This is the semester task for the Robotics Systems subject in the Hochschule Emden/Leer.
Created good 3-dimensional FIFO sorting algorithm in the restricted area (Workspace of the robot covers just a small part of the table) for the "Sorting robot". Welding robot very accuratly covers top surface of the part.
You can find video examples here:
General view (click):
Welding and inspection (click):