Planetary geared extruder variant on EZFlex

[Glacian22]

Hey all! One of my ongoing frustrations with my rostock was the extruder. I started with the huge, original one that came with the kit, which was a pain. Then I upgraded to the ezstruder which was better by far, but would skip when I stressed it too much (even after tweaking the current). I made a modified, printable version of the ezstruder that worked with an MK8 hobbed gear for roughly 34% extra torque, but even then I could sometimes make it skip when printing PLA at high speeds and thick layers. So I said screw it, planetary geared motor time.

I started from Nylocke's EZFlex design, and made a some changes. The bearing arm now sandwiches a 608 bearing instead of only being on one side; this requires support material, but it's super easy to print even so. To stress test it, I've spent the last week and a half printing some huge things for a client...roughly 100 hours of print time with PLA, running .25mm layers, .4mm nozzle (prometheus), 70-100mm/s, and not a single skip! Basic ingredients are a planetary geared nema 17, MK7 hobbed gear with 8mm bore, passthrough bowden connector, spring, some screws. http://www.thingiverse.com/thing:744759

I'll probably put it on youmagine too, but as I already had a thingiverse account that's where it's living for now.

[bot]

Perfect timing! I'm gonna print one of these instead of hacking about with my ezstruder.

Got any more pics of the install? Hmm... it would be nice if it had a grove mount designed to fit the e3d mount. I should design a remix of the remix!

[Glacian22]

Remix away!

[duvdev]

Hi looks good.

what kind of planetary geared motor do you use? can you posr a link where i can buy it?


thanks

[Renha]

that? http://www.omc-stepperonline.com/high-t ... p-295.html

[Nylocke]

Nice. Did you use Fusion360 to change stuff or another application? It would be cool if you posted the source files if it was the former.

[Renha]

wouldn't you mind if I'll remade this in OpenSCAD to be easy editable, etc? I'm not sure I'll do this, just maybe

[mvansomeren]

Have you tried this with any flexible filament?

[bvandiepenbos]

Nice!
Thanks for sharing this design, good timing because I am also really fed up with the skipping ezstruder.
I am going to print one and give it a try.

Looks good, although I would like it to have adjustable spring pressure, I might see about adding that.

[Renha]

and what is "Passthrough bowden connector"? Any concrete links please?

would geared motor from there http://www.tridprinting.com/Electronics/ enough, or we need stronger one, maybe like in previous link?

[Nylocke]

He's using the same hardware that I use on the original, just click the link in my signature and go to the link there, it has a BOM.

[Glacian22]

The motor from TriDPrinting should work just fine...basically any planetary geared nema 17 will have way more torque than the default motor on the ezstruder. I'm slightly ashamed to say I made all of my changes with Sketchup, since I'm still learning Fusion360, but I can post the skp files if you like. ^^ And the bowden connector is this one: http://www.dta-labs.com/collections/hot ... en-coupler

[Nylocke]

I used the one from E3D, but its pretty much the same.

[Glacian22]

So Nylocke, funny story: the one thing I was going to change and didn't get around to was widening the path that the bowden tube runs through, since it's really really tight. But then I figured it'll at least help the tube stay super securely in place if nothing else. Then I tried printing a vase with .3mm layers at 110mm/s, and I guess the backpressure from the hotend was very high because the extruder forced the bowden tube all the way out of the body and through the connector. And it still didn't skip, hahaha!

[Nylocke]

Wow, nice! I always reamed the hole with a drill so the tube goes through and is just a bit snug, otherwise it can rotate sideways.

[bot]

What firmware settings are you using to drive the TriD geared nema17? I got one too, and am going to be installing it along with an e3d (when I get a break in orders - sheesh it's busy right now). Do you use the stock settings or dial it in differently?

[Glacian22]

No changes to the firmware, and I adjusted steps per mm in eeprom just be telling to extrude 100 without the bowden tube connect and seeing nudging the number till it was actually 100mm. I can go check it at some point.

[JFettig]

Did you make current changes? I imagine it needs less current - but I'm not sure what it would need to be set to.

[Glacian22]

Actually I didn't needed to adjust the current at all, surprisingly.

[bot]

Thank you. Did you already have your steppers current changed to kysan steppers? I have the non-kysan steppers on my rostock.

[Glacian22]

Okay, I just checked my configuration.h, and it looks like I have my extruder motor current set to 210, but I make no guarantees that that's the *optimal* number. It does however work well for the motor I'm using, which is this: http://www.phidgets.com/products.php?product_id=3325. The gearing on this motor seems to have a tiny bit of backlash, while I just picked up one of these http://www.robotdigg.com/product/90/Gea ... pper-Motor, which is a little lower torque, but no observable backlash. Haven't played with it yet though.

[precision]

Wow, thanks for this.. I printed it up and got it running today and wow.. all the weird seams I had are completely gone. Best of all the motor is barely warm to the touch, let alone hot enough to melt the filament in the extruder anymore.

[Glacian22]

I'm glad it's working well for you!

[Aflac]

I was talking to a friend of mine who is in to milling and cnc routers and stuff like that but had not gotten into 3d printing yet about this idea. He said the big thing to watch out for in geared motors is backlash.

How big a problem is this and how much backlash does it take before we care?
I see that the motor someone linked earlierhttp://www.omc-stepperonline.com/high-torque-g ... p-295.html
Says it's is backlash is <=1%
Is that good or bad and how comparable is it to non geared steppers.....wow auto correct wanted to talk about non geared strippers....

[Aflac]

I guess my real question is what is the disadvantage to these geared steppers? Why are they so rarely used?