CNC Welding

> Just wondering if anyone has experience with MIG welding with a
> gantry style CNC system.

No experience (yet) with CNC, but more than a little with full automatic
welding setups.

First place I would look, for ideas anyway, is

http://www.bugo.com/

(not a shareholder, just a user of some of their gear). I would be happy to
answer any specific questions you have, but I would suggest direct email may
be more appropriate. Alternatively, you may want to post the same question
on the newsgroup sci.engr.joining.welding

> I am wanting to set up a MIG on my profile cutting table - 3500mm x
> 2000mm. I am wanting to know possible pit falls to look out for, and
> any 'lower' cost solutions for interfacing and sensing the weld.

One possible pitfall is the work moving while welding. You want to get the
fixturing right, for a run that length.