Micro-machining of nano-polymer composites reinforced with graphene and nano-clay fillers

Following a comprehensive review of nanocomposite materials and their machinability, this paper details experimental results from the micro-slotting of two different nanocomposites reinforced with graphene platelets and nano-clay fillers as opposed to their base material matrix. The evaluation includes the quality of machined surfaces characterised by SEM, cutting forces monitored using force dynamometry, and surface roughness measured using both contact and non-contact techniques. The evaluation included four filler percentages by weight between 0.1 and 1% in addition to 0% with the plain matrix material. The effect of feed rate is also evaluated at 3 levels (10, 20 and 30 µm/rev) with cutting speed at 4 levels (15.7, 31.4, 62.8 and 94.2 m/min). Dry cutting experiments were performed on an ultra-precision desktop micro-machine tool. Uncoated tungsten carbide end mills 1 mm in dimeter were used in all tests. Surface roughness increased gradually with feed rate while cutting speed had no effect. Ra values ranged from 0.1 – 0.35 µm. Common increases in cutting forces with either feed rate or cutting speed were observed. Forces in general were higher for the material reinforced with 0.3–0.5% nano-filler. Negligible tool wear occurred following the cutting of 140 slots of 100 µm depth (removing 182 mm³ of the material).