Re: [CAD_CAM_EDM_DRO] Re: Machine construction.

> One way to maintain accuracy using a gantry might be
> to raise the table/frame sides high and securely (since you are
> talking 12" z-axis movement, and glide the basic horizontal gantry
> over these so the gantry's "arms" are as short as possible.

This is in fact the way almost all new gantry machines are built. They are
often referred to as 'portal' mills, as the structure ressembles and
archway, which is also termed, a portal. The machine is essentially sitting
on top of a pair of walls.

With big machines, you can literally work around in the work area. But I
thought that things might get a bit squashed if you want to scale it down to
a desktop sized area, as the walls would block your access to the table
quite a lot.

I have seen numerous portal mills specified for a positional accuracy of
0.001mm. The design offers excellent access to the work piece for the work
it's self and can be built to be just as strong, if not more so, than a
standard VMC - I have seen two manufacturers offering the design right up to
the point of machining solid titanium.

Best wishes,
John