PLA and moisture

Vertex 3D Printer Vertex - Issues while printing
1

I bought my K8400 at Christmas and I’ve been using it intermittently since then with the filament more-or-less permanently loaded. I’m maybe 2/3 of the way through the 1st Kilo spool of PLA. A few days ago I came across this http://3dprintingforbeginners.com/how-to-store-3d-printing-filament/ and started looking up further details. I then unloaded the filament and put the spool in one of the vacuum bags mentioned. Today I also noticed that a couple of filament offcuts I’d left lying around had become very brittle and snapped easily.

Yesterday I reloaded the filament and it took 2 attempts - the first load didn’t work so I unloaded and tried again. After a few seconds of clicking extruder it made it through and I printed a couple of very small things. Then I tried a 20+mm cube as a test (I’ve switched to Simplify3D so wanted to calibrate). I noticed a few black specks in the plastic during printing, then after about 10mm the filament tube started shaking and there were some strange noises. I noticed the top surface was no longer smooth and the was sort of ‘fluffy’. I think the filament wasn’t being extruded smoothly. I stopped the print unloaded the filament.

I will start next time with a new spool, which is still packed, assuming it will load, maybe I have a blockage somewhere.

Has anyone experienced problems with PLA & moisture? Could my experience be explained by that? Should I unload the fiilament and store the spool when I’m not printing for a few days? The humidity where I have the printer is around 44% at the moment, but it’s been in other rooms and we’ve had a lot of snow & rain recently so probably days with higher humidity.

I’d be grateful for some tips.

John

2

I keep my PLA in an big airtight box with one of those rechargeable silica packs.

But that said, many others have told me that they’ve successfully printed with PLA that’s been hung on a rack for years. So it seems that moisture absorption might not be such an issue with PLA. It certainly is with ABS, but I abandoned that particular filament a long time ago!

3

Thanks, I’ll probably unload a pack away when I know I’m not printing for a few days.

4

Could it be that the filament only gets weak for the first 70cm or about that length?
I cannot confirm 100% but I see filament breaks mostly when I try to load used filament but when I cut away some length and try again it doesn’t break that easy.
Could it be that the extruder squeezes so hard on the filament that it’s structure changes and the first length becomes weaker?

Just a thought though…
Erik

5

I wrap my spools in clingfilm seems to work well pla and abs seems to work

6

H60 has a very good point.
When I load different filament on my machine I cut off the end and then bend it to see if it’s brittle.
If it is I will cut it back some more until I can bend it without it snapping.

7

Don’t forget that PLA is very sensitive to cold. Always work it in a warm place or warm it before using it.