Re: Bolt-On Gearbox Extruder Experiment
Most up to date revisions for the Bunny and Bear Geared Extruder will continue on Thingiverse
Re: Bolt-On Gearbox Extruder Experiment
Just a little word of caution as I found out.
If you are printing the whole thing out of PETG, be warned that the part that goes around the bottom of the heatsink and is nearest the heater block, WILL soften and droop onto the heaterblock if you print at 270 Deg and up!.
I found this out to my detriment on the skelestruder, but on the skelestruder, the botom part is a seperate piece, so I got some polycarbonate and reprinted just this part and now have no issues running the hot end at 295 Deg C.
So maybe consider modifying your design so that the bottom piece is a seperate piece which can be printed out of polycarbonate.
It's just a suggestion. 🙂
Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.
Re: Bolt-On Gearbox Extruder Experiment
Yes, I noticed that piece on the Skelestruder. Raises the debate as to whether that vs just printing entire extruder in PC. I haven't tried that. PETG is my usual material. I get up to PC only for my fan nozzles.
Re: Bolt-On Gearbox Extruder Experiment
There looks to be quite a bit of bridging on your design, I don't know if you have managed to successfully get PC bridging working reliably, I'm still trying to find working settings (Rigid.Ink Natural clear PC). I'm still undecided whether to go for a hot end upgrade to be able to print higher than 295 Deg C, but first have to exhaust everything I can do at 295 Deg C max.
Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.
Re: Bolt-On Gearbox Extruder Experiment
Yes, Greg did use a lot of bridging in the Bear extruder. At this point, my variant is fully functional.
I'm thinking about the MK3 and MK3S extruders. Both of those could receive the Bunny Science treatment.
Is it worth doing the MK3 extruder?
Could skip it and just do the MK3S extruder - would be simple except for needing to also correct its filament path error. As pointed out by ButterworthDesign on this forum, Prusa has filament over-impinged against the Bondtech drive.
Might be better to base mod on his filament path corrected MK3S extruders.
Re: Bolt-On Gearbox Extruder Experiment
Just for giggles, and since I really like this idea, I made one that fits the butterworth extruder w/ laser sensor. I have it printed but can't test yet because I don't have a 140mm belt on hand. Where is a good, reputable place to buy GT2 belts?
Re: Bolt-On Gearbox Extruder Experiment
Looks good.
I simply grabbed a pack from Amazon https://www.amazon.com/gp/product/B014QJBVOY
Mine is up on Thingiverse now. https://www.thingiverse.com/thing:3571022
Moving the Motor Even Further Back Towards Axis!
Ii just realized, on the Bunny and Bear extruder, I can push the motor body further towards the x-axis by flipping it around 180 degree and pushing the motor partially INTO the motor plate. With that maneuver, Bunny Science will achieve a lower mass and SMALLER moment arm than a motor mounted directly on the face of the extruder.
Pulley would move to in front of motor and we would flip cable to run motor in reverse
Here is a quick comparison
Re: Bolt-On Gearbox Extruder Experiment
Oof, that's gonna be close to the left hand Z... but I'm sure you've already considered that 🙂 Definitely pancake motor only!
Re: Bolt-On Gearbox Extruder Experiment
Printing prototype for the retrograde motor plate version for BNB extruder now....
This will give the Bunny and Bear extruder three, interchangeable motor plates. They all attach/detach without removing main extruder body.
- Direct drive
- Standard Geared (can use short body or full size NEMA 17)
- Retrograde Geared (moves motor 14 mm close to axis, but require short body motor)
Re: Bolt-On Gearbox Extruder Experiment
This si fascinating stuff. I am really contemplating this over Bondtech.
--------------------
Chuck H
3D Printer Review Blog
Re: Bolt-On Gearbox Extruder Experiment
The Bondtech is a fine extruder. I actually have one sitting on my bench, but probably not going to install for a long time. The quality differences that just going geared already have me quite satisfied with my print surface finish. Flexibility for experimentation is also high on the list for me. Whereas the Bondtech would quickly get you to the peak of Prusa extruder performance, It's not one for experimentation.
Mass with a Bondtech is lower - you may be able to print a bit faster. That doesn't matter to me as much as quality. So the tens of grams difference isn't noticed at the lower speeds I use to max out surface finish.
With three types of motor plates on my Bear, I can get maximal print quality AND flexibility for motor testing.
Re: Bolt-On Gearbox Extruder Experiment
I'm impressed with how fast you are iterating through these designs. You must have a lot of time available for hobbies. 😁
Re: Bolt-On Gearbox Extruder Experiment
Soo... crazy idea here. If this works well on E-cycle artifacts... why not X/Y for those stepper VFAs? We've already seen that 0.9 degree motors will squelch those. But it stands to reason that the same could be achieved by a gearbox and increasing the steps/mm, all without the cost of a new motor (and associated issues like sensorless homing no longer functioning correctly, or needing to match the drive current)
There's plenty of room to fit one on the Y frame under the bed. X might be a bit trickier and best served with a new X-end though.
Re: Bolt-On Gearbox Extruder Experiment
And she's working....
Files are at https://www.thingiverse.com/thing:3560341
Motor is as far back towards x-axis as possible. Only 1 mm clearance from X-motor end.
As for gearing the x and y axes, I'll leave that experiment to someone else.
RE: Bolt-On Gearbox Extruder Experiment
Soo... crazy idea here. If this works well on E-cycle artifacts... why not X/Y for those stepper VFAs? We've already seen that 0.9 degree motors will squelch those. But it stands to reason that the same could be achieved by a gearbox and increasing the steps/mm, all without the cost of a new motor (and associated issues like sensorless homing no longer functioning correctly, or needing to match the drive current)
There's plenty of room to fit one on the Y frame under the bed. X might be a bit trickier and best served with a new X-end though.
Plus you would also increase the torque for moving the bed!, so win win.
Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.
Latest version
The latest gearbox extruder project finally implements MK3S sensor and separately printable hot fins
RE: Bolt-On Gearbox Extruder Experiment
I was contemplating this further in terms of a planetary gear and the previous slop concerns for compactness and possible use on X/Y as well. I think it should be possible to mitigate/eliminate the slop of a 3d printed gear system with a split/anti-backlash gear as outlined here:
https://www.brighthubengineering.com/machine-design/65169-how-does-an-anti-backlash-gear-works/
Unfortunately, I'm not a materials engineer so I can't comment on whether this can be successful with something like PETG or PLA as a material. I've seen it on nylon gears in commercial products for sure, optical drive laser sled carriers, specifically.
RE: Bolt-On Gearbox Extruder Experiment
If we use one of the bolt-on gearbox solutions, would we expect to have to print at lower speeds?