There are very few freeware programs to view cnc-gcode files. Unfortunately many of them, born as freeware, have been, little by little, trasformed in a business. Business is business, but not all people of the world can afford the purchase of a well done software particularly when it is used in an hobbystic environment.

A very simple but efficient program to see the gcode/cnc files before to start the milling procedure is Basic CNC viewer, a software under development but still useable, with good ideas behind the implementation that can be used to view pcbs and manufacts gcode files before starting the cnc machine.

.