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Cycloidal drive adapter for Smart Effector [WiP]

Posted by o_lampe 
Cycloidal drive adapter for Smart Effector [WiP]
January 27, 2018 11:43AM
I started to design an adapter to mount my unemployed cycloidal extruder drive, but I think the smart effector adapter could be of general interest for other direct- or cable driven extruders as well. It replaces the fibre-washer and acts as a wing nut, too winking smiley

The motor and gearbox fit pretty good, but I'd like to know, if the center of gravity has to be right above the nozzle to make the strain gauge sensor work properly?
It is a work in progress. I have to figure out a better way to mount the idler gear, than it was in the original version.



Edited 2 time(s). Last edit at 01/27/2018 01:42PM by o_lampe.
Attachments:
open | download - cycloid-smart_adapter.stl (215.5 KB)
Re: cycloidal drive adapter for smart effector [WiP]
January 27, 2018 12:12PM
Looks good! Do the rods remain clear of the extruder body at all effector positions within the printable area?

The position of the centre of gravity shouldn't affect the strain gauge because it looks for a change in strain, not an absolute value.

Edited 1 time(s). Last edit at 01/27/2018 12:13PM by dc42.


Delta printer calibration calculator, mini IR Z probe, and colour touch screen control panel: [escher3d.com]

Large delta printer, and other 3D printer blog postings: [miscsolutions.wordpress.com]

Disclosure: I have a financial interest in sales of the Panel Due, Mini IR height sensor, and Duet WiFi/Duet Ethernet.
Re: cycloidal drive adapter for smart effector [WiP]
January 27, 2018 12:22PM
Thank you dc42!
It doesn't bind anywhere on my 350mm bed. I could print right in front of the X-tower:


Have you heard of anyone trying to use a direct drive extruder on the smart effector?
Re: cycloidal drive adapter for smart effector [WiP]
January 27, 2018 12:40PM
I've not heard of anyone else using a direct drive extruder on the Smart Effector, but this is something we are looking to do. How well does the cycloidal extruder work? I might try it on my Delta.


Delta printer calibration calculator, mini IR Z probe, and colour touch screen control panel: [escher3d.com]

Large delta printer, and other 3D printer blog postings: [miscsolutions.wordpress.com]

Disclosure: I have a financial interest in sales of the Panel Due, Mini IR height sensor, and Duet WiFi/Duet Ethernet.
Re: cycloidal drive adapter for smart effector [WiP]
January 27, 2018 01:39PM
The NEMA14 pancake is almost too strong. With the original idler clamp, I had a few issues with grinding. OTOH, the retraction speed was lower than I'm used to. If I had the chance, I'd rebuilt it with a lower gear ratio. I actually don't remember what the ratio is, have to read the original thread again. 1:12 or 1:16 IIRC?

I just did a few dry tests: reduced yerk from 2400 to 1200mm/s² and raised amps from 1.0 to 1.2A
I could print a stored file with lots of short infill tracks with 200% speed without issues. ( no extrusion yet, so ringing is not tested )
Re: cycloidal drive adapter for smart effector [WiP]
January 27, 2018 03:10PM
There are quite some people out there using a Remote Direct Drive extruder on the Smart Effector.
The Nimble has a nice adapter that fits perfectly and is developed with a few users till it was a simple matter of bolt it on and done.

I know, I am biased, as I co-developed the thing.


Lykle
________________________________________________

Co-creator of the Zesty Nimble, worlds lightest Direct Drive extruder.
[zesty.tech]
Re: cycloidal drive adapter for smart effector [WiP]
January 27, 2018 04:09PM
Quote
o_lampe
The NEMA14 pancake is almost too strong. With the original idler clamp, I had a few issues with grinding. OTOH, the retraction speed was lower than I'm used to. If I had the chance, I'd rebuilt it with a lower gear ratio. I actually don't remember what the ratio is, have to read the original thread again. 1:12 or 1:16 IIRC?

I just did a few dry tests: reduced yerk from 2400 to 1200mm/s² and raised amps from 1.0 to 1.2A
I could print a stored file with lots of short infill tracks with 200% speed without issues. ( no extrusion yet, so ringing is not tested )

What kind of Nema 14 pancake do you have ? What torque ? I am surprised about this 1A ! How about heat ? The specs I saw so far are max 0.5A.
This ratio is indeed too high, I use regular gear, ratio around 4, a regular Nema 14 28mm. To gain some 40g I am looking for a pancake.


"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)
Re: cycloidal drive adapter for smart effector [WiP]
January 28, 2018 02:26AM
Quote

I am surprised about this 1A !

Sorry, the 1.2A were meant for the XYZ axis' to take care of the extra weight.
The pancake is a 14HR05-0504S.
The gear ratio is 1:16, maybe powdermetal has chosen this ratio to have a smoother movement. Those cycloidal drives are not good at low gearing.
Re: cycloidal drive adapter for smart effector [WiP]
January 28, 2018 06:59AM
Hey o_lampe,

clever idea to mount the drive unit in an angled way - provides a much better packaging especially for the rods' clearances!

Currently I am running my 4HR05-0504S stepper motor at 0.4A (with 8825 drivers) without motor cooling, using 1.75mm filament (retract: 0.3mm, speed 10mm/sec, accel. 4000mm/sec^2). The retract/speed settings seem quite conservative, but with direct extruders the distance to the nozzle is quite short, giving a crisp nozzle response.

The gear ratio 1:16 was initially developed to safely drive 2.85mm filament. 1.75mm material requires way less force and this ratio easily promotes grinding at fault conditions. A lower gearing would be feasible for sure - has been on my todo list for quite a while...
Re: cycloidal drive adapter for smart effector [WiP]
January 28, 2018 08:15AM
Hi powdermetal, glad to have you back grinning smiley
I'd go for 1:6 or 1:8 ratio. But with a lower gear ratio the force vectors between housing and the gears get worse ( higher friction ). My idea would be to add bronze bushings to dowels for the shell contour. Just like tiny cam-followers.
As a nice side effect the excenter could be bigger and therefor easier to print.
Re: cycloidal drive adapter for smart effector [WiP]
January 28, 2018 09:38AM
Following with interest
Re: Cycloidal drive adapter for Smart Effector [WiP]
February 11, 2018 11:59PM
what's the weight compared to titan pancake combo?
Re: Cycloidal drive adapter for Smart Effector [WiP]
February 12, 2018 02:46AM
With alu-housing it's a little under 100grams. The Titan with pancake stepper is more like 250gr IIRC.


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