Anybody tried designing a rotary add on?

New Home Forum Mostly Printed CNC – MPCNC Hardware Development – MPCNC Anybody tried designing a rotary add on?

This topic contains 49 replies, has 15 voices, and was last updated by Profile photo of John John 1 month, 1 week ago.

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  • #7192
    Profile photo of ualdayan
    ualdayan
    Participant

    I have some spare steppers around, and I was thinking of trying to come up with a rotary style attachment (like you see for Chinese laser cutters). Just wondering if anybody else has started on that at all (no need to duplicate it if it exists elsewhere already).

    #7200
    Profile photo of karltinsly
    karltinsly
    Participant

    If you’re talking about a 4th axis, we recently had a discussion about that here: http://www.vicious1.com/forum/topic/laser-etch-wood-dowel-ideas-needed/. I don’t think anyone here’s done it, but we did talk about some interesting possibilities.

    #7212
    Profile photo of ualdayan
    ualdayan
    Participant

    Ahh yes, exactly what I was talking about.

    #11587
    Profile photo of Leo69
    Leo69
    Participant

    I just printed a prototype that i probably won’t get a chance to hook up and test until next weekend.cost was under $25 total thanks to bobwomble’s 3 jaw scroll chuck on thingiverse. I really only built this for laser projects but I’ll experiment with it to see if anything can be done with wood if i can make it a bit stronger.

    #11592
    Profile photo of Ryan
    Ryan
    Keymaster

    Sweet.

    #11605
    Profile photo of Leo69
    Leo69
    Participant

    Thanks. this is just 15% infill for fit test but i intend to run it until it breaks:) kinda nervous about testing on wood.I’ll need to borrow some riot gear in case the work gets airborne!

    #11607
    Profile photo of Ryan
    Ryan
    Keymaster

    Make sure you are wearing safety glasses, and have multiple video cameras running!

    #11611
    Profile photo of Barry
    Barry
    Participant

    With that kind of gearing can it really go that fast?

    #11617
    Profile photo of Jeffeb3
    Jeffeb3
    Participant

    “remember this: there is no more important safety rule than to wear these — safety glasses.”

    #11618
    Profile photo of Leo69
    Leo69
    Participant

    This is an indexer and not a lathe so the precision and holding torque are preferred over speed.If you look at 4th axis add-ons on eBay or amazon you’ll see reduction gear boxes or similar belt and gear configurations. This doesn’t need to rotate any faster that your cnc can cut or laser etch material.

    Assuming you have 3inch diameter stock. Circumference of material is 9.42inches and assuming you can cut at 60ipm means you only need about 6.37rpm on the rotation speed and I’m sure this design will exceed that considerably.

    #11620
    Profile photo of Barry
    Barry
    Participant

    Right, I was commenting on your parts going flying comment. Pretty cool that we can print this kind of stuff, and it works.

    #11621
    Profile photo of Leo69
    Leo69
    Participant

    Ahhh.lol. definitely moving the wife’s car out of the garage for this. I’m going to change a couple of things and reprint before i test. I’ll keep you all posted.

    #11624
    Profile photo of Barry
    Barry
    Participant

    What could possibly go wrong?? 😉

    #11913
    Profile photo of Leo69
    Leo69
    Participant

    Update: won’t have time to test today.my belt on the headstock was a bit loose, i made a mistake calculating distance between centers. Fixed that, reprinted at 30% infill which feels strong enough for sure. Also designed and printed a motorless tailstock with a chuck for extra insurance;) hopefully I’ll cut something In the next couple of days.

    #12211
    Profile photo of Dwayne Gonzalez
    Dwayne Gonzalez
    Participant

    Any updates?

    #12368
    Profile photo of Barry
    Barry
    Participant

    I miss that show.

    #12437
    Profile photo of Leo69
    Leo69
    Participant

    Project delayed. The ramps board on my printer died so i borrowed one from the mpcnc .Replacement on the way.Als looking into how this will work on marlin set up. I know some simple firmware mods, like allowing cold extrude, will be required in order to use the extruder output for rotary axis but I’m hoping that’s all.

    #12440
    Profile photo of Ryan
    Ryan
    Keymaster

    You should be able to just switch the rotary with the X or Y axis and call it a day. I’m more worried about the CAM side of it. I think fusion has a rotary option.

    #12480
    Profile photo of Leo69
    Leo69
    Participant

    I know that wrapping the code should work with xory axis but since i don’t plan on adding an extruder i was wanting to dedicate that output to the rotary permanently so i dont Need to swap stepper connections. Aside from setting steps per mm and allowing cold extrude, can’t think of anything else getting in the way.

    #19248
    Profile photo of Oscar
    Oscar
    Participant

    Have you made any progress? I’am really excited to see if the 4th axis can work on the extruder output and how that would be controlled.

    #19269
    Profile photo of Alvin
    Alvin
    Participant

    +1 on this one 🙂 I was just looking to add a rotary yesterday for the mpcnc laser.

    #19322
    Profile photo of Leo69
    Leo69
    Participant

    I’ve tried a couple of vector line drawings so far. Converted to gcode using dxf2gcode and then wrapped the toolpath using Scorchworks gcode ripper. There are some issues to overcome on the CAM side. Marlin set-up is easy since it’s just another axis steps/mm configuration but most CAM software will only allow Axis selection of ‘A’ or ‘B’ for rotary and there is no ‘E’ option which is what Marlin uses for the extruder.

    This can be dealt with by either:

    1) Editing the wrapped gcode and replacing all A/B axis moves with E axis moves.
    2) Minor Marlin firmware edits to treat A/B axis moves as E axis moves.
    3) If you have source code (Scorchworks gcode ripper source is available) then modify that to produce the E axis gcode.

    Another issue is with Scorchworks gcode ripper. I’m sure there are other non-freeware solutions but I’m trying to use open source tools wherever possible. Anyway, Scorchworks is crashing when trying to wrap laser raster engraving gcode. It probably has something to do with the tiny, incremental moves involved with this type of engraving but haven’t had time to debug and patch. Haven’t tried cutting any wood on the rotary yet. I can’t think of anything that I’d want to make just yet but leaning toward a totem pole.

    Other tools that can wrap gcode about a rotary axis are CNC wrapper and Vectric Aspire but these aren’t free.

    #19333
    Profile photo of Leo69
    Leo69
    Participant

    I guess I needed a kick in the ass to get me working on this again.
    UPDATE: I thought my gcode files were the problem with Scorchworks gcode ripper but I actually found some bugs in the way complex numbers are being passed to the TCL/TCK libraries. I’ve patched most of the bugs …. I think…. and also added wrapping options for wrapping Y or X axis to E(extruder) axis to make this MPCNC-friendly as shown in the attached screen shots. Hope to test this open source solution soon:) This will allow rotary laser engraving using either image2gcode or dxf2gcode if all goes well but the gcode ripper software will accept any gcode file as input and create wrapped output so it should work with gcode produced by almost any CAM package.

    #19342
    Profile photo of Bill
    Bill
    Participant

    Really looking forward to seeing this work. It could be very useful for customizing pool cues, assuming you could open things up to allow a long cylinder with most behind the chuck.

    #19526
    Profile photo of Leo69
    Leo69
    Participant

    First trial run today, actually 2nd. I entered the wrong belt pitch into the reprap calculator for the first run so the image was stretched out. Now that the settings are right, everything seems to be working. Image from vicious web site converted to dxf, then converted to gcode using dxf2gcode, and finally the Y axis toolpath wrapped around the E (Extruder) axis and fed to MPCNC running Marlin. I like the 3 jaw chuck but I’m thinking of whipping up a scaled up ER-collet type system since I’ll mostly be working with round stock from hope depot. Getting there though…

    https://youtu.be/ihawzSSQpxg

    #19532
    Profile photo of Ryan
    Ryan
    Keymaster

    DAM! So with the scorchworks program you are working on, you can give it a diameter of your work piece (after you input your gear ratio I would assume) and go from there? If so that is awesome.

    Maybe a 3 jaw chuck on the business end and a steady rest on the other end, should be more versatile?

    (about to start working on organizing the info a little better … chugging the caffeine now.)

    #19548
    Profile photo of Leo69
    Leo69
    Participant

    Drinking your caffeine this late? Date must have gone well:) Yes, the steps per mm setting in Marlin is based on the gear that’s driving the chuck which is an XL 25T pulley which has a 5.08mm pitch and results in a 25.2 steps/mm config in Marlin. That’s a one-time setting. The gcode ripper software will take a gcode file as input, which can be a laser file or a cutting file, and wraps the gcode about an axis based on the entered stock diameter. I take no credit for gcode ripper, it belongs to Scorch at Scorchworks web site. I noticed the software was crashing with most of the test files I was using so I debugged and added options to wrap about ‘E’ axis for the MPCNC crowd.

    The 3-jaw chuck on the tailstock is definitely overkill for laser engraving but I’m going to try the router on this thing next and I want extra holding power for that test. I’m not a big fan of the chucks after initial testing because they require too much Z axis clearance height to allow the jaws to open. I think I’m going to re-design using a scaled up collet system, like an ER-11 type deal with different sized collets for different sized stocks. My main accomplishment for now is proof of concept for Marlin and Gcode ripper. If you can think of a good design for the rotary then please be my guest. I’m definitely an amateur where that’s concerned. I’m going to make a few changes to mine and do some router testing before I prepare a write-up and BOM and turn this thing loose.

    #19560
    Profile photo of Ryan
    Ryan
    Keymaster

    High five!

    Okay I understand now. Mounts will be hard, The option to mill rectangular on the rotary is going to be a cool feature but will require a 3 jaw or similar. For now that is up to the end user, You are killing it on the heavy lifting (software). Mounts will be easy when the software cooperates.

    #19667
    Profile photo of Alvin
    Alvin
    Participant

    thread favorited and subscribed 😀

    #20022
    Profile photo of Leo69
    Leo69
    Participant

    Update: The 3-jaw chucks don’t seem to hold the material well enough for router work and quite a bit of run-out which is no good for V-carving. It might be because I printed the 3-jaw chucks in PLA which is the least recommended material according to the designer. I’m printing a collet set-up now and will see how that goes. Also wondering if Nema 17 has the balls for router jobs. If I don’t get this resolved by the weekend then I’ll just post software and instructions and recommend for laser use only with my current set-up.

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