Baked-pla.

[rewolff 0]

We've had the "translucent" PLA come out a bit milky:

However we've now baked the PLA at 100-110 C for 90 minutes and now it comes out much clearer:

Is this the best performance we can expect for jumps, or do we need to find even better settigns?

[Daid 306]

You baked the final object or the PLA before extrusion? Because that result looks pretty good.

As for the strings, check the google groups for the retraction settings test from florian. With the experimental dwindle settings in Cura it is possible to get better (or worse) results.

[rewolff 0]

We baked the PLA before printing.

We have the impression that trapped water boils in the hot end (Duh!) and causes some springyness in the system: the water-vapor can be compressed. So during extruding you sometimes hear a pop of hot gasses de-pressurising. So baking the PLA means the whole system is stiffer. So when the extruder motor stops, extrusion stops quickly afterwards. While with some hot water in the extrusion unit, the gas will expand and push out some more plastic.

[futurejames 0]

Did you guys just toss it in the oven, spool and all?

[joergen 2]

However we've now baked the PLA at 100-110 C for 90 minutes

Just out of curiosity, the filament didn't deform, or stuck together? PLA usually gets soft at 59C, so I would expect it turning into mush under its own gravity at 110C, plus the ABS spool also starts to get soft, although I don't expect major deformation.

[rewolff 0]

Oh. Yeah. Forgot to say. 1) I have bought a few different colors which ended up spoolless... That said, we were still in the testing phase: as you say we were afraid we might ruin the whole batch of PLA, so we didn't put it all in at once.

Yes, the PLA looks a bit different. When it comes off the spool it looks like it was once straight, but has given in and now wants to be curled. But the amount of curl remains the same for meters at a time.

After baking it looks as if taking a turn every 10-20 cm and then there is a piece that's straighter than the previous part. But it feeds just fine! Apparently the filament diameter is still that 2.84 mm that I measured.

[phut 0]

That's interesting and certainly doesn't match my observations with heating up PLA printed parts.

I had a circular part which was about 45.5mm initially, which I then had push-fit to another solid (metallic) part - later I decided I wanted to take it off so heated the solid up to about 50-60 degrees (keeping in tune with the PLA gets soft at 60 degree thing) which ended up shrinking the part down to about 44.2mm.

I guess it might be that on a 3mm section it's not an observable difference on the very-nears.

[rewolff 0]

Lots of plastics "remember" what happened around the time they cooled.

So you have those food-containers that suddenly "remember" being flat if you heat them to 60 degrees.

There is a bit of "tension" in printed PLA. even though it's less than ABS, I've had trouble that a larger box came loose from the bed due to shrinking. So what PLA "remembers" when you heat it is that it was supposed to be a bit smaller, but it HAD to be bigger to fit on the layer below. However the neatly extruded 3mm filament doesn't remember anything. Maybe the odd-looking curved sections have something to do with that. But the diameter stays firmly the same....