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Another warping issue  

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buckeyestargazer
(@buckeyestargazer)
Estimable Member
Another warping issue

Newbie here.  The printer is working great, but the first serious print I did ended up having a slight bow.  I built an enclosure for some electronic devices.  It is basically a box 100x70x30 with a lid.  I print the lid and box at the same time, side by side.  Both the box and the lid bowed a little after the print was removed from the hot bed.  The first layer adhered well to the bed and when the print was completed everything looked great.  I took the box and lid off the printer after the bed had cooled somewhat (but not fully cool) and the box and lid were both perfectly flat and smooth.  The warping occurred sometime later.  

So how can I prevent this warping?

Sorry for my vague description.  I'm very new to this and don't even know the right lingo to use.  Thanks in advance.

Posted : 20/02/2020 7:46 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Another warping issue

Hi Buck,

it's possible that you removed the model whilst it was too warm, and introduced the twist at that stage...

could you let the parts cool completely next time...

PLA glass transition temperature is usually somewhere around 60C.  
https://prusament.com/media/2018/07/PLA_datasheet.pdf

clip from reprap PLA page https://reprap.org/wiki/PLA

PLA is harder than ABS, melts at a lower temperature (around 180°C to 220°C), and has a glass transition temperature between 60-65 °C, so is potentially a very useful material. It does exhibit higher friction than ABS however which can make it difficult to extrude and more susceptible to extruder jams.

clip from https://www.sciencedirect.com/topics/materials-science/glass-transition-temperature
Glass transition temperature is described as the temperature at which 30–50 carbon chains start to move. At the glass transition temperature, the amorphous regions experience transition from rigid state to more flexible state making the temperature at the border of the solid state to rubbery state.

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 20/02/2020 10:01 pm
buckeyestargazer
(@buckeyestargazer)
Estimable Member
Topic starter answered:
RE: Another warping issue

I'll leave it on the bed next time until it is fully cooled and see if that fixes it.

Posted : 20/02/2020 10:58 pm
buckeyestargazer
(@buckeyestargazer)
Estimable Member
Topic starter answered:
RE: Another warping issue

I printed the enclosure again and this time I left it on the bed until it reached room temperature.  The lid stayed perfectly flat this time.  The box was better also but there was still a tiny bit of bowing along the long axis.  It's so slight that I can't even see the bow with my eyes but putting it on a flat surface I can slightly rock the box back and forth.  

I'm printing with Prusa PLA, bed temp 60C, hot end 215C, 15% infill, 0.15 QUALITY.   I have the smooth magnetic bed.  

Posted : 21/02/2020 6:57 pm
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