After-market extruder head

Forums 3D Printers Cube 3 After-market extruder head

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  • #27
    Mechanizer

    Ok, so here’s a rough concept for adding an after-market extruder head to the cube to be able to print more types of filament. Being able to use different feed gears, idlers and having some adjustment may improve performance. I’m reusing/redesigning the FTF concept above to do this.

    I’m using an extruder head from Amazon, some parts form Servo City, and a handful of printed parts. The purchased parts comes to a total of $15.75 (plus shipping). Here are the links:
    https://www.servocity.com/5mm-id-x-10mm-od-non-flanged-ball-bearing-sold-in-pairs
    https://www.servocity.com/5mm-stainless-steel-precision-shafting

    The amazon link doesn’t show up for some reason, just search for this and you’ll find it:
    Iverntech 3D Printer Right Hand MK8 Extruder Aluminum Frame Block DIY Kit for RepRap Prusa i3

    The extruder head looks kinda crappy but I could use some of the parts and redesign other portions of it to make it better. But that’s another topic, right now I’m just trying to determine if this concept’s feasible. There may also be better head units available that could be used instead.

    Basically, the original cube feed gear slides inside another printed gear and is secured with set screws. So it’s just being used as a driver.

    Then the gear ratio is changed via a set of idler gears (this is what the bearings and shafts from Servo City are for) which then drives the extruder head.

    I measured between 9.6 and 9.7 mm OD on the original cube gear and the new extruder gear is 11 mm OD. That’s a ratio between .87 and .88, so I’m using 32 and 28 teeth gears which has a ratio of .875. Hopefully that’s close enough, but I have no idea how sensitive it is to changes in filament feed rate.

    If anybody has any suggestions to help improve this concept, let me know. Also, does anyone know if it’s possible to change the direction of the extruder drive motor? That would eliminate one of the gears. Thanks.

    • This topic was modified 2 months, 3 weeks ago by No BullNo Bull.
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    #50
    MajorOCD

    Looks awesome!! Feel free to redesign the extruder hub any way you see fit.

    • This reply was modified 3 months ago by No BullNo Bull.
    #51
    MajorOCD

    This type of drive gear works much better. This is the hobb-goblin from E3D.
    https://e3d-online.com/hobb-goblin-5mm-drive-gear

    Can you adapt it to use one of these? They make it with a 5mm ID and 8mm ID.

    • This reply was modified 2 months, 3 weeks ago by No BullNo Bull.
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    #45
    Mechanizer

    Yeah, I saw those. I’m thinking maybe getting the extruder assembly and one of those and swap out the feed gear.

    • This reply was modified 3 months ago by No BullNo Bull.
    #46
    Mechanizer

    And yeah, I could make the middle gear smaller and even put it off to side slightly

    • This reply was modified 3 months ago by No BullNo Bull.
    #47
    Mechanizer

    So here’s the diameter of the hobb goblin:

    That number compared with the 9.6/9.7 I measured on the original cube gear is the ratio I need for the gears (I think). But it may take a few tries to get the speed right.

    • This reply was modified 2 months, 3 weeks ago by No BullNo Bull.
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    #48
    tprothma

    Hi Mechanizer, good work…
    You may want to figure out if there is a way to reduce backlash.
    I really don’t like our dependence on the cube extruder either.

    I was thinking of a version without extra gear but uses a coupling that adapts to the end of the motor and goes directly through hobbed bolt.
    We can figure out the gear ratios and tune that with speed adjustments in software.

    https://drive.google.com/open?id=1NGdyJsdpVEmj8pnNcFKvvKHkhS-XAsdG

    Thanks,
    Tim

    • This reply was modified 3 months ago by No BullNo Bull.
    #49
    Mechanizer

    Hey Tim,
    Thanks, I’ll keep that in mind about the backlash – I suppose with retraction that could be an issue. I’m looking at using more purchased parts (gears, plates, etc.) instead of printed parts which may work better. I can get all the hubs and gears I need from Servo City for relatively cheap.

    We were trying to come up with a way to do this with the cube software, hence the extra gears, but I like the option of direct drive and 3rd party software as well. I’m not sure if I’ll be able to get the speed exactly right with gears anyway, so I may have to go the software route if the gears don’t work. I’ll try to come up with a direct drive concept as well.

    • This reply was modified 3 months ago by No BullNo Bull.
    #52
    tprothma

    Unfortunately the extruder gear on the printer is unique, but if it could be reused then that would be sweet. Reuse of that gear may be a way to solve both the ratio and backlash problem all at once. I think the best aspect of direct drive type I’ve seen on other extruders is the tension capability that we do not have with the cube 3 native design and as a result it seems our printer is intolerant of slight variation in filament thickness. I’m operating under the assumption that the main flaw is the need for tension, and that the gear won’t wear out (it may eventually wear out).

    I think you’re going to find the challenge is coupling to the square drive on the motor to any hobbed gear. But thinking through this a lot of people make their own hobbed gear with bolts.

    Good luck, and keep us posted.
    Tim

    • This reply was modified 3 months ago by No BullNo Bull.
    #53
    Mechanizer

    Alright, I got busy with some other stuff but I’m back. Here’s what I have on the direct drive option:

    I still got a couple of details to figure out but it’s pretty much done. Now I have to figure out how to change the speed. I know some of you have gotten simplify 3D to work with the cube, but I don’t want to buy that. I would like to use slic3r, and I found an old post from someone that claim they created a python program to work with the cube. Here are the links:
    http://cube3d.createaforum.com/general-discussion/anyone-tried-slic3r/
    https://github.com/spegelius/CubePostprocessor
    The post says it’s for the cube2, will that work with cube 3? Has anyone tried using slic3r? Can this program be modified to work with cube3?
    Any help would be appreciated. Thanks.

    • This reply was modified 2 months, 3 weeks ago by No BullNo Bull.
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    #54
    MajorOCD

    As-is it will surely not work with the Cube 3. A lot of things have changed from the Cube 2 to Cube 3. But since it produces BFB code, I’m sure it can be adapted for the Cube 3.

    Excellent find!!

    • This reply was modified 3 months ago by No BullNo Bull.
    #55
    tprothma

    Hi Mechanizer, I can help you on the speed, but it will take a week or two for me to find time to post my profiles and python code. Not at all based on what was done in the link you sent, in fact what spegelius is doing is fairly simple but does not give full control. Also some things he’s doing won’t work for Cube3. Simplify3D is definitely the best slicer, but you can get by with some free slicers as well, it’s just that you’re kinda on your own as I don’t have the time to match up the settings for a second slicer. Also there’s some built in functions that I suspect are unique to S3D.

    On your direct drive design, not quire sure I understand what’s happening yet.
    Is the grey part the existing extruder and you’re just adding a pass-thru shaft?
    Are the brown parts bearings? I see that the red is the traditional direct drive.
    What are you using for cad, I’m using mostly Solidworks these days but also have access to Creo.

    Tim

    • This reply was modified 3 months ago by No BullNo Bull.
    #56
    Mechanizer

    Hey Tim, below is a breakdown of all the parts. I’ve added another piece which was missing in the earlier picture – the hub that interfaces with the cube. Basically, the original cube drive gear mounts inside a set screw hub, that hub bolts to another hub that mounts the 5mm drive shaft for the extruder gear. The red part is the extruder assembly and the brown parts are bearings. I use Autodesk Inventor for CAD – I could send you step files if you’re interested.

    Still scratching my head on what to do about the slicer, as the programming portion is a bit over my head.

    • This reply was modified 2 months, 3 weeks ago by No BullNo Bull.
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    #57
    tprothma

    Mechanizer, my software works with the native cube prints, but you have a little less control for fine tuning. I just have never tried to sync up with Cura or other profiles.
    Tim

    • This reply was modified 3 months ago by No BullNo Bull.
    #58
    Mechanizer

     

    tprothma wrote:
    my software works with the native cube prints

    Tim, excuse my ignorance but I’m not quite following you. Are you saying I could change the speed and still use the cube print software?

    Just so I understand, you use S3D to create the g code file, then your program takes that file and modifies it to work with the cube? And you can change the speed in S3D?

    • This reply was modified 3 months ago by No BullNo Bull.
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