An updated version of this project has been posted to printables: https://www.printables.com/model/1623216-slim-iphone-case-iphone-78-and-se-gen-23

Minimalist hard case

For iPhone 7, 8 and SE 2020.

Bottom edge is rounded and barely protrudes beyond edge of phone for a comfortable grip.
Tested on iPhone SE 2020 with perfect fit.

Print parameters:

• Printer - Ender 3-pro (modified)
• Filament - Polycarbonate (CC3D)
• Nozzle - 0.5 mm
• Layer height - 0.2 mm
• No supports

I have also printed it in PETG, but the edges cracked rather easily and was not as comfortable to hold. I think PLA is simply too brittle.

Printing tips:

• Make sure your flow is well tuned. Over extrusion will cause oozing on the surface. Under extrusion might cause gaps or poor adhesion in the edges, making them brittle.
• If your edges crack, try reducing perimeter speed to improve layer adhesion. Or scale up the model in x or y by 0.5% to increase tolerance.

Post processing:

• Sand the edges and back with sandpaper 180 grit or higher until you are happy with the texture.

To install on phone without cracking i suggest:

1. Slide phone all the way into the top.
2. Snap in bottom right corner.
3. Snap in bottom left corner.