Use of bidirectional electrolyte flow to improve PECM uniformity

Non-uniform machining in the pulsed electrical chemical machining (PECM) of an anode surface is a consequence of unidirectional electrolyte flow through the inter-electrode gap (IEG). As it traverses across an anode surface, the electrolyte accumulates ohmic heat, which in turn increases electrolyte conductivity and anodic dissolution. This leads to a dissolution gradient along the flow path and consequently anode surface geometric error. This research investigates the use of the bidirectional electrolyte flow to homogenize the time-averaged temperature and time-averaged dissolution across the IEG. A comparison of data derived from unidirectional flow PECM experiments and bidirectional flow PECM experiments show that bidirectional flow can reduce anode geometric error by a factor of 17 along a 98.7-mm flow path. Furthermore, this can be done without the loss of machining efficiency. Multi-physics simulation analyses of these processes show that bidirectional flow does effectively homogenize time-averaged temperature, current density, and dissolution rate. Graphical Abstract: [Figure not available: see fulltext.]