Electeical cabinet earth and low/high voltage

Hello,

I built a CNC mill and I would like to make a nice organized electrical cabinet. At first I wanted to separate low and high voltage parts, but I think it should not be a problem to build them in 1 box.
Is noise a big issue or is it ok to build it together?

My other question is about grounding. I have 3 power supply with a metal frame and an earth terminal. I would like to leave the wires to make it easier to organize the cables. The metal frames of the power supplies will be bolted into the steel mounting board with helical springs to make a better connection. Each supply will have at least 2 bolt in it. Is that enough for earth grounding or should I still go with the cable?

The proper method it to ground bond all the metalic parts to each other by a green, green/yellow or bare conductor.
Also set up a star ground plate somewhere on the main chassis where ground conductors terminate, together with the incoming service GND conductor.
Get a copy of NFPA79, there is a copy floating around in PDF on the web.
Also see the Siemens guide on equi-potential bonding and grounding PDF's
Al.