Stethoscope - Single Patient-Disposable

Posting this to share my remix of the Glia Project GliaX Stethoscope. Mainly to share additional sources for items that I had to track down that were easliy available to me from Amazon but to also share my remixes of parts that I modified based on the resources available to me.

Background
My wife works in a hospital and last week she came home and announced that they were looking for help making disposeable 3D printed stethoscopes. I did some google-foo on 3D printed stethoscopes and found the Glia Project. Having already donated a large number of face shields to the hospital already I had a supply of PETG on hand. From some other projects I also a few meters of tubing that was a pretty good match and some plasticard for doing some prototype runs. Even without all the right components I was able to make a pretty darn good prototype, good enough to order some real supplies and offer up my services to the hospital.

For the original release of this Thing I remixed a single part needed to insure functionality. There are a couple other changes I'd like to make but the hospital has approved production of this design so I will list the suggestions for changes but won't be making them myself at this time.

Also, for simplicity for others finding this Thing, I have included the original STL files that i didn't remix here. My parts are labeled -remix, the originals are not. If you want to get the complete Glia package you can check out their sites: Thing Github Site.

*****Update 24 Jun 2020 -
I have been printing now been printing these for over a month. At the begining of this project I began coordininating with our local hospital and community on fine tuning the parts to optimize for quality, ease of assembly and printing speed. I have provided over 200 of the latest design to the hospital and by all reports they are performing better than the disposable stethoscopes the hospital was using pre-COVID. I have uploaded all the latest STL files for the parts I have been producing. The only original part I still use is the head itself. I'll provide details of the remixes below.

Parts List
Large Silicone Tubing
Ordered New (not exactly 8mmx13mm but close and has a 1/16" thick wall which is nearly 2mm):https://www.amazon.com/gp/product/B000FMWTSY/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1 Leftovers from previous projects (unavailable to reorder at time of posting):https://www.amazon.com/gp/product/B078RMSDTL/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Small Silicone Tubing
https://www.amazon.com/gp/product/B07D33VN72/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Silicone Earbuds
From Glia project (US Amazon link):https://www.amazon.com/gp/product/B006XGJMEK/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 Also work but Medium size not Large (much cheaper):https://www.amazon.com/dp/B01KNZG5DW/ref=cm_sw_r_oth_api_i_WzyTEb4ARBP1R
Report Covers
https://www.staples.com/Staples-Side-Lock-Report-Covers-5-Pack-White-20592/product_919872

Remix Details
The first remix I did was to modify the ring part to accomdate the thinner diaphragm. One of the most challenging parts to find was a report cover with the correct thickness (since thickness of cover isn't really a critical dimension on report covers, those numbers aren't advertised). Since I'm in the US I don't have access to the Canadian only Staples part listed (others have mentioned this issue also). I found what appears to be a very similar item and ordered it. The problem was that it is only .2-.25 mm thick. This resulted in the diaphragm being slightly loose in the head because the outside of the ring reached full depth on the head before the diaphragm was clamped firmly against the spacer ring printed on the top of the head. A simple Z scaling would have resulted in the face of the ring being only 1 layer thick. Hence the remix here of that part. It was re-drawn from scratch with dimensions ensuring that there would be at least 3 layers in the face of the ring and having the sidewall being 0.5mm shorter. This change allows the thinner material to be clamped firmly in place and provided a significant improvement over the loose version.

*****Update 24 Jun 2020 - New remixes
1 - Update to Ring (v8)- Found that depending on the filament brand used I would occasionally still get a loose fit of the diaphragm so the latest version reduced the sidewalls by another 0.5mm. IT IS CRITICAL that the ring hold the diaphragm tighly to the spacer on the top of the head. If the diaphragm is loose the stethoscope will not work.

2 - We found that the original spring design was moderately stiff and somewhat brittle when printed in PLA. Additionally, as stated in some of the comments on the original design, it was somewhat difficult to get the ear tubes aligned and installed into the spring. The remix of the spring reduces the thickness of the middle of the spring making it somewhat looser and significantly less prove to fracture if printed in PLA and flexed to a straight line. The holes for the eartubes were also adjusted to ease assembly. Although this remix was specifically tuned to work with the new ear tubes, the original ear tubes will also work with it. It also prints in 1/2 the time as the original.

3 - The blunt ends of the original ear tubes made it very difficult to get the 4mm ID tubing on them. The remixed ear tubes have a much longer bevel on the end where the tubing goes making them MUCH easier to assemble. However there is now a support built into the new version to support the longer bevel that must be removed before assembly. I also removed the large tabbed raft at the ear end of the tube and replaced it with a smaller one to save space. This little raft also need removed before putting on the ear buds.

4 - Remixed the Y to remove the rafts for space savings on the build plate. Also optimized the wall thickness to be a multiple of .4mm.

Proposed Additional Remixes
1-Fillet head for easier removal from build plate (2mm radius) - Still haven't remixed the head
2-Remove tabs from parts for easier removal from build plate. They may have been needed for the original ABS parts and the Mk2 build plate, but I don't think I need them for my Mk3 with the PEI plate and they are VERY hard to remove. - DONE