Milling Machine – Circuit Boards

Overview

We are using the Modela MDX-20 and cad to mill out circuit boards.

Step 1: Setting up the machine and board

Place a sacrificial layer like an old PCB stock sheet at square(1,1) with double-sided tape (make sure it is flat, otherwise, the board will not be milled properly).

Place the PCB sheet you are milling at square(2,2) also with double-sided tape.

You will be using a 1/64 bit for milling the traces, and a 1/32 bit for cutting the board.

So start with the 1/64 bit, loosen the screws and place the bit in, tightening just enough, but not too tight :)

In terminal, type: move 1 1 (that moves the x and y, respectively)

On the machine, use the up and down button, to adjust the z position. Get the tool as close as you can and then manually lower it (by untightening screws, letting the bit touch the board, and then re-tightening the screws). This is how you zero the bit.

Step 2: Uploading file and changing settings in cad for milling

You can either upload a png or a cad file.

Using a png file

    set z min to -.005
    set z max to 1
    set x min and y min depending on the location of your board.
    set contour to -1.
    set the tool diameter to 0.0156 (that's 1/64)
    set xyz speed to 4.

Contour and save the file (don’t send to machine).

Using a cad file

some uncommenting to do(these are usually towards the bottom of the files:

     make sure that dpi is set to 500: dpi = 500 # high resolution for machining
     make sure that this line is uncommented: cad.function = pcb.board

and then make sure all the other settings mentionned for the png are the same.

Screen shot of cad window with the settings for milling

Step 3: Sending the file for milling

Since sending the file from cad does not always end up with a complete board, we save the file and then send it through terminal.

cat myFileName.rml > /dev/ttyS0

Step 4: Uploading file and changing settings in cad for cutting

      set z min to -0.065 (width of the board).
      set z max to 1
      set x min and y min depending on the location of your board (same as when milling)
      set contour to 1
      set the tool diameter to 0.0312 (that's 1/32)
      set xyz speed to 0.5

We left nz at 1 and the modella was just fine cutting the board out with one pass at that speed.

Contour and save the file (don’t send to machine).

Screen shot of cad window with the settings for cutting

Step 5: Sending the file for cutting the board

Same as with sending to mill, go through terminal to be sure the Modela completes the traces.

cat myFileName.rml > /dev/ttyS0

PDF for download

TutorialMillingMachineCircuitBoards

External Links