ISO 2081 - Interpreting Coating Thickness

Good morning all,

we request our plating supplier to coat parts to this spec.

From our understanding the thickness should be between 12 to 20 microns to be acceptable.

We believe that this is in any individual place on the part, other than bent areas where you could not get a ball of 20mm into.

Our supplier is informing us that the thickness measurement is an average reading accross a face?!?

E.g. on a flat plate we have readings of 30um on the edges but in the middle of the part we have readings of 5um?

We believe that this is a failure, but we are told that the average is 17.5 and its ok.

Any advice would be gratefully appreciated.

Andy Mason

Leicester UK.

BS EN ISO 2081 is the international standard that specifies the requirements for electroplated coatings of zinc with supplementary treatments on iron or steel. It includes information to be supplied by the purchaser to the electroplater, and the requirements for heat treatment before and after electroplating.

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The ability of a zinc coating to prevent corrosion is a function of its thickness and the type of service conditions to which it is exposed. For example, the rate of corrosion of zinc will generally be greater in industrial exposures than in rural ones. The type of service condition should be taken into consideration when specifying the minimum coating thickness. Chromate conversion coatings and other supplementary treatments enhance the corrosion resistance of electrodeposited zinc coatings and are commonly applied after electroplating.

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Don't you specify minimum coating thickness too?

hi,

thanks for your reply.

Yes we typically state the customer specific requirements or in this case a generic statement of 12 to 20 microns. But, the supplier is stating that this figure of 12 minimum can be measured as an average accross the face of a part.

We disagree with this, and believe that the minimum must be achieved in any one measurement with our Elcometer.

Am i correct or does my supplier have the right answer?

Regards,

Andy

ARM129 said:

hi,

thanks for your reply.

Yes we typically state the customer specific requirements or in this case a generic statement of 12 to 20 microns. But, the supplier is stating that this figure of 12 minimum can be measured as an average accross the face of a part.

We disagree with this, and believe that the minimum must be achieved in any one measurement with our Elcometer.

Am i correct or does my supplier have the right answer?

Regards,

Andy

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Andy,

A minimum spec of 12 microns can not be interpreted as an average. But then, I always wonder why the specifics are not discussed and agreed upon during contract review. Many of these frustrating discussions take place after the contract is awarded and/or the P.O. sent.

The Elcometer people have this to say: "Coating Thickness by Elcometer."

Stijloor.