CNC PCB calibration
Posted: Thu Sep 22, 2016 11:39 pm
more along the lines of Pauls posts but with my CNC for PCB isolation milling.
I finally got the Microscope set up so I could do some measurements of some feeds, speeds and depth of cut calibration cuts using different bits
Bits Im using are 20 Deg Engraving VBit
0.6mm PCB Cutter
0.4 end mill
You can see the quality of cuts vary between the types of cutter, so is a trade of using the Vbit for the very fine work which give a ragged cut as opposed to very clean cuts for the end mill and PCB cutter. (the board is easily cleaned up with fine emery board or wet n dry so is not an issue)
These two images below are for the bit width calibration within the software, i.e. bits are not normally the size they are suppose to be so the diameter is tweaked in the cutting software, when the upper traces = the lower gaps it means that the size in the software is correct. Smallest track size on Left of screen is 1mil (1 thousand of inch) also I don't yet have my stepover dialled in and hence why I have some copper artefacts left because of the difference between the advertised cutter size VS calibrated cutter size.
So with the bit diameter calibrated it is showing me that minimum trace is 1mil and min clearance is 12mil This was done with a 30Deg VBit The calibration test starts at traces 1mil up and increments by 1 up to 25 mil this is done on both Traces and Clearances.
Feeds, Speeds and Depth settings.
These are calibration cuts at different feeds and depth, ones showing is for 0.050mm depth of cut, again the ragged edge is VBit engraving bit. Measurement ruler is in 0.1mm increments.
So with my 20Deg Vbit I'm getting ~0.2mm width of cut
Some SMD foot print tests
I finally got the Microscope set up so I could do some measurements of some feeds, speeds and depth of cut calibration cuts using different bits
Bits Im using are 20 Deg Engraving VBit
0.6mm PCB Cutter
0.4 end mill
You can see the quality of cuts vary between the types of cutter, so is a trade of using the Vbit for the very fine work which give a ragged cut as opposed to very clean cuts for the end mill and PCB cutter. (the board is easily cleaned up with fine emery board or wet n dry so is not an issue)
These two images below are for the bit width calibration within the software, i.e. bits are not normally the size they are suppose to be so the diameter is tweaked in the cutting software, when the upper traces = the lower gaps it means that the size in the software is correct. Smallest track size on Left of screen is 1mil (1 thousand of inch) also I don't yet have my stepover dialled in and hence why I have some copper artefacts left because of the difference between the advertised cutter size VS calibrated cutter size.
So with the bit diameter calibrated it is showing me that minimum trace is 1mil and min clearance is 12mil This was done with a 30Deg VBit The calibration test starts at traces 1mil up and increments by 1 up to 25 mil this is done on both Traces and Clearances.
Feeds, Speeds and Depth settings.
These are calibration cuts at different feeds and depth, ones showing is for 0.050mm depth of cut, again the ragged edge is VBit engraving bit. Measurement ruler is in 0.1mm increments.
So with my 20Deg Vbit I'm getting ~0.2mm width of cut
Some SMD foot print tests