Ph.D. Proposal Presentation by JingYing Zhang
Wednesday, April 21, 2004

(Dr. Steven Liang, Chair)

"Process Optimization for Machining of Hardened Steel"


The objective of the proposed research is to develop a scientific,
systematic and reliable methodology to design optimal tool geometry (edge
preparation, clearance angle, tool nose radius, etc) and cutting condition
(cutting speed, feed rate and depth of cut) to achieve specified process
performance goals under the satisfactory surface finish (surface roughness,
white layer thickness and residual stress distribution) and any other
practical constraints, such as tool wear, available horsepower, dynamic
stability for the hard turning process. In order to achieve this goal, a
comprehensive modeling scheme and novel optimization strategies will be

Part performance is decisively influenced by the finishing process which is
usually undertaken by grinding. With the advent of Polycrystalline Cubic
Boron Nitride (PCBN) cutting tools, hard turning has the potential to take
the place of traditional grinding process because it offers comparable part
finish, lower production cost, shorter cycle time, fewer process steps,
higher flexibility and the elimination of environmentally hazardous cutting
fluids. However, there are still several fundamental issues to be solved in
order for hard turning to be a viable technology, such as form accuracy,
surface integrity, process planning and optimization. Optimization of
cutting condition and tool geometry is becoming crucial so that hard turning
process can obtain the longer tool life, better surface integrity and higher
precision. Various experimental, numerical, and analytical studies of hard
turning have been made available; however they are fragmented and
uncorrelated pieces of information that cannot be used for process planning
in an effective manner. A suitable modeling scheme to use the existing
experimental, numerical and analytical knowledge into the process planning
is desired. Furthermore, due to the complex nature of the hard turning
process, a systematic optimization method based on evolutionary algorithms
is proposed to deal with a general class of hard turning optimization