Prusa i3 Direct Drive Bowden Extruder

by indieflow Jan 24, 2013
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what do you have wrapped around your hotend?

Hey guys, do you know if this would work in its current form with a Hexagon hotend?

It’s definitely not made for the Hexagon Hotend but it wil fit with a little bit of force. I also drilled out the holes for the pneumatic push fittings to fit 3mm filament. I am making a remix for the hexagon. I will also try to make one for 1.75mm filament.

I have this set up running on my I3. I really like it accept the hole for the M5 push connector is to large and my connector is popping out on the extruder. I barely know how to run Open scad and tried to shrink the hole from 10 to 8. Either its my ignorance or the code isn't working properly in Oscad. Any help would be great. I also wanted to increase the hole depth from 5 to 6.

Can you provide 3d model source files ? I am trying to slightly change it for all metal hot-end and dual extruder

If you read the info page for this design you will find a link to my Git Repository which is where all the source files are held for you to tweak and adjust how you wish :)

I am sorry, actually I am reading the info page quite often but in many cases there are a few useful informations.. You are the bright exception :) so thank you

4x m3 nuts.
8x m3 washers
5x m3x10mm cap screws.
2x m3x14mm cap screws.
4x m3x40mm cap screws.
1x 4mmx12mm round bar or threaded bar. //Cut a m4 bolt to size.
1x 4mm OD, 2mm ID pneumatic fitting with m5 thread.
1x mk7 drive gear.
1x 624 bearing. //idler bearing.
1x 625 bearing. //used for motor shaft support, can be used without.
4x springs.

Do you think this hotend mount can be made out of PLA? Or will it melt?

I think it may last in PLA, especially if only printing PLA!

Oh, and could you mention what bearings are needed for the extruder? I have ordered some with a 5mm id but they don't look like yours. Mine have a much smaller OD.

Haha okay, it's important because the printer with best precision is currently set up to print PLA :) Don't want to risk melting it ;)

I've been building a 2nd machine and now I'm converting it to 1.75mm filament so this setup of yours will be applied because it looks rock solid. Only thing is that I have different bowden tube couplings, so I would have to edit the files somehow. By testing I've found out the perfect hole size to print so the holes can accomodate my couplings.

If you've used OpenScad before you should find it easy enough to alter my design on Github.

Hey Indie, I have created a 30mm fan version of your J-head holder! If I upload it, would you like me to tag it as 'based upon' your design? I haven't used any of your files, just re-created the looks and how it works kinda.

I have been designing a lot of hotend holder solutions, but the key into making a printable one was to use the clamp that holds the J-head to first mount the J-head and then conceal it because the clamp is on the same side of the holder as the X-carriage is.

Couldn't create the extruder completely, because I am using a different kind of hobbed bolt, it's the MK8 I'm using and this causes the idler bearing to not reach in deep enough to clamp the filament against the hobbed gear.

You're right, I shouldn't try to fix an effect, but fix the cause ;)

I'll edit is to accommodate the bearings I have. Haha, I can't believe I was thinking this backwards and uninventive!

can you share the scad files for the double mounting plate?,

Sorry that part was designed using Solidworks!

even better for me, could you upload it, please?

Would this work on the Makerfarm i3?

Shouldn't be a problem as long as the X carriage is compatible with the J-Head holder, or again your X-axis smooth rods are at the same spacing to use the same X-carriage I use!

Hi, I've cloned the repository but the X carriage is different from the one in the photos. Is this an error? Could you upload the STL of the right X carriage?

Would be great If anyone could point to a valid X carriage on thingiverse.

What size fan is being used ?

Had anyone success with 3mm filament?

Hi Indie, which X-carriage and X-ends are you using here?

I am trying to build a MendelMax 1.5 and theres no X-ends and carriage in the files and I would like to try a vertical X-axis and ordered a J-Head because I want to build a bowden-type extruder.

Thanks for this nice studer, though I am using 3mm, so I hope ifala's version works for me.


all other parts used in the construction of this printer can be found on my Github page, link above in description



I found out the normal plan of the MendelMax includes 2x 10mm rods for the Z-axis, but I really want to use those prusa i3 looking vertical X-axises so I'm making it 8mm so I can use this kind of construction like the one you are showing here :)

I'd be happy if there was a version for 3mm ... your job is exceletente ... :)

Sorry guys I'm really busy with other projects at the moment, though the source code is all readily available on my Git linked in the description for you to alter and tinker with! Would be ace to see some derivatives get posted :)

Prusa i3 Direct Drive Bowden Extruder 3dita mod
by ifala

Make a doubleEX>>?

That could easily be achieved by printing 2 sets and mounting them side by side! A simple 4 hole to 2 hole plate is all that would be needed to mount them on the X-carriage.

Another option would be to mount opposite each other (either side of smooth bars), here you would just need to restrict axis movement so as not to collide with the frame!

As requested I've uploaded a Dual Mounting Plate so that 2x Bowden systems can be mounted side by side. A simple modification which will allow either J-head to be easily removed for maintenance purposes etc.
I've also uploaded a rendered image of it in position. This has not been tested so first person to test it, please post pictures :)

I have buy all adapter tubing... ehhehe I print And I post photo ..THANKS!

Question.. Is 3mm filament or 1.75?

All 1.75mm as I find 3mm isn't as easy to use with a direct drive bowden!

I have all for 3mm ! please can do a 3mm type? with the hole for the Pneumatic Fittings M10 like. many thanks!

If anyone doesn't have a printer and wants a set up like this I've just put a set up for sale http://www.emakershop.com/browse/listing?l=511http://www.emakershop.com/brow...

Love it, I too am a massive fan of the Bowden system What cold end are you using here?

This is designed to house a J-head hotend nozzle, I used a Mk V

Recently the X carriage was updated and put the hole spacing 30mm apart instead of 20mm, mind updating it for that change?

Keep in mind that neither the compact_extruder nor the dual-compact-extruder in the single_plate folder in the Prusa3 repository are updated for that 30mm wide adjustment!

Silly question but if you plan on using this extruder for your i3 why would you want the larger X-carriage that has been enlarged for bulkier extruders? Why not use the original, reducing on weight and plastic cost!

Because there's no "original" and "larger" choices in the main branch. Why should everyone who wants to use this, have to hunt down an old carriage, when the new one is the default. I don't see the need to further fragment the design by having "old" and "new" carriage variations for everything, I'd rather just use what is considered the current revision.

It's all good, I edited the scad myself - only had to change like 5 lines. Offset of the mount holes, (from -12 and +12 to -17 and +17) and increase the x dimension of the top cube which forms the fitting mount.

If someone runs across this, and tries to build on the current main branch of the i3, it's not going to work. I figured I'd ask for the updated revision so that others don't have to recreate the work I just had to do.

Fair comment, though why alter parts (ie X-carriage) to fit other parts that you may not be using! The main files will always alter to best fit the incorporated generic setup at the time hence why above I placed a link to my fork of of the Prusa i3 which has this setup!

If I where you, I would just add right x-carriage to the files, this eliminates all the moot points. I am going to use this on my Wilson build, can you please post the right carriage?

What bearing are you using at the top of the extruder?

As detailed in the .scad file the top bearing is a 625 which is used to take away any sideways force on the Nema shaft, it isn't necessary to use the extruded if you don't have any though!

Any chance you could upsize this for 3mm filament? :)

I've adjusted the .scad file so that 1.75 or 3mm can be easily adjusted for filament, though without knowing your pneumatic fitting thread dimensions (which will obviously be different) I can't export you an stl! If you let me know I will adjust a file for you :)

I trialled a 3mm version over the weekend and wasn't very impressed! Due to the extra force required to push the larger filament through I had to increase nozzle temp, reduce speed and still the motor ran hot!

Think I'm going to stick with 1.75mm and would advise it for direct drive extruders! Pluses def out way the few extra pounds it costs!

Try and drop your microstepping - you'll get more torque and less heat at the expense of a bit more noise. I've had mixed results with 3mm Bowdens.

How does one drop their microstepping for a single motor (in the firmware I assume)?

FWIW one could simply add either a heatsink to the stepper or add a fan to cool it. My direct drive NEMA17 for my Cupcake came with a 40mm fan.

Usually hardware jumpers or DIP's - but some hardware allows you to do it via firmware. You may still have to run the motor hot, but in general you get more torque with less microsteps.

Thanks for this, do you know what size bolts / nuts / springs/ bearing we need?

If you click on the link above for github and then select either part you should see the scad file data which lists all parts needed at the top. Also if you download the file and open via OpenScad and press F5 you will get a visual representation of how the parts go together.

I've done it this way so that if I change any thing it is auto updated on GitHub! Any problems let me know :)

What motor are you using?

Nema 17's from ZappAutomation