[POORIAPK]

Hi Pooria - The design shown is good but it can be better. The issue with a rotary on the bed of the machine means that the Z height will need to be much higher then the bed requires. This means for normal use (using the bed) the Z axis will be extended downwards a long way and therefore will not be rigid. If the rotary is something that will be used alot then it is better to place it at the apron (the front) of the machine in a well or to the side of the machine again in a well. This makes the Z axis more compact and stiffer. It also means the bed is available for the normal work without upsetting the rotary set up. If the rotary is something that will be used alot then definitely don't make one that sits on the bed. In the case of the Maverick it has a bed cover so in "normal" use the rotary is covered and the space is available for flat sheet work. My first machine had an apron and I miss it. Was great for doing edge work.

Usually with a gantry machine it has a lot of forward envelope due to the Z axis and spindle fwd offset. It therefore has lost space at the rear. Using the fwd space for the apron does not take much effort as the spindle will reach it easily... You can put the rotary on the apron if it is not often used. If you have to reach over it for normal use it would become an irritation.

Here is such a machine. It has the rotary to the side and an apron for edge work. I suggest you look at this style of machine.
Maverick 4×8 | Legacy Woodworking Machinery, LLC

Peter

edit - the machine you imaged with the steel bed and rotary will be difficult to access due to the walls on the long axis. If you do a high rail design with walls make the gantry in the long direction so you have easier access to the machine bed. I expect that machine will use a bolster for its work. A bolster is a sub table that gets assembled off the machine then gets craned onto the machine and it gets bolted down. Thats great for production work if you have cranes and forklifts and require rapid setup / changeover times... I expect something like the maverick works better as it will allow side access. If your machine is big side access will be needed.

I've seen the operation of a machine from the company you linked to, and I must say, they make high-quality machines, even though they are a bit pricey . Initially, I was planning to use the space behind the spindle and the rear of the machine to house electrical components, like building the electrical box into the structure itself. As we know, most machines that place the fourth axis on the side or front typically have a shorter Z-axis compared to my machine, and I decided to take full advantage of the taller Z-axis. While placing the fourth axis on the structure, as you mentioned, would indeed provide better machining conditions—thanks for pointing that out—I'm not planning to use the fourth axis frequently, and the material I'll be machining on this axis won't be very large. I'll have to see how things evolve in the next version.