Polymeric matrix composite materials presents advantages in a great number of applications due to their high specific strength and stiffness, wear resistance, dimensional stability, low weight and directional properties. As result of these properties and potentials applications exists a strong need to understand the manufacturing processes, particularly the machining process of these composite materials. This paper presents an investigation above the modelization of the cut, turning of small workpieces, on two materials: a polymer PA 6 (Polyamide) and a composite PA 66-GF30 (reinforced with 30% of glass fiber). The tests were carried out polycrystalline diamond tools (PCD). The objective of this experimental study is to evaluate the influence of the glass fiber reinforcement on the friction angle (rho), shear angle (phi), normal and shear stresses (sigma, tau), chip deformation (epsilon) under the cutting parameters prefixed (cutting velocity and feed rate). The experimental model was compared with the theoretical model of Merchant.