Fans in series or parallel

I've been running with a single fan cooling the filament, but I've been finding I really need two fans facing opposite directions to get proper cooling on both sides of a print.

I'm running the duet at 24v right now, with a single 24v fan off the fan header. would it be better to run two 12v fans in series, or two 24v fans in parallel?

Edited 1 time(s). Last edit at 06/03/2016 02:41PM by Masterjuggler.

The problem with running 2 fans in series is that there is no guarantee that they will share the voltage equally, especially if one of them stalls because of an obstruction. So it is better to connect fans in parallel.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Thanks for the tip. I'm actually contemplating using a single centrifugal fan feeding into multiple printed loc-line ducts, so I may not have to wire up multiple fans at all. I might just experiment for the heck of it though. In any case, air from a single direction is definitely not enough to get proper cooling as far as I'm concerned.

Be careful you don't overdo the cooling thing. I "upgraded" the print cooling on my Mendel variant and ran into problems with layers not adhering well. I think my problem was that the cooling air was being directed too closely to the nozzle and the filament was cooling too quickly before it could adhere properly to the previous layer. I'm actually getting better results by turning the print cooling off for all but the smallest objects and even then, only tuning it on after about 10 layers or more. Mind you, I've only ever played with PLA and mostly at 0.3mm layer height, other filaments/different layer heights may act differently. Juts a word of caution...........

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deckingman
Be careful you don't overdo the cooling thing. I "upgraded" the print cooling on my Mendel variant and ran into problems with layers not adhering well. I think my problem was that the cooling air was being directed too closely to the nozzle and the filament was cooling too quickly before it could adhere properly to the previous layer. I'm actually getting better results by turning the print cooling off for all but the smallest objects and even then, only tuning it on after about 10 layers or more. Mind you, I've only ever played with PLA and mostly at 0.3mm layer height, other filaments/different layer heights may act differently. Juts a word of caution...........

I think there is a lot in this, my experience so far with PLA and zero layer cooling has been nothing but positive, but bearing in mind the sub 15c ambient temperatures in been printing in this could just be a winter thing.....
No way I would try to do the same thing with the ambient above 30c
So I agree, be careful of over cooling and uneven cooling and also consider the overall ambient temps

I think a lot of tiny objects get printed and need to be cooled so cooling becomes entrenched in all the recommendations but people then move on to bigger objects and get all sorts of layer issues.

My long standing trick for small parts in ABS is just to print a few of them, gives each item time to naturally cool enough whilst still retaining enough layer heat for good adhesion for the next layer

The amount of airflow I'm getting isn't really the problem, as the side the fan duct is currently pointed at is getting great cooling with perfectly fine layer adhesion. The problem is the other wide of the prints, that are not getting direct airflow over them from the fan. I can clearly see a difference in quality when the same model is turned 180 degrees, using the same print settings.

I figure if I get too much cooling, I can just set the fan speed at a percentage under 100. As long as all sides of the model get equal cooling.

Agreed on the "too much cooling" front.

I over-engineered a fan to blow just under the nozzles, right at my print. But the problem wasn't that print quality suffered, it was that the nozzle got cooled too and the heater couldn't keep up. So the temperature would drop until I got a "thermistor decoupled" error (in Repetier, not RepRapFirmware).

Took me forever to find because it didn't happen when I was testing things, only when I had some print that happened to have enough need for cooling that the fan would run for a few minutes solid. I thought my 12V supply was drooping for a while.

I run at 25% fan maximum now, and things work pretty well.

Just keep that in mind if you encounter something like it.

I appreciate the input on over-cooling. I'll keep it in mind as I'm testing, but I don't think I'll have to worry about because a) I'm not actually upping the airflow. I like where I'm at, it just needs to come from multiple directions, and b) I've got a V6 hotend running 24V. If I can make a fan setup that can prevent it from reaching 200C (what I print PLA at), I'm calling it an accomplishment haha.

I'm working on designing a loc-line style duct with multiple hoses coming from the fan that I can orient however I want. If it doesn't work, I'll go with my original plan to use two fans and I just won't use 100% power.

Edited 2 time(s). Last edit at 06/06/2016 02:58PM by Masterjuggler.

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Masterjuggler


I'm working on designing a loc-line style duct with multiple hoses coming from the fan that I can orient however I want. If it doesn't work, I'll go with my original plan to use two fans and I just won't use 100% power.

That'd be good to see. It's something I've thought about myself. Be sure to post some pics if it works.

Will do. As it turns out, I can't find any adapter that would fit my needs on thingiverse, so I'll have to cad it up first. That'll happen once I have the centrifugal fan (should arrive in a few days) and can take exact measurements. I've already been experimenting with the loc-line hose itself, and I've managed to get the tolerances such that I could probably also use it to run coolant to a lathe without leakage. Go 0.05mm layer height

Edited 2 time(s). Last edit at 06/07/2016 07:37AM by Masterjuggler.

I undersized my cooling a little bit or to be more precise: probably my fan outlet is too far away. Okay that was my first design, I am no trying to print the second one. But I saw something interesting:
It seems there are two types of PLA out there:
One type does not need much cooling (eSun/NuNus/kiboplast/3DPrima). My current setup works really fine. I also could print without second cooling fan.
The second type needs much more cooling and my current setup is not good enough (3DFilaments.ie/Eins3D.de/hindl/Filamentworld)

I am wondering why these PLA-types are so much different and if you can say something about the quality. I only heard positive feedback of the second group and many different feedback of the first group. For me I got the best results with eSun and 3DFilaments.ie. The other ones from the second group I have not tested yet very much but it seems like they are a little bit better than eSun.

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Slicer: Simplify3D 4.0; sometimes CraftWare 1.14 or Cura 2.7
Delta with Duet-WiFi, FW: 1.20.1RC2; mini-sensor board by dc42 for auto-leveling
Ormerod common modifications: Mini-sensor board by dc42, aluminum X-arm, 0.4 mm nozzle E3D like, 2nd fan, Z stepper nut M5 x 15, Herringbone gears, Z-axis bearing at top, spring loaded extruder with pneumatic fitting, Y belt axis tensioner
Ormerod 2: FW: 1.19-dc42 on Duet-WiFi. own build, modifications: GT2-belts, silicone heat-bed, different motors and so on. Printed parts: bed support, (PSU holder) and Y-feet.
Ormerod 1: FW: 1.15c-dc42 on 1k Duet-Board. Modifications: Aluminium bed-support, (nearly) all parts reprinted in PLA/ ABS, and so on.

At the end of the day, the quality of the filament can be almost completely compensated for just by tuning the printer well. That said, I really don't know whether or not my filament (hatchbox) is "good quality" compared to other filaments. What I can tell you is after the past year of working with it, I can get some damn beautiful prints out of it with the proper settings.

Quote
Masterjuggler
At the end of the day, the quality of the filament can be almost completely compensated for just by tuning the printer well. That said, I really don't know whether or not my filament (hatchbox) is "good quality" compared to other filaments. What I can tell you is after the past year of working with it, I can get some damn beautiful prints out of it with the proper settings.

I have loved Hatchbox filament. Right now I've got a black ABS and a yellow "Performance PLA" (they were out of the regular PLA), and they have both been treating me really well.

And I've had some bad results with black filament from other vendors--seems like it's a common place to hide the slag plastic, since you can't see it under the black.

I just printed an adapter to mount the centrifugal fan (arrived today) on the 40mm axial fan duct. It now cools parts so fast, the bed doesn't keep them warm enough, and they pop right off haha. The v6 does a beautiful job staying at temperature though. Of course, this is at 100 percent with the duct pointing at one spot. I'll do some testing once I've finished designing the multidirectional loc-line duct. Hopefully I'll get around to that in the next week when I have some time.