Chrome Machine Roll Defect

[SPCoop]

I am currently working on a project for detecting and measuring “Gloss Bands” in chrome plated machine rolls. These “Gloss Bands” are essential a visual defect that is transferred onto the product. When viewing in certain lighting/angles, the surface appearance of the roll shows variation.

Any explanation for this? Appears the difference in undetectable by Gloss meter, leading me to believe the term “Gloss Bands” may be a misnomer.

Thanks.

 

[WKTaylor]

SPCoop... SWAG...

Assume that this plating is 'flash' or thin protective... not 'engineering' which is excessively built-up and then precision-ground to specified dimensions...?

Are the 'gloss bands' showing any signs of color [specifically yellow, blue or blue-green?]?

Plating tends to mimic [follow] the micro contour [waviness/lay] of the underlying machined/ground surface.

Also, anode placement and batch agitation may have to be adjusted.

Regards, Wil Taylor

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[EdStainless]

The gloss meter won't pick it up on such a highly reflective surface, it swamps the meter.
Rolls that require uniform plating are usually rotated while being plated because it nearly impossible to get the current distribution uniform enough to prevent banding.
A post-plate grind and polish is the only way to get optimal uniformity.

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P.E. Metallurgy, Plymouth Tube