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

Author

Sriram Praneeth Isanaka, Missouri University of Science and TechnologyFollow

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 -140 °C 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 coat was identified using contact angles measured with high resolution digital photography, and was found to be teflon which made a contact angle of 105° 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, page iv.

Advisor(s)

Leu, M. C. (Ming-Chuan)

Committee Member(s)

Richards, Von
Tsai, Hai-Lung

Department(s)

Mechanical and Aerospace Engineering

Degree Name

M.S. in Mechanical Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Spring 2009

Journal article titles appearing in thesis/dissertation

• Rapid Freeze Prototyping of Investment Cast Thin-Wall Metal Matrix Composites I - Pattern Build and Molding Parameters
• Improving build speed in Rapid Freeze Prototyping through increase of heat transfer

Pagination

ix, 44 pages

Note about bibliography

Includes bibliographical references (pages 41-43).

Rights

© 2009 Sriram Praneeth Isanaka, All rights reserved.

Document Type

Thesis - Restricted Access

File Type

text

Language

English

Subject Headings

Heat -- Transmission
Manufacturing processes
Rapid prototyping

Thesis Number

T 9488

Print OCLC #

436221105

Link to Catalog Record

Electronic access to the full-text of this document is restricted to Missouri S&T users. Otherwise, request this publication directly from Missouri S&T Library or contact your local library.

Recommended Citation

Isanaka, Sriram Praneeth, "Increase of heat transfer to reduce build time in rapid freeze prototyping" (2009). Masters Theses. 85.
https://scholarsmine.mst.edu/masters_theses/85