Figure 9 shows the corresponding av

Figure 9 shows the corresponding average polishing currents in A depending on the respective applied polishing potential difference U as a function of the adjustable polishing head gap. The range of the average polishing current I extends from 4.7 to 14.1 A (Figure 9) and this is an indicator that more area (23.5–70.5 cm2 with JEPP of approximately 0.2 A cm−2) is being polished with increasing average current. Furthermore, the trend in average current corresponds with the average area roughness of Figure 8. The variation of the average current decreases with increasing voltage and there is a tendency to reach a stable average current value range of 5 A to 7 A.