Experimental derivation of process input parameters for electrochemical precision machining of a powder metallurgical tool steel

Powder metallurgical steels are used for tools because of their properties, such as toughness, wear resistance and hardness. During the machining of the tool, the material is hardened. Consequently, the subsequent finishing of the tool is a challenge, as conventional manufacturing processes reach their limit of machinability due to the hardness. An alternative manufacturing technology is electrochemical precision machining (PECM). The PECM process, which is based on anodic metal dissolution, can be applied to machine metallic materials without force, cracks or burrs, regardless of their hardness [1]. Due to the process principle, the mechanical properties of the workpiece are not changed. As a result, the PECM process is suitable for finish machining of tools and finishing of tools. A significant challenge for PECM is the material-specific removal functions [2]. In this paper, the material removal functions of the hardened powder metallurgical steel S390 [3] are analyzed using experimental tests and the achievable surface quality is shown. Subsequently, process input parameters for electrochemical precision machining of S390 are derived.