The paper presents a consistent numerical simulation method for calculation of heat sources and heat fluxes in milling processes. First of all, by means of finite element simulation of the interrupted chip formation process the cutting heat source is calculated. Next, the non-steady-state heat fluxes into the workpiece, the chips and the tool are computed numerically. The computed fluxes serve as boundary conditions for thermo-mechanical FE workpiece and tool models. The numerical models are fitted and verified by experiments of S235 steel. The simulations show a good match with the force and temperature measurements of the cutting processes. (C) 2017 The Authors. Published by Elsevier B.V.