Comment by xyzzy_plugh
1 day ago
I think this is a good point, insofar that how bacterial resistant the stethoscope is relevant. Stethoscopes made of stainless steel are going to beat anything 3d printed by a significant margin.
1 day ago
I think this is a good point, insofar that how bacterial resistant the stethoscope is relevant. Stethoscopes made of stainless steel are going to beat anything 3d printed by a significant margin.
It definitely doesn’t help that prints from filament printers are very porous, 100% infill or not. Maybe sealing it with epoxy after printing would help?
This seems like another case where the hobby has discovered the 3d printer hammer and forgot that cnc tools (lathe, milling machines) are often better and faster for the job. Or if plastic is what you want injection molding is something you can do on a hobby scale and it is much better (but unlike the others this isn't something you can go from CAD to widget)
In my experience it is very rarely the case that setting up machine tools is faster than 3d printing. And even when it's faster, it's not less trouble. And you have to go and acquire materials in suitable shapes and sizes, and deal with cleaning up chips and offcuts, and deal with deburring and cleaning the part after it's finished.
The 3d printer is always ready and always has material in the right shape. It doesn't make a lot of noise, it doesn't make a lot of waste, the parts come off the machine clean and dry and ready to use. It's really hard to overstate the convenience of 3d printing.
I doubt the diaphragm which actually touches the body, or the flexible tubing of expensive scopes can be sterilized in an autoclave. This diaphragm here is cut from cheap plastic and easily replaceable, the tubing is silicone. I do not believe the flexible tubing on the expensive ones is usually silicone and replacement diaphragms probably cost as much as this whole DIY scope. Metal is resistant to heat, but porous still, so disinfecting with alcohol isn't enough, if you got nasty on it. Never in my life have I seen any doctor pulling a stethoscope from a sterile paper bag. It's likely not as clean as you want it to be.
I believe, in practice you should avoid putting it directly onto the heart, keep a layer of healthy skin in-between. Given the scope of the scope, that may be acceptable, considering the alternative may be direct skin2skin contact with your patient...
But yeah, generally, 3D printed objects are not easy to sanitize properly.Eg. their porosity makes them not safe for repeated food contact. I mean, the glass transition temperature of ABS is 105°, so you could dip it in boiling water, but that's not enough for making it sterile and consequent water inclusions are a welcoming place to start a new family a few hours later for any remaining spores. You could try fractional pasteurization and heat drying, in a pinch, at the end of times.