There are 2 methods how to apply solder mask on our PCB. First consists in use of solder mask dry resist film. Second - we can use a cheap special solution primary used for PCB repairs. Both methods should be successfully applicable to our project. Another modification of config file is necessary for this step. Copy existing config file fpcconvert.config to fpcconvert.sm.config in project directory. Next, change/add following lines:

ADDED_PAD_RADIUS            = 150UM
FEED_RATE_MILLING           = 200
USE_RASTERIZATION           = true
RASTERIZATION_INVERT        = true
RASTERIZATION_FILL_POLYGONS = true
RASTERIZATION_TOOL_WIDTH    = 250UM
S_LASER_INTENSITY_COMMANDS  = true
PROCESS_PADS_ONLY           = true

                            

ADDED_PAD_RADIUS increases radius of all used pads for 150 micrometers. Feed rate is increased to 200 millimeters per minute. Setting RASTERIZATION_TOOL_WIDTH to 250 micrometers gives 4 lines per millimeter. PROCESS_PADS_ONLY tells fpcconvert that no connections between pad will be drawn. To solder mask creation, fpcconvert uses component's pads instead of solder mask layers as they are defined in FreePCB. The command syntax is similar to process described in the section called “Generate top and bottom g-code files for milling”. Bottom side:

                  

./fpcconvert.sh -c examples/niveaDice/fpcconvert.sm.conf -xm examples/niveaDice/niveaDice.fpc -fgcode -o examples/niveaDice/niveaDice.bot.sm.ngc -lbottom

                        

Top side:

./fpcconvert.sh -c examples/niveaDice/fpcconvert.sm.conf -m examples/niveaDice/niveaDice.fpc -fgcode -o examples/niveaDice/niveaDice.top.sm.ngc -ltop