Abstract
Micro-milling is an inevitable machining process for the fabrication of products with complex shapes and high dimensional accuracy. However, this process usually needs post-processing operations to remove the burrs formed from the ductile materials. This research work focuses on the development of a micro-milling strategy to suppress the formation of burrs during machining and hence avoid post-processing operations, consequently reducing the cost of the products. During micro-milling, a LN2 jet was positioned ahead of the tool movement loci resulting in a change of microstructure at the top layer of the workpiece surface, enhancing its mechanical properties with the subsequent reduction of excessive plastic flow during the shearing process. Micro-hardness tests were performed below the top layer to conform the speculation and evaluate the effect of cryogenic treatment and a significant increase in micro-hardness was found. The experimental results reveal a significant decrease in the burrs formation due to the cryogenic treatment with an enhanced machining quality in terms of cutting forces, chip morphology and surface roughness.
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•Cryogenic assisted micro-milling of material with high ductility•Analysis of burr formation and effect of cryogenic environment•Vibration of tool in longitudinal direction at ultrasonic frequency and low amplitude•Analysis of the machining performance in terms of cutting forces, tool wear, chip morphology and micro-hardness•Reduction in burr formation was found by the application of cryogenic assistance over the work surface.