Research FFF material for medical prototyping

[wjbdesign 1]

Dear Ultimaker Community,

hopefully one of you could help me out with a material choice my current research project.

I am involved in the development of an open-source swallowing sensor for Parkinson patients. At this stage I am trying to find the right material for functional prototyping. The sensor will consist of some small parts in a FFF printed housing which will be placed around the neck.

 

Some of the main requirements/criteria for the material choice are:
-The material should not absorb to much kinetic energy since vibrations of the throat are used to measure swallowing (so no rubber like material).
-Bacterial built-up should be reduced as far as possible.
-the material can withstand ethanol and other hospital cleaning agents.  
-the material should be hypoallergenic and dermatologically safe.

 

Order points worth mentioning.
At this stage, the sensor will only be used indoors.  

an Ultimaker s5 will produce the parts 

 

any advice is welcome, 

[geert_2 557]

At least for prototyping, I would begin with classic materials like PET or even PLA. But do some smoothing on their surface to reduce layer lines, so dirt and bateria have less grip. These do withstand desinfecting alcohol.

 

For smoothing, have a look at the thread I did some time ago, with lots of pictures of the result. Search for: PLA and PET smoothing with dichloromethane.

 

Chloroforme should also work, but I haven't tried that (too much hassle, requires special permissions here). Be aware that after smoothing, the parts will breath-out that chemical for several hours, so you need to give them time to dry completely.

 

[geert_2 557]

Forgot to say: due to the dissolving-effect of the solvent, the outer layer of the parts gets soft for a while. So that will leave fingerprints, and it may warp the whole part if it is thin. Also, if you print with little infill, it may evaporate the solvent inwards into the hollows, where it keeps working. I found that a mould I printed with 25% infill and of which I smoothed the inside (=where the cast comes), began to warp slightly after one month. I think that might be a result of the dichloromethane-solvent, because it never happened in similar unsmoothed parts in the same conditions (=room temp, average moisture).

 

[wjbdesign 1]

@geert_2 thank you for your advice! I was thinking of Pla smoothing myself for phase one. In the meantime, I also read the most relevant chapters of 

PLASTICS IN MEDICAL DEVICES: PROPERTIES, REQUIREMENTS, AND APPLICATIONS by Vinny R. Sastri. 

 

Based on the information of the book, I will probably use PP for phase two. 

 

I can recommend this book to anyone who is dealing with similar situations (despite the lack of information about FFF). The book is detailed yet self-explanatory.