Title: Effect of cooled compressed air on the machining force and surface roughness generated by face milling of CW50/PEEK

Authors: Carlos A.G. Aita; André J. Souza; Émerson S. Passari; Arnaldo R. Gonzalez; Guilherme V. Schirmer; Jeferson S. Jesus

Addresses: Department of Mechanical Engineering (DEMEC), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil ' Department of Mechanical Engineering (DEMEC), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil ' Department of Mechanical Engineering (DEMEC), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil ' Department of Mechanical Engineering (DEMEC), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil ' Department of Mechanical Engineering (DEMEC), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil ' Department of Mechanical Engineering (DEMEC), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil

Abstract: This study examines the effect of cooled compressed air (CCA) at -60°C on machining force (F_U) and surface roughness (R_a) during face milling of CW50/PEEK. A 3-factor, 3-level Box-Behnken-based Response Surface Methodology was applied to design and analysis the experiments. Results show that CCA reduced F_U by 25% and R_a by 30% compared to DRY cutting. Abbott-Firestone curve and probability density function confirmed improved surface quality with CCA. SEM images exhibited surface defects in DRY-machined samples, which were absent in CCA samples. Then, CCA can minimise matrix softening, enhance brittleness, reduce cutting forces, facilitate chip formation, and prevent surface defects. Finally, overlaid contour plots indicated that the lowest F_U and R_a values in DRY milling are achieved with a low axial depth of cut (a_p), low feed rate (f_z), and medium cutting speed (v_c), while with CCA, the optimal levels are low a_p, low f_z, and low or high v_c.

Keywords: face milling; CW50/PEEK; machining force; surface roughness; Box-Behnken design; BBD; Abbott-Firestone curve; AFC; probability density function; PDF; scanning electron microscope; SEM.

DOI: 10.1504/IJMMM.2025.150052

International Journal of Machining and Machinability of Materials, 2025 Vol.27 No.4, pp.345 - 368

Received: 27 Sep 2024
Accepted: 12 Jan 2025
Published online: 28 Nov 2025 *

Full-text access for editors Full-text access for subscribers Purchase this article Comment on this article