u/Dear_Term_3632

I have been designing a CNC mill for milling aluminium and wood. What are some design physical challenges that most designs encounter that I can try to design out? What is the best option for stepper motor drivers? I've designed it for 2 stepper motors that move the spindle assembly, whereas most designs have 1 and the bed moves rather than the spindle assembly, is this a good idea? I realise a moving bed is easier and cheaper but do I have to change it to that? Thank you.