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Electrocoating (E-Coat) Die Cast Aluminum - Safety & Surface Finish of End Product

Hello, I'm a Design Engineer for a company which manufactures medical oxygen regulation devices for hospitals and home healthcare.

We are investigating some alternative processes for making parts we use in our products. Currently, we are looking into aluminum die cast and the supplier has recommended a black e-coat process for finishing the parts. Both die casting and e-coating is new to me (and my company). We have always dealt with machined aluminum parts with a sulfuric anodize (both clear & colored) or plastic (predominately nylon) molded parts.

With regards to the e-coat process, standards for medical oxygen dictate that, if the product burns (assuming it's flammable) that it be non-halogenic (the fumes are benign, essentially). Generally, does the e-coat process meet this requirement? Will e-coat materials burn?

Secondly, how much will this finishing process improve surface finish (if any)? One of the parts we are considering acts as as sealing surface for some o-rings. The typical recommendation for surface finish in this type of application is between 16 to 32 microinches. Does anyone have any data on typical surface finishes on e-coat die cast aluminum?

Any other finishing recommendations for aluminum die cast given the above information?

Your valuable insights are most appreciated. Thanks.

Mark Gilbert
Design Engineer - Naples, Florida
July 21, 2011

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Theoretically, everything burns, only the temperature at which it burns, varies. Basic science aside, E-coat either clear or black is essentially a paint and should burn when exposed to fire. The best way to find out what you need is to contact the nearest office of PPG. They will have the MSDS for the products and you might get the information you need. Best of luck.

Gurvin Singh
Mohali, Punjab, India
August 4, 2011