Itty Bitty Double Extruder

[TechMasterJoe]

Yeah, but I've typically found cyber Monday to be iffy as far as internet performance. Today's actually been better than usual.

Ya I can see that a lot of sites are slow newegg is crazy slow right now. I got a new gaming laptop just now a painful 1673$ but I wanted 32gb of ram and a good gpu because I'm in both solidworks and master-cam x8 all day.. I was going to order a new hexagon 3mm and nozzles guess it's got to wait lol

[RobH2]

Do you have a weight of that whole setup?

As I was building this and testing it with 'clough42' I was interested in the weight also. I weighed my standard Wade's extruder (Magma hot end) and it was 607 grams. The dual hexagon weighed 701 grams. Not bad to add less then 100 grams to get a dual rig.

One nice side effect I've found is that if I'm careful, I can swap filaments out on the head that's not printing (if I'm not doing a dual head print) and save time. I'm printing with PLA now on my left head and I just switched out the ABS on the right head to nylon without messing up my print. That's nice.

[jprochnow]

Let's see a video of this thing printing! I'm looking forward to a dual extruder!

[AbuMaia]

Do you have to really ramp up the retraction distance in order to avoid oozing when printing with the other hotend? Pull the filament completely out of the melt zone?

[RobH2]

I haven't gotten to the point of tweaking oozing yet. That will come up soon. I'll also get some video sometime soon. That's a good request.

I've printed PLA and ABS so far. Both printed beautifully. I haven't had one jam yet. In fact, I was cleaning a head and at the bottom you can see that the melt zone is perfectly aligned to the Hotend height. So no melting is occurring where it should not that might cause a jam.

I'm printing Ninjaflex right now and it's working well, the filament path is sufficiently encompassing well such that the filament can't bend and snake out anywhere. I didn't make any modifications to 'clough42's' original design to accommodate Ninjaflex. I'll be testing Bridge Nylon and PET+ in the next few days.

DualHexagon_HeatZone.jpg Ninjaflex_01.jpg

[clough42]

Do you have to really ramp up the retraction distance in order to avoid oozing when printing with the other hotend? Pull the filament completely out of the melt zone?

I'm currently retracting 10mm when switching hotends. This is just a setting in slic3r, and it seems to work pretty well.

The other key to preventing oozing is to tune the temperatures. I'm finding that different colors of filament have different melt profiles. I can get nearly ooze-free performance from black at 240C, but I've got the orange down to 220C, and it's still oozing more than the black.

I have confirmed the temperatures with a thermocouple, and the temperatures are correct (or at least responding the same). I'm reading 9 degrees cooler than the reported temperature with the thermocouple in contact with the top of the heat block. The thermistor and thermocouple temperatuers track together up to about 150C, where they diverge, and up in the 250C range, I see the 9 degree difference. It could just be a thermal gradient in the block, or it could be a small error.

I'm using the default Marlin Type 1 tables.

[clough42]

I'm printing Ninjaflex right now and it's working well, the filament path is sufficiently encompassing well such that the filament can't bend and snake out anywhere. I didn't make any modifications to 'clough42's' original design to accommodate Ninjaflex.

Really? Ninjaflex? That's awesome. I thought I was going to have to do some more work to get that one working. The filament is unsupported below the bolt for about 4mm. Maybe with 1.75mm filament, it will need more support.

[RobH2]

Yep, Ninjaflex printed really well. No issues of any kind. That photo above was the first test of it and was printed at 220C. Yea, I'm guessing 1.75 filament won't be so lucky.

[clough42]

Let's see a video of this thing printing! I'm looking forward to a dual extruder!

This is a live stream of a test print. It should be running for the next eight hours. Unless it fails utterly. After that, I'll come back and put in a better link and upload a time-lapse.

https://www.youtube.com/watch?v=UAGA5TIkg9w

I'm printing this:

http://www.thingiverse.com/thing:11687

[clough42]

This is a live stream of a test print.

You can see the home/autolevel/priming sequence starting at 06:30. I'm using Roxy's enhanced G29 code.

Here's the startup sequence:

• Heat the bed
• Start heating the nozzles
• Home and probe for autolevel (G28/G29)
• Park at Z=0 with both nozzles off the glass
• Wait for both nozzles to reach temperature
• Prime the left nozzle wipe it onto the glass
• Prime the right, retract it slightly and wipe it onto the glass
• Print alternating loops (Slic3r)
• Print

Slic3r prints the outside ring with the left nozzle first; that's why I retract the right nozzle slightly. This keeps it from dribbling while the left nozzle prints loops. After that, Slic3r automatically handles the retracts.