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

Quote
nebbian
it doesn't detect when the filament makes its way out of the filament guide path (after the extruder gear)

Hmm, I have never had that experience with either Ninjaflex or TPU. But then, my filament path is fully enclosed and I think more and more people are being aware of it, so it probably is a problem that is reducing all the time. I would like a load cell (strain gauge) in the hot end somewhere to measure pressure created by the filament pushing.

The current issue is that the placement of the sensor in the middle is not good for PCB design. David would prefer to have the sensor chip on one side, then the processor and then the wire connection. And in mine I need to sensor centered. So it will be a balance between design for PCB and design for mechanical ambidextrousness (obviously not a real word, but you get my drift. I hope)

In reality, this could be made, no real issues with it. But to make it viable and practical it will need a little more work.

Lykle

Edited 1 time(s). Last edit at 02/16/2017 03:27AM by Lykle.

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

tTPVuWR.png

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?

i read that davids filament sensor isn't anyway affiliated to this product, they are coming up with a sensor to fit a broad range of extruders then just this

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up and running
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Chris, you mean that this sensor is not only for the Nimble? No of course not.
This is one of the reasons I used a simple clip to clip to the Nimble. Simply replace that part to make it fit any other system.
There would be no point at all to develop something that is limited to only the Nimble.

But do you have any ideas? Any way to make it simpler or easier to use?

Lykle

My interest is far more partisan :-) The one that I am working on - quite separately to Lykle and the Nimby team - is specifically designed to suit my printer combination. As such, I don't have the constraints that Lykle describes (symmetry, flexibility etc.) but much of what we are doing is very much aligned.

Lykle, some thoughts:
1. use a micro torsion spring for the pressure wheel. Cheap and long lasting with a constant force - I think the plastic spring will degrade over time
2. use a flat steel / spring steel pressure plate (much like the spring steel arm on microswitches) This way you could remove the need for the pressure arm, roller, bearing and perhaps more. If the spring steel arm is vertical then feeding it could be fully automatic with no need to manually retract it to feed the filament. Sure, there will be a bit of friction but not enough to be an issue and while the steel plate might wear over time this will be negligible and cheap and easy to repair if it does wear.

I must say that I'm very tempted to build mine into the mounting plate that separates the Nimble from the Chimera heatsink ......

Richard

Hi Richard,

Yeah nice idea. Move the Nimbles up a bit and add a sensor in there. Interesting.

Shit, too many ideas rattling around in my brain.

Lykle

The wheel has already been invented:



Just sayin'

Edited 1 time(s). Last edit at 02/16/2017 08:44PM by nebbian.

Quote
nebbian
The wheel has already been invented:

Wheeled-micro-switch-touch-switch-Button-switch-switch-Five-times-packaging-sales.jpg

Just sayin'

Not sure what you are sayin' We have already discussed that the microswitch will detect a complete break but not a slow down / slippage situation and the entire switch is too big to use as a tensioner.

Anyway, I've overlaid my sensor assembly (bearings, hobbed wheel, magnet and board) onto my mount (Nimble and Chimera) and it looks like it will fit and only add about 8mm to 10mm to the thickness.

Hmm, time to do more detailed design, I think!

Richard

My filament movement sensor assembly is now complete - and works a treat. Here is a photo of the double version for the Chimera etc. It is populated with only one actual sensor as I'm still developing and refining it - and designing the mount (so constrained until the Nimble arrives)



Richard

Nice work Richard!
Love the way you managed to get it into a simple clean package. What are the issues you are still working on?
Do you want me to modify the adapter to make the box fit in?

Your constraint is about to be lifted as your Nimbles will be arriving within a week or so. All orders will be shipped by the end of week 21.
Can't wait to see it all in operation and printing for you.

Lykle

Edited 1 time(s). Last edit at 05/13/2017 10:43AM by Lykle.

Hi Lykle, I've got it sorted now. I needed to change the size of the magnet wheel and add more magnets. I now have 24 magnets arranged around the edge of the wheel so get about 1 pulse per mm. I'm currently using them on my old belt driven extruders and will update the Thingiverse files of that to include this as an option. I've redesigned our mount almost completely - I narrowed the carriage by 10mm to get more Y-travel and have redesigned the rest of the mount based around the dimensions and positioning on the one we did together. The whole assembly (carriage, bushes, mounts, filament monitor, fans etc.) will be significantly lighter than what I have now.

Here are a few diagrams:






Can't wait for it to arrive - will you be posting it, or Brian? And did I see that you had moved back to the Netherlands?

Richard

I don't get how the air can escape the heatsink? The fan-shroud seems to cover everything. ( brown and black parts in pic above )

There is a 4mm gap either side of the heatsink so air is forced through the fins from the front, out the sides, and then ducted back so it remains in contact with the sides of the heatsink to continue cooling until it is finally expelled at the rear.

This because the cooling effect is enhanced by keeping the air in contact with the heat source longer. I also use a slow turning, quiet, 40mm fan with a decent static pressure in favour of the 30mm screamer. The 40mm fan moves more air but slower.

I hope that helps.

Once proven, this will be published on Thingiverse with my other designs

Richard

They say that a picture tells a thousand words so......


I forgot to mention earlier that air cannot escape downwards onto the heatblocks - it must exit rearwards.

Oh, Lykle, I also forgot to mention that I've given up on putting the filament monitor between the Nimble and the Chimera heatsink - I just couldn't get the PTFE tube to work in a way that I was happy with. It will now go above them as in the diagrams above.

Richard

Edited 2 time(s). Last edit at 05/14/2017 03:52AM by RGN01.

Hi Richard,
No, I went to visit family, back in Cyprus now. Brian will ship, he has been stuffing boxes all weekend in prep for the final push to ship it all.

Nice work! Like the way you narrowed it down to this.
But 24 magnets? wow!

I know what you mean with the PTFE. There is no good way to do it after the Nimble, as you will want to still be able to print flexible material. Putting it above the Nimbles is the logical place. That is where we are planning to put the standard sensor.

Looking forward to see the working result!

Lykle

Yes, I use 24 1mm x 2mm magnets in each wheel. These are arranged N-S-N-S facing the Hall effect sensor. My next experiment is going to be a latching Hall effect sensor. This will give a state change for each magnet and not give multiple pulses if the wheel moves backwards and forwards small amounts - for example during retracts.

Really looking forward to assembling this all.

Richard

I can imagine. And I am anxious to see the results.

Talking about results, the first Nimble is in the hands of a customer. Nice post about it: [forums.reprap.org]

Shipping yours on Monday.

Lykle

Edited 1 time(s). Last edit at 05/19/2017 03:59AM by Lykle.

Great news and the Nimble looks good!

What shipping method is being used? I hope not surface mail! :-)

Richard

Edited 1 time(s). Last edit at 05/20/2017 03:14AM by RGN01.

You should have it within a week.
But of course you will get the tracking number so you will know exactly where it is and when it will arrive.
Looking forward to some nice photos of your setup, show off those Nimbles!

Lykle

So my Nimble has landed in the UK but as it is a bank holiday weekend and I'm at a conference most of next week I won't see it until Friday at least so I've been doing final prep for it by printing out some pieces to test my mount using the mock up I downloaded.

These photos show how the Chimera heatsink is enclosed in a shroud so that the air is ducted around it. I printed them very fast and have not cleaned them up in the photos so please excuse the messy prints.



The fan is a 40mm Noctua fan - I use them becasue they are almost completely silent, move a reasonable amount of air and have a higher than average static pressure ability.

I've made some adjustments to the mount but now that I know it all fits I will reprint it, this time a bit slower!

Richard

One more photo to show the Chimera heatsink in the fan housing - it reminds me of a radiator in a vehicle of some type!


Despite the shroud going almost all around the heatsink, there is almost no resistance to air moving past it as proved by the good old 'blow test'!

Richard

Quote

it reminds me of a radiator in a vehicle of some type!

I guess you refer to the Rover Mini?

Yes, that's it! I well remember working on those many years ago.

Richard

Quote
RGN01
Yes, that's it! I well remember working on those many years ago.

Richard

They are still alive and kicking! This was my last one until I sold it to a guy in Switzerland.




A Mini based Kit car: GTM Rossa

Sorry for OT, I got overwhelmed...

Oh man that brings back good memories! Thanks for that!
Brings me back to when I was building this: [youtu.be]

Richard, have your Nimbles arrived now?
Hope you have seen the review Michael posted of it? [www.sublimelayers.com]

Let me know if they have or haven't, then I can chase them up.

Lykle

Apparently they have been intercepted by Royal Mail who have slapped on nearly £30. I've now paid that and expect the package to be delivered tomorrow.

If you are not already considering it, I suggest that you guys may want to look at alternative distribution methods for European customers as that additional charge (which will be even worse percentage wise for orders of only 1) will slow uptake of what I fully expect to be a technically very sound product.

Richard

Yep, we are looking into it. Thanks.

The volume is getting such that it is relevant to consider other means of shipping.

Lykle

My Nimbles arrived today and I'm busy mounting them on the carriage.




This one shows the mount for the filament monitor - it still needs the cover and magnet wheels.


I also need to print the stepper motor mounts and then assemble everything (upgrading to 24V heaters at the same time).

Richard

Print stepper motor mounts?
The lovely aluminium brackets supplied with the Nimble are not enough?
Or do you mean mounts to mount the brackets on?

Lykle

No, the aluminium brackets are very nice but I needed an offset and to hang them from the horizontal steel top on the frame so came up with these:


Richard

While I'm here, some more photos of the upgrade:
As it looks now:


The magnet weel for filament detection - it has 24 1mm diameter by 2mm long magnets embedded in it.


Showing the primary components of the filament detector:


And here showing the clock spring I use for tension:


Richard