Masters Theses

Title

Increase of heat transfer to reduce build time in rapid freeze prototyping

Abstract

"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.

Advisor(s)

Leu, M. C. (Ming-Chuan)

Committee Member(s)

Tsai, Hai-Lung
Richards, Von

Department(s)

Mechanical and Aerospace Engineering

Degree Name

M.S. in Mechanical Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Spring 2009

Pagination

ix, 44 leaves

Note about bibliography

Includes bibliographical references (pages 147-150).

Rights

© 2009 Sriram Praneeth Isanaka, All rights reserved.

Document Type

Thesis - Citation

File Type

text

Language

English

Library of Congress Subject Headings

Heat -- Transmission
Manufacturing processes
Rapid prototyping

Thesis Number

T 9488

Print OCLC #

436221105

Link to Catalog Record

Full-text not available: Request this publication directly from Missouri S&T Library or contact your local library.

http://laurel.lso.missouri.edu/record=b7077110~S5

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