Cut Shrinkage Not Allowed Machining

As I can get from the language (and the test)- the cut shrnkage must mean machining micro cracks - but this particular wording is new to me.

I think it means do not freeze or cool rapidly after machining. That is how I would understand the statment.

Really a strange term!

I just can think on a specification written by a non-english speaking person (as me)

Some possible meanings:

- grinding cracks, independent of size, not allowed. Remember that MPI was discovered by grinding chips pattern around grinding cracks.

- Any surface "shrinking" by lapping, grinding,...to match final dimensions as this will change the final surface over which it's intended to make the MPI.

Kind regards

I've not come across this exact term before but I may have a suggestion: we manufacture a large component from a circular billet 600mm dia. The machining process involves removing approx. half the original billet in two triangular chunks. If we do this in one hit, the residual stresses from the forging process are released and our carefully sized bores go all over the place. We now rough machine the majority of the material and put it aside for a few days to allow it to move, then we do the fine machining. This seems to work fine. We consulted with our material suppliers and they said that these stresses could not be taken out by heat treatment.

This could be described as 'cut shrinkage'

Drew

I think what it may mean is: Once the part is machined and MP tested, a check of it's dimensions must not show a reduction of dimension due to shrinkage. If so, the MP test is void and has to be repeated after the part has stabilized. I'm guessing the part is a large casting.