Remote Direct Drive effectors for E3D Chimera / Cyclops (Zesty Nimble et al)

Needing to print flexible filament for a customer, I started looking for a remote direct drive type effector for my heavily modified Prusa i3 derivative printer and E3D Cyclops / Chimera with Bowden feeds back in September 2016. In early October I signed up and paid to join an early-birds programme for one such design of unit as I was assured that "we will collaborate closely, proof design, iterate, double check etc" and that "Shipping is expected to start in around 2 weeks". After a flurry of early emails during which I shared quite a few ideas and suggestions, communication dried up to a dribble separated by quite long periods of no response. I finally withdrew from the program early this year after my customer gave up hope - and lost faith in me, cancelling his order. I am expecting my money back from the programme any day now.

Luckily, as I was reaching the end of my tether with regards that program I found a mention of the Zesty Nimble and explored that option. I'm glad I did.

I have since been working with one of the designers of that effector (Lykle Schepers) to create a customised mount for the Cyclops / Chimera and 2 Nimbles. Lykle offered to do the development work based on my published design We had great fun over the course of a few weeks and Lykle has published his design This great design provides the option to mount one of 4 proximity sensors, the Cyclops / Chimera and two of the Zesty Nimbles.

Here it is in my chosen configuration, with the David Crocker proximity sensor.

I have attached three other diagrams showing alternative proximity sensors. These have to be tested but my initial assessment is positive for all bar the BL Touch sensor (as I do not have one of those).

There was some comment on another thread (since deleted) that the heatblocks on the diagrams show a configuration that will not work in practice as a result of the thermistor screws and heaters clashing. While this is correct, I have found the most successful configuration is to have the two heatblocks in line, facing away from each other. This is wider than the heatsink but not deeper / thicker and has worked for over 18 months on my existing setup without any issues.

The mounting frame also sports attachment points for detachable side cheeks to mount layer fans and various other fittings if required.

I'm now waiting to receive my Zesty Nimbles and will report back when they arrive.

I'm very keen on sharing this because I think that the positive attitude and can-do approach shown by Lykle should be recognised and applauded.We did as I had hoped to do on the other early bird program and I am 100% sure we arrived at a better solution together than either of us would have on our own. This is in the true spirit of this whole 3D printing thing and open source collaboration, isn't it?

Richard

For avoidance of doubt (as I have been accused of collusion on another thread), I want to be very clear that I am simply a customer, trying to build the best printer I can and prepared to provide my ideas and thoughts and experience for nothing in order to do so and to further this fantastic technology for the good of all.

This is largely a hobby for me - I have no commercial interest at all in the 3D printer and accessories market and have shared almost all my designs for printer upgrades and many other things (the reason for not sharing all of them is simply my lack of organisation and the fact that not all of them were worth publishing!). In the spirit of full disclosure I do design and print things for other, totally non-affiliated, sectors and these designs will probably never be made public as I do not own the rights to them.

Other than the diagrams, I have not received anything from Lykle or Zesty Tech and fully expect to pay whatever the going rate is for the Zesty Nimbles I order when they are ready. I may get them early when they are ready but that, too, will be in return for my feedback and I hope to assist development.My 'payment' is seeing my ideas helping shape a technology that I believe in. Nothing more!

I have no axe to grind - if I did I could have named the product and supplier that let me down but chose not to. My intent is only to share good when I find it.

Richard

Hi Richard,

Yup I let you down, delays over-running. It happens. Genuinely sorry about that.

My delays are my own fault and some way beyond even my own comfort zone. I hold my hand up. Something Tiny is happening here . Flex3Drive is the original, and superior product. Once my focus turns outward again all will be good. too many hats to be worn and not enough hours.

Regarding the refund, paypal tell me your funds arrived in your account two days ago, and the DD came out of my bank two days ago. All happens at the same time. However it was a pain that paypal decided to deliver the refund as an echeque even though the funds were in available in my paypal balance. In any case, you have the refund.

Its the way it goes sometimes. Yes a lot of work involved, and its hard sometimes. I guess one or two may fall by the way side during this period. Now that shipping is starting I should have any concerns back under control pretty quick.
ATB
Jason.

Edited 3 time(s). Last edit at 01/24/2017 03:41AM by Mutley3D.

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Flex3Drive.com

Hi,

Thanks Richard,

Here is a new image with the complete Chimera modeled, including the wires and bolts etc for the heat block.
These are the new heat blocks with the cartridge thermistor. These are slightly bigger than the "old" heat blocks.
It still fits and still enough room for sensors. But it was a good point about the positioning of the heat blocks, so I now made the standard model that I use complete with all the wires and cartridges needed.

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Lykle
________________________________________________

Co-creator of the Zesty Nimble, worlds lightest Direct Drive extruder.
[zesty.tech]

So looking at this it does look interesting. However, when I was using the E3D Chimera hotend, I had issues with the idle nozzle would rub and scrap across the top of the layer that was currently being printed by the non-idle nozzle. This lead to some failed prints as well as determining the start height for z=0 extremely temper-mental. Primarily because you have to be close enough to squish the 0.45mm stream into the bed/previous layers, it doesn't give you a lot of room for the idle nozzle. On some of the commercial dual nozzle setups I've seen, they have a mechanism to tilt the hotend to give a larger clearance of the non-printing nozzle.

With your design, have you experienced similar issues with the idle nozzle being drug through the current layer or do you have a way around this very tight clearance?

AFAIK Richard is using a Cyclops.

That gave me the idea of making it flipflop in height. But that will not work, because then the nozzle is not perfectly vertical.
So the next test is to see how much angle is needed to lift the nozzle high enough and if that influences the print quality of the nozzle in use.
And with a mount like this, adding a flipflop mechanism should not be to hard to do.

Hmm.
Lykle

I am using a Chimera at present - and have been for about 18 months. I have a Cyclops but it did not work well with PLA and the E3D tech support said this was a known issue and to use ABS. As I mostly print in PLA I've kept on using the Chimera.

I initially had that lifting problem you describe but have largely sorted it. The key fixes included keeping the non-printing nozzle hot and, most importantly, get the vertical adjustment of the two nozzles correct.

I am now able to print 0.2mm PLA layers easily, 0.1mm about 80% of the time. The other 20% fail within the first layer or two and appear to be when the fist layer does not adhere properly or has inconsistencies in height.

In short, persevere until you get the nozzles level.

My approach is to fix one nozzle in height, drop it to printing height for that nozzle with a sheet of A4 printing paper beneath it. Adjust height (all the while keeping the other nozzle out of contact). Once happy with that, drop the second nozzle and rotate the paper from side to side. If it rotates around either nozzle then that one is too low. When properly adjusted it should rotate about either nozzle with about the same amount of effort.

This is fiddly and time consuming but can be done!

I also considered some sort of swiveling mechanism a while ago but no longer see that as necessary.

Richard

Oh sorry, I thought you still using the Cyclops option.
Nice way to check the nozzle heights, pretty clear and usable. Thanks.

Here is how I will mount my Nimbles and Chimera on my Delta printer, with a simple double mount.
It is a double bottom part, with the rest of standard Nimble parts mounted on top.
Looking mean in black, don't you think?

To be clear about this, I am using a cheap Chinese clone here, just to make sure my new effector is ok and it all fits and works the way I want it to.
Once I am happy with the effector and the air tubing underneath, I will order an original Chimera to actually print with. Still some work to do with the tubing routing underneath. But that is a different subject.

Lykle

Nice to see the Zesty on sale, are injection moulded pieces still something we can expect in the (Perhaps distant I know) future? What have you used to produce the current ones? what material? What sort of heat resistance can we expect from them? Lots of questions I know, but I'm looking to perhaps get a few of these for machines I'm building at the moment.

HI, yes happy to finally get there, it was/is a hard struggle.
As to materials, the design is mold ready, so there is every chance that we will eventually get there. Currently only the gears are injection molded (POM), as they are critical. The shells will be SLS printed using NyTek 1200 PA. This is the same type of materials we have been using for our prototypes, but a little stronger and the surface finish is a little bit better.

The first production samples of the metal bits are coming in. We have the brackets, and the custom hobbed wheels. They look great. So yes, we are on track and hoping to deliver the first Nimbles soon. Richard cannot wait, he is so eager to use them.

It was an interesting discussion with Richard about the Dual Nimble. I suggested it, but eventually he wanted to stick to 2 separate Nimbles, for added flexibility. Also it allowed the whole unit to be a little more compact and gave space on the outside to mount fans and other extra's, simply by rotating the units inwards a little. These things are so adaptable.

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Lykle
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Co-creator of the Zesty Nimble, worlds lightest Direct Drive extruder.
[zesty.tech]

OH man!

I have to say I love the way people are jumping in to help.
It is great to see how much help is offered and how many new ideas are coming in.

This is the way I used to see the 3d community, helping each other improve.

The list is growing and thank you guys for helping out so much. I am not going to name them all as the list would be a bit long and I have not received permission from everybody who helped, but Richard, Andreas, Ted, Mike and all the others, thank you.

Current collection

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Lykle
________________________________________________

Co-creator of the Zesty Nimble, worlds lightest Direct Drive extruder.
[zesty.tech]

Quick note to let you know we started with a new way to show the development of the adapters.

All are open for view using Trello. You can see where we are in the stage of development, making it as open and transparent as can be.
Have a look if you are interested.

Adapter planning

If you want an adapter for the Nimble designed, simply go to the request form.

All adapters designed by us will be available as STL and as STEP files, so you can download and modify as much as you want.

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Lykle
________________________________________________

Co-creator of the Zesty Nimble, worlds lightest Direct Drive extruder.
[zesty.tech]

Again, I cannot emphasise how happy I am with the help and work done by others, the collaborations are really delivering results.

last job was a mod to fit 2 Nimbles to the Big Box IDEX option, done by the great Greg himself. Amazing how quickly it was whipped up and he did teach me a new little trick. Learn something new every day.

Sure,it is keeping me working till deep in the night as all these guys are spread out over the world, but man I am loving it.

Lykle

I've been experimenting with filament monitoring so designed this.

It uses Hall effect sensors to provide 12 quadrature encoded pulses per revolution (2 sets of 12 pulses). I'm waiting for the shafts and bearings and still have to add a tension spring to put a bit of tension on the rollers.



Hope it works when complete!

Richard

Looks good.

Will be interesting to see how you want to apply the spring tension.
Only real problem I see is that you have almost no access to the "ears" of the breech block.
You need to be able to squeeze them together to open up the breech.
But that is easily solved with a little hinge near where the bolt goes through into the Nimble.

Lykle

Haven't really thought about that yet - I guess a hinge would work or maybe I'll just increase the gap between the filament monitor and the Nimble.

I've now sourced and ordered tension springs - will finalise the design when I receive them.

Richard

Since we are talking about the filament sensors, here is a preview of what we were planning.



The idea is that in the center there is a magnet rotating. Under that magnet is a sensor sensing the rotation.
On the left is a pressure wheel, pressing the filament against the magnet using a 3d printed "spring" in dark blue.
On the other side is a clip that will allow you to clip it to the Nimble.
The shape needs to be simple and easy to use. At the same time it needs to be symmetrical so it can be used on the left handed Nimble as well.
In this case you can do that by switching the two dark blue bits. Disadvantage of that is the fact that the sensor is then running "backwards"

The advantage of a modular approach like this is that the unit is not limited to the Nimble. Any attachment point can be used, simply by changing the mount block.

David (Escher3D) and Tony (Think3DPrint3D) are looking into this and working on the PCB. The method of getting the filament clamped and the magnet rotating is still looked into as my design is deemed too simplistic. These guys know what they are talking about so I will bow to their judgement. Still think it will work tho. :-)

Any comments?

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Lykle
________________________________________________

Co-creator of the Zesty Nimble, worlds lightest Direct Drive extruder.
[zesty.tech]

Looks pretty good to me Lykle!

One issue with that class of design is that it doesn't detect when the filament makes its way out of the filament guide path (after the extruder gear) and bypasses the hotend altogether. I've had a few of these failures lately, it would be great if there was some way of detecting that the filament is no longer going through the hotend. I've no idea how to do that, however!

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nebbian
Looks pretty good to me Lykle!

One issue with that class of design is that it doesn't detect when the filament makes its way out of the filament guide path (after the extruder gear) and bypasses the hotend altogether. I've had a few of these failures lately, it would be great if there was some way of detecting that the filament is no longer going through the hotend. I've no idea how to do that, however!

Design a better path for the filament? I have only ever had this when either changing filament mid print and I don't pause the print, or ninjaflex. I'm still yet to find a decent way to print this horrible stuff.

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Origamib

Design a better path for the filament? I have only ever had this when either changing filament mid print and I don't pause the print, or ninjaflex. I'm still yet to find a decent way to print this horrible stuff.

Yeah, flexible filaments. I'm using TPE, which (I think) is softer than ninjaflex.

If there was a way to detect filament flow (or pressure) _after_ the extruder, then it would be really useful for me.

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nebbian

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Origamib

Design a better path for the filament? I have only ever had this when either changing filament mid print and I don't pause the print, or ninjaflex. I'm still yet to find a decent way to print this horrible stuff.

Yeah, flexible filaments. I'm using TPE, which (I think) is softer than ninjaflex.

If there was a way to detect filament flow (or pressure) _after_ the extruder, then it would be really useful for me.

FWIW, [forums.reprap.org]

Mike

I feel as though good design still wins the day when it comes to this problem. A filament sensor after the pinch wheel seems backwards to me as it overcomplicates the path from extruder to hotend. ninjaflex and other flexibles like to bunch up, and if you make the filament path after the extruder longer in order to insert a sensor or stylus, then you allow it to bunch up more and create more friction, adding to the problem. The solution is to make the filament path after the extruder as short and smooth as possible. This is one of the reasons we invest in a good hotend for a polished heatbreak. Perhaps these same tolerances should be applied to the extruder in order to remove areas where flexibles can escape or stick.

An indirect way of sensing filament jam would be to observe (Firmware-internal) the relation between extruder heater-PWM and extruded material.
A sudden drop in PWM indicates that no new filament reaches the heating chamber, while the extruder is still pushing. That won't work immediately after mid-print temp changes, but it's a starting point ( and its for free )

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RGN01
I am now able to print 0.2mm PLA layers easily, 0.1mm about 80% of the time. The other 20% fail within the first layer or two and appear to be when the fist layer does not adhere properly or has inconsistencies in height.

I find using multiple processes with S3D makes printing with very small layer heights infinitely simpler, print first layer at 0.2mm then so far, I've gone as low as 0.05 for the rest successfully.

I like the design, Lykle, but must say that I generally don't trust 'plastic' springs - I'll be using wound extension springs.

I particularly like the orientation of the sensors with the shafts facing forward like that. I'll probably review my design as a result.

Not sure why David and Tony are concerned about the magnet rotating? Despite my comments about plastic 'springs' above, if the 'spring' creates enough pressure and the magnet is free to rotate and has a non-slip surface it must rotate, I'd expect. Is the concern about longevity and the fact that the magnet and pressure roller are both cantilevered and this might cause uneven wear? Do you have ball bearings for both?

Richard

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briangilbert

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RGN01
I am now able to print 0.2mm PLA layers easily, 0.1mm about 80% of the time. The other 20% fail within the first layer or two and appear to be when the fist layer does not adhere properly or has inconsistencies in height.

I find using multiple processes with S3D makes printing with very small layer heights infinitely simpler, print first layer at 0.2mm then so far, I've gone as low as 0.05 for the rest successfully.

I'm doing something similar with the first layers but do have problems occasionally. It may be the bed print surface or the levelling (I must move the printer periodically and have yet to set up bed 'levelling').

Richard

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o_lampe
An indirect way of sensing filament jam would be to observe (Firmware-internal) the relation between extruder heater-PWM and extruded material.
A sudden drop in PWM indicates that no new filament reaches the heating chamber, while the extruder is still pushing. That won't work immediately after mid-print temp changes, but it's a starting point ( and its for free )

You're a clever, clever man. Food for thought. Many thanks

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o_lampe
An indirect way of sensing filament jam would be to observe (Firmware-internal) the relation between extruder heater-PWM and extruded material.
A sudden drop in PWM indicates that no new filament reaches the heating chamber, while the extruder is still pushing. That won't work immediately after mid-print temp changes, but it's a starting point ( and its for free )

Really clever although I think that while it will be effective for detecting filament breaks and the resulting big change in thermal behaviour, it will be less effective at detecting gradual slow down and under feeding (due to clogged teeth on the hobbed wheel, for example) as the smaller thermal behaviour changes could be the result of external factors like the sun moving across the printer. This gradual slow down is more of a concern to me as a complete break is easy to detect with a micro switch. It also seems that it would require an appreciable amount of processing power and that may make it non-viable for lower powered controllers.

Richard

Thank you both for the flowers I was happy with this spark of geniality myself because it came out of the blue.

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RGN01
...
This gradual slow down is more of a concern to me as a complete break is easy to detect with a micro switch.
It also seems that it would require an appreciable amount of processing power and that may make it non-viable for lower powered controllers.

I guess it would fit in the thermal runaway section of firmware. It's a matter of a few variables; averaging and comparing with a preset hysteresis. An M104 in the gcode will reset the variables.

Where would you put the micro switch? On the entrance of the extruder? It would be clever to combine both methods.

I'm on my mobile at present so not able to get to my CAD tool to test this but my current thinking would be to add it to the base between the Nimble and the Chimera heatsink - even if it makes that slightly thicker.

It may be necessary to use a chisel- or wheel-ended probe to enable the microswitch to be mounted remotely.

Firmware changes are way out of my comfort zone so my current thinking also involves adding wheels and magnets between the Nimble and heatsink but, again, I need to see how this will look when I can draw it.

Richard