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--- pcbetching [2022-02-01 17:17] – jtdburton
+++ pcbetching [2022-02-12 17:09] – jtdburton
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 There are a few approaches to this process. These instructions will assume you're using KiCad and FlatCam (both open source) for PCB design and file manipulation.
-Make sure to design your board with nice thick traces - start with at least 0.8mm and then try going smaller once you've got the hang of the masking and etching process. Try to fit everything onto a single-sided board if possible, as this means you can use the laser cutter for machining which is currently much simpler than the CNC (see notes under "Cutting" below).
+Make sure to design your board with nice thick traces - start with at least 0.8mm and then try going smaller once you've got the hang of the masking and etching process. If you can fit everything onto a single-sided board, you might be able to use the laser cutter for cutting and drilling; if not, you'll need to use the CNC (both options are detailed below).
 The first thing to create is your trace file. In KiCad, go to File - Plot. Set "Plot format" to "SVG". Select your copper layers ("F.Cu", "B.Cu", or both). Tick "Plot Edge.Cuts on all layers" (this is to help you align the mask to your cut board), make sure "Drill marks" is set to "None", and click Plot.
 Open your plot file in your vector editing programme of choice and invert the colours (assuming you're using negative photoresist film - see notes under "Exposure" below). In Illustrator, the easiest way to do this is to create a white filled rectangle slightly larger than your board, put it behind your traces, and then select all and click "Edit" - "Edit Colours" - "Invert Colours".
+===== Cutting (CNC)  =====
+The CNC is a bit tougher to get going on than the laser, but it opens up a lot more options, most notably two-sided boards.
+Start by going back to KiCad's Plot dialogue. Make sure "Edge.Cuts" is the only layer selected. Select the Gerber plot format and click Plot.
+Now click "Generate Drill Files...". Select "Excellon" as your file format here, and tick "PTH and NPTH in single file". Make sure the "Absolute" and "Millimetres" options are selected and click "Generate Drill File".
+Open up FlatCam and use File - Open Gerber to load your edge cuts and File - Open Excellon to load your drill plot.
+It's a good idea to go into the "Options" tab at the left here and make sure "mm" is selected as FlatCam defaults to inches.
+Double-click the drill plot in the file list. You can skip over all the CNC settings here, just enter your tool size under "Mill Holes" (a 0.7mm bit is usually good) and click "Generate Geometry".
+Now go back to the "Project" tab and double-click the new drl_mill layer.
+Enter your CNC settings here. Typical values will be around -1.6mm cut Z (this is the thickness of your board), 1mm travel Z, 200mm/min feed rate, and 10,000 RPM spindle speed. Click "Generate".
+Back in the "Project" tab again, you'll have a new .drl_mill_cnc layer. Double-click this, and enter "M30" in the "Append to G-Code" box (this is an "end of program" signal, and LinuxCNC won't process a file without it). Click "Export G-Code". Grab the SD card from the CNC laptop and save your gcode file on there with the file extension .ngc.
+The procedure for the edge cuts is similar. Double-click the .gbr layer in the Project tab, enter your tool size under "Board cutout". The Margin setting is best left at 0. The Gap size setting can be used to add a few points around the  edge of the board where it's not fully cut out from your stock, so it stays anchored in the CNC router. 4mm tabs are a good size. Once all these are set, hit "Generate Geometry". Then go back to the Project tab, double-click the new .gbr_cutout layer, enter your CNC job parameters again, and click "Generate". Back to the Project tab one more time to open up the .gbr_cutout_cnc layer and export the g-code.
 ===== Cutting (Laser Cutter) =====