Necessacity of TCP in Welding Application? [ArcWelding PowerPac]

Hi Friends…

  1. Will any one explain me the need for TCP in welding applications?
  2. Is it only for making the teaching easy & fast??
  3. If TCP MEAN ERROR IS WITHIN 2mm, then is it OK to teach the welding component with this much error??
  4. TCP Mean error achieved is <=0.3mm & after we complete teaching of the component if the gun collides & bends, then if we again achieves TCP Mean Error <=0.3mm, then is it needed to have fine touch-up for the welding stitches???