Too much cooling?

#1
I broke my fan shroud shortly after building my printer. That is OK though because i have successfully printed 2 replacements. The first one was printed without a fan shroud (obviously). It came out with the right shape but it did not look very good. The second was printed with the ugly fan shroud. The purpose of printing the second one was to see how much having fan shroud improved overhand print quality. It drastically improved print quality especially with overhangs. My second shroud looks great!
The Catch is that now my prints have been warping one side off of the print bed. Most of my prints especially big ones finish very warped and uneven. Before I start messing with the cooling settings. I just want to know that I am working in the right direction. Could this be a problem with something other than too much cooling? Uneven print bed maybe?
 
#2
Let's simplify and work through some logic here.

Print 1: no cooling, no warping, but bad overhangs.
Print 2: yes cooling, yes warping, good overhangs.

Based on that I would tell you to adjust a setting in slic3r which mandates the fan off for the first x amount of layers. It's currently set to 1 but you could increase it to 2 or 3. (it's in the filament --> cooling section).

Give that a shot, but there's a good chance that it's also an uneven print bed. Try what I said before adjusting the bed.
 

GORDON.LAPLANTE

Administrator
Staff member
#3
Make sure you have the fan off for the first two layers and the 1st layer temp is cooler than the other layers. Also make sure to sand the bed often to get the best adhesion.

Cooling it very important but it does lead to some curling especially for ABS (in which case you may want it off completely).
 
#4
It's important to note that PLA has a much higher heat capacity than ABS, meaning that ABS cools down a lot quicker. So an active fan is much more important for PLA.

Which material are you using?
 
#5
I am using Colorfabb PLA (Almost all gone). And I have 2 rolls of generic PLA from Filament Outlet which I bought from Amazon.

I get this problem with both of them. The Colorfabb does adhere much better though.

Re: Simplified Logic.
Both prints used the same G-code. I have not touched any settings in cooling. Using the latest slicer config for single 3.5mm extruder from Gordan.

First fan shroud print( No fan shroud ) : Although a "successful" print, the overhangs were rough and ugly.

Second fan shroud print(Now printing with an ugly but functional fan shroud): Looks great, works great, and no warping.

I only get warping with LARGE prints which I did not get before.

Also worth noting, it warps off the bed on the left side every time. Never any other side. The last few days the temperature in my shop has been 55-60 degrees.