I own a ShopBot, been using it for the past 9 years. I recently was asked to give an introduction class to cnc at the local FabLab.

Class went ok except it took a long time to convert the students designs from dxf files to tap cutting files. The CNC at the FabLab runs on Mach3 software which uses tap files. I converted them in class on my laptop using the Aspire software.

Is there a free or low cost software to do this so students could do it on their own?

The point of the training is for them to continue doing cnc work.