Experimental investigation on LASER cutting performance of sustainable polylactic acid (PLA)/Azolla pinnata (AZP) bio composites using Box–Behnken design (BBD)

Biodegradable polylactic acid (PLA) - based bio composites have attracted considerable interest as sustainable engineering materials owing to their biodegradability and environmental compatibility. Despite their growing potential, the machining behaviour of PLA/Azolla pinnata (AZP) bio composites under CO 2 laser processing has received limited attention, particularly with respect to the combined influence of reinforcement content and machining parameters on cut quality. Therefore, this study investigates the CO 2 laser machining characteristics of solvent-casting PLA/AZP bio composites containing 10, 20, and 30 wt% AZP. A four-factor, three-level Box–Behnken Design (BBD) was employed to evaluate the effects of cutting speed (10–20 mm/s), laser power (30–40 W), pulse frequency (20–40 kHz), and AZP content on material removal rate (MRR), kerf angle, and heat-affected zone (HAZ). Analysis of variance revealed that laser power was the most influential factor affecting MRR (21.5%), whereas pulse frequency and cutting speed predominantly governed kerf angle (26.3%) and HAZ (14.4%), respectively. The developed response surface models demonstrated satisfactory predictive capability for the investigated machining responses. Multi-response optimization identified the optimum machining conditions as a cutting speed of 20 mm/s, laser power of 40 W, pulse frequency of 40 kHz, and AZP content of 10 wt%, corresponding to a desirability value of 0.8658. Under these conditions, the predicted MRR, HAZ, and kerf angle were 0.24,725 g/min, 0.41,344 mm, and 0.315°, respectively. The findings demonstrate that appropriate selection of CO 2 laser processing parameters can significantly improve the machining quality of PLA/AZP bio composites and provide a useful reference for the precision machining and process optimization of sustainable bio-based composite materials.