Itty Bitty Double Extruder

[usarmyaircav]

I could be wrong, I have really only been printing 4 months or so, but I don't think it is typical for people printing ABS to use a print cooling fan. I have only done ABS so far and have not used a fan. I think it would be counter productive as ABS loves to lift off the bed at the corners, and a print fan would probably aggravate that.

[gmay3]

I agree with you usarmyaircav. I got similar cracks between layers when my fan accidentally turned on during an ABS print. I'm sure there are some circumstance where you would want the fan on for a short time when printing ABS (maybe during long bridging?) but generally I would try it with the fan off and see if this improves your results.

[avluis]

After a few prints with rafts and auto support (and slic3r 1.1.7), I now have the trouble parts printed out with much improved internal integrity.
Here is the part cooling double fan shroud with a raft:
https://www.dropbox.com/sc/4t6kha248...aCPooOWVoXKpta

I was even playing it dangerously:
https://www.dropbox.com/sc/rj0mbijty...bkNx20r5Ii9pea
But it turned out ok in the end (if you know how to measure your filament...):
https://www.dropbox.com/sc/e4tq77gqy...p79oJu9aAtGoha

I also printed out the double hexagon fan shroud and the single for comparison (and backup):
https://www.dropbox.com/sc/yg6ipjz5r...WKVboHb-D-37qa
Very pleased with how much stronger the parts were with slic3r 1.1.7 - so thanks goes to clough42 for his tips (and his Itty Bitty Double Extruder and his other parts in general)~

[stridera]

Awesome. Downloading slic3r 1.1.7 now

[clough42]

Yup, I have the .4mm nozzle. I had it set to 60% infil with .2mm layers. I reprinted with support material and the curved parts at the top looked great, however, the straight sides were still brittle. I'm thinking if I make the double the layers maybe? It looks like it goes from thin to sturdy near the top. I didn't take pictures of my latest print. (Cracked the side walls while trying to clean off the raft.

Do you do print cooling on both abs and pla?

I typically use print cooling with ABS on parts like this, to the overhang angles thin walls. I use print cooling all the time with PLA.

[clough42]

I could be wrong, I have really only been printing 4 months or so, but I don't think it is typical for people printing ABS to use a print cooling fan. I have only done ABS so far and have not used a fan. I think it would be counter productive as ABS loves to lift off the bed at the corners, and a print fan would probably aggravate that.

It's a trade-off. The cooling fan gives you much more precise prints, with better overhangs and tighter bridges. But you're right, it can also increase warping. It all depends on the parts. Solid parts with long, straight filament strands the length of the part between 5 and 10mm up from the bed are the worst for warping. Parts with lots of holes don't warp as much because there isn't as much force caused by shrinking of these long filaments up high.

So...you want print cooling if you have small details, significant overhangs layers with very short build times so they don't solidify and get mushy, or even if the hot end spends a lot of time over one spot, keeping it hot with radiant heat.

You don't want print cooling if you have a big part with long filament strands that's very prone to warping.

To reduce the warping, you can make sure you have good adhesion (good hairspray formula, application technique and bed temperature, or some other magical formula like PEI or 3d-eze). Then, you need to keep stray drafts and spill air off the bed. This could come from outside the printer or from hot end or electronics cooling fans. Keep the fan off for the first 5-20 layers, depending on the needs of the individual part, and then try to keep the air focused on the part that needs cooling.

My hot end and fan systems are designed to keep stray air off the bed, and to focus the print cooling air right where it's needed.

But...your mileage may vary. Different parts respond very differently. For example, if your part requires the hot end to stay in one spot, dropping lots of detail close together, the cooling fan works great. But if the hot end drops something droopy and then quickly moves to the other side of the part, the cooling air goes with it, and it doesn't really help much.

[avluis]

Woohoo! Almost done:
https://www.dropbox.com/sc/aeoi401io...MNRDYGDIyEa3ma

But time for some sleep.
--
Besides what is mentioned on the first post, is there anything else I need to be on the lookout while making the final wiring touches and then moving on to Marlin?
--

Edit:
All installed, time to celebrate. I'm also testing a commit for Marlin (which raises Z Axis after Probing - didn't Roxy have something like this?) so I threw it on a video for them to look at:
https://www.youtube.com/watch?v=dNtTYOOITH8

Time to configure slic3r and start calibrations.

[clough42]

Woohoo! Almost done:
https://www.dropbox.com/sc/aeoi401io...MNRDYGDIyEa3ma

But time for some sleep.
--
Besides what is mentioned on the first post, is there anything else I need to be on the lookout while making the final wiring touches and then moving on to Marlin?
--

Edit:
All installed, time to celebrate. I'm also testing a commit for Marlin (which raises Z Axis after Probing - didn't Roxy have something like this?) so I threw it on a video for them to look at:
https://www.youtube.com/watch?v=dNtTYOOITH8

Time to configure slic3r and start calibrations.

Looking good.

Yes. There are a couple of forks out there. I'm not sure what has made it back to the master Marlin code.

Beckdac's fork with Roxy's changes is here: https://github.com/beckdac/Marlin

And my fork of that with branches preconfigured for my extruders is here: https://github.com/clough42/Marlin

[sniffle]

Looking good.

Yes. There are a couple of forks out there. I'm not sure what has made it back to the master Marlin code.

Beckdac's fork with Roxy's changes is here: https://github.com/beckdac/Marlin

And my fork of that with branches preconfigured for my extruders is here: https://github.com/clough42/Marlin

At this point Roxy's g29 enhancements and z probe repeatability have been merged into the main trunk of marlin :-)

[clough42]

At this point Roxy's g29 enhancements and z probe repeatability have been merged into the main trunk of marlin :-)

And the lift before retract?