Starting to design out my build, looking for critique

[Chrono]

Don't skimp on the BOB it's just as important as the controller and the single most troublesome part of any machine when it's done on the cheap.
The UB1 is good BOB, thou i'm not keen on the spring loaded terminals but other than that it's well made and very capable.
I've seen Many electronics geeks try to Roll there own and 99% fail resulting in wasted time only to buy one in end.

Got it. Makes sense to me... There are just too many variables for me to try and get it on the first try, and on the second I would likely be overshooting the cost of the UB1 anyways.

You can get Hi-win from china and the ballscrews are Ok for the money. They also sell C5 if you want little better.

You don't need 25mm rails for machine this size and it will actually negatively affect the machine compared to 20mm rails because of the extra inertia etc the motors will have to deal with. These may seem little negative things but together they add up into large negative which affects performance.

I have checked again, and as it turns out, my memory was wrong... I was already planning on using 20mm rails, and that is what is in the CAD model. I am planning to get them from china, but HIWIN vs china rails are still 300$... Would that be worth it, or are the chinese ones good as well?

Regards the VFD it will damage the VFD eventually by switching it off and on thru a relay. It's also not safe due to capacitors causing a delay in it powering down.

Not looked at the schematic too close but will take a look. The schematic Joe used mostly came from me so should make sense..

Got it. So the only E-Stop for the VFD then is the mains switch and the internal E-Stop signal, I am guessing?