Fan on print

What makes some printers need fans to cool the prints and some do not? I always had mine on because I saw so many other people using it with the same printer that I had (QUBD Two Up). I feel like my prints need it but many other people don't have a fan and they get some amazing results.

Edited 1 time(s). Last edit at 07/11/2015 01:20AM by tim3716.

Its not the printers that need the print fan, its the material.

Abs does not because it causing problems,
PLA does need the fan otherwise the layers wont join.

I agree, its about the material needs. Cooling on ABS isn't usually helpful IMO. PLA is melted easily enough that when you print small areas/details &@ slow speeds PLA stays hot/too warm and deforms/burns. If you're printing simple parts/wide footprints &@ higher speed I don't think the fan is all that helpful. If you can't print fast or are detail focused I would recommend forced airflow of some kind.

Are there known times (rules of thumb) when using a fan on PLA is detrimental?

Hmm... I don't know of one off hand... maybe when you're printing close to the minimum melting temp? But even then It can help with bridging as it would cool the material as soon as it comes out of the hotend and stiffens it in mid air. but if you don't do a lot of bridging stuff... meh...

It's at least nice to have as an option, my machine currently has 3 regular ~50mm fans pointed down at the table that have some effect but not as intense as some of the squirrel cage setups I've seen. My chamber is also usually heated btw, so if I use them its a lot of fan in a general space, but not nearly as much cooling going on as open/framework designs.