Brian Hoefler

Publication Date

1997

Document Type

Dissertation/Thesis

First Advisor

Nagy, Peter Victor

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Mechanical Engineering

LCSH

Metal-cutting--Simulation methods; Time-domain analysis

Abstract

Global competitiveness is forcing manufacturing companies to make a critical review of every aspect of their businesses. In most machine shops, the profit margin is typically quite low. Optimized processing is required to ensure a profit. Simulation of metal-cutting processes provides substantial opportunities for enhancing throughput, decreasing costs and improving product quality. The use of computer simulations to avoid unstable cutting processes is one area where significant gains can be realized. Time domain simulation models were developed for both plunge feed turning and slender endmilling. Simulations were conducted using C++ computer programs. Chatter (i.e., excessive tool vibration) is shown to exist beyond a stability limit of chip width for both cases. Sinusoidal varying tool displacements are demonstrated to contribute to regenerative surface waviness (i.e., causing varying chip thickness) for all chip widths. A nominal tool displacement that is proportional to chip width arises due to the tool compliance and force exerted on the tool. When chip widths are below a limiting size for stability, displacement amplitudes decay towards the nominal tool displacement value. For chip widths at the stability limit, a constant amplitude of the tool displacement around the nominal value occurs. A constant growth of the displacement amplitude occurs for chip widths above the stability limit. Generally, the growth rate in the amplitude is fester for larger amounts of excessive chip widths. However, the amplitude growth is limited when the tool momentarily and repeatedly leaves the cut corresponding to chatter. Experimental verification was performed utilizing a Kistler force dynamometer, a Tektronix data acquisition system, a Renault lathe and a Mori-Seiki machining center. Good correlation was achieved between experiments and simulations.

Comments

Includes bibliographical references (pages [90]-93)

Extent

viii, 102 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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