Evaluating the influence of reinforcing fiber type on the grinding process of PEEK’s composites

Polyether ether ketone (PEEK) and its composites are widely used in the biomedical industry due to their superior properties. The presence of glass and carbon reinforcing particles will improve the strength of the polymers while affecting their machinability. The cutting speed, dressing speed ratio, and different reinforcing fibers were defined as input parameters. Grinding forces, specific grinding energy, surface roughness, the surface topography of the workpiece, and wheel loading ratio were selected as output parameters of this research. Surface roughness is strongly affected by heat generation in the grinding zone. The experiments showed that pure polymer, GFRP (glass fiber–reinforced plastic), and CFRP (carbon fiber–reinforced plastic) induce maximum wheel loading ratio, respectively. The maximum wheel loading was calculated as 31% for pure polymer, and the main mechanism is melting. The highest cutting forces were measured when grinding pure polymer, followed by carbon, and glass fiber composites. The grinding forces were also affected by wheel loading ratio. Normal and tangential grinding forces increased up to 67% and 57%, respectively, by severe cutting conditions. The minimum specific grinding energy of PEEK and its composites was around 2.5 J/mm 3 . Additionally, increasing the cutting speed to v c = 15 m/s (despite lower inducing cutting forces) and decreasing the dressing speed ratio to q d = −0.3 surprisingly caused a rise in the roughness of the ground surfaces (for all three materials) due to a higher heat generation in the contact zone.