Littmann Classic II SE - Stethoscope Diaphragm and Retaining Ring

Slightly Adjusted dimensions from Bouggo's Model - allowed successful print in PLA+

I just made things slightly larger which allowed me to snap-fit the retaining ring on the stethoscope when printing in a non-flexible PLA+ material

Even then, fitting it was difficult, and pretty much I can't remove the ring again without breaking it.

If printing again I would probably add maybe 1mm to the diaphragm dimensions, but play around with the dimensions and see what works for you.

SETTINGS:

Retaining ring in PLA+
Diaphragm in Transparent PLA.
 

Layer Height 0.1mm (I only have a 0.4mm nozzle, so maybe this is placebo)

Retaining ring settings were for Rectilinear top and bottom pattern, Added a brim for adhesion on the retaining ring.

The diaphragm is such a thin piece that the Internal Solid Infill pattern makes a big difference to stiffness.

Concentric circles gives you a more flexible diaphragm, rectilinear gives you more stiffness.

I printed with top and bottom surfaces rectilinear but concentric infill. I actually thought this would be too flexible but I got it fitted and it gives good results. 

FITTING:

Snap fit, Using some kind of lever to work it over the edge of the stethoscope ring. I used an iFixit tool. Unfortunately this did scratch the plastic.

Once it was 80% of the way around, I just pushed down against a table and it snapped into place.

The diaphragm pretty much slotted into the hole, and I used the same tool to slot the diaphragm into the ring.

Sounds pretty good.

Same model, slightly adjusted dimensions from Bouggo's Model - allowed successful print in PLA+