Wednesday, January 13, 2016

When not to use the cooling fan

I'm printing a job of a character holding a staff at various sizes. At 2" tall the model prints fine. A little larger, it's fine. But jump to 6 inches tall and the prints failed repeatedly.
I tried everything. I made the staff thicker. more shells, added supports (manually), brought the printer in doors. No matter what I did the result was always the same. The staff and arm would be off, or they would fall over all together, and cause a cascading failure. The funny thing was on my replicator 1 the model worked, but on my replicator one the overhangs looked terrible because it doesn't have a cooling fan.

...wait a minute.
On the FlashForge there's a cooling fan that blows cool air right onto the plastic as it comes out the left nozzle. It makes PLA prints very happy. It's a pain in the butt if you ever need to get at the extruder assembly, but it generally made the prints pretty. However, in this case, could the air from this thing be what was causing terminal wiggle when the staff got too big? To experiment I turned the fan off and tried again.

Sure enough that's when this model's prints started succeeding. So I pulled the fan duct off so that I wouldn't have to remember to turn the fan off with every print (and moved the printer back into the cold garage so it's effect was less necessary) until this job was finished.

Cooling fans. Sometimes they really improve a print, but sometimes, when making tall towers, they can be the death of them. Go figure.

1 comment:

  1. I've found only PLA should have the fan on. Luckily S3D allows variable control so stuff like the wood filament I can run the fan at 20%. Basically if the filament runs out like water and hits the bed before solidifying (at printing temp) then the fan is needed.


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