Same print (still in process), two days, two attempts. The only differences:
40% infill vs 20% (40 seemed unnecessary)
Drying the filament overnight in a sealed bag of Silica Gel
Cleaning the nozzle with the hot-pull method
Looks as though the 40% needed bed height adjustment?
I didn’t touch the bed height between prints. I suspect what you’re looking at is just the fact that I tossed the 40% (after removal) next to the 20% still in process. The first layer on both was perfect.
@John_Roth it definitely shows a good representation of 20 vs 40 infill.
Have you tried cubic infill? It’s much less jerky than honeycomb.
Here’s a picture of first layer of each… Looks perfect in my opinion (if not slightly under-extruded)
missing/deleted image from Google+
@Geoffrey_Forest I haven’t - but I really haven’t had any issues with the honeycomb at all. I think it prints a bit quicker on my Delta.
Don’t really think a day with silica is going to do much. Maybe a few weeks with multiple swaps to fresh dry silica.
@Nathan_Walkner Heat creep?
Maybe I’m being obtuse, but I don’t see the failure on the 20% infill version. Did it fail to adhere to the bed?
@Ross_Bagley No, the 20% printed perfectly. Only posting both for comparison. And I could be wrong, but I don’t think the difference in infill was a factor in the quality.
@Ryan_Carlyle You think that maybe only the outer filament on the spool had absorption?
@Ross_Bagley Yes
@Howard_Story possible because it’s a slow process, but the bigger issue is, a kilo of plastic holds a lot more water than a little silica packet. I did the math a while back and you need something like 300-400g of dry silica (not used/old) to fully dry a kilo of saturated plastic.
@Ryan_Carlyle depends on the plastic. Nylon (PA 6, specifically), for example, will absorb up to 2.0% of it’s weight when immersed in water for 24 hours. ABS, by comparison, will absorb about 0.30% (depending on the specific polymer make up)
PA6 saturates around 9-10% (and that takes a couple weeks at 73F when immersed). In 50% RH, at 73F, the equilibrium is around 2.8-3.1%
It needs to be dried to ~0.1% for good extrusion results.
ABS saturates around 1% when immersed, and equilibrium at 50%RH ,73F around 0.37%.
It needs to be dried to 0.1%-0.15% for good extrusion results.
So, 1kg of Nylon can hold about 90g of water. 1kg of ABS can hold about 10g.
@Taylor_Landry1 Yeah, very true. I believe I did the silica math for ABS. Silica won’t dry nylon in any meaningful sense.
Basically the issue is that wet silica won’t absorb water from dryish plastic. If you want the drybox to hit 15% RH (a pretty good value for ABS in my experience) and your silica starts at 5% RH equivalent water content, then the silica can only absorb an additional ~4g water per 100g silica. Basically you need a giant silica pack per spool, and it has to be FRESH silica, or it’s not accomplishing anything. The little 10-40g packs shipped with the spools don’t cut it.
Yep, and really, without heat, you’re never going to dry the plastics properly unless you’re maintaining a strict RH% for very long periods of time.
Passive drying, even with molecular sieves, is just not the right method.
@Taylor_Landry1 I’ve made it work for PLA and ABS with weeks/months of “soak” time in the drybox, but even in a year with fresh CaCl2 desiccant I haven’t ever passively dried nylon or PC successfully to a low enough moisture content without heat.
Oh sure, it can be done (weeks/months being the operative phrase), but to the OP, 1 night with some desiccant is not the reason for the print difference.