MACHINING CFRP: COMPARATIVE PERFORMANCE OF CNC MACHINE TOOL AND SERIAL-KINEMATIC ROBOT

Recycled carbon-fiber composites are gaining importance as industries pursue more sustainable material strategies, yet their heterogeneous microstructures and reduced stiffness make them challenging to machine consistently. This study compares how a conventional 5-axis CNC machining center and an industrial robotic system perform when milling and drilling recycled CFRPs, with the goal of understanding how machine rigidity and process stability influence both material integrity and energy use.

A set of controlled experiments was carried out to measure cutting forces, spindle torque, power consumption, and surface quality across varying feed rates, spindle speeds, and tool engagement conditions. These tests reveal how each platform’s structural stiffness and motion-control design shape its response to the dynamic demands of machining recycled composites, which are particularly vulnerable to deflection-induced damage and unstable cutting, compared to first-use CFRP laminates.

The results show that the CNC system consistently provides higher stability which produces smaller force-induced deviations, lower specific energy consumption, and cleaner surface benefits that help preserve the already variable structure of recycled CFRPs. The robotic system, while more compliant, performs well in machining recycled CFRPs under optimized low-load conditions, indicating its potential for flexible machining tasks where adaptability and workspace size outweigh the need for high precision.

Overall, this work offers new insight into how recycled CFRPs can be machined more reliably and sustainably. By clarifying the respective strengths of CNC and robotic platforms, the study supports informed integration of both technologies into future recycling and remanufacturing workflows.