Positioner for cubic frame

What's the best way to weld large cube frames using a robot? Put them on a carousel so you can spin them however you want, of course! A company engaged in welding robots and plasma and laser cutting commissioned me to make this carousel for their customer's products. The industrial positioner has a cross frame with an optimized shape. This was done to reduce the moment of rotation of the frame around the axis since the largest frame has a side of 1700 mm, and the smallest 730 mm. At the same time, it is undesirable to allow the base to bend from the load or breakage from the accidental fall of heavy structures. This made it possible to obtain a better weight/strength ratio. Guides for the movable platform are attached to this cross, this allows you to fix a practically unlimited number of sizes of standard products (at the time of development there were more than 23 of them). All mechanisms and fastenings are only manual in order to reduce the cost and simplify the design, but pneumatic actuators would fit in here quite easily. The speed of work has increased so much that while one welder was doing everything manually on a simple jig, the robot manages to make 3 of the same ones, while most of the time is spent loading and unloading and rotating the positioner. Therefore, if you add a 2nd positioner, there will be about 5 products at the same time. And all this with higher quality products, greater accuracy and lower cost of work. During the design process, this welding jig was, of course, tested in the RoboDK robot simulation software to make sure that it would work as intended, as well as to find the most convenient positions and welding torches for the robot