New to LB… revamped a Mach3 setup to generic controller. It has laser and spindle output, and x, y, z, axes. Have seen a bit of dialogue about dual axis drive,… I am thinking that LB does not have
the ability to make a z-axis act like a secondary y-axis… correct ??
I’m a bit concerned about hard wiring in the second y-axis to the primary one, in case of overdriving the power supply. It’s just a diode laser,… anyone have any thoughts about it??
Thanks for any thoughts.
Don’t know what you mean here.
Lightburn is really a 2d program although it can manipulate the Z axes to some extent. You would have to check up on how extensive Lightburn can use the Z.
Always a concern…
Most of this hardware is not designed to be paralleled, not a good idea with semiconductors, as they may not turn on/off at the exact same time with the same signal source.
It would help greatly if we were not trying to guess as to what you wish to accomplish.
Many times, there are ways to handle issues, built in, you just don’t know about it…yet 
Good luck
LightBurn doesn’t control motors and leaves that responsibility to the controller. Does your controller setup have the ability to treat Z as secondary Y?
Is this an Arduino based controller? If you have access to source-code you may be able to configure it to suit your needs.
Routers need dual Y axis drives because of the high cutting loads. Some pull with one drive but they aren’t as strong. Lasers don’t have cutting loads so generally they have one drive, two shafts and pulleys connected to either end of the X axis. So if you have two stepper motors then just connect both to the Y axis drive. Look up how to wire steppers in parallel.
If you have two drives and want to keep it that way, laser controller only have one Y output. Not sure how best to wire that without doing some research.
Gentlemen… thank you for the responses… This forum is one of the best I have encountered in my short visit.
Pretty much clarified my question, thank you. Makes sense that the LB doesn’t need to control the mechanics in micro detail.
What I discovered is… just swapping the leads from one coil on the second y-axis motor, then paralleling the wires in the plug, worked just great. The little bit of test driving I did, seemed to show the motor drive circuit chip staying cool with the fan. Perhaps longer duration events may prove otherwise. I will try and measure the current draw from the dual y-axis, as the specs on the controller show a max of 3.5 amps. I (fingers crossed) don’t think they will experience that much, but that is just guess at this time.
I will post pics and results when the machine is functioning close to anticipation.
Many Thanx again
Ray
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I’m glad it’s working so far. Since two motors share one drive you may see some loss of steps during high acceleration, which you can always reduce, or increase drive amperage.
One other advantage of completely separate motors and drives is that you can also have independent limit switches that zero motors independently.
So wiring two motors like that might cause alignment issues eventually. Maybe not a big deal for a diode laser but a big problem for a CO2 laser. Which is why you don’t see dual Y axis laser cutters.
IMHO, it just seems to me that it will complicate the whole thing… having two Y motors…?
Agreed but that’s the way routers are designed. Probably never mentioned unless your converting a router to laser. Which have a lot of similarities.
Complicated? 3D printers generally have dual Z axis controllers. It’s what ever the machine needs.
I don’t know why they call it this either - in the GRBL source code it means Dual-Motor axis drive or Dual Driver axis but either the transliteration or translation gave us some unfortunate terminology. It is a thing though. There is a compile-time option to build it right into the controller.
The code is written on the github repo (repository) and it’s so well documented that it literally tells you which lines to ‘comment out’ and ‘un-comment’ to activate the other motor.
To make it even more interesting - the second motor is usually installed facing the opposite direction so it has to turn backwards compared to the first motor. It’s already written, ready and waiting.
Stepping up to flash controller firmware is a ‘level-up’ kind of experience. It’s outside LightBurn - you’re pushing whole new understandings and processes into the brain of the engraver - the downside is the potential of creating a moderately expensive and ineffectual door-stop “Bricking the controller”.
Thank You John Johnson.
The more responses I get from you knowledgeable types, the more I understand that I don’t understand a lot.
The previous setup was to be a screw shaft drive system for a router, started in 2007, but life got in the way. Sourcing equipment was a nitemare at the time, with no guarantee of quality… hence a lot of
stuff got returned.
Then came “maker” companies that supplied turnkey setups, which was a godsend to me.
Testing the cnc waters included a belt drive system, and thus the “two motor axis drive” came to be.
Having put my toes in the Mach3 pond, for the last few years, I learned how easy it was to reverse the
second motor, (which yes, faced the opposing direction), by a check /click in the software. The breakout board had an extra ‘A’ motor port.
(A lot of you probably have much more experience with it than I)
Since this issue came up, I have seen inexpensive GRBL controllers available that include an “A” axis or even a “Y1 + Y2” port(s) on the y-axis…so it would suggest that the double motor drive system may be a ‘thing’ particularly with we who are just getting into cnc. Perhaps that would be the quick and dirty way to solve my problem.
I originally used the Mack3 system for cutting and texting only, but recently got interested into the engraving side as well, to compliment a friend’s hobby of miniatures.
LB came up as a good fit, but also have had ‘LaserGRBL’ suggested.
Dating myself here, …I remember Fortran, C+, and DOS… so GRBL would be a challenge.
…but if it is not a big deal, as you suggest, it may be a way to convert the ‘Z’ axis to a y-2nd axis.
I did find that doubling up with the two sets of motor wires, on the tiny crimped on pins for the connectors of both motors is frustrating, and also doesn’t give me a lot of faith they would last.
Again… I do appreciate the input.
Best Regards
Ray
I hear you, I’m pretty sure I got the last Fortran course in my university days.
I’m certain that GRBL is written in C++ and that you will be able to read the well commented source code without having an awful time with it.
Enjoy!
If you have a large frame (especially along the X-axis) there could be practical benefit to having 2 motors on the Y-axis.
What specific controller do you have? There may be a switch or pins that you can jump to have it copy another axis. So just handle this on the hardware side. Else there may be some things you can do on the GRBL side. There are pre-built solutions as well but will depend on specifically what controller and MCU you have.
If you’ve done programming of any sort you will pick up grbl pretty quickly, so don’t think your ‘wisdom’ years were wasted with languages like the Fortran… fortunately I moved on to b, basic concepts still hold, it moves stuff from a to b…
Instead of writing to memory, it’s writing to the controller.
Same game, just obfuscated with strange names and preconceived ideas…
Good luck
Ok… sorry, only way I could thief a pic of the controller was from the Amazon add.
I was a bit disappointed, in that absolutely no info came with it, no switches, no pin plugs,
But once you helped me getting the connect from LB with the driver file, I was happy the laser turned on, and one axis moved.
Pretty sure my best solution will be to replace it with a 4 axis controller. Readily available and inexpensive. I can save this one for the 3-D printer kit.
In the mean time, I have soldered a second parallel plug onto the y-axis, …Should be able to test it today, after the enjoyable chore of putting those ittsy bittsy pins on the wires for the plug.
Hoping to make a wooden award for an upcoming pickleball tournament, so feeling a little pressure to
get things moving. I can only imagine the hickups I’ll run into to see results.
The machine is 4ft (X), by 2 ft (Y)… useable space is 35 x 18 inch. so there is quite a leverage on the second motor end of the gantry. Have’nt attempted to measure the play between the ends of the
X arm… the non-powered drag on the motor (Nema 17s) is quite substantial.
Initially used cutter for cutting model aeroplane parts, and was happy with the accuracy in airfoil replication.
This looks like my ‘Woodpecker’ from one of my CNC3018 type machines.
I would think it should run without a problem.
There are schematics, I’ll see if I can find mine.
On my version the labeled X, Y and Z limit inputs were, in reality Z, Y and X.
Good luck
I can see the need for a second motor given the size of this.
I think @jkwilborn has correctly identified the board as a Woodpecker. Looks like v 3.4 but I can’t quite read the silkscreen.
Make sure you’ve reversed the leads for one of the steppers assuming they’re mounted mirrored from one another.
After a bit of searching I don’t see any apparent easy software solution for this. There is a software configuration to allow dual-axis for certain Shield products that have an A-motor and not relying on hardware cloning. I would have to think this could repurposed to allow this for Z but not sure how much modification would be required.
32-bit grbl variations allow for a lot more configurability in general. New features on Atmega328p are storage constrained at this point.
Thanks Gentlemen
Managed to get some effective test cutting / engraving done today, so the soldering and pinning must
have been ok. Now I need to spend time learning the nuances of the program and how to get it to
do what I want.
I’ll give the program some time to sink in, then I think I will change out the controller to something a little more applicable and suitable.
Definitely the re-coding of grbl to try and get the z-axis to operate as a Y axis is quite a bit too daunting
for me at this stage. … so solving issues with mechanical /electrical works better for me.
Can’t thank you enough for getting me through this start up.
No doubt I will be back on the forum… maybe sooner than you want.
Best Regards
Ray
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