Investigation of the Effect of the Position of the Cutting Tool Tip on the Geometric Tolerances and Surface Roughness in Turning Process

Normally, cutting tool tools are directly used by assembling on the CNC turning machines. The position of the tool is not controlled relative to the centre of the work piece. It is assumed that the cutting tools are manufactured in standard sizes. However, the cutting tools composed of many parts, such as insert, shim and holder, etc. Many companies can manufacture these parts in universal tolerances. In this study, turning tests were carried out to investigate the effects of the height of the insert from the machined workpiece axis. AISI 304 stainless steel material was turned on a CNC lathe using a carbide cutting tool with a negative backward rake angle. The cutting tool were tested for three levels, such as, at the workpiece axis (0.0 mm), above of the workpiece axis (+0.5 mm) and below of the work piece axis (-0.5 mm). In the experiments, three different cutting speeds (100, 150, and 225 m/min), three different feed rates (0.15, 0.25 and 0.35 mm/rev), three different depths of cut (0.8, 1.3 and 2 mm) and two different insert radius (0.4 and 0.8 mm) were preferred for the cutting parameters. L36 model, which is an option in Taguchi method, were selected to perform the tests. Surface roughness, circularity and cylindricity on the machined surfaceses were controlled. The results were evaluated by Taguchi and ANOVA analyses. The results figured out that the height of the cutting tool affected the geometries of the machined surface. The rate of the effects is 1.37% on the surface roughness, 10.89% on the circularity deviation and 4.49% on the cylindricity deviation. The H:+0.5 lead to have a positive impact on surface roughness and the cylindricity deviation.