I have to design a 5-axis head assembly for plasma cutting in one month, i.e. controlled ABZ axis rotational unit.

Looking for different approaches to implement. Any ideas highly appreciated.

Made a quick search at a weekend, and it looks like "big boys" rotating the AB axes over the tip of the torch, to avoid XY corrections.
The different approach is to use "scissors" mechanism (but it translates the movement over the tip too).

Pros and Cons of the approaches?

A guy here posted pictures and video of a waterjet 5 axis he built. It was awesome! You should look for it.  The head rotated 360 around a vertical axis and the torch tilted on a vertical plane with the axis at the material suface through the use of a curved track

Thanks! Vertical axis seems to be the easiest and... obvious way

But the size (and the weight) does not look good, especially for plasma. So I tried to find a more exquisite way first.

Meanwhile, progress so far.

I was not sure if all the angles are available for the torch, in the previous design. So repeated the college Math and wrote the program to calculate the angles available for the torch (3 is for 30 deg, 4 for 45 degrees). There is a huge gap in the angles available for the torch, so this design is flawed (for example it can draw a circle with 45 degrees bevel, but can't with 30 degrees).

Spent a couple of hours to draw all the ideas I can imagine, including some really stupid. Then run the program for all of them. Some of them should work, though.

Returning to the general idea with a vertical axis.

Vertical axis design has other issues to be solved...

1) What is the best angle to install axis B (solved)

2) 720 degrees freedom of axis A  and how to let the hose rotate with an axis. The answers are either bearing ring (really big and heavy again), or bobbin for a torch hose.

One-hour conversation with bearings supplier...   and I have two bearings 80mm inner diameter 1250g each.