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Hey! This thing is still a Work in Progress. Files, instructions, and other stuff might change!

multi spool filament feeder

by blairq May 4, 2018
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Hey how to Controll this thing or waht software /code Is needed for it can you help me out pls

try klipper, its working for me now.

Good job. Looks good. The idea is innovative. I intend to print this for some of my 3d printers. But I have not yet decided, whether I am going to use a duet wifi with duet x2 expander with i have laying around , or whether I will use multi-controller boards with a klipper. someone has experience with this, the klipper part.
I am also looking for the design for the filament cutter, shown in someone's video. Because this eliminates the possibility of blocking when removing filament. If anyone can help me with this. Thank you.

Sorry but this thing is totaly unusable.

There is a single STL with all parts in one.
And the images does'nt match the la version.

Is this a fake or juste a mistake ?

dude. the entire desing is availabe to fully download in any format u like on the provided link.

tinker with it. extrude your face all over the parts. do as you like.

as long as you comply with the licence.

its a work in progress. cheers.

Okay so I am ready to build this beast, I have most of it printed, what I need to know is what size hardware to hold each piece together. I am guessing you use a 8mm threaded rod for the lane selector, I have a ton of MG90's what I don't quite know is the rods that hold this thing together what are you using? 5mm? 6mm? I am assuming that there are several threaded rods that go thru the length of the unit to hold it all together. Or better yet do you have a list of hardware you used? I am sure the lengths depend on how many lanes you want. I am going to start ordering the stuff to build it. I just got my duetex5 so I have a ton of extra stepper channels, limit switches PWM outputs and servos outputs. There is also some bearings that are used to push the filament against the hob gears.

Onto the GCode, so this is what I am going to try.

1) When a tool change is requested, the servo will pinch the hob lever so it engages the hob gear. Then the extruder, and the hob will retract the filament, I am going to add a sensor to detect when the filament is retracted past the selector house. Then it will go a little more then the servo will release the selector. Once that is done the stepper will drive the selector back to it's home limit. This is all done in the tool change pre.gcode file that executes when you request a tool change.
2) The tool change post.gcode file is called which will drive the filament selector to the correct lane of the filament to be loaded. Then it will engage the lever to pinch the filament against the hob gear. Once that is done then the filament drive will engage and drive the filament to the filament detector. If it doesn't detect the filament after a certain amount of steps it will pause the print. Since there is no filament in that lane. If the filament makes it to the sensor then it will drive the filament the length of the feeder tube to the extruder. Once the filament reaches the extruder the hob leaver is released. Then the tool change is completed and then the purge tower is printed to clear out the old color from the extruder.

I am asking myself if I need to add 1 or 2 filament detectors. The first one at the extruder to make sure that filament is present, and the second one at the lane selector to detect when filament is retracted past it, and also to detect when filament is being fed that it reaches the lane selector. I am also wondering if some sort of cutting blade should be added so the filament can be cut clean during the retraction. The biggest issue I see with this is the string at the end of the filament when you retract it from the hot extruder.

blairq is this already usable? Should I print it? How can it fit on a Bowden setup?

Blairq I am downloading and printing it out from the Fusion 360 archive, I can see this thing working. I have a Duet, and I will get the extra stepper motors, to drive this. I am going to start with the base design, I will help out with this project. I will code up in gcode for a duet to drive this and if needed I can also develop the electronics to drive this thing. I am researching how we can integrate this into printers with a multi-material slicer, like simplify 3d or something.

Okay so I printed the changer out I have a couple of mechanical questions. 1 It seems that the lever system has no spring to lift the cam that pushes the filament into the hobbed gear, also there is no easy way to adjust the tension on the hob gear, mechanically. Yes you can adjust the servo's position a little bit but that is difficult since you have to edit the macros that change the filament that is being fed.


"1 It seems that the lever system has no spring to lift the cam that pushes the filament into the hobbed gear"
no springs. its a compound lever. if u push too hard it squeezes the filament and leaves it flat like a Linguine . try not to.


 get a rumba board  or get a one driver 

"stepper expander" -- google that --
for your ramps . or just wire a driver to some pins. u need like 3-4 i dont remember well. or get a fysetc f6

hack the world.

 my idea now is to use klipper. 

Oh I have on my duet the ability to operate the servo, that is not my problem, so your saying that the lever exerts enough force to linguini the filament. Okay well I will order the parts to finish it. I was just playing around with one and I'm missing the HOBS, and rods to hold everything together. I have the steppers just missing the mechanical parts to couple everything together. The servo should be easy to integrate, I got a dozen of those MG90's SG90's and the likes. What I like about this design is that you could have many different filament bays. You could stack them in banks of 2, 3, 4, 5........., 10.... 20. Okay 20 is a bit silly but it could be done if there was the desire to do so. I do have a old flash forge dreamer that does 2 filaments, and that makes some cool prints. However, with petg, it seems to slop the drippings of one extruder all over the other one's work. I see this as a way to upgrade my other printers without that issue.

you must check every lever pair and every port to work properly while assembling it. check all the levers needs to move to the same angle to work. sand as needed

the levers are quite tricky . in case you didnt understand how they are supposed to work watch this video (old design... ) https://youtu.be/1e9xceqAUlw
sorry it is in spanish.
when u insert the filament it is suposed to open the lever and get stuck. not passing through. and when u push the lever to the desired position it should move the filament so when the extruder stepper moves it can go freely out.

its somehow tricky to make it work if ur printer or slicer settings are a bit weird. anyway u can use a drill and a 2mm drill bit to "make it work"

Mi entiendo, en todos. I do speak some Spanish. I see that the levers have a small range of travel, those mg90's aren't the most precise servos, and don't have great resolution. I will build one and see how it works after I get back from a business trip next week. As far as the slicer interface the Duet allows for Gcode on tool change, that is where I am going to put the program to operate this. I will post the code into a project, so people can download it, once I get it working.

So this needs two stepper drivers. I can easily make a PCB with them since most people have RAMPS which have 5 driver slots and you need 2 for this, 4 for XYZE so you are one off. And keeping this independent is nice. Don't you think?

hi! nice you are interested. i dont think u keed extra electronics. just get a direct drive extruder without gears. and start playing with those macros with the duet.

there is a guy already doeing something like it. his design is heavely inspired on mine. https://www.youtube.com/watch?v=cLydXt-zUXM

he used all bondtech gears. expensive a.f. not my idea.

What do you plan on doing for the electronics?

Is there a file out there where you can print each part separately at all. Because every time I go to print it it is all together as one unit.

dont print it dude, its not finished.

check latest version here, if u like it, download and do whatever u like with it.


its not for the faint of hearth.

What do you think of adding a filament sensor to each filament input? Just a simple endstop.

you can screw something on the imput. where the pc4-m10 fitting goes.
i already have a switch that can go there but the mechanical switch itself i designed that part on is crap.

A integrated solution would be cleaner ;)

An integrated solution would be cleaner ;)

This is a really nice design and I'm excited to see it fully functional! How far along are you? Do you need help with the firmware/software side at all?

check this, latest design with a servo. havent printed it yet , filament prices roared where i live


Will this work with marlin? Very interesting

im making a patch for marlin head

Looking great, can't wait until you have it finished!

yeah.. having issues with my chinese low quality mk8 hobbed's .. may redesign the lever . it was designed to gently push the filament but looks like the only way to reliably move the filament is to throw the 500 pound gorilla over it .

Hi Blairq, have you thought about using something similar to the dual drive gear that trianglelab sell on aliexpress? Instead of a skate bearing and a hobbed gear, a dual interlocking design. The teeth could mesh together using the idler lever in the same fashion as it does now, but provide significantly more force on the filament.

yeah i have a couple of those , one on my bondtech clone.. i think i didnt publish it... yet
but fact is that it is expensive , im looking to handle at least 6 different filament spools and thats like 60 usd.... and this needs to be cheap. becouse im cheap :P

edit: attached a picture of the extruder (with those gears u said ) that goes on the other end of this beast.

I'm currently running a Zesty Nimble, which is a remote direct drive extruder. entire thing adds 30g to the gantry (Ultimaker 2 clone). Best piece of kit I've purchased for my FDM. Insanely expensive, and I had to save for a while, but I've never had to babysit the printer wondering if the aliexpress hobbed gears are slipping or not, which was a huge issue for me previously (was using a bowden style printer).

Your design is already a significant advancement over the prusa design, bondtech gears or not. I can't wait to get this printed and start playing with it!

Is the development active?

I've read on the description that it isn't intended to use as an extruder. However, did anyone tried to use it as such?

im still on the design phase..

So it will work as an extruder right? if not how do you intend to have 6 motors being 3 for XYZ 1 for filament selector 1 for the feeder and another for the extruder. I think the feeder and extruder could be only one, and I don't see your point of having two, it doesn't work

oh litle john snow, dont be so pretentious, it is NOT intended to be used as an extruder. it is intended , as stated, to be used as a FILAMENT CHANGER

u know like when u pause your printer to change your filament mid print, with your hand, or when u wanna start printing with another filament at start, or when the sensor on the carriage of this thing im building .. "senses" that the CURRENT filament is runing out. an throws a M600

and there lies the reason you cannot use this as a normal bowden extruder , once you have run out of filament you have no way of know it becouse the filament will just get stuck on the carriage and ..well.. u have no way to move it any more.

remember. filament changer. automatic.

now for the drivers part : i have a fingin azteeg with 8 drivers.

nah , well i have it but it is not a necessity . normal ramps have 5 extruders. u only need one more. drivers need 3 pins and ramps have plenty of them , look at reprap wiki u have a lot ideas of how to add another driver to your ramps, i myself will use the spare slots on my rambo , or my fysetc f6, or my azteeg x3 pro.

Moreover how do you use it has a filament changer? since the motor for the filament changer is grabing the filament and the extruder has to push not only the filament but also the dead motor of your filament changer.

I think you could acommplish a very nice bowden extruder with this. The question is, do you wnat to make this fantastic?

You do have a way to know if the filament sensor is after your thingy!

once the spool of my first printer who is hanging from the wall got stuck. when i woke up in the morning the printer was hanging from the spool.

u gotta have a manly man extruder.

Ok, that means you are the right guy to make this a bowden extruder also. Let's go

right, now throw me some cash, 400 percent devaluation on my country (my paycheck, not filament cost)

Man you just need to put some hobgoblin and you have an extruder

i really like how scalable this design is, well done mate

indeed, scalability was a key factor

Nice work, the idler design is clever.

Thank you for your fusion link

now that the new prusa is out this may look like a copycat but this iteration of the design is like a year old.
prusa one is good but the idler design is....

and... thre steppers... really ...
no stackable? only 5 input ports max?

no filament purge port? yeah. $$$

see ya in a year.