Abstract. Temperature fields evolving during metal cutting processes have also been of major interest. Temperatures in the tool influence the wear behaviour and hence costs, temperatures in the work-piece are directly responsible for later product quality. Due to the high significance of temperatures, many modelling attempts for temperature fields have been conducted, however failed to deliver satisfying results. The present paper describes a novel analytical model using complex functions based on potential theory. Relevant heat sources in metal cutting as well as changing material constants are considered. The model was validated by an orthogonal cutting process and different real machining processes.