Re: Part orientation

From: Atif Mehmet Yardimci (
Date: Fri May 16 1997 - 10:24:23 EEST

On Thu, 15 May 1997, M. Burns ( wrote:
> On Thu, 15 May 1997, Guy Allen Brady wrote:
> > Hate to be trivial, but you should be aware the material properties will
> > not change with build orientation, only mechanical properties (there is a
> > difference).
> Okay, Guy, help me out here. I have been giving some thought lately
> to the influence of structure (micro- and milliscale) on properties of
> materials, and I am not convinced that there is a way to distinguish
> material properties from the properties (mainly mechanical) that arise in
> a given configuration. Am I wrong about that? What about a glass wisker
> vs. bulk glass? Does glass have an defineable intrinsic tensile strength
> that is independent of whether you happen to make it into a window pane
> or a wisker? (If the answer to that is yes, then your explanation should
> become an corrigendum to my book, where I discuss this briefly but didn't
> know about any such intrinsic properties.)
> Best regards,
> Marshall Burns

My 2 cents worth:

Most of the RP processes do have the ability to generate 'structures'
inside a part at a number of scales. For Fused Deposition these would
be road, layer and part scales. At which scale would you be interested to
define the properties on?

The building blocks of RP techniques, e.g. roads in Fused
Deposition, would have intrinsic properties that one can rely on. But
as the scale of interest is expanded gradually to a set of multiple number
of roads -> layer -> part, mechanical and transport properties (e.g.
thermal conductivity) become less intrinsic (structure dependent).

Still, identical porous structures made out of different materials would
behave drastically different due to the differences in their building
block properties. And this is the happy domain of heterogeneous materials
and composites.

Best Regards,
     Atif Yardimci

Manufacturing Processes Laboratory +1-312-355-0478 / +1-312-413-7408 [voice]
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