Measurement of the force loading is a significant type of measurement in mechanical engineering applied to analyse important aspects in the machining process. In addition to the determination of specific material constants, it is possible to analyse, for example, various machining strategies, geometries of tools or the degree of wear of the cutting edges of cutting tools. This master’s thesis deals especially with the last two mentioned aspects which are subjects of an experiment on end mills with PCD inserts sharpened by a different technology. In the introductory part the cutting forces are theoretically analysed along with their measurement possibilities and the technology of the production of the mills including their sharpening – WEDM and EDM-G. One chapter is concerned with the milling of plastic materials, as PVC was the material used for the workpiece during the experiment. The first experimental part is devoted to the analysis of sharpened tools followed by the measurement of forces using the piezoelectric dynamometer and the subsequent analysis of the influence of the different tool geometry. The last conducted experiment monitors how the overall cutting forces of individual end mills sharpened by different technology changed over specific milling time slots.