Is there any reason to keep the drives and computer in seperate boxes? I won a Dell Optiplex GX110 PIII 733 512mb 40gb off ebay and the box is huge. It is the sit on your desk with monitor on top style. There is room for a breakout board plus 3 drives inside with heat sinks on the outside. A friend salvaged a german 24v (adjustable to 27v) 10a power supply for this project. I had started building a seperate enclosure for the drives and power supply, but the optiplex is so big, I could bolt the PS to the outside of the computer enclosure and it'd all be one unit.
If I go with the optiplex enclosure for everything, I'm stuck at 27v dc tops. With a seperate enclosure, I can gang three 12v 20a transformers to get arond 50vdc. Drives will take up to 80v. Motors are 2.5v 4.6a. The 24v 10v. supply will cover the volts x 10 and if I went gonzo, I'd be smoking at 20 x motor volts.
I'm wide open for suggestions. I have most everything ready to start the kit. I still have to make motor mounts for the X/Y table, and have yet to decide if I'm going to put new tight german lead screws in it or save them for another project. Hard to tell what is backlash and what is cosmolene at the moment on this cheap chinese prodct. Although it'd be more work to adapt the lead screws now, It'd be less work than using the ones in the table now and changing later.
heat is the main reason. You can ventilate the box, and the problem is solved. I like the idea of one box. Matt Shaver of EMC fame has a computer with everything inside and a LCD on the side of the computer case. I am pretty sure that Sherline's cnc has everything inside the computer.
I have my driver board mounted in one box with heatsinks and fan. This box is mounted very close to the mill with parallel cable to the computer. I have a second box which is an old AT computer case for the power supply.
The room in the PS box is great for arranging all parts in a way that air can be directed at the hottest items. I have 3 fans on the PS box. One fan pulls air out of the box and two fans push air into the box on the transformers (4 24VAC) and the bridge rectifiers. This PSU puts out 38VDC at 16amps. Plenty for motor upgrades.