[bobJandal]

Greetings.

I am looking for ideas as to why machines are so commonly made with the worktable moving in x,y, instead of it being stationary and the spindle moving in x,y,z.

Downsides I see to this approach are:
- a much greater load to be moved on the table axes, which will vary as the workpiece varies.
- much larger area required for the machine, since each axes length = travel + saddle, and in the case of a moving table, saddle can be quite big, relative to travel.
- inability to mount a workpiece that is bigger than the worktable (well, conveniently, anyway).

I am sure that those who make these machines (such as Haas, Cincinatti) know far more about these things than I - can someone help me understand, please.

Thanks.

Tom.