revwarguy: Oops, sorry. I misread your post and my response was poor.
Often there are two fans with j-head:
PLA needs cooling. So you should have some fan pointing at the printed part. The fan can be on the head or an external big one.
ABS benefits from cooling too but you can do without cooling too. When you overdo cooling of ABS you get layer delamination. So you should cool only a bit and just right with ABS (if you cool it at all).
Often there are two fans with j-head:
- one cools the hotend itself (its PEEK cooling fins) so that the heat does not creep up the hotend (this prevents deformation of the PEEK part with higher temperatures and hotend jams when filament would be melting too high (in the PEEK part));
- one cools the printed part (that is the one which I though you mean by "pointing at nozzle" (since the other one is not pointint at the nozzle (orifice) but the PEEK lining)).
PLA needs cooling. So you should have some fan pointing at the printed part. The fan can be on the head or an external big one.
ABS benefits from cooling too but you can do without cooling too. When you overdo cooling of ABS you get layer delamination. So you should cool only a bit and just right with ABS (if you cool it at all).