Z-Axis - can you break it out to external stepper driver?

For me, the Z axis on the controller board seems underpowered when you add anything larger than a router - a spindle for example. its a lot of weight on the axis. I’d love to just break it out to a separate driver and have a higher voltage and current and a bigger motor on that axis. I would just need access to the gnd dir step and enable pins. I’m looking at the board and not having a great deal of luck seeing anything. Anyone have any thoughts?

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This might not be the answer you want…

Take a look at the pinout of the Z-axis driver IC. You can tack on a wire on the Dir, step pins, GND is board ground, lots of places to pick that up. It shouldn’t be too hard to hook up a geckodrive (https://www.geckodrive.com/g201x.html) , and I think I’ve seen a couple people that have done so. All that said, if you’re going to do one, you may as well do the others, why not replace the whole controller board assembly with an offboard GRBL board (it’s just an arduino, then add a GRBL breakout board, here’s how it lays out https://blog.protoneer.co.nz/grbl-arduino-g-code-processor-pin-layout/ ) and separate axis drives for all of them?

On the other hand, replacing the Z axis with a screw drive instead of the belt drive might be a better first step - the belts stretch, etc and will do that a lot more with more weight on the Z axis like that. There a link over here: Z axis Ball Screw Conversion Kit . I’m using this one, as are several others here, and they seem to be working pretty well. I’m not using a different spindle (not yet, anyway), but it’s pretty robust.


Hey first and foremost, thank you so much for the reply! so nice to have such a helpful response!

you are right, looking at the datasheet - (I found one here: http://static6.arrow.com/aropdfconversion/c0ad1fc5aed11355bcdf587c1ead6a8f168e0e77/81324476675604a5977-datasheet.ashxlaen.ashxlaen.pdf) I could hook something up, but it would be tough to make such small patch to break out the wires.

I thought about replacing the board completely, but I wonder if things like the geckodrive or Arduino alternatives would work with the carbide motion software and the probe?

I actually am building a z upgrade, but the stock z motor doesn’t even have enough force to turn the screw with the spindle on there (2.2KW). this is the start of the design using prototyped 3d printed bits, it uses TR12x2 rods

I could go get the conversion kit, and I might, but I still think I am going to have the same issues with the underpowered Z.

Here’s my thoughts right now:

  • buy the z upgrade - motor likely still underpowered
  • upgrade the electronics - might lose the use of the probe (or carbide motion?) and lose the support of carbide3d
  • If I switch from Carbide motion to universal gcode sender - does the probe still work?

Ideally I want a screw based Z with a higher current motor, with carbide motion and a working probe. Its a real shame carbide3d didn’t break the motor pins to allow for easy expansion. I know the sparkfun guys did when they did their carbide3d board.

Yes, the Carbide 3D Probe will work with any software — it’s just a closing of a connection.

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Ok Will so then that clears things up a bit.

Maybe the answer is just to get a G540 (https://www.geckodrive.com/g540.html) and something that runs GRBL and then take the motor current out of the equation. I guess if its running GRBL 1.1 then the carbide motion software may even still work - if not I will have to give UGS a go.

Final thing to work out is what the GRBL control bit is going to look like - I guess these are a couple of options:

I’m thinking I go with the db25 shield with an uno and try that. I was trying to stay as faithful to the shapeoko design as possible with my Z screw upgrade but looks like I’m going to lose the whole control system :open_mouth:. not much I can do though if I need more power.

The sparkfun board is just a version of the previous shapeoko board. It doesn’t output the raw direciton/step stuff, it has onboard drivers, though it does have some convenient pads for picking them off.

UGS works fine with the carbide probe - you have to give the probe module the dimensions of the probe, but other than that, works great.

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Man you should do a tutorial on using UGS with a shapeoko and probe, it would be so useful!

The sparkfun has the breakout ports in the middle that are perfect for what I’m doing here or for anyone that wants to take a single axis out to an external driver.

As it happens I just ordered the gecko and everything I need to make this work and I basically spent hundreds of dollars because Carbide3D didn’t add 4 copper traces to their PCB :frowning: :sob:

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