Any good light weight direct extruder/hot-end?

zapta

@fcwilt said in Any good light weight direct extruder/hot-end?:

I also tried the Flex3drive but much prefer the Nimble.

How does the nimble handle TPU? With bowden I have good experience with the bondtech dual drive approach which grips and drives the filament from both wheels.

Alexander Mundy

I print 40 hardness TPEE no problem with the Nimble. The aforementioned Nema8 was a conversion by another which does away with the cable and places the stepper directly above the Nimble with adapters he designed. The stepper is this one.

https://www.moonsindustries.com/p/nema-8-standard-hybrid-stepper-motors/ms08hy1f4050-000004611110028968

As to my personal preference I use the cable system as comes with the Nimble with escap (now Portescap) P430–258-005-01 disc magnet stepper motors with windings in parallel on my deltas. I think there are only a couple of us using these.

With them I run maximum instantaneous speed changes (jerk) of 600 mm/min instead of the recommended 40 mm/min for standard steppers. Acceleration of 1500 mm/s^2 instead of the recommended 120 mm/s^2 for standard steppers. This keeps retract settings “normal” or above “normal” if wanted, and pressure advance does not interact with the lower settings to cause bogging down print speed.

Pros:

Rotor inertia is a very low 3 g-cm2, 200,000 rad/s^2 acceleration so it can stop and reverse quick for retract and return.
100 steps/rotation (3.6 degree) so 1/2 the required steps/mm to keep from a large number of needed steps with a 30:1 reduction which shortens driver pulse width and the corresponding rise and decay don’t get too short.
2.5 ohms resistance and 3.5 mH inductance per phase with 2.3 V/kstep/s back EMF so quick ramping up and down of step pulses.

Cons:

10 to 12 oz/in of holding torque & 0.93 oz/in detent torque which is lower than even the recommended NEMA 14 pancake but I haven’t had any problems with the lower torque even driving a volcano close to max volumetric.
I do actively cool them with a small fan because they get warmer than I like without, but don’t think it would be absolutely necessary.
They are extremely expensive unless you can find them used.

https://www.portescap.com/sites/default/files/p430_specifications.pdf

samlogan87

I run a G3 flex3drive which I love. Changing filament was a little annoying at the beginning until the guide clearanced itself a bit and now it is easy. It’s really well made and solid which I liked. They have just released G5 and it looks to be a tidy bit of kit. I would look at them as well.

Regards
Sam

zapta

Thanks @alexander-mundy, that's really good information.

Does the nimble's flex cable wears out over time? IIRC I read posts here to this effect.
Do you know how the shaft of the nema 8 is attached to the nimble? It has a 3.5mm D shaft https://www.moons.com.cn/medias/MS08HY1F4050.pdf?context=bWFzdGVyfHJvb3R8OTM3MTMzMXxhcHBsaWNhdGlvbi9wZGZ8aDBhL2hiNC84ODI1NjI4NTI0NTc0LnBkZnwzMTUwZTA1ZjAwZjI2MDY5ZjFjOGQyYjhiMTc4ZWY0MWIzYTAwN2I5ZTU2MGJhMmU1YmM0YmYzZmFmODY4NDk0&attachment=true
Any reason not going with the direct nema 8 appraoch?
I am thinking getting the sidewinder nimble to have the nema8 mounted lower. Is this reasonable?

Alexander Mundy

@zapta

He designed an adapter and had it shapeways printed that accepts the small D shaft and has a square end that goes in the worm gear where the cable normally goes.

My cables are original black sheath version (well they sent us original buyers replacements shortly thereafter because of a production defect) and they have been using a newer version for some time now but I don't have the red sheath version. I have had no problems, but I'm a hobbiest printer. However I have followed the Nimble since the beginning and have not heard of cables wearing out, only a few production issues here and there.

Can't speak to the Nema 8 since I've not tried it.

fcwilt

@zapta said in Any good light weight direct extruder/hot-end?:

Thanks @alexander-mundy, that's really good information.

Any reason not going with the direct nema 8 appraoch?

I am thinking getting the sidewinder nimble to have the nema8 mounted lower. Is this reasonable?

Hi,

When you say "direct nema 8 approach" do you mean not using the normal Nimble cable?

If so, that would seem to defeat the purpose of using the Nimble in the first place, which is to get the stepper motor mounted to the frame instead of some part of the moving gantry.

Frederick

gtj0

@fcwilt said in Any good light weight direct extruder/hot-end?:

If so, that would seem to defeat the purpose of using the Nimble in the first place, which is to get the stepper motor mounted to the frame instead of some part of the moving gantry.

Frederick

It depends... With the Nimble (which I also use), you get the high ratio gearing which allows you to use a smaller stepper like the NEMA 8s. Balance that against the mass of the drive shaft, which you still have to move, and it may be a better arrangement for some.

zapta

@gtj0 said in Any good light weight direct extruder/hot-end?:

Balance that against the mass of the drive shaft, which you still have to move, and it may be a better arrangement for some.

IIRC, several people mentioned in posts here that the flex cable tends to wear out. Is it so?

gtj0

@zapta said in Any good light weight direct extruder/hot-end?:

@gtj0 said in Any good light weight direct extruder/hot-end?:

Balance that against the mass of the drive shaft, which you still have to move, and it may be a better arrangement for some.

IIRC, several people mentioned in posts here that the flex cable tends to wear out. Is it so?

I've had it for almost a year now and had no issues.

Alexander Mundy

@zapta said in Any good light weight direct extruder/hot-end?:

@gtj0 said in Any good light weight direct extruder/hot-end?:

Balance that against the mass of the drive shaft, which you still have to move, and it may be a better arrangement for some.

IIRC, several people mentioned in posts here that the flex cable tends to wear out. Is it so?

I've had 2 for over 2 years and they are just fine. As I posted before, I am a hobbiest so probably just 30 kg or so of filament used.

martink1974

i got a flex3drive to reduce weight on my delta and could not be happier , seems for most part a solid and functional design , changing out filement is a doddle and just getting it dialed in at moment first few prints are looking good and easy to get up and running

got retractions dieal in after a few prints and its harder to see but

the 4th benchy came out mint

huge improvement over my previous bowden v6 and bulldog extruder setup

fma

With such ratio, I think a DC motor (+encoder) would be much better than a tiny stepper motor (either using the cable or in direct-drive config)...

zapta

Looks like Zesty and the likes bring happiness to their owners so I placed an order for a Nimble to reproduce it here. I believe that the E dimension is the weakest link in my printer, print quality wise, so decided to focus on it. First I will use the Nimble with its flex cable and then will decide if to upgrade to a light weight direct motor drive.

fcwilt

@zapta said in Any good light weight direct extruder/hot-end?:

First I will use the Nimble with its flex cable and then will decide if to upgrade to a light weight direct motor drive.

The cable makes a good carrier for the wiring to your gantry.

I also have a bowden tube there to guide the filament from the spool holder to the Nimble.

Frederick

zapta

@fcwilt said in Any good light weight direct extruder/hot-end?:

I also have a bowden tube there to guide the filament from the spool holder to the Nimble.

This is one of my qualms regarding the flex drive cable, adding a third thing going to the head.

fcwilt

@zapta said in Any good light weight direct extruder/hot-end?:

@fcwilt said in Any good light weight direct extruder/hot-end?:

I also have a bowden tube there to guide the filament from the spool holder to the Nimble.

This is one of my qualms regarding the flex drive cable, adding a third thing going to the head.

The bowden tube is optional but it does keep the filament from flopping around.

And using the cable for the wire carrier gets rid of any other wire carrier you may have.

I'm very pleased with the Nimbles. I really like how easy it is to change filament. When you remove the little part that presses the filament to the drive roller you have direct access to the top of the hotend.

Frederick

gtj0

@fcwilt said in Any good light weight direct extruder/hot-end?:

I'm very pleased with the Nimbles. I really like how easy it is to change filament. When you remove the little part that presses the filament to the drive roller you have direct access to the top of the hotend.

Frederick

Me too.

I actually use a long piece of 4mm ID PTFE tube from my dry-box all the way to the Nimble to keep the filament in a controlled environment along the entire path.

martink1974

i did look at the nimble before getting the flex3drive , but the design of the flexdrive seemed more robust , and i noticed dc42 used flexdrive extruder on his delta kits

i could not be happier at this point had a couple so spools of filement through it so far and no clogs , filement path has zero restriction when changing material , even flex materials have no problems

gtj0

@martink1974 Heh, I started with the Flex3Drive but had issues both with customer service and robustness. Sounds like they got those things sorted out.

zapta

Flex3Drive have a ~75g nema direct extruder listed on their web site

https://flex3drive.com/product/g5-nema8-cyclops-pre-order/

Edit: this is the single nema8 extruder, very reasonable price and ~75g https://flex3drive.com/product/g5-nema8-extruder/