Compact ATX Case (~18L)

This originally started as a modification of Ephyxis's 'Compact ATX Case (13.2L)' but I had a tower CPU cooler and no PCI-E riser cable, and didn't want to have to buy new stuff. The case is slightly larger with a volume around 18L.

I re-arranged the back to make everything fit and re-created the right side (motherboard tray) using the Intel ATX specs and Protocase documentation. Most of the other panels were re-sketched and extruded with a new (same size) honeycomb pattern cutout. There is no location setup for SSD/HDD as I only have NVME drives on this PC

An inner lip was added to the left panel for threaded inserts for mounting, all separate corner connectors were integrated in the panels and a small shelf was added to the bottom to support the PSU

Required hardware is similar:

• 11 x M3x4 threaded inserts (9 x motherboard, 2 x PCI-E)
• 11 x M3x6 bolts (9 x motherboard, 2 x PCI-E)
• 42 x M4x6 threaded inserts
• 42 x M4x10 flat head screws
• 4 x 6-32x5/32" ATX PSU mounting bolts (standard bolts aren't long enough)

This was the most compact design I could come up with without new hardware. The case sits on my desk slightly behind/under one of the monitors, and I have it facing backwards, so the power button is on the back, and I have access to the all the USB, audio, etc ports on the back

There isn't much space between the PSU and GPU, but the entire case is vented, and heat hasn't been an issue. I also shortened and sleeved the PSU cables to make it cleaner. 

I used PLA-CF for the finish. This was a slow print for me, as the PLA-CF I used wasn't great above about 40mm/s.

Using a 0.6mm hardened steel nozzle at 15% infill, 102% flow  and 0.15mm layer height (with adaptive layers) at 50mm/s it took the better part of 7 days to print. Any parts with threaded inserts got extra walls/perimeters and infill for strength

All parts except the back can be printed with external face on the build plate. I only used supports on the back panel as there is a suspended cutout above the PCI-E mounting, all other parts can be printed support free.

N.B.: 

1. You'll need a 3D printer with a build volume of 330mm x 270mm and that's printing almost to the edge of the plate. All my parts were printed on my Neptune 3 Max running Klipper with Elegoo PLA-CF
2. Thanks to infiniteoffset for pointing out the PCI-e slot spacing, I designed this around the motherboard I have (MSI MAG Z790 TOMAHAWK) and it's design skips the first ATX spec'd PCI-e location.

Re-modelled pretty much all panels, changed PSU and GPU location. 

Integrated the corner connections into the top and bottom panels and did away with PCI-E clamp in favour of threaded inserts