iPhone 11 Flexible case

When the Apple rubber/plastic/felt case for my iPhone 11 wore out and fell apart I thought I would have a go at designing a similar case made from one piece of TPU to get a bit more practice in Fusion 360.

After about 10 printed revisions of the design trying to optimise the fit of the case and the action of the side buttons this is the final result.

The design was optimised for A95 stiffness 3DJake TPU so if your use a different material YMMV with the action of the buttons as they were tweaked to feel right (not too sensitive, not too stiff) with A95.

The design was optimised to work well with a 0.2mm layer height, although it also prints and works nicely at 0.1mm. 0.2mm will give more texture to the curved sides and a bit more grip when holding the phone but also tends to pick up more dirt in the layer lines and is harder to keep clean. 0.1mm will stay cleaner and look less (hardly at all) like a 3d print.

I printed mine directly on a textured PEI bed with no raft - this gives a nice texture on the back. I don't recommend using a brim as it's not needed and it will leave a sharp edge that will be difficult to remove accurately.

Default Cura slicer settings put the z seams and most translation moves on the inside of the buttons - so you might need to cut/clean away some stringing or z seam zits from this area to ensure the buttons work optimally. While you can move the seams elsewhere I've found this causes visible print defects on the outside of the case so just leaving it on defaults and doing a little post processing to clean it up works out better and leaves no defects visible on the outside of the case.

As with any TPU this will need to be printed slowly. I printed mine at 40mm/s at 215C. Print without any support structures with partial part cooling fan enabled to give good bridging performance at the top of the ringer switch hole.

Update: Added version 2 of the model with some slight changes.

There is now a slight fillet on the edge running below the speakers and lightning socket to remove the sharp edge there. I've reduced the width of the gap at the bottom slightly.

I've also reduced the chamfer depth of the camera cut out and changed the chamfer on the bottom outside perimeter slightly to give more lines of contact around the camera cut out area on the first layer.

Before this I was finding this corner would sometimes lift from the bed during printing as the first layer was only 2 lines wide here. You could use a brim instead of course but trimming a brim away neatly all around the bottom edge without leaving a sharp edge would be difficult so I've tried to optimise it to be printable without a brim.