1 Topic by poppinfresh

  • poppinfresh
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  • Registered: 2015-11-19
  • Posts: 46

Topic: Old PLA - can it make prints warp or not stick to the bed?

I have some PLA that has been in an air conditioned office for about 6 months.

The humidity is usually around 40% - 60%

When new, I don't recall having issues with PLA prints sticking.   In fact, I recall it was more often hard to remove them from the bed.   But now it's hard to get prints to stick.    I'm having roughly 80% of my prints lift off the bed at about 50% completion.

I can actually see a small amount of curling (lifting) of the print before it finally detaches from the bed.

I'm just wondering if this is what PLA does as it gets older or absorbs moisture from the air or if it is most likely something else?  Would putting it in an over at a low temp like 150F for an hour help ?  I know it starts getting soft at around 200F.

There is no sputtering at the extruder and the prints otherwise are great.    They just aren't sticking to the bed.

My best guess is that the PLA is curling too much as upper layers are laid down.

I think I'll remove this PLA and try another roll just as an experiment come to think of it.

2 Reply by AZERATE

  • AZERATE
  • AZERATE
  • PRINTiT
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  • From: Chicago
  • Registered: 2013-11-28
  • Posts: 2,077

Re: Old PLA - can it make prints warp or not stick to the bed?

TPU aside, all filaments will take in moisture over time. Some, like nylon and ABS, are more prone to it than others.
I recently printed 2 year old PLA and it printed flawlessly. I owe that to a few things though:
1) better quality of filament will be more reliable, new or old
2) I keep spools in a ziplock bag with silica in a closed closet
3) when in doubt, toss the spool on your heatbed and crank the heat 100-110c in an enclosure...a large microwaveable lid will help as well. Cook that puppy for 1-3 hours depending on how bad you think the moisture is.

Of course, try another spool. I've noticed that you can find some awesome and reliable ABS sub $20, but you seem to get what you pay for with PLA.
If neither are stick, use a purple glue stick, blue painters tape, or Aquanet. If you attempt the Aquanet, just remember that it will take time and effort to come loose. I've broken glass removing PLA

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