I built a MakeCNC 3 axis CNC mill a few months ago and am driving it with LinuxCNC and one of the cheap “blue” Chinese driver boards. Since I have an EE background (software eng professionally) I made all the board mods and got it going. On some CNC projects I get good results but on many others I get crappy results. Messed with timing, feedrate, etc.
I’m thinking of moving to a Smoothieboard to put all these hassles behind me. The idea of having an embedded real-time computer handling all the motion control is very appealing. I’m trying to wrap my head around a CNC project workflow with a Smoothieboard. Do I put GCode files on the SD card of the board and send commands over a terminal session to have Smoothieboard execute it? How do I jog the axis of the machine to get everything homed and do a touch-off? Is there a GUI app running on Linux that provides a clean front end to do these types of things?
The CNC machine I built is using NEMA 23 300 oz-in motors wired bipolar. I am running a industrial 24 volt, 10 amp power supply.
I have a lot of professional software development experience with Unix and Linux, serial I/O, USB, etc. I don’t have a lot of experience with CNC, GCode, machine setup, etc. Any pointers about setting this up would be greatly appreciated. My first goal is to get a stable CNC machine running.
Thanks for any help, info, advice.
Ken
Imported from wikidot
Hi !
I built a MakeCNC 3 axis CNC mill a few months ago and am driving it with LinuxCNC and one of the cheap "blue" Chinese driver boards. Since I have an EE background (software eng professionally) I made all the board mods and got it going. On some CNC projects I get good results but on many others I get crappy results. Messed with timing, feedrate, etc.
I’m thinking of moving to a Smoothieboard to put all these hassles behind me. The idea of having an embedded real-time computer handling all the motion control is very appealing. I’m trying to wrap my head around a CNC project workflow with a Smoothieboard. Do I put GCode files on the SD card of the board and send commands over a terminal session to have Smoothieboard execute it? How do I jog the axis of the machine to get everything homed and do a touch-off? Is there a GUI app running on Linux that provides a clean front end to do these types of things?
So, you have many options.
As you said you can just drag/drop the gcode file and start it from a serial terminal.
You could also use any number of host programs to talk to the Smoothieboard ( those can also do jogging, homing etc ) like Pronterface, Octoprint, Repetier. Most of those are 3D printer specific but will work fine for a CNC mill. They can also upload files and run them.
You could also connect to Smoothie via ethernet and use the web interface to control the machine.
The CNC machine I built is using NEMA 23 300 oz-in motors wired bipolar. I am running a industrial 24 volt, 10 amp power supply.
What is the current rating for those steppers ? Please note Smoothie can handle only up to 2amps, you need external drivers for more.
Cheers 
Thanks for the rapid reply! I’m getting pretty excited about using the SmoothieBoard.
The motors I’m using are “285oz-in bipolar rating, 205oz-in unipolar rating. 3v, 3A”. If Smoothieboard’s drivers are rated to run 35 volts at 2 amps (70 watts) then shouldn’t be able to run 24 volt at 3 amp (72 watts) pretty well? I’m not too educated on continuous current draw of these steppers. If I am not running them at full speed but at only 30 - 40 inches per minute wouldn’t the current draw be much lower than 3 amps?
Stepper motors are pretty complicated beasts
Long story short, if it says 2A, you shouldn’t use 3A motors ( though you could wire them, and they would work, just at lower torque ).
And steppers actually use more current when not moving, and less when moving at top speed
As I said, complicated beasts