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material finish notes

Question asked by Steve Krause on Sep 29, 2017
Latest reply on Sep 29, 2017 by David Matula

I am looking to see what others do when calling out on a fab drawing the powder coat finish on a metal part.  Where I work over the years we have done that in a few different ways.  We usually get good results from all the different ways but we want to standardize on a one set of notes for our powder coated finishes.

 

We are an electronics company producing rack mounted equipment and peripherals.  We powder coat a lot of product a textured black and we screen graphics on the front and back panels.  Sometimes we use lexan overlays and labels.  Some production is done by local vendors in the US.  Other parts are done off shore in Asia.

 

Our goal is to use notes that insure that all black metal parts have the same look. I believe we need to be calling out Color, Texture, and Gloss in the Finish section of the fab notes.

 

But there is potentially more than one shade of "BLACK" for the color.

 

There are different interpretations of "FINE TEXTURE".

 

There are different interpretations of "LOW GLOSS".

 

1) One approach we have used is to define our companies paint number as a company paint spec number.  For example we have our DPS059.  On the fab notes we say "FINISH PER DPS059".  The fab shop is given the definition of DPS059 in a our PLM system.  The name in our system is BLK FINE TEXTURE LOW-GLOS and attached to that item in the PLM system is the manufacturer Cardinal and the manufacturer's part number C241-BK303 with Cardinal's spec sheet that says "C241 - BK303  Polyester powder coating Semigloss hytex Black"

 

I we know that every manufacturer isn't going to buy and use Cardinal when we ask them to powder coat the part but that note has usually gotten us what we want.  In some situations we have attached multiple manufacturers when we learned from the powder coater that they are using something equivalent and we have confirmed that it works from seeing their output.

 

2) A long time ago we worked with color chips and had them available to pass to the vendors when we put on the fab notes something about matching to our paint chip.  Pretty subjective and time consuming.

 

3) Lately we have also taken the approach of just putting in the fab drawing notes: FINISH: COLOR: BLACK TEXTURE: FINE TEXTURE GLOSS: 20% GLOSS PER ASTM D523 FIRST ARTICLE APPROVAL REQUIRED The first article approval can be problematic since it puts a delay in the process so sometimes we leave out that line. Using a percentage of gloss as measured per ASTM D523 seems to lock down the gloss nicely.

 

But I don't know how to specify black since paint companies have multiple versions of black.

 

Also is there a texture standard for powder coating?  I know there are plastic mold texture standards like from Mold Tek.  Are their powder coat standards for texture?

 

What do you guys do?

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