Material Effects and Tool Wear in Vibration-Assisted Machining

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Abstract

Research Method

Results

Supporting Materials

Abstract

The research objective of this new NSF award is to test the hypothesis that micrometer-amplitude vibration of a diamond cutting tool will reduce forces, improve surface finish and decrease wear of the tool. Faculty members and graduate students in material science and mechanical engineering will measure and model the material removal process and define the parameters that control tool forces, tool wear and surface finish for the selected materials. Materials have been chosen to provide a range of physical and chemical properties that will test proposed concepts of material flow, temperature generation and wear mechanisms. Unique techniques for measuring the chip geometry, surface finish, tool edge sharpness and diffusion of the carbon from the tool to the chip/work piece will be used to describe the details of the process. This project will quantify the vibration conditions needed to create high-quality surfaces on materials such as steel, glass or ceramics that were thought to rapidly wear diamond tools. Steel is the most frequently used engineering material due to its excellent properties, availability and low cost. A national and global demand for ultra-precision steel parts and systems with sub-micrometer accuracy exists in automotive, medical and optical industries. Precision glass and ceramic components are also in high demand.

Vibration assisted machining (VAM) has been incorporated in precision machining processes since the early 90s, and has proven benefits when compared to standard DT such as reduced tool forces and tool wear. During the VAM process, the tool is lifted from the work piece and returned to cutting in cyclic manner at high frequencies (1000s of Hz). This motion leads to improvements in tool wear and forces, yet maintains high quality surface finishes. Due to the virtues of VAM, materials that were previously deemed unfit for machining because of their high abrasiveness, brittleness, or high ferrous content, can be machined to optical quality finish. While these benefits are remarked upon in numerous scientific articles, results are empirical, and no one has addressed the scientific principles behind VAM, nor quantified these improvements with regard to changing process parameters. This project will study this machining process in detail, quantify improvements in surface finish and tool wear, and elucidate the reasons why such improvements are possible.

Research Method

Results

Supporting Materials

The following faculty, students, and PEC affiliates are involved in this project: