Stacked dual markforged kinematics possible?
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I at last finnished rough design of my new quad machine using stacked dual markforged kinematics. Well, the hard part i did - the XY plane with rails, idlers, motors, frame, toolmounts... Z is easy now i guess.
Now embarking on ordering parts to build an XY plane prototype and do some milling.
As said, plan is “just” to stack dual markforged (layout similar to great Muldex design by John Mulac) and making it a bit more compact.
So this brings X U V W and dual Y (Y and A). And tripple Z (BCD... are these even needed?) when finnished..BUT
Before i shell out bunch of cash for a prototype XY stage, i am now looking at M669... is quad markforged even possible? I fear i got too ambitious and got spoled by “no limits” philosophy using Duet & RRF. I hope i am wrong.
99,9% sure i have to go with Duet3 just because a whole lot of movement will be going on there with very intricate stuff in multiplication. Along with number of stepper driver requirements...
So will i be able to set the firmware for this quad markforged? Or is Dual Markforged as good as it gets?
Worst case, i see there is an option to swap motor mapping on toolswaps and just run the machine as two independant dual makforged sets but that is less than desired or ideal due to having to load practically half the config on toolswaps..
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@maracmb, after I implemented CoreXY, CoreXZ, Core XYU and CoreXYUV kinematics, I got fed up with having to add a new kinematics class every time someone wanted another variant of CoreXY. That is why RRF now has a universal linear kinematics class, which supports any kinematics for which the motion of every axis is a linear combination of the motion of each axis motor, up to the maximum number of axes supported. For Duet 3 MB6HC that number is 10 for release 3.2.2 and 15 for the 3.3beta releases. So quad MarkForged kinematics is supported already. You just need to provide the right movement matrix in the M669 command.
If your Y axis is a single axis with two motors, then with RRF3 you don't need to create another axis for the second motor. Similarly if you have a single Z axis driven by three motors.
Depending on the rated current of the motors you want to use, a Duet 3 Mini 5+ and Duet 3 Mini2+ daughter board and some expansion or tool boards may also be an option for you.
Duet WiFi hardware designer and firmware engineer
Please do not ask me for Duet support via PM or email, use the forum
http://www.escher3d.com, https://miscsolutions.wordpress.com -
@dc42 i love you. People should tell you this more often.
Ok, i can go and spend my cents and empty all my socks. When ready, i will nag for guidance to set the matrix correctly if i don’t figure it out myself.
What kind of sad way would be having only one Y?
With motors being cheap, need for racking prevention and speed/torque high, i was thinking of going 4 Y motors on each corner split into two axes for each dual x gantry so i can mirror both Ys and all Xs. This way, each of dual X gantry can also home and square itself on homing, no need for some rods linking both sides avoiding motors etc. Building this as a platform to build on and work with for a while, so no shortcuts. -
@maracmb, if you have dual independently-driven X gantries, then those are dual Y axes, so you do need to create another axis for the second one.
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@maracmb for the record... Mind blown! 🤯
Good luck with your build!
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@maracmb Also for the record, I've been running CoreXYUVAB (3 stacked XY gantries) for a couple of years. Using a 5 input mixing hot end, I've demonstrated printing at 300mm/sec using single motors. So I'd say that using 4 motors per XY gantry is simply overkill and might lead to more problems than they are likeky to fix.
One thing to bear in mind is that no slicer (that I know of) will generate the UVABnn moves. I use a Python script to post process the gcode file. An alternative method is the map all the motors to single XY axes after homing. -
@deckingman said in Stacked dual markforged kinematics possible?:
One thing to bear in mind is that no slicer (that I know of) will generate the UVABnn moves.
Your case is different, since you have 'one toolhead split into three gantries' (bare with me for this loose interpretation), while @MaracMB will have four toolheads. In his case he can slice using 4 extruders and write the kinematic/toolchange scripts accordingly.
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@deckingman hello. Since we’re on records, first things first: Big fan of your work!
But regarding my little Quad; i do have a IQEX i3 build already for a year now and learned it’s quirks. I popped an extra IDEX gantry on Z towers (dual independent) and made heightadjustable mounts. Works more than great. Slicing is easy once you know what slicer does and what firmware does. Won’t teach you that, you know more than i do i guess...
independant tools make it very efficient and friendly. Even if I only have 4 materials loaded and print with whatever. But my current IQEX a bedslinger... while speed is limited, it is not the crucial issue. Yes, it is an issue but not that big. 80-90mm/s for production prints is just fine for a machine worth sub 1k printing quadruples... it will stay with me in the future no doubt... I primarily aim for more efficient formfactor & to be able to enclose it for nylons, PC and similar for functional parts (up to 90c buildchamber, no more), have freedom of Y offsets between paired toolsets and to just make a new machine. This last point is more or less main intrigue. And since i am building it my own, I’ll make it a challenge -
@maracmb said in Stacked dual markforged kinematics possible?:
Ahh, OK. Slightly different usage case to me. Hope it goes well.
.................. And since i am building it my own, I’ll make it a challenge
Yup - a challenge is always good.
