GMNA GMN11174 PDF

This document outlines a method to quantity the loose and loosely adhered foreign material in and on sand cast (i.e. greesnsand, precision sand, semi-permanent mold, and lost foam) cloacks and heads ready for shipment to the GM final maching plant. Iron and aluminum castings are included. At a minimum, the final operations (foundry, heat treatment, painting impregnation, or cubing/pre-machining) that ships the casting to the final machine plant is required to perform this test. The use of the test after any other operations is optional, but recommended, at least until there is shown to be stable and capable.

Its purpose is to insure that the cleaning methods utilized before the oart reaches the final machining source are operating correctly and removing excess foundry materials, cleaning media, prequenching materials, cleaning media, premachining burrs and any other foreign material that could overwhelm the machining plants washers.

The method involves two steps:

1. Step one involves impacting the casting top loosen retained material, and then collecting the loosened material by material to fall out of passages. Compressed air may be used to blow material out of th casting. Determine and record the weight of solids collected. (Foundry slang term – "Trunk" Test).

2. Step two involves a visual inspection of all surfaces of the part, documenting any potentially detrimental loosely adhered foreign material on the surface of the casting (i.e. burn-on, burn-in, core or pattern coating, fragile metal fins from core/moid misalignment, excess metal in the form of the EPS beads from lost foam cast parts, etc.) and comparing lo a standard established for the specific part.

Note: Nothing in the specification supersedes applicable laws and regulations unless specific expemtion has been obtained.

Note: In the event of conflicts between the English and domestic language, the English language shall take precedence.