Modulation-Assisted Machining
Abstract
Chip formation in machining occurs by severe plastic deformation. The specific energy of material removal in machining is large compared to various deformation processes, being determined by the energy dissipated at the shear plane, and in the secondary deformation zone of the tool-chip contact along the rake face. It has been known for some time now that the application of a controlled low-frequency modulation to the machining, a process called modulation-assisted machining (MAM), has many benefits including discrete chip formation, enhancement of fluid action at the tool-chip contact, and altering the mechanics of chip formation. Furthermore, the morphology and structure of the chip at different length scales are controllable by the modulation conditions, including creation of discrete chips with controlled shape and size. To better study MAM and its capabilities, a compact piezo-actuated modulation device and associated experimental measurement system was developed. The performance of the modulation device has been characterized over a range of modulation conditions. This device/system overcomes major barriers to study and implementation of MAM, by enabling access to a wide range of controllable MAM conditions in frequency-amplitude space. This new system has enabled controlled examination of MAM, including the mechanics of chip formation and chip morphology, deformation levels in the chip, fluid effects, and energy dissipation. The capability to achieve important benefits such as enhanced machining performance through chip management, reduction of thermo-mechanical wear, production of metal fibers and particulate, and surface texturing are demonstrated in exploratory studies using the modulation system. Implications for industrial implementation of MAM in various machining configurations are discussed.
Degree
Ph.D.
Advisors
Compton, Purdue University.
Subject Area
Industrial engineering|Mechanical engineering|Materials science
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