Dimensions Apply Before or After Plating

[Mike S.]

Standard Y14.5 says if a part is to be plated, painted, anodized, etc. the spec must specify whether the dimensions listed apply before or after plating/painting, is completed -- i.e. DIMENSIONAL LIMITS APPLY AFTER FINISH or DIMENSIONAL LIMITS APPLY BEFORE FINISH.

Which way does your company do it, and what industry are you in?

Thanks!

[Coury Ferguson]

In Reply to Parent Post by Mike S.

Standard Y14.5 says if a part is to be plated, painted, anodized, etc. the spec must specify whether the dimensions listed apply before or after plating/painting, is completed -- i.e. DIMENSIONAL LIMITS APPLY AFTER FINISH or DIMENSIONAL LIMITS APPLY BEFORE FINISH.

Which way does your company do it, and what industry are you in?

Thanks!

I have seen it with both dimensional call-outs. I prefer the "After" more than before. But, that would be your Engineering Groups decision, on how they want to call-out the dimension, in my opinion.

[quality1]

Our products is enclosures and HDD Brackets, so it's after.

[CarolX]

In Reply to Parent Post by Mike S.

Which way does your company do it, and what industry are you in?

The age old question - but since we are a job shop and work to customer drawings, it varies - some say before, some say after and some don't specify.

I prefer the "apply before finish".

[AndyN]

When I specified pcbs (circuit boards) it was after plating. Some mechanical parts we had were also after plating, because they were cosmetic plating/anodizing finishes. Threads on fasteners are after plating because the thread will be potentially tight and not assemble.

[Ron Rompen]

In my past incarnation (automotive) all dimensional limits applied to the finished product (i.e. after heat treat, deburr, plating, etc). I have seen it specified on a drawing that dimensional limits applied BEFORE plating, with plating thickness called out as a separate line item, but this was not the norm.

In my current position (commercial, industrial and residential lighting) we specify only the unfinished part, as the assembly work is done prior to the paint operation.

[Cari Spears]

In Reply to Parent Post by Coury Ferguson

I have seen it with both dimensional call-outs.

Same here. At my last job we dealt with bearing journals and ballscrew, acme and v-threads with tight form tolerances, etc. so it was all "after plate", but when I was working with automotive sheetmetal stampings (mostly structural/frame stuff) with zinc or ecoat or whatever, I saw mostly pre-plate.

[bobdoering]

I have seen both call outs, especially in threaded products - depending on the nature of the plating and the critical nature of the thread. Some plating features simply cannot be easily controlled due to current density variation. You can control the machined feature very closely, but you hope for the best from the plater. It also depends of the type of plating. Hard plating (such as chrome) is more critical to the final function that soft plating (such as phosphating). It depends on straight thread versus pipe thread. Straight thread is less tolerant of the use of pre-plate dimensions.

It is not a comfortable position to plate or heat treat to a final dimension.