Help for a CNC setup, please

[libory]

Hello all, I' m making my first CNC to cut foam. I'm doing a research about it and I have the hardware in the way (post).

I want to use MACH3 with my CNC. I've installed and saw the demo and I have one problem I can't understand.

How do you calibrate the axis with the software? I read about it and not sure if I'm sure to understand. do you play with the steps the motor does and the movement the axis does in mm.?

Another cuestion please, if this is right if I define the 0.0.0 or center in some point of the table board and imagine I'm cutting some piece of foam and in a half way there is a power cutoff.... does it mean I need to recalibrate all again? do I need to tell the software where is the 0,0 again? Because It doesn't have any feedback from the motors so the software doesn't know where the motors position are.... I guess.... I'm a bit lost...

If anybody can spend a few minutes of your time I would apreciate it....

Thanks a lot....

[jsheerin]

To calibrate your movements, there is a parameter for each motor you are running in a mach3 screen - motor tuning. You tell it how many steps it takes to move a unit. Either an inch or millimeter. If you are off a little bit, you can adjust this number. So you can calculate what you think you should need, make a cut or movement, measure the result, and fine tune the number.

I'm not an expert on the power off, but I had this happen to me the other day. My power strip was overloading and shutting down in the middle of a cut. I basically did what you said - rezero the machine and then start again. Actually I found a line in the program that was close to where I stopped and started there. This worked for me because I was just surfacing my spoil board - a flat piece of material. In other cases it might be hard to rezero as you might have cut off your zero reference.

[Hirudin]

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How do you calibrate the axis with the software?
...

There is a tab in Mach3 called "Setup" or something like that. In there (on the bottom left) is a button to set the steps per unit, the button is probably labeled something like "calibrate axis".

What you do is get something with a known exact length*, "zero" the machine on one end of the block, move the machine to the other end of the block, and use that to calculate the number of extra/deficient steps.

*A gauge block is probably ideal, but a 1-2-3 block would probably work, or in a pinch a parallel, as hoss2006 uses in this video...
http://www.youtube.com/watch?v=OTHdgk12EcI]Mach 3 Steps Calibration

Note: hoss2006 doesn't use the "calibrate axis" button in this video, I'm not sure why.

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Another cuestion please, if this is right if I define the 0.0.0 or center in some point of the table board and imagine I'm cutting some piece of foam and in a half way there is a power cutoff.... does it mean I need to recalibrate all again? do I need to tell the software where is the 0,0 again?
...

Typically you'll zero to your part. Usually you'll pick a corner, say the bottom-left (or south-west) corner, and zero your tool there. If the machine quits during the job it would probably be a good idea to reset the zero. If the original zero position is no longer available (it's cut off or something) then you need to zero to another place on your part. This will probably also mean you need to run the post-processor of your CAM program with the updated zero position.

[Al_The_Man]

Another cuestion please, if this is right if I define the 0.0.0 or center in some point of the table board and imagine I'm cutting some piece of foam and in a half way there is a power cutoff.... does it mean I need to recalibrate all again? do I need to tell the software where is the 0,0 again?

Probably a good thing to view the on line tutorial video's if you have not already.
If you had stored your panel position in a work offset table, G54 - etc you would only have to home zero.
Then go back to your part zero via G54 and if necessary run the program through to the line number that it quit at and restart there.
Al.

[jsheerin]

If you're replying to me, I have viewed the tutorials. I don't have my home switches set up yet, so I couldn't do that (they're on there as limits, but I have dual x motors, so I need to get them aligned correctly before I can use them to home). I'm in the 'using my machine to finish itself' stage at the moment.

Thanks,
John