Thank you for this, this is tremendously helpful!!!To demonstrate the principle on a straight run fillet all you would need is a rail, carriage and some sort of drive.
Either a length of cheap linear rail from china or make your own up with a few bearings and some lengths of tube.
Something like a adjustable dti base to hold/position the torch.
Drive could be as simple as a length of rope in a loop going around a pulley at each end, small dc motor with a cheap speed control, put a wheel on the end of the motor and wrap the rope around it a few times.
Micro switches at each end of the rail. Tap into the torch trigger wires. From the start position giving the carriage a small push by hand will be enough to ping that micro switch which would start both the drive motor and the welder at the same time. When it gets to the far end it would stop.
You can show that to the management and tell them that if they give you the budget to buy some stepper motors, some belt drives, some rail and pay you for the hours to put it together then all the feed speeds, start welds etc can be programmed for each job.
If you need to make custom tracks for welding around curves etc that might need a bit more thought though.
A welding plant that can interface to cnc is not a cheap item (unless you find a used one) but aside from arc failure detection most functions could be computer interfaced without too much trouble.
For anything other than welding straight runs maybe consider a robotic arm. I was offered a abb unit with a 1600mm reach for £3k a couple of months back.
Mint condition with all the bits. You would still need to interface the mig somehow and it would take you a few hours to teach it.
You would also need to jig the parts so they were inserted in the same place each time but depending on the tolerances required that might be simple enough.
A robotic arm is probably a lot more versatile if you would be changing parts frequently although a rail system would probably give quicker cycle times.