Increase of heat transfer to reduce build time in rapid freeze prototyping
"The main objective of this research is to reduce part build time by increasing heat transfer from the ice parts built using the Rapid Freeze Prototyping (RFP) process. An investigation into the smallest thickness that can be achieved by the RFP process was also conducted, with the factors that could affect the thickness of the part built including substrate temperature, volumetric feed rate, table velocity, nozzle frequency, nozzle standoff distance, and head pressure were considered. A mechanism has been devised to cool the substrate to as low as -140⁰C for reduction of part build time. The mechanism, although effective for parts of small heights, proved ineffective with increase in height of ice parts. Others means like the use of forced convection and the concept of chilling plates were investigated. Forced convection produced desirable reduction in part build time with the undesirable formation of frost on the ice parts. The use of chilling plates was developed to enable effective transfer of heat with the aid of conduction. To ensure that the frozen ice from the deposited water can be easily removed from the chilling plates, various surface coats including latex, mylar, and teflon were investigated. the most effective surface coast was identified using contact angles measured with high resolution digital photography, and was found to be teflon which made a contact angle of 105⁰ with water. The experimental results were substantiated with simulations performed using Fluent. The improvements in the build speed after incorporating the chilling plates were measured to verify the trends predicted from the simulations. We have successfully achieved a 75% reduction in part build time with the use of chilling plates coated with teflon films of thickness 0.1 mm"--Abstract, leaf iv.
Leu, M. C. (Ming-Chuan)
Mechanical and Aerospace Engineering
M.S. in Mechanical Engineering
Missouri University of Science and Technology
ix, 44 leaves
© 2009 Sriram Praneeth Isanaka, All rights reserved.
Thesis - Citation
Library of Congress Subject Headings
Heat -- Transmission
Print OCLC #
Link to Catalog Record
Isanaka, Sriram P., "Increase of heat transfer to reduce build time in rapid freeze prototyping" (2009). Masters Theses. 85.