Drilling Behavior of Flax/Poly(Lactic Acid) Bio-Composite Laminates: An Experimental Investigation

This paper aims to investigate the effects of machining parameters such as spindle speed, feed rate and drill diameter on machinability of flax/poly(lactic acid) bio-composites, to analyze the relations among cutting forces, drilling-induced damages and crack propagation of the drilled samples. In particular, a set of drilling experiments were conducted using different drilling conditions and a new low-cost measurement set-up was developed to measure the cutting force during the drilling operation. In addition, the analysis of variance (ANOVA) was applied to identify the significance of each individual cutting parameter. The experimental results indicate the relation between the thrust force and the machinability parameters of flax fiber reinforced bio-composite. The increase in spindle speed reduces thrust force and delamination size of the drilled holes, whereas an increase in feed and drill diameter leads to a considerable increase in both thrust force and delamination factor. The effect of spindle speed on peripheral damage was not significant for the drills tested, though the feed rate was found to play the key role on the delamination damage area. The best hole quality was achieved with the samples drilled at spindle speed and feed rate of 3000 rpm and 0.11 mm/rev, respectively.