I am going to start building a CNC machine this year, have done quite a lot of research so far and for the electronic side of things and I intend to use 3 gecko drive controllers, servo motors and this http://www.campbelldesigns.com/breakout_board_plus.htm interface board.
The thought that is troubling me now is whether to build a CNC router, or CNC mill. The only CNC machine i've had experiece using is http://www.suregrave.co.uk/2516.htm <--- this router which they have at my school. I have got used to using this machine now, so I wouldnt want the thing I build to have a lower spec than this.
Somthing I like very much about this router is the size of the table (25" x 16") - (my machine would have to have a work area at least as big as this) but the thing I dislike with the school machine is the speed, - the top speed of 3"/sec is not very fast, and when milling hard plastics like polycarbonate I can only run it at about 1.5 inch/s @ 0.5mm per pass. It is not very powerful and cant do more than 1mm per pass even in soft plastic. I'm guessing that this is because it has rather weedy stepper motors but I could be wrong.
The types of materials I want to be able to CNC will be mainly plastics such as HDPE and Polycarbonate, composites like carbon fibre, and 6061 or 7075 T6 ali.
It is unlikley I will need to machine steel or similar metals.
I suppose my question is, If a built a CNC router based on this design - http://www.suregrave.co.uk/images/cipher2516.gif and used a decent sized servo motors on each axis, would I be able to machine aluminium with it and would I be able to machine plastics faster than I can do at the moment on the school machine ?
As for the depth/thickness of the materials, I will not need to machine any materials thicker than 30mm.
So..... should I go for a router or a mill?
Any thoughts, comments, opinions etc on this topic would be apricieated.
Dominic
http://www.ukrobotics.com