Closed Frame Machine Design

[ammaratef45]

What do you mean by closed frame ? Is it like a commercial machining centre with an enclosure

Also steppers are very capable - do you need servos?

I need servo cause i want to test control theories - it is graduation project
I need design ready and tried cause my major is not mechanical engineering and i need this task (mechanical body) to be easy
And finally closed frame word is not my own description
I got it from book >> this is the chapter described that part https://drive.google.com/open?id=0B1El2XHLhbSCU1hYX1hTbUZfeVE

Any clarification will be helpful
I really thank you for your reply