Analysis of influence of the shape of cutting insert on change of the parameter value describing the deviation of the profile of surface roughness

The article presents the influence of the shape of the cutting insert on the surface roughness of the material after medium-fine turning machining. The analysis of measurements of the Ra parameter describing the arithmetic mean deviation of the surface roughness profile from the centre line of the profile by the mechanical and contact method was made using the Hommel Etamic Waveline 20 profile (Gdynia Maritime University). The tests were carried out on three stainless steel X2CrNiMo17-12-2 / 1.4404 shafts with a diameter of 80 mm, subjected to medium-precision turning machining at a length of 270 mm, using three cutting inserts made of tungsten carbide shaped T – triangular, C – rhombic, W – trigonal manufactured by Pafana. Values of used parameters are turning speed Vc = 150 m/min, depth of cut ap = 2 mm and feed f = 0.2 mm/rev. The parameters have been selected according to the manufacturer’s recommendations. The tests were carried out three times, five measurements on the length of the turned part of the rollers. The first test was made after collecting one layer of material, the second test was carried out after collecting five layers of material, and the third test was made after collecting nine layers of material. The article describes the differences between the used tiles and their effect on surface roughness, presents the results of the research, charts of measurements with averaged values and descriptive statistics of the Ra parameter were presented. It was noted that for all measurements of the Ra parameter, the smallest values were obtained using a W-shaped cutting insert. The Ra parameter using the C and T shaped plates increases with each subsequent measurement. The largest value of the Ra parameter is obtained using the T.