Micro structuring tool steel components using Precise Electrochemical Machining (PECM)

Surface structuring offers great potential for modifying frictional properties for various applications, such as complex forming processes like sheet-bulk metal forming. The production of surface structures in micrometre range is challenging for manufacturing processes in particular when machining hard-to-cut materials like hardened tool steels. Precise electrochemical machining (PECM) has great potential for surface structuring and shaping of metallic materials regardless of their hardness with high surface quality and comparatively very short process times, especially when structuring large areas and batches. Micro structuring of hardened tool steel surfaces using PECM is investigated in this paper. Surfaces of high-speed tool steel and hot-work tool steel are structured using a commercial PECM machine with neutral solution of NaNO _3 as electrolyte. In a process sequence, PECM tools were manufactured in a first step producing selected structures by high-feed milling (HFM) and micromilling (MM). In a further process step, the negative shape of these complex structures was machined using the PECM process. Through this process chain, new types of structures can be generated which have different tribological properties than their corresponding negative shapes of HFM and MM structures. Tribological behaviour and wear properties of the structured surfaces are investigated through ring compression test (RCT).