Starting French MPCNC

Hello guys
I’m french and i starting a MPCNC project , with covid-19 , it’s time to finish …
All the parts is ok , I begenning the software …
I use a ramps1.4 & and Arduino mega2560, I have uploaded the lasted version of marlin avaible on the dowload section from the website, But I don’t know to change variable step/mm and create a home ?
I can move but on the screen XYZ are ???
Can you help me to progress ? Thanks

Don’t worry, the question marks are normal. Marlin is originally 3D printer software and expects every operation to start by homing to limit switches, because the bed is always in the same place. For CNC operations the top of the work piece is in a different place for each job, but you want it to be zero, not some fixed ‘home’ location. Just drag the router to wherever you want zero to be and turn on the machine (or use the custom function to zero the axis). Unless you do tool changes, homing isn’t really necessary.

To change the steps/mm, edit Configuration.h and reflash the arduino. The setting is called DEFAULT_AXIS_STEPS_PER_UNIT, and it’s about line 720 in my file.

ok Robin , thanks for your answer,
I have changed the steps/mm values to 100/100/400 and it’s ok, i have good results

When I start the arduino , I have this message :
414 bugfix is there an error ? can i resolve it ?

I anderstand the start position is the Home, but, when I start my arduino the position is X=? Y = ? Z =?
what can I make to have the start position is automatiquely X=O Y=0 Z=0 ?

thanks

“414 bugfix” is the firmware version number. It’s not an error message.

I don’t think there’s an easy way to make the question marks go away without homing, but once it’s running, it will display the position.

ok, if i understand correctly, it is necessary to make a manual homing at each start ?

No, homing is not necessary. You can do everything relative to the start position. Lots of us have machines with no limit switches, where homing is not possible. We just live with the question marks as they don’t cause any problems.

ok, a friend makes one MPCNC ( 4 years ago ) and he help me too.
for test, He sent me a file to draw a car , this file is ok with his machine, but when I start his file on my machine, The Z axis go down and don’t stop. I’m should stop manualy the machine.
Do you have an idea why this file work whith his machine and don’t with mine ?
Is there possible troubles with differents marlin ?

  1. The machine will assume wherever you start is 0,0,0. You can change this in the LCD. I think it says, “Set Home Position”. Maybe someone with an lcd handy can confirm that? You do not need to home the machine, but you do have to set that position. The brute force way to set the origin is to just restart the machine where you want the 0,0,0.

  2. Just so we can check out the machine, start with the test crown from milling basics. That is the fastest way to make sure the machine is basically working. Then you can run the car code.

oups , OK I anderstand for the XYZ home , I restart the machine to have .
I tested the crown file, it’ s ok
well done

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Well done wonderful machines