To cool or not to cool

[jotto 0]

When should you use the cooling fan, for PLA, PVA and PETG respectively? Always, or only on the first layer? Or not on the first layer?

(In my case, I have an Ultimaker 3)

[geert_2 557]

I use this on an UM2:

- PLA: always on. Bed at 60°C.

- PET and NGEN: off when the model allows it (e.g. a thin flat model without overhangs), then it can be printed on bare glass. On at 40...50% if required to prevent overhangs from sagging, but then it requires bonding aids (dilluted wood glue or so) to prevent warping. Bed at 80°C.

[jotto 0]

I use this on an UM2:

- PLA: always on. Bed at 60°C.

- PET and NGEN: off when the model allows it (e.g. a thin flat model without overhangs), then it can be printed on bare glass. On at 40...50% if required to prevent overhangs from sagging, but then it requires bonding aids (dilluted wood glue or so) to prevent warping. Bed at 80°C.

 

Thanks a lot!