processes. This dissertation presents the development of the scalable and expeditious additive manufacturing (SEAM) process, which hybridizes binder jet printing and stereolithography principles, capitalizes on their advantages to produce a new metal AM processing route. The SEAM process is not only suitable for high production environment but also capable of fabricating components with excellent accuracy and resolution. Once fully developed, the process is well suited to bridge the productivity gap between metal AM and TM processes, making it an attractive candidate for further development and future commercialization as a solution to high production AM.After several proof-of-concepts, two fully functional prototypes were designed specifically for the processing of metal suspension, and subsequently constructed at Michigan State University. The relationships between cure depth and metal particle size for several metal suspensions were characterized, whose results were used to determine the appropriate processing conditions for each suspension. An innovative 2-step curing strategy was devised and applied to the printing process, which not only prevents sedimentation of metal powder particles in the print bed but also enables the fabrication of overhang geometry without supporting structures. Using the developed printing technique and processing parameters, 3D green objects were successfully fabricated for all the metallic alloys of interests. A series of experiments were subsequently carried out to characterize the thermal decomposition of the photopolymer, whose results were used to develop a debinding cycle that completely removes the binder while maintaining part structural integrity. The activated liquid phase sintering process of SS420 parts were optimized by utilizing analysis of variance, which arrived at an optimal sintering condition that produce parts with above 99.7 % relative density without any geometrical distortion. For Haynes 214, the supersolidus sintering behavior was characterized with respect to sintering temperature and holding time. The transient deformation behavior of the sintered parts with respect to holding time and temperature was also captured, whose results were capitalized to develop a 2-step sintering technique to produce fully dense parts with complete shape retention. The development of a numerical sintering model, the Olevsky-Skorohod model, was studied and implemented in a finite element analysis software, which can be used to aid the prediction of part density evolution and deformation during the sintering process.
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