Describe the properties needed for the diaphragm

[mrjohnc]

It looks like the suggested diaphragm material is not available in a lot of countries (including in the UK, or at least not under that name). It would be really helpful if the properties needed could be described, its unclear how the material should behave, how flexible etc.

[sebgus]

I've found that the diaphragm should have a thickness of around 0.7-0.9 mm and should be made of a relatively hard plastic material for optimal performance. I ended up using a A4 paper folder from here: https://www.jula.se/catalog/hem-och-hushall/kontor/kontorsmaterial/document-storage/mapp-001996/

You should be able to find something similar in the UK.

[thecrazy]

Was any thought given to printing the diaphragm? The layer heights are small enough and if printed directly on the print bed (no support) one side would already be nice and flat. A simple sanding could be all that's needed on the other side (if even required). You could also redesign the head to print upside down and have the diaphragm built into the model. If lowering the cost and print time is the goal you may also try building the Y (junction) into the head's outlet. Also, I wish you would make a version built with people foraging through scraps in mind. Earbuds is not an easy find, but whatever flexible hose they end up using (if small and flexible enough) could be inserted in the ear without hurting. All you need then is some sort of adapter to attach the tubes to a metal wire (coat hanger?) shaped like a U. Before anyone makes a comment about 3rd world not having 3d printers you are wrong. Surprising what they can do with nothing.

[tareko]

Hi,

Apologies for the delay responding. There are a few pieces here, so I'll try to take them one by one.

Was any thought given to printing the diaphragm?

Yes. We haven't had success with this, and considering the ease of finding the folder covers, we don't consider this a priority at the moment, since the acoustics change fundamentally with any change in thickness. It would be great if somebody wishes to work on this, but this is not on Glia's agenda.

You could also redesign the head to print upside down and have the diaphragm built into the model.

This is unlikely to work due to the curves involved in the bell, but maybe there are other ways of achieving the goal of a single printed part.

If lowering the cost and print time is the goal you may also try building the Y (junction) into the head's outlet.

This would double the tubing required, which is actually the most expensive part of the stethoscope. The original Harvey Stethoscope by Welch Allyn used to do this. I suspect they stopped for similar reasons.

Earbuds is not an easy find

Happy to hear proposals on this, however we consider this part ubiquitous considering they are given with most earbud type devices. What is your context that this part is hard to find?

All you need then is some sort of adapter to attach the tubes to a metal wire (coat hanger?) shaped like a U

Super happy to see a sketch of what you think this might look like. I can't visualize it at the moment.

Before anyone makes a comment about 3rd world not having 3d printers you are wrong

Agreed. In Gaza, we have been able to develop 3D printers with local resources.

tarek : )

[johnsonm]

The diaphragm on a Littmann is, I understand, BoPET (mylar). I purchased 7.5mil BoPET sheet which is widely commercially available and inexpensive, and measured the same thickness as an ADC diaphragm exemplar. I'm not a medical professional, but the person who requested my 3d printing help to experiment said that the BoPET diaphragm substantially improved cardiac sounds over the PVC report cover diaphragm.