I have a problem with my arduino grbl cnc project. I have a big old japanese milling machine which I am going to upgrade with cnc controls. Machines X, Y and Z movements run with hydraulic power, but they are controller with quite small stepper motors. My plan is to replace old stepper motors with nema17 size steppers and control them with arduino based cnc shield. Actual problem comes with Z-axis. There is mechanical brake to hold Z-axis position. So I need to get an control signal from arduino/cnc shield to release the brake when Z-axis is in operation. I am not using spindle control so there is free channel, but how can I change the function of this output?
Hello, and welcome to the V1 community forums.
We’re going to need more details of your machine and how that Z axis brake works before we can give you good advice.
Most of us here aren’t using GRBL on a cncshield, although a bunch of us have used them in the past.
Can you get us more details about your project and what you’re starting with?
As an aside, are you in Japan?
I spent time in Tokyo and then Tanegashima in 2020 to launch a spacecraft, and am going back eventually in 2028 to launch another one.
Hi,
My father bought this machine long time ago as a scrap metal, because control system had been destroyed and it was not possible to control it manually. X,Y and Z movements are operated by hydraulic motors that have originally been controlled with some sort of stepper motors. He replaced old steppers with simple geared dc motors, and operated machine manually just by controlling voltage with pot. meters. And now I have started this project make this machine back to cnc as it has been originally.
I am located in Finland, this old Makino machine is from Japan.
The machine is old and heavy. Inside the control cabinet is a contactor that enrgizes some sort of magnetic coil which opens the brake. Brake unit itself is located inside machine in quite difficult place. So I just need one potential free dry contact.
My plan is to use GRBL with arduino CNC shield and nema17 sized steppers. As this is is just a hobby I am not into investing too much on this one.
What a very interesting project. It will be awesome to see it running again as a CNC.
So, back to your original question about GRBL and cncshield…
The CNCshield boards I’ve used in the past supported the older stepsticks that aren’t UART controlled (e.g. no TMC22xx series), and had a relatively limited current drive capability. That’s probably OK for you, but may be something you want to consider VS a newer system like one of the FluidNC controllers.
I recall that there were spindle control IO available, but it was a relatively weak current drive capability and when I played with this I used an external relay. This may be something you need to.
Let’s start with more details about the contactor that runs your machine’s brake. Do you have pictures and a schematic for how your machine is wired? (in general, not just for the spindle brake)