Effect of minimum quantity lubrication on surface roughness in micro-milling.

摘要

The size of micro machined pans is decreasing and complexity is increasing. A very high tolerance and good surface finish is required to comply with these miniature products. Application of cutting fluid has significant influence on the surface finish. Because the use of flood cooling causes economic and environmental problems, an alternative is desired. Two potential alterations are dry machining and Minimum Quantity Lubrication (MQL) machining. MQL delivers small amounts of fluid precisely to the cutting zone.;This research experimentally investigated the effect of the MQL on the surface roughness when micro milling is carried out on stainless steel 304. A full factorial design with four levels of feed, two levels of spindle speed, and MQL or dry were performed. Both the sidewall and floor surface roughness were measured and analyzed. The MQL significantly affected the floor surface roughness in terms of 3D arithmetic average surface roughness index Sa. The improvement of the surface roughness with MQL is pronounced at feed rates lower than 1.6 mum/flute with over 50% reduction in Sa values. The MQL has negligible influence on the sidewall surface roughness in terms of Sa. However, when 2D sidewall surface roughness, Ra, along the feed direction was analyzed, MQL is found to be significantly better than dry machining.