Experimental Study on the Cutting Forces in PTFE Orthogonal Cutting

The study aims at analysing the effect of the glass micro fiber content on the variation of the cutting forces in the orthogonal turning process of two types of polytetrafluoroethylene: PTFE and PTFE S25 (25 [wt%] glass micro fibers) with a polycrystaline diamond (PCD) tool. The influence of the process parametres (cutting speed and feed rate), as well as that of the geometrical parametres of the cutting part of the tool (rake angle gamma when the clearance angle alpha and the incidence angle chi are constant) on the two components of the cutting force (cutting force, F-z, and feed force, F-x). The values of the turning forces were recorded with a Kistler piezoelectric dynamometer (type 9257B). Experimental results indicated that the value of the cutting force decreases with the increase of the cutting speed. Moreover, the glass microfiber content influences the value decrease of the main cutting force component. A statistical mathematical model, determined by linear regression, was developed to analyze the influence of varying parametres on the cutting force components (F-z and F-x).