You problem finding a setting in Cura might be that Cura is not showing it
to you.   By default you get a very "dumbed down" list of settings.   But
look undr "prefferences --> Settings" and there is a long list of setting
and checkboxes.  If you check the box Cura will show you the setting.
 Most of these you wil never touch but some are "must haves".

You absolutely ned to be able to control the wall thickness and the skin
thickness.
You likey want to be able to control the kind of infill, lines, triangles
or Gyroid.  I use the latter mustly

I run an informal strength testing program when printing racing quadcopter
bodies  I intentionally broke some parts.   Here is a rule:  Strenght is
mostly in the skin but you need enough in-fill so  the skin does not deform
when the part bends.  In PLA deformation equals breaking.   PLA is like
building with glass.  Use large tubes filled with air and it will be strong
like a coke bottle.   Thin sheets are weak like window glass.   The coke
bottle does not get its strength from the air inside the bottle but by its
shape.      Use PLA as it it were glass, not as if it were aluminum.

Given the above the best PLA designs are "puffy" and thick.    Doing this
with aluminum would be expensive but PLA is filled with 20 to 30 percent
density foam inside.   With PLA parts the cost is mostly in the surface
areas, not so much the volume.

Also like the coke bottle make every surfave curved and non-flat.  The
compound curves are strong.  Like the hood of a car is stong only after the
sheet metal is stamped into a compound curve.

It takes a while to get your brain around the fact that PLA is not metal or
wood and very complex shapes cost nothing.   At first we design stuff as it
if were machined but we can do better.

One thing I want to learn is to use "generative design" tools.   This is
basically a shape optimizer an will re-design parts based on the loads and
other constraints.  The software comes up with shapes no human would ever
think of but turn out stronger and lighter.
https://www.autodesk.com/solutions/generative-design



On Wed, Jun 3, 2020 at 3:13 AM andy pugh <[email protected]> wrote:

> On Wed, 3 Jun 2020 at 07:27, Gene Heskett <[email protected]> wrote:
>
> > 50% fill makes very strong parts, but 20% fill is strong
> > > too.  I usually use 20% or 25% infill.  If I want stronger parts I'll
> > > increase the number of outer layers.
> >
> > I'll have to ask how you do that with cura?
>
>
> Presuming that the part has been placed on the bed in Cura.
> Then in the bar at the top, where is lists the printer, the extruder /
> material and the quality, click the quality section, and you will seee a
> drop-down of all the settings.
>
> Then in the "Shell" section you can choose how thick you want the wall, and
> how many lines.
>
> I think that if your printer can print at 100% then it is probably
> under-extruding. There should be only barely space for 100% fill, and so
> you would expect cumulative oozing errors to build up.
>
> I typically print at no more than 25% fill, and for foundry patterns I am
> down at 5% to save time.
>
> --
> atp
> "A motorcycle is a bicycle with a pandemonium attachment and is designed
> for the especial use of mechanical geniuses, daredevils and lunatics."
> — George Fitch, Atlanta Constitution Newspaper, 1912
>
> _______________________________________________
> Emc-users mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/emc-users
>


-- 

Chris Albertson
Redondo Beach, California

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