I love this breakout board, designed by Francesco Truzzi: https://github.com/ftruzzi/ATX-Breakout-Mini

With this board you can reuse an old ATX power supply as Your Lab power supply! I bought the board as a kit with all electronic parts here: https://shop.blinkyparts.com/de/ATX-Breakout-Board-Ein-Praktischer-Bausatz-fuer-das-Labornetzteil-zu-Hause/blink231342 - a onlineshop for makers from Germany, shipping worldwide.

But there was an issue, it had no case or something I could mount it to - so I made this one. :-D

It´s easy to print, fits even on the Prusa Mini builtplate.

The basic case consists of the two parts: front and back, which can be srewed together by using either standard M3 hex nuts or heat inserts.

Two optional parts: 

• The bottom_part can be screwed to the bottom front of the board, so you can easier see the voltages of the sockets. You can set filament changes after 2mm hight (for “GND”) and after 2,6mm hight (for the other text), to display the text in colour. Or just paint it after printing, if You like. :-)
• The voltmeter_holder can be mounted with cable ties on the big cabel connector like shown in the picture. It fits an 23 x 11mm voltmeter like this: https://www.ebay.de/itm/153869585920?hash=item23d3578e00 . Needs to be printed with support. You can secure the voltmeter with a drop of hotglue. (this is not included in the kit)
   

Bill of Materials:

• Obviously an ATX power supply and the breakout board (kit)
• 4 standard screws for mounting ATX power supplys to cases (Toothed Hex 6/32 Screw)
• 8 M3 hex nuts standard + 8 M3 cylinder head screw 20mm or longer
• OR
• 8 M3 heat insert nuts (M3x5.7x4.6) + 8 M3 cylinder head screw 10mm or longer
• cable ties (optional)

Printing instructions:

I printed it in PETG with 0.2 Layerhight, 0.4 Nozzle, standard Prusa Slicer Quality settings, 15% Infill Gyroid on the Prusa Mini+. I would recommend increasing the Infill for the handle of the back_part to ~30%.
Support is only needed for the voltmeter_holder, and I suggest 0.1 Layerhight for this. (optional part)

It should fit all standard ATX power supplys, I tested it with 3 different ones.
Please let me know if you notice problems with your ATX construction form.