The objective of the investigation was analysis of the wear of milling cutters made of sintered carbide and of boron nitride. The article presents the life period of the cutting edges and describes industrial conditions of the applicability of tools made of the materials under investigation. Tests have been performed on modern toroidal and ball-end mill cutters. The study has been performed within a production facility in the technology of high speed machining of 55NiCrMoV6 and X153CrMoV12 hardened steel. The analysed cutting speed is a parameter which significantly influences the intensity of heat generated in the cutting zone. Due to the wear characteristics, two areas of applicability of the analysed tools have been distinguished. For v_c ≤ 300 m/min, sintered carbide edges are recommended; for v_c > 500 m/min, boron nitride edges. For 300 ≤ v_c ≤ 500 m/min, a transition area has been observed. It has been proved that the application of sintered carbide edges is not economically justified above certain cutting speed.

The ability to effectively predict tool wear during machining is an extremely important part of diagnostics that results in changing the tool at the relevant time. Effective assessment of the rate of tool wear increases the efficiency of the process and makes it possible to replace the tool before catastrophic wear occurs. In this context, the value of the effectiveness of predicting tool wear during turning of hardened steel using artificial neural networks, multilayer perceptron (MLP), was checked. Cutting forces and acceleration of mechanical vibrations were used to monitor the tool wear process. As a result of the analysis using artificial neural networks, the suitability of individual physical phenomena to the monitoring process was assessed.

In this paper, an analysis of various factors affecting machined surface texture is presented. The investigation was focused on ball end mill inclination against the work piece (defined by surface inclination angle a. Surface roughness was investigated in a 3D array, and measurements were conducted parallel to the feed motion direction. The analysis of machined surface irregularities as a function of frequency (wavelength A), on the basis of the Power Density Spectrum - PDS was also carried out. This kind of analysis is aimed at valuation of primary factors influencing surface roughness generation as well as its randomness. Subsequently, a surface roughness model including cutter displacements was developed. It was found that plain cutting with ball end mill (surface inclination angle a= 0°) is unfavorable from the point of view of surface roughness, because in cutter’s axis the cutting speed v_c ~ 0 m/min. This means that a cutting process does not occur, whereas on the machined surface some characteristics marks can be found. These marks do not appear in case of a* 0°, because the cutting speed v_c * 0 on the fill I length of the active cutting edge and as a result, the machined surface texture is more homogenous. Surface roughness parameters determined on the basis of the model including cutter displacements are closer to experimental data for cases with inclination angles a* 0°, in comparison with those determined for plain cutting (a= 0°). It is probably caused by higher contribution in surface irregularities generation of plastic and elastic deformations cumulated near the cutter’s free end than kinematic and geometric parameters, as well as cutter displacements.

In this paper, a comparison of tool life of sintered carbide (with TiAlN coating) and cubic boron nitride (CBN) ball end mills is presented. Experiments were carried out on hardened steel X155CrVMo12-1 plate during milling process with a constant surface inclination angle (α) and variable cutting speeds (vc) and feeds (fz). Cutting forces (Fi) were measured and presented in function of tool wear (VBB). Specific cutting pressures were also estimated in function of tool wear (VBB). Their values are applied to cutting force model formulation, which includes tool wear. The research revealed that in certain range of cutting speed tool life acquired for sintered carbide can be higher than that obtained for cubic boron nitride tool. It was observed, that for cubic boron nitride cutter abrasive wear was dominant independently of cutting speed. In case of sintered carbide, catastrophic wear of cutting edge was found for cutting speed vc = 500 m/min