Products made from powder materials differ in their structure significantly from parts made using traditional manufacturing methods such as rolling, casting, or forging. Particular interest is in parts made by powder metallurgy (PM) based on iron infiltrated with copper (Fe--C -Cu PM). In the first part of this research, analysis of the Fe--C -Cu PM part is performed. Another aspect of this research is an investigation of the post-processing of PM parts, especially using conventional machining such as turning. Accordingly, the second part of this research is directed at studies of technological assurance of Fe--C -Cu PM part in turning. Different structure of PM parts also requires a different approach to their machining which was the main object of this research. In the evaluation of technological assurance, the surface roughness parameters were chosen as the main quality identifying parameters.