Author

CHENGHAO ZHAO

Date of Award

2009

Degree Type

Thesis

Degree Name

Master of Applied Science (MASc)

Department

Mechanical Engineering

Supervisor

Mukesh K. Jain

Language

English

Abstract

The major advantage of the Powder Metallurgical (P/M) manufacturing
process is its ability to shape powder directly into a final component form with a
primary goal of a high quality, homogeneity of density and mechanical properties
and productivity. In this research, powder die filling, powder transfer and powder
compaction process have been studied in succession using a novel experimental
set-up that utilizes a high strength transparent wall section to observe and record
the particle movement and powder compaction during the entire sequence
leading up to the formation of a green part. The natural powder pattern itself, as
observed from the transparent wall section, is utilized for obtaining full-field
displacement and strain measurement for the first time. This strain field data is
converted into density distribution data and is validated through other commonly
used density measurement methods. The test set-up and the strain
measurement technique offer a means of quickly obtaining density distribution
data in select cases. In addition to the above, several powder flow characteristics
during die filling, powder transfer and powder compaction under a range of test
conditions have been noted through a series of high-speed photographic
recordings. The role of transfer speed and friction in the development of density
gradient and crack formation has been experimentally assessed. Another new
method of density measurement based on surface roughness of the compact has
been investigated. Finally, powder compaction simulations of the lab-based
experiments have been carried out using modified Drucker-Prager Cap model
within the ABAQUS CAE. The simulation results are in good agreement with
experimental data.

McMaster University Library


Download

Share

COinS