Printing lower temps - nozzle temp drops too much when fan comes on
 
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talz13
(@talz13)
Eminent Member
Printing lower temps - nozzle temp drops too much when fan comes on

I've spent the last day trying to print my hatchbox PLA at lower temperatures (195 works, but currently trying for 198) than default (210). Once the print is established, it's going ok, but the problem is the 2nd layer.

The first layer prints fine at 215 with the fan off, but once it starts the 2nd layer and the fan kicks on, the nozzle temp will drop to ~180, which is too low to reliably print at. The temp will come back up, but often this is enough to weaken the 2nd layer so that the upper layers are unstable, and may easily delaminate / get knocked over during the print.

I guess I'd want some option to allow the nozzle temperature to stabilize after the fan comes on, but not sure how that might be accomplished.

Any ideas?

Prusa i3 MK3 kit
MK3/S Upgrade Kit
FW 3.7.0
Slic3r PE 1.41.3

Posted : 01/08/2018 1:23 pm
RetireeJay
(@retireejay)
Reputable Member
Re: Printing lower temps - nozzle temp drops too much when fan comes on

Try reducing the fan speed from 100% to 75% or even 50%. In Slic3r PE, you even have an option for going to 100% for bridges while being slower for the rest of the print. Also, you can delay the fan coming on until layer 3 for example. I think that when the fan comes on 100% at layer 2, there is so little "object" there that the fan is blowing on essentially a flat surface and that forces air to blow on the heater more than it would after the object builds up some height.
Also, since you're posting in a MK3 forum, presumably you have a MK3. The revised Extruder body and fan shroud do a better job of controlling the air flow. I had the same problem as you (at a higher temperature for PETG) that was helped by using the revised parts.

Posted : 01/08/2018 2:14 pm
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