Class days, or class hours? Sixteen days is over 120 hours of instruction. If each class is less than two hours long, like 55 minutes, there isn't a lot of projects you can do while teaching the basics. CNC is coding, running a machine, and the cutting variables of the tooling. If it is a basics course, you can really only teach them enough to be PHDs. Gloss over each area with an installed program in a machine to run the schools initials or name in small peices of aluminum.