Using a fan on PLA is a given but using one on ABS much less so. In fact the idea is often greeted by a surprised comment of "really? a fan on ABS?". My lsat printer was a Makerbot Clone, the Wanhao Dplicator 4S, and I equipped it with this fan upgrade:
I can not say that I know exactly why this fan worked as well as it did but it did! Specifically it preserved fine details while printing ABS without causing the print under the extruder to warp or pop off the build platform. I surmise that this was because the small targeted streams of air directed at the extrusion area rather than larger flows directed all over the area under the extruder assembly.
It was this idea that I am attempting to implement with my fan ducts. I am feeling pretty confident that we are heading in the right direction with the details but have gotten concerned about part strength after a conversation on the Ultimaker Forum with gr5 who is one of the most knowledgeable folks out there. He suggested some testing so that is what I did!
|3D Print Filament - Strength Tests|
|PLA w/ 100% Cooling||14.3|
|ABS w/ No Fan (215c)||7.1|
|ABS w/ No Fan (245c)||6.6|
|ABS w/ 40% Fan (245c) - My Mod||4.8|
|ABS w/ 60% Fan (215) - My Mod||4.6|
|ABS w/ 60% Fan (245) - UM Standard||2.6|
My test was pretty simple. I printed a little test piece as shown below. Place at each end to secure it to a leg of my desk and a baggage scale. Pull and record the point where it breaks. Recorded results on iPhone so as not to miss anything!
The results were interesting. PLA was twice as strong as the strongest ABS which had been printed at 215c with no fan. Strangely ABS printed at a higher temperature was a little weaker? Using a fan did indeed weaken the ABS print but my mod caused less weakening than did the standard UM cooling solution.
A new result. ColorFabb NGEN filament. Just splurged on a reel and am liking it other than the price! It had a breaking point the same as PLA, it seems as easy to print as PLA, and it has a higher glass point.