4.7L Mini ITX case, easily printable (2 major pieces), sandwich layout, no extra thread inserts, standoffs or feet required by ecor

Last crawled date: 3 years, 3 months ago

Overview
The idea behind this case is to be simple to print in terms of setup, required parts; and designed from scratch with 3d printing in mind versus taking an existing sheet metal case and cloning it.
I took inspiration for the assembly from the ASRock Deskmini series, and the k39 case for the layout and feel (although at a higher volume). Internal volume is about 4.7L
I print relatively slow (35-50mm/s) and use 1.75mm filament, so with my estimated price of ~$28 (high side) per kg of PETG filament
Spine: 170g, $5, 1 day to print
Case: 390g, $11, 2 days to print
GPU support: 5g, $0.15, 30 minutes to print
Not taking labor, parts or electricity into account, you'll pay around $16 for a mini itx case ( plus riser, I know)
Printable area required:
235x110mm for the maximum bed dimensions and ~200mm in height
All the fastener threads can be made with a metal screw (M3 and M4), no need to tap or weld thread inserts, just be careful when threading, and assembling it.
Before you start
Given that this is plastic, you'll need to keep some things in mind before printing and assembling it:
It will flex a little bit, but not enough to wobble when fully assembled and printed correctly
It won't feel like higher end aluminium cases because it's plastic
You'll need to do a good job cleaning up all the orifices and vents before screwing anything onto it, I didn't do great job (see pics) because I'm lazy, but also this is not my main computer, so I don't mind the extra micro strings
It will be more sensitive to overtorquing the fasteners than metal cases, so BE EXTRA careful or risk losing your threads
You'll need to have your printer properly dialed up for tall and long structures which means:
Proper dimensional calibration (failure to do this will result in poor assembly)
Proper flow calibration (over extrusion won't only affect appearance, it will also affect height and the nozzle may touch at the higher layers, which will deform it)
Proper bed leveling (large area is more sensitive to bad leveling)
Just the right bed adhesion (be careful of too much bed adhesion given the big area touching the bed)
Proper first layer height and bed texture/quality when printing the case, as the face of it will reflect your bed surface and first layer quality. Mine didn't came out great because of that, but yours can.
A printer that doesn't wobble/vibrate (tall structures may suffer from vibration, particularly the spine which needs to be somewhat straight and thin)
Print orientations
Case orientation: front face down (open cube at the top)
Spine orientation: back face down (IO shield down, tall-thin structure at the top)
GPU bracket: back face down
No supports
Material
Minimum material:
PETG.. particularly DO NOT PRINT SPINE IN PLA!!, the case MAY be more lenient, but I can't recommend it
Let me repeat that for you: DO NOT PRINT THE SPINE IN PLA
Be prepared to clean up a lot of strings (PETG) :)
Requirements
You'll need fasteners (M3 and M4, be very careful with torque), a PCI riser 200mm in cable length, 300 mm total (I tried only 1 but others may be compatible),
a CPU cooler with a max 38mm in height, a GPU that is at most 185mm in length (with a PSU with thin wires or ~175 for bulky wire ones), a Flex ATX PSU, and a MiniITX Motherboard.
This case supports 1 external SSD that is at most 9.5mm in thickness or you can always switch to M.2. I only tested a motherboard with an M.2 on the front, unfortunately the riser MAY interfere with one in the back depending on its position.
Stuff I used
Fasteners:
Set of M3-M5 flat head hex (look better, but you have to be cautious with torquing)https://amzn.to/33jtiRJ
...OR...
M3:https://amzn.to/3l1wN5m
M4 nylon:https://amzn.to/39inUC0
GPU Riser:
Phanteks "300mm" (end to end, cable is 200mm) 180 Degree riserhttps://amzn.to/2V0kSKB
Power Button:
Generic push button with 2 pin 0.1" connector (custom made, link is button only)https://amzn.to/3fDmNOo
If you drill a 12mm hole through the thin wall of the button it will fithttps://amzn.to/37avcVR
.. or similar ~12mm diameter buttons
GPU (max clearance: 2 slots, ~175mm for PSUs with thick wires, ~185mm for modular/thin wire PSUs), I used a GTX 1650:https://amzn.to/3l1x9ZK
PSU (thick and not very flexible cables, this is the worst case scenario IMO and works):
SilverStone, 350 Watt Flex ATXhttps://amzn.to/37ckwWD
CPU:
AMD Ryzen 3100https://amzn.to/3nVLyIK
CPU Cooler (clearance is about 38mm.. not great, I know):
Noctua NH-L9a AM4https://amzn.to/37avgF5
Motherboard:
B520https://amzn.to/3652GWs
Others
Filament:
SUNLU PETG (orange/black combo)https://amzn.to/3m85Iif
Exacto knife for cleaning extra materialhttps://amzn.to/3mc06Ui
My printer is a CR10 V2 and it's able to print the case:https://amzn.to/2V3RQcS
How to assemble/build
Clean up all the stringing and residue from all holes, particularly the ones that require threads
(don't tap, because in my experience this makes the thread too loose in PETG and the hole too wide) Thread the 3 holes in the case (M3), the 2 holes for the riser (M3), the 4 holes for the motherboard (M4) and the one for the GPU bracket (M4), this last one may require a nut given that sometimes one may want to overtighten it trying to secure the GPU, but it may not be necessary if you're careful. Use metal bolts for this, and do it slowly. M3 holes should be ~2.8-2.9 mm in diameter, M4 ones should be ~3.7-3.9mm and you should be ok, if it's less, try to make it the proper diameter, if it's more, you're kinda screwed, try filling up the wholes with baking soda and crazy glue, and redrilling/threading/tapping (never tried this, but it may work). You DON"T need to thread the PSU holes, the hard drive holes, the power button hole. These rely on the component's thread.
Install riser, try to bend it as compact as possible, route it through the back of the motherboard
Install IO shield
Install motherboard with everything attached to it, except cables, this will give rigidity to the spine
Install the GPU and its external bracket to secure it
Install PSU (BUT DON'T LIFT THE ASSEMBLY YET OR YOU RISK DAMAGING IT)
Install your SSD/HDD
Route all the cables to their destinations and bundle the rest at the "front" of the case, try to make it as compact as possible while leaving about 3-4 mm at the very front for the assembly to go into the case
Tie the bundle of cables to the spine tightly too, so that this gives rigidity to the spine/psu assembly
If you have a modular cable PSU, secure it through the back with a zip tie into the spine/assembly, so that it doesn't move from the back.
Insert the whole spine assembly into the case, making sure the top center rail/guide is aligned
Flip the case face side down, so that the spine assembly goes in easier
Make sure the spine is aligned with the "bottom" (in this orientation) "sockets" and push gently from the middle/top (in this orientation) spine, so that it goes all the way in. Depending on your printer tolerances, it may be more or less tight, but if everything lines up it should be no problem.
Fasten the 3 screws at the "top" (in this orientation) once the spine is flush with the case