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Ultimaker2 Feeder System - Improvements and Ideas

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Interesting, but I think imperfections in the mesh might cause problems with retractions, as the secondary drive gear will suffer a small change in phase relative to the primary drive gear when the drive is reversed. This could cause too much destruction to the filament when the print requires many retraction along the same piece of filament.

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My extruder had stopped pushing filament entirely because there was not enough pressure on it to move it, so I made an ugly hack mod to the existing extruder. It is printing/feeding very consistently now.

First, I printed a pulley type cover for the idler bearing (on a different printer, since my UM2 wouldn't print). It's a small circular pulley type wrap for the bearing which fits on it tightly. It is 2mm thick at both edges, and 1mm thick in the middle. Second, I cut away the entire left side of the casing between the two bolt holes, to remove all of the areas of the casing which might rub on the new, larger pulley/bearing assembly.

Here is how it looks now, with the nasty edges and everything. LOL

Extruder Hack

Edit: Oh, I also adjusted the metal filament drive cylinder so that the biggest teeth were centered on the filament while it rides in the groove of the pulley.

 

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Cool idea!

 

Here is an idea I had for a feed mechanism. Please excuse the drawing I'm on hols with the family and only have the kids pens to work with :)

 

The sketch shows two taper wheels one being the drive and the other driven by the gear at the base of the taper. The filament in orange is pressed into the taper by a profiled bearing that is sprung.

The mechanism has two interesting benefits.

1. The bite provided by the two tapers should allow for much greater pushing force before slipping. (it's used on most feed systems for bar peeling where force and bit are critical)

2. Now this is the interesting bit. The taper means that a thicker filament moves out on the taper to a smaller diameter i.e feeds less. Thinner filament moves into the taper to a larger diameter i.e feeds more.

Point two should provide a more consistent flow through the nozzle with no need to monitor filament diameter prior to the feeder to correct for inconsistent filament diameter.

Now the angle of the taper is critical to the function of this system. I'm only at the idea stage so far and would really like to know what everyone thinks.

 

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Ah... Just looked at this again without the wine.

Theoretical the system works as planed however to correct filament variations on a range of diameter from 2.60mm through to 3.1mm the drive wheels would need to taper from a diameter of 1.7mm to 1.2mm! This would correct for any filament variation withing the stated range.

However this would not work in practice with such small drive wheels :angry:. Bummer!

Still... nothing ventured nothing gained.

 

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Ok so here is what I have so far. This started because we want to convert our old Makerbot Replicator 2X to use a 3mm E3D-V6 hotend with stainless steel nozzles for use with carbon filled fillament (see: http://umforum.ultimaker.com/index.php?/topic/10141-nickel-plating-nozzles-for-carbon-filled-filaments-updated/)

I started off by making a drive gear type similar to printerbot's (and a few others) version. Everything is currently printed using ColorFabb XT-CF20 filament but the results so far are very promising. I am unable to make the filament "slip" and the motor skips steps before it slips so I'm pretty happy with the pressure on the filament. There is minimal marking to the filament itself. Plastic gears won't work in the long run but it serves as a good test.

I am using an 5:1 planetary stepper (http://www.omc-stepperonline.com/gear-ratio-51-planetary-gearbox-high-torque-nema-17-stepper-17hs191684spg5-p-40.html) but I may switch to a 19:1 or something in between.

MB-Drive%2BGear%2BUpgrade-V6_6.jpg

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MB-Drive%2BGear%2BUpgrade-V6_2.jpg

IMAG0058.jpg

IMAG0054.jpg

IMAG0056.jpg

 

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that is absolutely awesome! it looks like you are not using any bearings, i would be worried about the gears moving apart on top..

very impressed! are you thinking of sharing the STL's ?

i would think plastic gears can be very viable as long as they are printed in ABS or something. I would however split the gears in 2 parts and add a little rubber band in the middle..

 

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that is absolutely awesome! it looks like you are not using any bearings, i would be worried about the gears moving apart on top..

very impressed! are you thinking of sharing the STL's ?

i would think plastic gears can be very viable as long as they are printed in ABS or something. I would however split the gears in 2 parts and add a little rubber band in the middle..

 

No bearings for the prototype, just wanted to test the function. There will be bearings in the final version (you can see them in the CAD model. Once I'm happy with the design I'll share the files.

I am still experimenting with the fit of the gears to get the best grip. I might see if I can get some stainless steel gears made but that might take a while.

 

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Hi to all of you feeder experts. I have been thinking of maybe putting my feeder directly above the printer. Pretty much in the center and not very far away from the extruder. Has this been tried?

I fail to see the point in putting it at the rear, making the ptfe tube very long. The shorter the distance the less prone to buckling and friction. And by reducing the length there will be less total elongation of the filament and maybe a more immediate response to retraction and hence less grinding.

Just a thought so far...

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Hello,

I see that the drive system of ideas continues the passions unleashed.

I recently completely redo my extruder design in freecad. This is for testing. I hope a few months to upload the new version.

For the record, I took all the elements of the previous version, including some dimentions. I increased as the other. It goes well this time.

 

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I fail to see the point in putting it at the rear, making the ptfe tube very long. The shorter the distance the less prone to buckling and friction. And by reducing the length there will be less total elongation of the filament and maybe a more immediate response to retraction and hence less grinding.

PLA is quite stiff, even brittle. Take 1m of PLA - it is quite easy to bend this into a circle. I.e. you can guide the filament tip anywhere you want it to go. Now try doing that with a 100mm length.

I'm not saying you're wrong, I'm saying that my intuition doesn't match yours, and also that the current way lets the filament be tucked neatly behind the printer. But if you think this can be improved then have at it! It would certainly be an interesting project for you to try.

Edited by Guest

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Both PLA and ABS have a comparable Youngs modulus. The filament will behave as a spring; compressed when printing and elongated when retracted. That change in length is proportional to its initial length. In addition it is forced into a curved shape.

If the feeder is placed in the middle above the build plate the extruder will only travel about 10cm in each direction. There still needs to be some curvature to account for the change of distance between the feeder and the extruder when it travels. But the distance can at least be cut in half.

I have three UM2s; two only operate with ABS and one purely with PLA. Under certain extreme conditions they all can suffer from underextrusion.

I am not a fan of putting the filament behind the printer as intended. This makes material change cumbersome. Instead I place material next to the printer in a low friction spool holder.

 

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Both PLA and ABS have a comparable Youngs modulus. The filament will behave as a spring; compressed when printing and elongated when retracted. That change in length is proportional to its initial length. In addition it is forced into a curved shape.

If the feeder is placed in the middle above the build plate the extruder will only travel about 10cm in each direction. There still needs to be some curvature to account for the change of distance between the feeder and the extruder when it travels. But the distance can at least be cut in half.

I have three UM2s; two only operate with ABS and one purely with PLA. Under certain extreme conditions they all can suffer from underextrusion.

I am not a fan of putting the filament behind the printer as intended. This makes material change cumbersome. Instead I place material next to the printer in a low friction spool holder.

 

Calum Douglas does this already. See http://www.calumdouglas.ch/3d-printing/ultimaker-3d-printer/vertical-down-filament-feed/

 

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Hi folks... I am a new Ultimaker 2 owner of just a month or so. And like noted above, I am already sick of heavy retractions causing the filament feeding to fail. 10cm of plastic chewed and eaten, 2+ feet of filament wasted. And of course, hours of printing lost to the recycler.

I have to ponder the question of an old welders term, Cast and Helix. When I pull a few loops of a reel, snip it off and toss it to the floor. The circle it relaxes to is its cast, and the distance between circles the helix. 3mm can be quite stiff. The problem for welders, is the same here. Any tube fed system is going to suffer from the spring in the coil, binding on the tube as it slides thru.

A reliable welding feeder normally has 2 sets of power pinch rollers. So the wire might slip on 1, but not on both. As well, a set of idlers are placed in advance to remove some of that spring. And for soft strands, material movement industries use a "Catapuller".

The tube is part of the fail, along with rollers harder then plastic. And not to get off topic, but why call it a Bowden anyhow? The patent for Bowden's says it is a mechanism to telegraph movement, pushing, pulling, or rotational. But if we call it a Bowden, there is at least one making a flex shaft affair that uses the tube as a real Bowden... I heard a rumor he might have done some design work for Ultimaker as well.

I am printing a new extruder frame, culled from this list. I also took the belt feeder design, and added a straightener ahead of the feed. Still working on the differential to power all the wheels properly, and am waiting for the various parts to arrive before I can assemble it.

I certainly am tired of trashed plastic and models. When its right, its so right I love it, nagging bits and all. But never have I had such issues with a printer. Four deltas in all sizes feeding 1.75mm just fine. So.. Wouldnt it be wise to just poach some old patents for wire fed welders? Or perhaps 'Force driving flexible round strand.'

Shrug :) Hopefully I get a good set of prints, so I can slap together something that stops that centimeter of plastic from looking like crack fed squirrels got after it.

Thanks for the tips and help from all in this post, least I know I am not alone. Hopefully just a few minutes away from finding a cure :)

Cheers

James

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Great tread here folks, wish I had time to read it all! :D

Just on another idea, why not just adapt something already made, so we don´t reinvent the wheel, like Anjin said above on the welders?

I for one have done that, I took this all-metal extruder from China and made some parts to fit the um2, to give it the right tension, etc, and it´s working like a charm now! The fact of the feeder being all metal is really a plus, and it´s not expensive at all, and you get the increased functionality of having an easy material changing mechanism (just pull the lever up and take the filament out).

If someone interested, I can take pictures and upload on youmagine, etc...

Cheers!

Edited by Guest

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Hi,

has anyone tried one of the following metal feeders / extruders:

 

 

Regards,

Nils

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Well, Sad to see this tread has lost momentum...

After some weeks of trying different designs, I came across something that works exceptionally well, I don't know if it has been mentioned already, but anyways I made some mods to it and intend to release it in a couple of days.

I made a version of this geared feeder, with less gears and a pair of ninjaflex wheels, as you can see in the pictures. It is working great!

I really think this has a lot of potential to become something widespread, as its really reliable and don't demand a lot of modifications to the stock printer, and even though I have mirrored the feeder to have the adjusting screw on the outside and then had to change the motor extruder direction, this is not mandatory.

DSC02347_25pp.thumb.jpg.9000907a2a089505d0a1c22a45f07f85.jpg

DSC02348_25pp.thumb.jpg.d7b80c3c4da511c93a92ebd8c4e07778.jpg

DSC02344-45-collage_25pp.thumb.jpg.2538dab25c8ef4211bc1bdcab43d0a2f.jpg

DSC02347_25pp.thumb.jpg.9000907a2a089505d0a1c22a45f07f85.jpg

DSC02348_25pp.thumb.jpg.d7b80c3c4da511c93a92ebd8c4e07778.jpg

DSC02344-45-collage_25pp.thumb.jpg.2538dab25c8ef4211bc1bdcab43d0a2f.jpg

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Hello,

I you have posted my latest version of the extruder. https://www.youmagine.com/designs/ultimaker-block-extrusion-free

This new version, however, is dedicated to the ABS. It take into account a larger withdrawal Coefficient.

Last thing. This version is 100% free. Indeed, designed with FreeCAD, open source, and printed on Prusa. That said, it is not impossible to decide .stl with Cura to print with Ultimaker.

I hope this version will allow you to redo your extruder, better to imagine other solutions around this design.

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Ok, I finally got around to publish the design of the feeder I'm currently using.

Ninjaflex Geared Ultimaker 2 Feeder

It is really reliable and even though you need some additional parts (bearings and other little thingys), it is really reliable and I'm getting the best prints since I got the printer, with a variety of materials!

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This might be a stupid question but haw do you change the extruder steps/mm (drive gear diameter)? I am trying to test my new extruder but can't seem to find a way to change the software to accept the new drive diameter. Any help would be greatly appreciated! :)

Edit: I'm using Cura 15.02 and have tried changing the E-Steps per 1mm filament but when I run the program it doesn't seem to have accepted the new value at the machine.

Edited by Guest

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