Ultimaker2 Feeder System - Improvements and Ideas

[profepaco 0]

I would like to see a picture of that on a UM2!

 

[ian 32]

will do !

these are just screen shots from the presentation I did last week.

Ian :-)

 

[jhertzberg 19]

I have been fooling around with a tractor design, but not as far along as you, Ian. I am using three o-rings as the tractor, two on side, one on the other, to make a self centering filament path.

 

[ian 32]

Here is a little more info on my design :-)

The design works this way.

You can click off the front easily.

Then release the left arm.

Left arm rises up opening between left and right arm.

Load any filament into the centre and push it up a little into the bottom of the bowden tube.

Then return the left arm and lock it into the according filament type position.

The whole design is mounted on two existing screws going to the right of the stepper motor.

The power is directly fed from the stepper into the bottom fixed right gear. The arm system is designed to accomodate any filament and still keep gear contact.. so the power is distributed to both arms equally.

Then the filament is very confortable held my the the outside profile of the lego rubber belts.

The power and traction is equal over a much much larger area.

Because the material is initally fed into the bowen.. the material does not move out of the mechanism. it follows because there is equal power being added to the complete filament piece and not only one or two points.

I want to find smaller good quality rubber belts and then make this simple design maybe 1 third the size.. then it becomes very practical and very sexy....

But it works great and is super simple in concept :smile:

Ian :smile:

ps.... the best system I found for using the round bolt coming out of the stepper feeder was actually to keep the knurled bolt tightly on there and actually design my profile with the grub screw into the back of my design and use that as the grip connector to drive my power drive ! Use the design.. dont fight it :wink:

 

[jhertzberg 19]

I'd love to adapt this for the UM Original. Could you use rubber bands between the blue parts on left and right arms, on the opposing diagonal from the silver parts, rather than a locking mechanism? This might give you greater tolerance of badly sized or out of round filaments than a fixed locking position would.

 

[ian 32]

that would be no problem I think !

I was also playing with a non fixed tension system but for now.. with the preset locking positions.. the filament is just held very snuggly in position and no problems... BUT !! as PLA gets older it can loose a little of its strenght and then the presets loose their powers... so a spring or rubber band would be a good idea !

Ian

 

[gr5 2,167]

Ian I recommend you try this with 1.5A to the feeder stepper instead of the default 1.25A. People have found that more than around 1.5A actually starts to get weaker again (strange!). You can do this by inserting this somewhere near the top of every gcode file meant for the UM2:

M907 E1500

1600 would be 1.6 amps and so on. 1.5A doesn't sound like a lot more than 1.25A but it is! This is not recommended with the current hobbed sleeve but with this rubber design (or with a spline sleeve) it should be great!

 

[eldrick 65]

Search any industrial supplier (mcmaster.com in US) for timing belts. You can get them in neoprene, silicone, or other materials that should be very grippy on the filament.

Great design idea, BTW.

You might consider making the cross-links longer, so that the filament is pinched between two opposing rollers, rather than bending the filament a bit between offset rollers.

 

[kitwashere 1]

Very cool idea. Maybe a good use for my short belts when I go direct drive on my UM1.

This could probably benefit with a solid piece running behind the belts (on the teeth side) to give it constant contact with the filament.

I had the idea (I'm almost positive I read this somewhere on one of the forums and didn't think of this myself) of a filament "pre-heater" to try and reduce friction in the bowden by taking the natural curve away. I had imagined it being after the feeder to make sure it wasn't too soft for the hobbed bolt/gear/whatever to grab on, but with your design I think making it a little sticky might be a benefit.

Great work man, and to everyone else working on the feeder. Lots of cool things happening in this thread

 

[nick-foley 5]

Has anyone used Robert's design on a UM1, and if so, what did you use for the knurled filament driver?

 

[conz 0]

OMG:

http://traverseda.wordpress.com/2014/05/23/makerbot-blatently-steals-and-patents-a-community-design/

Will this affect some of the design in this thread? Especial the design by Robert?

Is it correct, that the patent is targeting all feeder designed with a spring?

 

[skint 61]

Wow conz, thats a really interesting article. Makerbot really do look like they will lose a lot of fans over that move. The three users who did some of the original design work are not happy at all ! Honestly with the design though, i`m amazed that it is even patent worthy... surely someone could find some prior art to appose that move by makerbot.

"Head up thier arses" seems a good quote to use.

 

[IRobertI 520]

I doubt they'll lose any customers or fans over that move. Those of us who know what type of company they are either weren't fans in the first place or stopped being fans a long time ago. The bulk of their customers will never know and even if they did, they most likely wouldn't care.

I can say that I had a couple of opportunities to talk a bit of crap about them to the general public at the Stockholm Mini Maker Faire

 

[jhertzberg 19]

The top two items [Alternative Repositories to Thingiverse. Two things must happen now. First, we all stop posting designs to Thingiverse, especially designs for improving printers. No one here has the time and money to keep their work from becoming Makerbot's. Second, the gloves have to come off. We need to educate the potential printer buyers we encounter why buying a Makerbot is a bad idea, including "They are a company that looks at what other people are doing, then runs out and tries to patent it as their own. This matters because if you support them, your next printer will cost more, not less."

 

[nick-foley 5]

Yes, moving all of my designs off of Thingiverse currently...

I'm just going to put this here...

http://www.thingiverse.com/thing:342159

 

[skint 61]

Haha Nick, love it

 

[nick-foley 5]

What is the reason the (ludicrously patent-pending) makerbot extruder upgrade isn't a good choice for use on a UM? Does it work well with 3mm filament and the increased extrusion pressure of a bowden tube?

 

[kitwashere 1]

Someone in here said the motor on the UM1 wouldn't be able to keep up without the gear reduction.

 

[jeremie 13]

Someone in here said the motor on the UM1 wouldn't be able to keep up without the gear reduction.

 

Well, you always can use a reductor, like this 5:1 with stepper at $32

http://www.aliexpress.com/item/Gear-ratio-5-1-Planetary-Gearbox-stepper-motor-Nema-17-Planetary-Gearbox-3d-printer-motor-17HS13/1794790075.html

 

[ronniiraygun 0]

After reading through a lot of these posts and looking at the issues I think we have a materials issue between the knurl and metal bearing. The ABS or PLA is a softer material i.e. you are squishing a 14MPa material between to 600Mpa materials (numbers are a best guest approximattion). By doing so it will always be the PLA or ABS that must yield and grind down resulting in a feeding issue. With that basis has anybody tried using a urethane wrapped guide bearing instead of a steel one. If the durometer of the bearing was less than the PLA or ABS it would reduce the grinding and also provide a better grip on the material why using equal or less spring pressure.

 

[ronniiraygun 0]

I found a sleeved bearing and tubing combination that could be easy to try with little modification to the original extruder.

7751K72

 

$15.45 from mcmaster and tube 51825K52

 

[shurik 87]

Being fed up with black strokes of material popping up on my prints and clogging the head from time to time, it was the time to seek alternatives.

For some reason, the improved feeded version by Bas went almost unnoticed. After the metal ring was cordially sent to me, I printed and installed the feeder.

The old one has clear signs of wear and tear, no wonder I had to clean my printhead lately so often.

The new one looks nice.

I also received new Faberdashery shipment and happily tried it. Alas, not so good:

Even after the temperature increased to 240C, the test failed. Previously, with Colorfabb white, my printer reached 13-14mm3/s on 220C.

Is 240C normal for Faberdashery Red? Seems too much for me. The tube and the head were pristine clean.

Shall I try yet another feeder?

Puzzled...

 

[ultiarjan 1,223]

and here it is .... jet another feeder alternative for your UM2 ....

Based on looking at the different designs already available, I tried to list what I liked and disliked on them, to come up with the best design for my own taste. But first some remarks on the 2 designs that influenced mine the most (> Thanks Robert and Geeks for your great work!!!!)

 

My impression of the design by "|Robert|" (I printed it with the intention to install, butt never got to it cause I made this alternative..) > https://www.youmagine.com/designs/alternative-um2-feeder-version-two

 

+ Super cool looks

+ "quick release"

+ open design, easy to clean

+ Easy adjustment of the bearing pressure.

- the part of tube at the bottom that needs to be loaded from the back, don't like that I can't see if rubish is pilling up there.

- the tiny spacers used on the left screws (and the arm mounting on the motor screws).

 

 

My impression of the design by "Geeks" (from the pictures, I did not print it) > https://www.youmagine.com/designs/extruder-um2-version-2)

 

+ Easy adjustment of the bearing pressure.

+ Separate mounting of feeder and motor.

+ the guide arm (although I don't need it in my setup)

- closed design may be hard to clean, possible build up of fillament parts.

- no "quick release".

 

Some general guidelines I came up with before I started drawing....

* I don't mind additional components as long as it standard easily available stuff like bolts and nuts

* needs to fit on the back of the UM2, want to keep the drivemotor in its original place.

 

I liked to combine the following;

 

+ mechanicaly strong, easy to print.

+ "quick release"

+ open design, easy to clean

+ Easy adjustment of the bearing pressure.

 

nice to have;

+ Separate mounting of feeder and motor.

+ Goods looks... but mostly a matter of taste..

 

After printing I needed to sand the part of the main arm, where it connects with the bearing arms a bit ...

I printed all with 100% infill, as you see in the pictures not all parts are nice and clean, I had some issues with the original feeder and underextrusion ..... First thing I'm doing now is to print this feeder again ....

 

 

And just some mounting guidelines....

 

- print all the parts

- remove your original feeder by attachting a piece of string to the motor shaft, hing something a bit heavy on it so the motor will stay in place when you take out the screws.

- mount the right bottom screw part of the new feeder, so your motor will stay in place when you undo the string.

- take the original parts like spring and bearing, to mount on the new feeder.

- mount feeder, ready to go !

 

 

** first result looks promising, just finished a 1 hr print, looks perfect, much beter than before !!

 

I'm thinking to keep an eye on potential wear at the bottom fillament entrance, and alternative could be to make there a fillament connection just like the one on top with a short piece of tube... (but you would need to order these extra clips...)

 

 

>>> I'll put the design files on youmagine <<<

 

 

update; 30/6 , added a little knob for easy adjustment.

 

update; 2/7, as cor3ys already mentioned in the next page of this thread the arms holding the bearing are a bit to short (sorry, I only tested at low speeds...) updated the file. Version nr. 25 of the front and back arm have 2mm increased length.

 

at the same time made a little change for easier installing the m3 x 50mm bolt...

 

[3poro 9]

as I posted before I was using Roberts feeder design on two printers. After the latch broke on one of the printers, i replaced them with 100% filled parts. That worked. But after a while, extrusion on both printers got worse. Extrusion tests "only" achieved 8 mm³/s. I cleaned the nozzle to exclude clogged nozzles as a problem but that did not help.

[...]

I really don't know what caused the problems with Roberts design. There are no visible defects. I used them for roughly more than 100 printing hours.

 

I actually ran into a similar problem with Robert's feeder. It took me a while to figure out what the problem was; in my case the yoke was barely long enough to press the bearing against the knurled wheel. I don't know if the feeder has bent slightly due to heat from the stepper motor - in my case it's closer to it than normally:

http://umforum.ultimaker.com/index.php?/gallery/image/6106-feeder-close-up/

I first recognized retraction problems with softer filaments - then random under-extrusion problems appeared.

I fixed the problem by removing some material from the yoke and the feeder arm in order to allow the yoke to travel an additional 1mm or so.

In my case the feeder arm was also a bit loose fit to the feeder body, so I added a washer to make it tighter. Otherwise the arm turned slightly inwards our outwards causing the bearing to touch the filament only by its edge.

Now the feeder works like charm again

I've been very happy with the freely revolving feeder stepper motor hack. I haven't had any problems with the filament path anymore and I have better consistency of print quality throughout the print area.

 

[IRobertI 520]

I think I posted a longer yoke somewhere in the thread but I can't remember if I updated the file on Youmagine, I think I did.

Also, I know people hate the little spacers and I've tweaked the design slightly to get rid of them. Haven't printed it yet though. Also want to tweak the arm for printability. Inspiration has been a bit low lately though.