Increasing accuracy and machining speed in precise electrochemical machining of a micro injection molding cavity

In micro injection molding, cavities with high accuracy are required in order to fulfil the given requirements on precision. The molding inserts are often made of additive manufactured alloys in order to create conformal cooling or heating channels close to the injection molding cavity. Since these materials are usually harder than melting metallurgical alloys of the same composition, Precise Electrochemical Machining (PEM) represents a potential procedure for micro manufacturing of high precision cavities, because mechanical characteristics such as the material’s hardness and the ductility have no influence on the electrochemical machinability. In addition, no mechanical forces nor thermal impact influence the machining result. Due to the missing mechanical contact between the tool electrode and the machined cavity, filigrane structures with high precision can be manufactured even in mechanically hard to machine materials. The dissolution behavior of the work piece material is only influenced by its electrochemical attributes. In this study, precise electrochemical machining of a stainless steel (1.4301) plate is investigated. A complex shaped brass electrode is applied in order to create a complicated cavity, which would be difficult to be machined by conventional techniques. For the determination of the precision, the influence of an increasing feed rate on the resulting cross-sectional shape of the cavity as well as on the lateral widening and on the influence of a micro pillar is examined