Developing an Aluminum Casting Porosity Specification

[dsalcido]

All,

A customer has asked us to help them develop a porosity specification for their aluminum castings. They used to produce these in house and they knew what was good by "looking" at them. Now that they want to outsource, it is difficult to document and explain to a prospective Supplier how to "look" at them and judge acceptability. We have convinced them to document a specification/standard.

Does anyone have any that they woould be willing to share with me to use as a starting point? I am new to this type product so any help would be greatly appreciated!

 

[Coury Ferguson]

Use both Military (NDT) and ASTM standards to get you started, in my opinion.

 

[Crusader]

This doc works for our process and meets ISO 9001 - passed every audit. It's not a "spec" but it is a work instruction for the QC lab.

 

[RCW]

Crusader,

I like the use of photos with your sampling test. We've been having problems with our vendor supplying us pitted castings. My customer says to start setting up acceptable/unacceptable photos to use for inspection. Unfortunately the criteria for this has been which units my customer rejects for bad castings.

My question is, what do you do for conditions in-between the photos you attached? The worst case had a lot of pits while the best case has few. What about if it's 50% covered with pits - a condition between the two photos. Accept or reject the part?

 

[Crusader]

Crusader,

I like the use of photos with your sampling test. We've been having problems with our vendor supplying us pitted castings. My customer says to start setting up acceptable/unacceptable photos to use for inspection. Unfortunately the criteria for this has been which units my customer rejects for bad castings.

My question is, what do you do for conditions in-between the photos you attached? The worst case had a lot of pits while the best case has few. What about if it's 50% covered with pits - a condition between the two photos. Accept or reject the part?

Thanks. As for your question, I will have to ask my Foundry QC dept for the answer.

 

[JaxQC]

I know the standards reference x-ray but the method of defining size and amount is good. Either way the size for a particular casting grade doesn’t change if you’re visually looking at it or via an x-ray film.
If you’re going to go your own route, define both sizes and amount (ie Acceptable = nothing bigger than 3mm and no more than (2) occurring in a 1” zone).

Also make your limits either 3 or 5.
If three then one end is gross bad, middle is borderline, and other end is acceptable. Helps define a range.
If five (better for a color match sample of light and dark) then middle is acceptable, next one out on each side of that is borderline parts and the two ends are gross examples.

I think it’s best to not only show what’s bad but what should start raising a flag and what they should be striving for.

ASTM E505-01 , ASTM E155-05 Standard Reference Radiographs for Inspection of Aluminum and Magnesium Castings
Another related post: Best Method and Equipment for Measuring Porosity of Customer supplied castings

 

[Crusader]

we are revising our instruction. To show only 1 photo, which be the dividing line of acceptable and unacceptable.