Well, this was an interesting experiment.
I’ve been playing with the CNC USB Controller software and found a function to “Import Text”. The function opens a window that allows you to type in any text, in just about any TrueType font, and have it convert to G-code (and also DFX code). There are also some rudimentary font control and alignment options. The “Advanced” button allows you to control aspects of the cutting including the number and depth of successive passes taken by the machine. With the text set at 72 point (?), the resulting image (and g-code limits) is just under 40mm square.
CNC text input
CNC text cutting path
I tried some test cuts in plastic but soon found that no matter what feed rate I used, the end mill bit would gum up with melted plastic. I tried various size mill bits and at different feed rates but the results were much the same. A blob of melted plastic would gradually accrete on the end of the mill. The mill would then ‘smear’ the plastic, blurring the cutting contour. In addition, I had to pause the program regularly to remove this hard plastic build-up.