Mold shrinkage calculation

[Anonymous]

I had designed a mold earlier considering parallel and normal shrinkage value of 0.6% and 0.8% respectively, but now i am considering the mold shrinkage value of 0.7% overall(resultant). I need a method of calculating the product of earlier shrinkage percentage to new one. 

[franco.costa]

If we say that the previous mold shrinkage scaling which you had applied was X%, then applying a scaling factor of 1/(1+X/100) would get you back to your original geometry and then from there scaling by (1+ 0.7/100) will get you to the new compensated geometry which you want. So combined, that means you need to scale your existing geometry by (1 + 0.007)/(1 + X/100).

In the case of your parallel direction, X = 0.6%, so your total rescaling factor is (1.007 / 1.006)

Meanwhile for the normal (perpendicular) direction you X was 0.8%, so your total rescaling factor is (1.007/1.008).

[Anonymous]

That I had in mind, but my cad software is such that, i cannot scale normal and parallel discretely, I need to find volumetric shrinkage percentage derived from X=0.6 and Y=0.8 % respectively, also for volumetric resultant I require the value of Z axis, I don't know whether to consider 0.6 or 0.8 for Z axis. Need help

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@franco.costa wrote:

If we say that the previous mold shrinkage scaling which you had applied was X%, then applying a scaling factor of 1/(1+X/100) would get you back to your original geometry and then from there scaling by (1+ 0.7/100) will get you to the new compensated geometry which you want. So combined, that means you need to scale your existing geometry by (1 + 0.007)/(1 + X/100).

In the case of your parallel direction, X = 0.6%, so your total rescaling factor is (1.007 / 1.006)

Meanwhile for the normal (perpendicular) direction you X was 0.8%, so your total rescaling factor is (1.007/1.008).

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