CNC Mill

Contents

• Saftey
• Preperation
• Circuit Design
• RML Files
• Machine setup
• Fix Board
• Setup Machine
• Selecting Tool to Change
• Zero X-Y Axis'
• Z-axis Origin
• Test Cut Depth
• Fabmodules
• Machining
• Machine Reset for Outline
• Outlining
• Cleanup

Saftey

• Do Something

Preperation

Example: Circuit Design - TinyFABISP

You will need to create two separate RML files, one for the TRACES, one for the OUTLINE.
This is because they will require different cutters and slightly different settings. Traces is what we will mill out for our circuit, then outline is what will happen last to cut the board out from the board material.
Create/import your TRACES or OUTLINE in photoshop/gimp/etc. One good way to do this is to have a single illustrator file with two layers, one for TRACES, one for OUTLINE. Then you can simply save out each layer in turn as a separate .png file (with a high resolution of 1000 dpi).
Before saving, check that your images are the correct size for your circuit board (in mm, not dpi).
Note: whatever is white will stay, black will be machined. You may need to invert out image to get the white lines and black background.
I.e. White: material left behind will be the conductive copper (tracks) Black: will be the space around traces, some of this will be removed (not all).
(So for example, your board outline design should look like a black line around a white box)
You can orient the circuit board based on the orientation you want to cut it on the mill, landscape or portrait.
Quality Note on Illustrator : export as, on quality, select other and manual 1000 dpi
Save as YOURNAME traces and outline.png Then ALSO save as YOURNAMEtraces.png Then ALSO save as YOURNAMEoutline.png

RML Files

What are file types even?

On Fabmodules :
Output format: select Roland mill (.rml) (note MDX40 is similar to our machine and we can use this) Process: PCB traces (1/64) which is about 0.4 mm (so 1/32 is about 0.8mm) Input the settings as outlined below. Note that the zjog is the safe travelling distances above the board. Note also, that if in doubt, it’s best to mill the air above the board than to mill too far down. Or you can always use soft foam to try it out.
Terms: Stock thickness - thickness of the material e.g. 1.7mm Cut depth - the depth the tool will cut in one go. E.g. 0.6 will take 3 passes to cut 1.7mm

Setting up the Machine

Fix board

You'll want to start by washing your hands, you want to keep the board as clean as possible to avoid defects occuring.
Put the double sided tape on the back of your board, making sure that it doesn’t overlap and try not to touch the sticky bit.
Then stick your board onto the wax spacer (without the wax spacer the mill won’t reach the board as it’s too high). Overlap the board very slightly with the edge of the wax block to allow us to remove it afterwards. Clean Board again incase of residue.

Setup Machine

Selecting and Changing Tools

Know what tool is in what cartridge (1-6).
We need to come up with a good solution to this knowledge problem.
Press MENU until you reach the TOOL menu, then use the jogwheel to select tool the tool you want (1 or 2 typically). Press ENTER when selected. The machine will now switch tools.
If in doubt, check by measuring, or asking.

Zero X-Y Axis

Origin is front left of the cutting bed.
Move X and Y with spin knob.
Set origin with: origin + axis
Allow some space around the circuit board - don’t set 0,0 to be right in the corner of the copper board.
Press MENU until you reach the user menu, then press X/Y/Z to get the tool closer to the board (for easy sighting), then use the jogwheel to move the tool closer. You can press RATE to move more slowly/quickly to get the tool quite close to the board.
Then press X, use the jogwheel to move it to where you want your X0 to be, then press and hold ORIGIN to set this as your X0 origin value.
Then do the same for Y.
Note: you would do the same with Z, if we didn’t have a Z0 sense tool. Note that it looks like a gold stethoscope and can be plugged into the Z0 sensor/rotary connector at the back of the machine. NOTE: when setting Z manually, we have found that setting z0 as approx 0.03mm below the actual surface of the board works well.

Z-axis Origin

Get out the Z0 sense tool. Clean Z0 Tool
Remove rubber cover on socket. Plug into socket, with white arrow facing forward.
Place puck (black side down) on center of copper board.
Careful:

Test Cut Depth

Note: to test the depth of the cut, you can turn spindle on/off, by pressing SPINDLE and hold.
You can then rotate the jogwheel to increase the spindle speed.
Then you can press Z and move this down slowly with a rate of x10 onto the board.
Safer to leave spindle running on Z up in case of user error
If you want to inspect the piece, Press MENU until you reach the move menu, then go to VIEW this can be used to move the table close to the front.
If you want to, return the tool to the user XY position:

Fabmodules

Then goto fabmodules.org and use the settings as outlined below. Fabmodules can be used to control a range of machines independently from the machine’s own software.

• Speed 4mm/s
• x=y=z=0
• xhome=yhome=zhome=0, or you can make zhome=2 if you want it to stop just above the piece.
• zjog=2 (zjog is the safe travelling distance above the board - This needs to be above 0)
• Cut depth=0.1mm
• Tool diameter=0.4mm (1/64”)
• Num of offsets=2 (-1=remove all..up to 4...this is like ‘padding’ like on html)...1=only 1 milled layer around your trace 4=4
• milled layers around your traces.
• Offset overlap=50% (is overlap between the offsets from the ?)
• Path error=1.1pixels
• Image threshold=0.5

Machining

Then open VPanel for MDX-50 software.

Machine Reset for Outline Cut

• Select outline cutting tool.
• Send to User Origin
• Check Z-axis cutting depth origin - reset if needed

Outlining

Repeat machining steps from earlier converting PNG to RML and sending to machine - check cutting depth

Cleanup

Sand down the rough edge of the board
Clean the top of the board with soap and thin wire-wool (pressure is important here, we don’t want to remove traces)

Make it shiny :-D