Both of them are used for making tenon of aluminum window and door profile, the different between is as following:
KT-313 F End Milling Machine  is with 5 cutters, one vertical cutting blade and 4 milling blade, the milling blades can move backward and forward, up and down, so that it can make different shape on aluminum profile as following:

Blades of KT-313CM End Milling Machine is designed according to customers' processing request, it can process some special shape that KT-313F End Milling Machine can't process like this :