The market demand for machining and cutting of various plastics parts is in continuousincrease. The aim of this study is to extract prediction laws for surface roughness,cutting forces and temperatures evolution during the machining of two polyethylene pipesgrades (HDPE-100) and (HDPE-80). It was found that feed rate is the most prevailing factoron roughness criteria and that better surfaces are obtained during the machining of theharder HDPE-80 resin. Also, cutting speed improved surface quality for speeds up to 200m.min-1 but the rising interface temperature caused surface damage andmaterial rapid softening. Also, feed exponents, in mathematical models, were found to be 3to 4 times higher than those of cutting speed and depth of cut. An increase in the cuttingspeed led to a gradual reduction for the 3 cutting forces components (Fr,Fa and Fv) with a dominance of the tangential force(Fv). As expected, the value of the depth of cut had a large influenceon the temperature within the cutting zone. This temperature is slightly higher during themachining of HDPE-80 compared to that of HDPE-100 most probably because of hardnessdifferences. The analysis of variance (ANOVA) was performed to check the adequacy of themathematical models relating cutting parameters with roughness, cutting forces and globalcutting zone temperature.