Re: confused?

I would think that on such a long part, one could have a 21 ft by 21
foot work envelope and just move the part each time the machine
finished a section.

But then, I don't have Boeing's money to throw at such a machine.
Heck, I couldn't even pay shipping on the raw part !

Dave

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@p...> wrote:
>
>
> cadcamclub wrote:
>
> >Good day everyone,
> >
> >Trying to understand an article from the Techno-Isel site where
they
> >described configuration of a mill needed to machine a wing 105'x21'
> >____________________________________________
> >http://www.techno-isel.com/Tie/Boeing_5.html
> >
> >In theory, wing spars and wing skins made in one continuous
> >piece..... require metal measuring up to 105 feet by 21 feet. ...
A
> >standard CNC mill has a fixed length arm extending over a table...
> >the spindle would have to hang over 12 feet from the column,
losing
> >precision and strength.
> >____________________________________________
> >It appear to me that a spindle overhanging 12' from the column
(12'
> >throat) have a work envelope of only 12' in that direction? So, is
> >Techno-Isel confused or is it me who is confused?
> >
> >
> >
> The 12' overhang gets to the middle of the part, reaching across
the short
> dimension of the part. The work would have to be turned to do the
other
> half. The bed of the machine would have to be at
> least 105 feet long. This kind of work is usually done on a gantry
bed
> mill, which has an incredibly long bed, and pillars on each side of
the
> bed at the middle. there is a gantry spanning the pillars, and the
milling
> head (or heads) are mounted to the gantry.
>
> There are other designs, such as a fixed bed for the workpiece, and
the
> gantry is mounted on ways straddling the work, so it can reach any
part
> of the work.
>
> Jon