Awesome remote direct drive extruder

Samuel Pinches

If you haven’t seen this, you gotta watch this!

https://youtu.be/FrLicMf4B9k

https://www.youtube.com/watch?v=FrLicMf4B9k

Gandy

Ever since I watched this, I'm thinking about modifying my A5 - has anyone tried this, yet?

Gandy

For anyone interested, I started to design an adapter for the zesty nimble to the A5. It is in a very early stage and far from usable, but I'd be happy to get some feedback on this.

Samuel Pinches

Man, I wish JGAurora did something like this. Nice job. I really dislike bowdens...

Gandy

Oh, I'm just learning to dislike them, but then I can be a quite fast learner at times 
I could probably warm to the idea of keeping the tube for a reverse bowden, however.

itisnot_me

they have an old one on thingi https://www.thingiverse.com/thing:1843195

Gandy

I'm using that mockup for my adapter plate design, this thingy is linked on the adapter plate design resources page for the current v1.2
I will ask zesty tech to check my design before I order one, though.

itisnot_me

They said on the video they will make you one but it's always good to start the process.

I would love to get one but 100 is out of the question since I would need to get a new motor also. Would even know what length of wire to get either

Gandy

Just uploaded a new version which uses the existing bowden coupler to fasten the mounting plate to the print head.

Also contacted the guys from Zesty Technology to clarify a few questions I had.

Gandy

The game is on, I've just ordered my Nimble. I've come to an adapter design that seems to fit nicely with the A5 frame, doesn't shave off too much of the printable height and even allows to keep the frontplate (just in case that adds to the rigidity of the frame):

@Samuel Pinches my video taking skills are non-existent so there won't be a youtube video on this. But I will try to make a few stills of the conversion in case this makes an interesting addition to the wiki. The existing pages on modifications for the A5 are a great resource (as is the whole JGA wiki) and I'd be happy to contribute.

Samuel Pinches

Sounds awesome! Really looking forward to seeing your results. Photos of the setup would be great - and perhaps some before/after print tests?

Gandy

Will do. I'm hoping to resolve the extrusion problems I reported in the other thread, or at least improve things visibly. At least this setup should allow me to print flexible material.

Gandy

Here it is, with the cover plate removed for full disclosure:

Parts used:

• The Zesty Nimble Remote Direct Extruder
  
• Nema 17 Bipolar 1.8deg 13Ncm stepper motor (faster acceleration)
  
• Mounting adapter for the A5
• Side mount for the 3D-Touch
• JST-XH 4pole connectors for the motor cabling
• For filament management I reused the PTFE tube as a reverse bowden (with this holder)
  

Required firmware configuration:

• On a 8-bit board, E0 microstepping needs to be reduced from 1/16 to 1/4. Either set the appriopriate jumpers beneath the driver (remove the 2 outmost, leave the on in the middle) or by configuring the TMC2208, accordingly.
  
• Extruder steps/mm is now 650 rather than 100 as a starting value for calibration.
• E0 motor current needs to be adjusted; I fine-tuned that during a print for most silent operation. With a TMC2208, 350mA RMS seems to work; that would be Imax=494mA, or Vref=395mV on the A4988.
  
• Depending on how the motor cabling winds up, the E0 direction may have to be inverted.
• Retraction length can be dialed back to 1-1.5 mm (with FWRETRACT enabled, this can be adjusted on-the-fly, e.g. while printing a retract calibrating model; will only work with ABL, not UBL).
  

Drawbacks/open issues:

• At least with the TMC2208 driver and the MKS GEN_L V1.0 board, linear advance appears not to work properly
  
• This will put you back ~100 EUR (plus VAT)
• The extruder motor moves real fast. I'll need to find a way to reduce vibrations coupled to the frame. If everything else fails, I can detach the motor from the frame completely.
  

I took pictures of every step during the build that is not already covered in the excellent documentation on the Nimble. If anyone is interested, I will post them here.

chainbreaker2012

This looks fantastic, hope one day I can do a direct drive on the a5s.

Gandy

Finally I also managed to replace the original 8-Bit MKS GEN_L V1.0 board with the 32-Bit BigTreeTech SKR V1.3 - what a difference! Just mentioning this here to provide working settings for the Nimble on the 32-Bit board running the latest Marlin bugfix-2.0.x:

• SCURVE_ACCELERATION and JUNCTION_DEVIATION disabled
• TMC2208 RMS current for E0: 350 mA
• E0 µ-steps: 16
  
• E0 Jerk: 2
• E0 max acceleration: 450
  

Other than with the 8-bit board, these settings allow to use the Nimble with Linear Advance without any problems.

Richy_T

Nice. I was just about to make a post if anyone had done anything like this.

Gandy

It's been more than a year since the upgrade now and it's time to re-visit this thread and add a few comments. Meanwhile, I've also exchanged the original hotend with an E3D-v6, still with the Zesty Nimble remote direct extruder. Alas, while having improved a lot on the extrusion consistency, there still are inconsistencies I've never got rid of.

Let me get back to the before-after-comparison from my previous post. Notice the diagonal bands on the right single-wall-cube? The cross-section shows overall good consistency, but on closer inspection the wall thickness still varies noticably:

Over the time, I did lots of test prints trying to figure out if there is a periodicity to the artefacts that can be related to mechanical properties of the extrusion system. Long story short, I was able to identify two probable candidates: There is a correlation both to the pitch of the teeth in the hobbed gear and a full revolution of the flexible drive cable.

Just recently, I have learned that this banding is known to occur with other remote extruders as well, so a word of warning is in order.

All things considered, having made the conversion to a remote direct extruder improved print quality a lot over the original bowden setup for my A5. It also allows me to print flexible materials, which is why I wanted to loose the bowden in the first place. I've also learned a lot, which alone makes it worth the effort. 

Now that I've hit an intrinsic limitation of the remote direct extruder, I will probably explore other solutions, like a not-so-remote direct extruder. The Orbiter 1.5 just came out and it appears to fit my E3D-carriage with just minor modifications, while adding only 150g to the hotend assembly. I might share my progress on this in another post.

itisnot_me

Good to know that it was a mechanical problem. I always thought it was a problem with the printer

Also after digging deep (and learning not to be lazy) into my newer printers (not JGA ones) I have figured out the calibrating E-steps, then flow, and then the X/Y/Z steps will take out a bunch of problems with layer stacking and provide better prints. Other issues beyond that are printer specific like hot end quality and quality to extruder.

Also make sure you tune your vref, because if the motor is running hot then it will soften the filament and wont grab as much.

Always make sure that your hotend heatsink is not getting heat creep. It will also mess up extrusion

It is best to note that sometimes you might have to retune your steps every now and then as they will adjust with printing and environment conditions. I constantly print for my business and every now and then i have to retune my steps (mostly the Z)