In Pursuit Of Flat Bottom

[Anonymous]

I can’t find where I read it, so I might be recalling this incorrectly… :-0

However, I seem to remember something about putting a little drop of pva glue at each of the corners where they meet the bed during the print, and this was enough to stop them lifting as the print progresses.

That said, if the lifting force is very strong (i.e. vertical shrinkage is a problem), then physically preventing the corners from lifting doesn’t mean it won’t crack your print somewhere else. 🙁 Did you try a big brim?

The other thing you read is to start your bed off quite hot, turn off cooling for the first few layers, then lower the bed to just warm during the print. But my own experience with PEI is that it as it cools, PLA prints just start to pop off (you can watch it if you detach the PEI sheet from the bed - cools down really fast then), so I’m not inclined to believe that one!

I’ve had similar problems with big, long duration prints.

[BHudson @bhudson I have both RoboxDual and other Robox versions Arizona, USA]

@dmullerdesign The settings I use for T-Glas are attached. You can also go to the manufacturer’s website http://www.taulman3d.com

T-Glas comes in translucent colors only. I have not tried to paint it.

My personal experience with ABS, PLA, and nylon lead me to think that they are almost unsuitable for anything that is dimension and shape critical.

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I operate two Betas and four Production Robox.
I am the US/Canada Technical Support engineer for the Robox.
See my 3D Hub site at https://www.3dhubs.com/phoenix/hubs/ben

[BHudson @bhudson I have both RoboxDual and other Robox versions Arizona, USA]

The issue I have had with printing ABS with pads or brim to reduce warping at the corners is that the layers above the pads or brims warp anyway to about .125 inches above the bed. The way around that I have found is to make the base thicker. I have several parts where the first .125 to .250 inches are modeled solid and filled at 40% and they didn’t warp or pull up.

I operate two Betas and four Production Robox.
I am the US/Canada Technical Support engineer for the Robox.
See my 3D Hub site at https://www.3dhubs.com/phoenix/hubs/ben

[David @dmullerdesign My Robox is a Blue Commercial Version]

Be very quiet. I actually have my robot printing. Which, is something to behold, it only took around an hour to get the nozzle height to calibrate.

I’m running the test of the model I posted.

[click @click My Robox is a Green Kickstarter Limited Edition]

@bhudson thicker base? Hm. I’ll give it a go next time.

@dmullerdesign What I really meant is how high the mouse ears are? A couple of layers, height of base or thicker than that? I know you might not have an answer - but these options are ideas to experiment with.

[David @dmullerdesign My Robox is a Blue Commercial Version]

Hey, don’t get too keen. I’ve only just got it printing anything other than a blobby, stringy, peel mess! I have hei upon (seemingly randomly) a setting that works though, that model I posted is printing really well with an hour to go and doesn’t look like the curved edged exhibit the sort of curling you were witnessing.

[David @dmullerdesign My Robox is a Blue Commercial Version]

I can confirm that the box printed really well on normal, 60% fill. Dimensions were 75mm (actual 74.9mm) x 60mm (actual 60.8mm ???) with a 6mm radius edge. Pads were .7mm high and 20mm in diameter at the corners with no observable warping.

It’s worth a try, want to give the model a go?

 

 

• This reply was modified 2 years, 11 months ago by  David.

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[click @click My Robox is a Green Kickstarter Limited Edition]

@dmullerdesign maybe a picture of the bottom of the box? This suspense is killing me!!!

[David @dmullerdesign My Robox is a Blue Commercial Version]

Hmm, I sort of butchered it a little impatiently cutting off the ears and then running it over my bench sander (the last process is not to be recommended!).

Hang on, the main part of the base is okay though. Try to ignore the obviously crude and impatient sanding marks.

 

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[click @click My Robox is a Green Kickstarter Limited Edition]

Yes, it seems nice and flat. Although you have bottom of your case rounded anyway (nice job Robox :)) and some of the wrapping might be hidden in there.

I’ll try making my Raspberry Pi cases now with mouse ears and see what happens…

[Anonymous]

Mmm, that’s weird, my reply to this has disappeared?

[click @click My Robox is a Green Kickstarter Limited Edition]

After all this time I didn’t do anything regarding my cases (or any other enclosures) until this weekend. As you’ve seen, I’ve wound (wrong way round, grrr) reel with ColorFabb PLA/PHA and tried the same (very similar - just taller sides) case again.

And where are the results I am quite pleased with 🙂

Quite different to CEL’s while PLA: almost no warping at all! Actually one corner got lifter slightly:

but the same corner from different angle:

shows that it is just cosmetic feature - not real issue! 🙂

So, for now, I am going to blame the material - exactly what you said guys!

Ah, one more thing - I did listen @dmullerdesign and included mouse ears. They might have helped or it was just material - I won’t really know until make next experiment! 🙂

• This reply was modified 2 years, 7 months ago by  click.

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