Mad cap idea ... Will it work ?

Ive been toying with the idea of replacing my Y axis steppas with nema 23’s rather than 17 for more grunt.

Thats the easy bit…

Now comes the complex section.

Im already running dual ends on X and Y

Now im looking to add an additional set of end stops to the back end of the X Gantry.

This is to the facilatate Quad dual end stops on x all setting X Min and 2 X max

Once i can get these working on spare GPIO pins i am looking at adding a 2nd X /Z gantry !!!

This would be parked at the right when using the First Gantry and Z axis. Then on a tool change it fires a bank of relays to then enable the 2nd gantry with 2nd Z axis.

This would then home against the back of the first gantry that would be parked to the extreme left.

As i know the distance between them i can then zero in the 2nd gantry at a known point in space and carry on the Job now with a complacently different tool.

Then when done i can switch back to first gantry by homing gantry 2 to the right again , relays fire etc now you have the other gantry back in play.



Hopefully that makes sence any thought appreciated.

Am i mad to even consider attempting this?





2nd machine…easier and more useful probably about the same price. No comment on the 23’s.

I could see two gantries to make two identical parts in one job, but independence between the two really is so much easier with jusst a second machine, and pretty close to the same cost as trying two gantries.

Oh, and it’s you’re not your… :slight_smile:

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But moving a part to laser engrave post milling can end up tricky with the tool change and getting everything to line up up again is a pain in the … partly due to different tool offsets .

You can leave them both mounted and figure out the offset once and after that it is simple. Like using a dual extruder.

I don’t really see the point of this, but why not.

I’d rather do some interchangeable tools if I were you. At the end of a job the gantry would move, drop the tool and then pick up the other one and calibrate Z height again.

Seems to make more sense to me.


Ultimaker (I think) did something like this. They had two X carriages that would share the Y and build plate. It made sense for them because they were switching between materials constantly. Is there a benefit to changing tools often with CNC?

If this is interesting enough for you to do it, I think it would be fun to see. I would start by going back to one endstop and one motor driver per axis and use the extra endstop and driver port to add an axis. But then you’d have to have Marlin know about the endstops and that it should use axis A after that.

It’s certainly an interesting problem to solve. I’m just not convinced it wouldn’t be more complicated than it’s worth. But let’s just imagine it was done, and the hardware and software was easy to install. It might still be a nightmare to tune, but I can see the appeal.

Haha. “Your nuts” has a very different meaning than “you’re nuts”. Not sure exactly what I’d be voting for…