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cavity wall thickness


New member
Hi Gurus,

i know this is not the proper forum for my question so sorry to those who do not have interest in this discussion.

For the calculation of the side wall thickness of the cavity following formulae is used

View attachment 143


P : the pressure inside the mold

E : young modulus

F : tolerable flexure

C :constant factor

Up till this it is ok and now I want to know the formulae used for the recessed cavity as shown In figure below (it is not circular but rectangular form)

View attachment 144

thanks in advance



New member
Hi Asim,

What can I say, I saw your question, but I guess you start the problem in wrong way. First of all if you will want to calculate so excat the mould size, starting from stress analysess is wrong. I say this because ...after your carephull calculation, you will drill some holes ar make some pockets.(which will change almost radical your predicions)

My advice ... make your mouldbase to fit your systems, and if you have enough time ... make a FEA analys for critical parts. But as far I know a mould base will be always over-dimensioned on stress way of thinking.

good luck,

by the way, try to ask a moldmaker with some experience to see howwill chose his mould bases, and ... the most important ... why


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