Analysis of single-grain interference mechanics based on material removal and plastic stacking mechanisms in nanofluid minimum quantity lubrication grinding

摘要

Numerous researchers made theoretical and experimental approaches for force prediction in surface grinding under dry condition. However, the combined effect of both material removal and plastic stacking on single-grain interference mechanics has not been reported yet. The main objective of the work presents to propose an single-grain interference mechanics with the consideration of material removal and plastic stacking mechanism. Interference action of a single grain and plastic/fracture deformation condition of workpiece material were analysis, critical stress was obtained. Further, scratch test of single-grain was carried out under nanofluids minimum quality lubrication. the relationship of grain-cutting efficiency (β) and cutting depth (a_g) was obtained. Results indicated that the variation trend of the β presents an S-shaped trend as the a_g increases. Grain states, including cutting and ploughing, are decided by cutting efficiency (β). For experiment implemented scratch tests of workpiece material (stainless steel 440 C, Ra = 0.04-0.05 μm), the plough phenomenon appeared at a_g=0.023 μm, that is, the range 0-0.023 μm indicates the sliding stage. The cutting stage started at a_g=2.84μm. Unlike traditional grinding theory, after the end of the ploughing stage, the β curve suddenly increased and then entered the transition stage. The transition from the ploughing stage into the cutting stage is a progressive process. After cutting stage, β gradually tended to be a constant.