Rezumat
The experimental modelling of macro-distribution of etching rates (in normal direction and in the area of undercutting) has been conducted by using anodic dissolution of macroscopically non-uniform rotat- ing disk electrode from aluminium alloy D1 (Ag – Cu – Mn) partially insulated by thick self-sticky polyvi- nylchloride mask in NaCl solution (150 g/L) under direct current, pulse unipolar and bipolar (anodic- cathodic machining) current as an example. We demonstrate that under conditions, when ion-transfer rate controls dissolution rate (at high current densities iavg > icr), macro-distribution cardinally changes. In this case we observe significant non-uniformity of macro-dissolution, which exceeds non-uniformity of primary current distribution on a uniform disk electrode. On the contrary, under iavg < icr conditions a thick mask pro- vides more uniform macro-distribution (in comparison with primary distribution). We demonstrate that under conditions of iavg < icr and using pulse anodic-cathodic machining (a = c = 0.1 s, Qa/Qc = 10, where a, c, Qa, Qc – duration of anodic and cathodic pulses, and charge densities in anodic and cathodic pulses, corre- spondingly) maximum localization of anodic etching in micro-cavity (EF = 3.8 0.5; EF – etch factor: a ra- tio of etch depth to undercutting) is observed at maximum machining rate (which is several times higher than etching rate under direct current at the same average current density and the same value of passed charge) and maximum uniformity of macro-distribution of machining rates on considerable area ( 82%) of machin- ing surface.