Re: [CAD_CAM_EDM_DRO] confused?

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