UMO Direct pancake drive

[Neotko]

I'm working on this, so far the thingys seem to be where they should be. My goal it's to make a direct pancake driver with the standard umo/umo+ hotend.



So far it will use x2 0.5 gears 20º from Misumi. T15 (GEABN0.5-15-8-K-5) and T50 (GEABN0.5-50-2-B-5) So the gear should give enough 'punch' for any 1.75 filament.

The lower position of the motor it's to be able to use x1 30x30x10 fan (24v) focus on the motor & the ptfe (works wonderfull to make them live longer).

I suppose I'll use a reverse spring on the bearing to keep it small. But I never done something alike, so I might fail !

[LePaul]

So the extruder would be built into the print head? Interesting

[Neotko]

Yes at first I was going to build it above but I want to keep it as close to the head as posible to be able to print flexibles with high retracts without problems or oil. But that's just the idea so far

[Xeno]

Funny , I was thinking about the old forum posting about direct feeder

would you think the motor would also be powerful enough for 2.85mm ?
and how much total height would you lose with the extra height of the printhead ?

[Neotko]

Anders used this motor (I think gear less) and was only able to use 1.75mm. For me it's perfect because that's what I use. 3mm might be a bit too much but who knows...

Foehnsturm used this motor for his corexy machine with a bit higher gear ratio and worked fine (with e3d hotend).

The motor weight it's 64g and the gears etc shoud be a 10-20grms tops.

I'm still struggling to make the tensioner small so it don't eats much printing area.

[Anders Olsson]

Yes, I use this motor with a 3.5 mm knurled shaft on my UM2 direct drive feeder.
I actually recommended Foehnsturm to use this motor and he made a really nice geared design based on it.

I had plans to work on improving my design, but it did not happen so far, too many projects.

Anyway, 3.5 mm knurled shaft, no gear, 600 mA current and 1.75 mm filament works in my case, at least for normal printing, I did not push it with extrusion tests yet. 3 mm would need much more torque, meaning higher gear ratio or larger motor.
I will make a separate thread about my extruder I think to not interfere with Neotkos project
Nice design by the way, Neotko!

[Neotko]

Please inferfere !

Thanks! The parts so far fit on the original design screws and it will be a small bed reduction. I found that misumi sells 12 inner dia 0.5 gears, at that dia you could insert the mk7 inside the gear and cut some 5-6mm also they have 50-80 gearred tooth at 8mm bore, so you could insert the 8mm um2 gear, or the 8mm umo+ bolt.

[Anders Olsson]

I put my UM2 direct drive in a separate thread instead: viewtopic.php?f=35&t=41
But of course I will help you with design advices if you need

[Neotko]

Well so far seems that it might work. The area for the second extruder it's clear, so it should allow to have one normal extruder and another with this mini pancake.

I need to print it and check in the real world the problems, but the semi-IRobertI feeder seems that should work.



I still need to make the middle extruder area more secure, but that should be easier than the feeder part.

[drayson]

looks very promising... maybe some kind of quick mount to take away the second extruder if not needed might be also helpful.
But anyway - curiouse to see it in action

[Neotko]

Indeed the idea it's to make it hotswap. Anyhow, to make it solid I might end having to redesign the top wood part (as last resort).

The problem it's that I need to choose between being able to leave the first extruder entry point 'clean' (if I end using 2 hotends) or just a hotswap that uses the first extruder. I might just do that btw. Also to take out a bowden and insert a shorter one for the direct drive isn't that problematic.

I might end doing the top part as a solid that you can 'insert' and rotate to use just first extruder or second. This way the user can choose to use on a dual setup or on a single extruder setup, without having to do much changes...

Anyhow misumi hasn't send yet the gears, so I have all the weekend to finish/print it.

[Neotko]

Well the basic design it's ok. Since I posted it also on the umo forum I'll repost what I did post there... post post post post (BTW nice place to host the images) XD

This it’s current design (being printed as we speak) for a Pancake feeder for umo+.

The idea it’s to use the same Pancake motor that anders-olsson recomended to foehnsturm for his compact direct feeder on his corexy.



As you can see the motor uses x2 gears, from Misumi (they ain’t cheap, but they are ready to plug on the motor.

Also, on the back of the motor I will insert a 40x40x10 fan to keep it cool. But anders told me that on his test 0.6a where ok for 1.75mm. I will start there and check with a thermal camera to see how hot it gets.

The gears in use are:
GEABN0.5-50-2-B-5
GEABN0.5-15-8-K-5

The Pancake it’s a SANYO DENKI pancake feeder bipolar 0.8º 24VCC

The main idea it’s, like on the image that Anders-olsson shows, to make a feeder addon, that could be removed or inserted to be able to feed directly flexibles (and probably anything 1.75mm).

It will use a mk7 from reprapeurope and the area of the feeder it’s absolutly inspired on the IRobertI feeder (maintly because I don’t have a clue how to do it other way).

This it’s just a start, but as soon I get time (probably a few weeks...) I will assemble and start some tests.

The area that it’s more grey to me it’s the mA change, but I suppose a simple gcode prior using the direct feeder or going back to the normal feeder should suffice. Anyhow since Ultimaker Original firmware don’t have the cool things that Tinkergnome added to um2, I don’t know if it will be easy to manage or a pain in the arse.

Current status: Printing prototype

[Amedee]

I can probably easily add the stepper current in the UMO firmware...

[Neotko]

Yes pls pls!