Award Date

1-1-2004

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Mechanical Engineering

First Committee Member

Zhiyong Wang

Number of Pages

105

Abstract

This research investigates the phenomenon that cryogenic cooling can significantly improve the cutting tool life and the workpiece quality in hybrid machining of advanced materials, such as Reaction Bonded Silicone Nitride (RBSN). Several finite element models are developed in order to analyze the temperature fields developed and the stress distributions in the Polycrystalline Cubic Boron Nitride (PCBN) cutting insert during a hybrid turning process. The analyses performed reveal that the hybrid machining with cryogenic cooling of the cutting tool leads to a decrease of stresses in the cutting insert, especially when micro-cracks are present in the insert exhibits. It is found that a decrease in cutting temperature from 1740°C to 597°C led to approximately 660 stress reduction at the tip of the micro-cracks on the flank face of the cutting tool, thus significantly reducing the wear rate of the cutting insert. The findings are consistent with previously published experimental data.

Keywords

Cbn; Ceramic; Crack; Crack Propagation; Cubic Boron Nitride; Hybrid; Hybrid Machining; Insert; Machining; Propagation; Rbsn; Reaction-bonded Silicon Nitride

Controlled Subject

Mechanical engineering

File Format

pdf

File Size

2416.64 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

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