Department of Manufacturing Techniques and Automation, Faculty of Mechanical Engineering and Aeronautics, Rzeszow University of Technology, Rzeszow, Poland
Prof. Witold Habrat
Department of Manufacturing Techniques and Automation, Faculty of Mechanical Engineering and Aeronautics, Rzeszow University of Technology, Rzeszow, Poland
Machining of hard-to-cut materials with conventional processes is still considered as a challenge, as the special properties of these materials often lead to rapid tool wear and reduced surface integrity. For that reason, it is preferable to combine conventional machining processes with other technologies in order to overcome the problems of machining these materials. In the present work, laser-assisted turning experiments on a Ti-6Al-4V workpiece were conducted using AlTiN coated cutting tools in order to investigate the effect of laser heating on cutting forces, cutting temperature, tool wear and microstructure alterations. Two series of experiments were performed under varying cutting speed, laser spot diameter and workpiece diameter values; the first series involved only laser heating of the workpiece and the second both laser heating and cutting. The findings revealed the effect of process parameters on cutting forces and temperature determining the importance of workpiece diameter size, indicated the formation of martensite phase at the top of the heat-affected zone of the workpiece and also showed that high temperatures can lead to intensive tool wear, instead of having a beneficial effect for the cutting tool. Finally, finite element (FE) simulations were carried out in order to study the time evolution of the temperature field and calculate the heating and cooling rates during the process. From the FE results, relatively high heating and cooling rates were observed for smaller workpiece diameters and lower cutting speed, whereas the high magnitude of these rates justified the creation of the martensite phase through a diffusionless transformation.
This paper presents selected results of research in the field of grinding cemented carbide with the use of diamond grinding wheels. In the fundamental experiments two different types of diamond grinding wheels were used. The diamond grinding wheels were varied by bonding material. In the investigation, response surface method was used to predict grinding force components during grinding of the ductile cemented carbide CTS20D workpiece material. The grinding speed, depth of cut and feed rate were considered as input process parameters. Furthermore, the ANOVA (analysis of variance) was employed for checking the developed model results. The results revealed that grinding with the use of resin bond grinding wheel provides significantly lower grinding force components during the process. Moreover, the significance of models terms was determined. It was shown that for the adapted range of process parameters, grinding speed has significant effects only on tangential force for resign bond diamond grinding wheel
1 September 2016 in Archives of Metallurgy and Materials
Nanocristalline pure titanium in comparison to microcrystalline titanium is characterized by better mechanical properties which influence its wider usability. The aim of the research was to evaluate whether the grain size of pure titanium (micro- and nanocrystalline) has influence on the cutting force components and the surface roughness in the milling process. Models of cutting force components for both materials were prepared and differences between the results were examined. The feed rate effect on selected parameters of surface roughness after milling of micro- and nanocrystalline pure titanium was determined.
1 January 2015 in Archives of Civil and Mechanical Engineering