plating, anodizing, & finishing Q&As since 1989
High current density Electrodeburring
September 5, 2012
Q. It has always been suggested that high current density (CD) Electropolishing (well up into the gassing region) is best for removing burrs especially if certain features need to be kept sharp. I have experimented with deburring in the plateaux CD region (5A/dm2) and extreme gassing (60 A/dm2). The gassing CD region maintains sharpness on the sharp features while removing burrs where required whereas in the plateaux CD region, takes much longer (x 10 times) and totally rounds the sharp features by the time the burrs are removed.
Since there are many theories describing electropolishing i.e. anodic layer levelling.
Which theory best describes the theory that high DC is best for deburring applications....
A. There are two fundamental reasons for a greater rate of material removal on burrs during gassing: a) increased gassing at burrs surface accelerates the electrolyte circulation around them, and increases the rate of diffusion of the dissolved material and b) the current efficiency of metal dissolution increases with increased current density, Therefore metal removal rate is much higher on the burrs (since current density is higher on the burrs area).
September 24, 2012
Thanks for your detailed answer Anna,
Q. The burr removal at high current density is also accompanied by a reduction in surface roughness (20%-30%). One would imagine, with the large amount of gassing, that a viscous anodic layer would be difficult to form or even maintain and hence the effect on surface roughness would be minimal.
In comparison in the plateaux range current density the viscous anodic layer offers a smoothening effect on peaks and valleys.