Dynamic analysis of ultrasonic vibration assistant machining system

• Main Author: Chua, Danny Han Kwang.
• Other Authors: Lin Rongming
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/40212
• Institution: Nanyang Technological University

Vibration assisted machining has been proven many times for its capability to improve fabrication processes. In the conventional use of vibration assisted machining, vibratory motion is more often applied to the cutting tool in processes such as turning where the cutting speed is much lower than the vibration speed in order to obtain intermittent cutting. In contrast, this study investigates vibration assistance that is applied to the workpiece in a milling system where the cutting speed is much higher than the vibration speed. The vibratory cutting edge motion in such a milling system is expected to reduce the cusp error resulted from peripheral milling. To verify this, a one-directional ultrasonic vibration assisted milling system is designed and its machining dynamics is investigated in terms of its modal structure and machined surface quality. A modal analysis is first performed on the milling system to obtain its natural frequencies and other modal parameters. Machining tests are then performed with different machining conditions of spindle speed, feed rate and depth of cut to further understand the mechanism of ultrasonic vibration assistance for surface roughness generation. In general, an improvement in surface roughness is observed with an increase in feed per tooth in both feed directional and cross feed directional ultrasonic vibration assisted milling. Some explanations are offered to support these results at the end of this study.