How to drive 2 step-motor with 1 output - Xtool board

Lasers
1

Hello everyone,

I’m looking for some advice on the following project.

I have a D1 Xtool 40W laser head which I bought at the same time as the complete machine which was equipped with the 20W.
After a few trials with the 40W, I reassembled the 20W module with accessories on the original frame, so I’d like to use the 40W module on a larger, self-built chassis.

The chassis is 1500mm x 500mm, so I’ll have a working surface suited to my needs.

In the procedure for exchanging the original 20W for the 40W, I need to replace the X-axis rail on which the laser slides, as well as the controller board (and 1 or 2 accessories).

So I have at my disposal :

  • the 40W laser head
  • the original controller board
  • the 2 board left and right limit switches
  • I’m missing the mini-board front/back limit switch (which acts as both), but I’ve found one to order.

My frame will be based on an Openbuilds Acro (which I already have from a previous project), so I’ll have 2 motors to manage the Y axis. And here comes my problem.

The original Xtool works with a single motor for the X axis.

So I thought I’d go for a third-party controller in place of the original circuit, but the way the laser head is handled doesn’t seem “common” according to my research.
So I said to myself “I’ve got the original board, I might as well use it”.

After carefully removing the dissipative foam on the driver, and a quick look under the microscope, it’s marked TMC2208-LA, a very common driver.
My 2 motors that will drive the Y axis are Nema 17, and given their current, I can’t connect them in parallel on the same controller output.

The dissipative foam has been “glued” with a silicone that largely covers the drivers.

In your opinion, would it be possible to recover the pulses from outputs OA1-OA2 and OB1-OB2 in order to control a second driver for the 2nd motor? Is it possible to have an offset in this case?
Or connect the 2 motors to 2 new drivers which would be driven by outputs OA1-OA2/OB1-OB2 so as not to have an offset between the 2?

What do you think?

Thank you.

2

Typical stepper motor drivers are controlled/driven by 2 or 3 signs which are labelled Step, Direction and sometimes Enable. If you can get the Step, Direction and Enable signals to the current stepper driver then run those to an offboard/additional driver that should do the trick.

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3

as you can see, silicone poses a problem. And I have never undertaken to remove this kind of protection over cms.

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4

That ESP32 pins are all nice and exposed so if you have an O’scope and know how to use it you can drive the axis of interest and look for the pins which are used to control Step and Direction of the driver chip.

5

after about 3 hours of scraping with a razor blade, then cleaning with trichloroethylene, I managed to remove most of the RTV silicone. I did, however, damage a cms capacitor.

Blue Pin: ENABLE
Red Pin : STEP
Yellow pin : DIR

I have a craftsman specializing in micro-soldering 1 hour from my home, and I’m not equipped accordingly, so I’m going to take it to him and ask him to make me a tap for the additional driver.

Thanks for your advice.

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6

I would follow the traces to a component or a via, ohm it out and then wire a 30awg wire to each then then to a header glued to the edge of the board where a connector can be installed. $0.02