no-warp construction techniques

I´m trying to start a discussion about design-princibles against warping here:
[www.bitsfrombytes.com]

Quote

I´m currently printing this frame-vertex: [www.thingiverse.com]
With the settings I´m deliberately using there should be serious warping. However,
there is practically none.

With the V-shaped cuts in the bottom these are 3 separate objects during the important first few layers
that keep each other down. (Much like the special throw-away objects discussed here a while ago to keep the raft on the edges of a large object weighted down.)

There is no part long enough to form a lever and the levers that do form work both ways and reduce
the warping that is left to half the amplitude.
When the parts merge higher up there is already so much mass printed that it keeps the object down without effort.

I guess we have found a way to print large objects in ABS without requiring a heated bed for it!
And all it requires is a change in the shape of the object.
(My frame-vertex is also hollow but that does nothing to prevent warping in the first 5-10 layers. It just saves material and time.)

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How thick are the walls of your hollow objects? I'd be curious to see if the technique works with more solid objects - a hollow build does not have many layers for the thermal shear stress to build up in.

I've been getting around the warping by building the larger parts faster, in PLA, and with a larger nozzle size.

Wade Wrote:
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> How thick are the walls of your hollow objects?
> I'd be curious to see if the technique works with
> more solid objects - a hollow build does not have
> many layers for the thermal shear stress to build
> up in.

between single-walled and 2mm. But that´s nothing that
affects warping. The V-shaped cut in the bottom is.
Other things are currently being discussed in the thread I quoted from.


> I've been getting around the warping by building
> the larger parts faster, in PLA, and with a larger
> nozzle size.

The discussion is actually happeing in that OTHER forum.
Different temperatures and speeds do help, yes. You can also
keep the raft down with strong magnets or tape and such things.
But this is about construction-techniques, not printing.

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Well, you mentioned it here, and I like this forum better, so I'm responding here.

I was curious about the wall thickness, as I've found that warping is directly related to infill density - more solid objects warp more, in my experience with ABS. I've also thought a bit about breaking up the first few layers of a print to limit the length over which the thermal strain builds up, but I found with larger objects like the Darwin corner blocks, they would tend to crack and split again at higher elevations due to the warping stress. I think your broken-base technique would be quite impressive if it worked with objects with heavier infill.

Nophead put up a nice graph showing the relationship between infill density and warping here:
[hydraraptor.blogspot.com]

In the meantime, I've found that PLA has negligible warping even without a heated base, especially when printed quickly. Here's an edge shot of a Z-leadscrew-base printed at 1 mm filament, with 2mm thick walls at 50% infill:
[gallery.me.com]

Wade

Wade Wrote:
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> but I found with larger objects like
> the Darwin corner blocks, they would tend to crack
> and split again at higher elevations due to the
> warping stress.

This has already been discussed and we found a very nice
solution. Please at least read the thread in the other
forum then before repeating things here.
I like the BfB-forum better. Not just because it uses a
better forum-software and a nicer theme.

Marcus

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I did read it, I just wasn't much impressed by the glue solution to cracking.

Perhaps you shouldn't post here if you prefer the BfB forum?

Wade Wrote:
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> I did read it, I just wasn't much impressed by the
> glue solution to cracking.

I´m not refering to any gluing but to this:


> Perhaps you shouldn't post here if you prefer the
> BfB forum?

Well, perhaps I should indeed not have invited people from here
to join an interesting and productive discussion developing elsewhere.

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No worries - I was just saying that tongue in cheek. Somewhat.

Although I own one of BfB's original products, a cast Darwin, since BfB has switched to closed source I'm less inclined to participate on their forums. I'd rather contribute to on the open source side of things. I respect your invitation, but politely decline it. Unless I'm wrong and they are posting their source files, but a quick look around their home page turned up nothing.

Also, the image link you posted wants me to log in to see it, so I'm not sure what it is.

Wade

Wade Wrote:
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> Unless I'm wrong and
> they are posting their source files,

The sources for the 1.0.8 -firmware are in the download-section.
The 2.0.8 will follow but no date is known yet.

> Also, the image link you posted wants me to log in
> to see it, so I'm not sure what it is.

You don´t need to log-in to read. Only to write.

It´s am object that should warp significantly more then it
does. It has strategically placed holes.

>
> Wade

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Hi Forum,

if you are interested in a new filament with near zero warping look here:
pics included.

[www.bitsfrombytes.com]


greets
Kaipa