Characterization of Kerf Surface Using Complementary Roughness Descriptors in Abrasive Waterjet Cutting of Kevlar Fiber-Reinforced Polymers

Abrasive waterjet cutting (AWJC) is widely used for processing Kevlar-reinforced polymer composites; however, surface quality is typically assessed using amplitude-based roughness parameters like Ra and Rz, which offer limited insight into the overall morphology of the machined surface. This study investigates the use of complementary roughness descriptors—focusing on profile height, distribution, spacing, and slope—to characterize the kerf wall morphology generated during the cutting process. Measurements were performed across different zones of the kerf wall under varied cutting conditions, enabling the examination of how specific process parameters influence these descriptors. All investigated parameters significantly influenced the four roughness descriptors, which proved to be strongly inter-correlated, reflecting a unified material removal mechanism. Furthermore, a clear distinction was highlighted between the smooth, uniform top zone and the rougher bottom zone featuring diagonal striations, confirming the sensitivity of these descriptors to local variations in cutting conditions.