[EMAIL PROTECTED] wrote: > > I do wonder how accurate the positioning is for a 50 foot table > and how repeatable the positioning would be after a long move. > > That would still be one impressive machine. Well, this machine was supposed to have a 50 foot glass scale. Depending on the architecture of the machine's frame, and how close the scales were to the spindle, it could vary a lot. For instance, if the home position was at one end of the 50' scale, and you were way out in the middle of the table, then you'd be doing your cutting 25 feet from the home, and any differential thermal expansion between glass and iron would shift everything around. If the scale was constrained to the iron table, then there's be less quirky shifting of coordinates.
Also, on a 50' machine, there is an opportunity for orthogonality errors to be magnified to a huge amount. The bottom line is you don't make swiss wristwatch parts on a machine with a 50 foot table. You make wing spars, or boat keels, or hatches for space shuttles, and the tolerances on these parts take into account the limits of precision such a large part can be made to. Jon ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
