I have some floor mounted robots for unloading die cast machines. Specifically, they are the older ABB 4400 robots that are the parallelogram design, so the robot cannot reach behind itself.
Now, ABB's newest robots (for example the 4600) is not a parallelogram design, so axis 3 can rotate behind the robot and work in back while keeping axis 1 at 0 degrees.
The marketing videos make it look really cool when the robot reaches behind itself. And, I understand why that would be useful with small tabletop robots.
However, I have not figured out a practical application with a larger robot (30+ KG payload) where it would be better for the robot to reach behind itself. Actually, to me there seems to be safety concerns because the gripper and payload would be way above the safety fence.
Have you had some applications where having the robot reach behind was a big benefit?