(Dr. Steven Liang, advisor)

"Hard Turning Tests for Surface Integrity and Tool Performance"

Abstract

Precision hard turning provides an alternative to grinding in many finishing applications; it represents a significant potential economic savings. Yet, the thermo mechanics mechanisms of white layers formation on the machined surface and the positive residual stress are not completely understood and controlled which lead to some problems in the application of hard turning.

An experimental study was performed to investigate the influence and the interactions of the cutting parameters (speed, feed, depth of cut, flank wear) on these phenomena. The Design Of Experiment (DOE) method has been used to run turning tests in the special application of a hardened wheel hub of 62HRC. Temperature, forces, white layer depth and residual stress profile data have been collected and analyzed to be able to provide reliable information. The results will help in the decision of choosing cutting parameters in this particular case.

The first results after the rough tests show the following interesting results:

• White layers can occur even with a fresh tool.
• Temperature influences directly the white layer formation and residual stress.
• Feed and speed tend to have more contribution on the white layer depth than the depth of cut.