My medical molding projects


#21

she’s got the patience of a saint.

Before I went to medical school I worked part time as my wife’s surgical tech… Woe be to the tech who caused any delay in the OR. 5 minutes and they’d never find your body… Surgeons expect things to be more in lockstep and go according to plan, while in emergency medicine or hospital medicine (what I do) nothing ever goes according to plan, you learn patience or go crazy. But like her, I also do mostly research (only do 25% clinical care)


#22

I’m not married to a surgeon but working in a cardiac ICU I can confirm what’s been said. These surgeons make their rounds in the morning and they’re the nicest people you could hope to meet when dealing with patients.
If they’re doing a washout or a patient is crashing on to ECMO in the room they’re like Mr Hyde!


#23

Yep, pretty much the same. She still gets excited about high action situations, but she’s also a bit OCD and the “woe to those” aspects you describe are spot-on. :stuck_out_tongue_winking_eye: Nowadays she just works out her aggressions on the spin cycle, where she’s up to about 4 hours a week on average. Scares the hell out of me, because I don’t have that sort of exercise commitment and she’s trying to persuade me to join her. lol…


#24

For people like that, it’s “CDO” (has to be in order) :grinning: (I’ll groan for you) Go :glowforge: - Rich


#25

So update on the project, the molds are now done:


They really show extreme detail when you get up close (like every tendon, vein, wart, etc on the skin). Can’t wait to pour silicone.

But that’s not why I am posting the update, I have now completed the hardest 3D print I have ever made (and that’s saying something). I have printed the arteries. If you look at the CT reconstruction above you see the arteries coursing down the arm. I finally managed (took 4 tries as this is really on the ragged edge of what a FDM style printer is willing to do).

We are almost fully ready to assemble the radial artery catheterization simulator I am building with a colleague for both interventional radiology and interventional cardiology to train fellows in wire insertion under fluoroscopy, ultrasound and palpating. This is printed in E3D Scaffold (similar to PVA) as we will locate this inside our arm mold and then pour the silicone around it. Sadly 98% of this print is wasted support material, but damn, it freakin’ worked. This is about the resolution that simplify3D would even print the artery (when printed closer to horizontal it failed, as I needed the artery “oval” by the oblique angle to make it printable) as the diameter of the artery is about 2.75mm. Actually not even sure how I can get it off the support, but will try a razor, and can maybe use my hot knife if necessary with the flat cutting blade on it?


#26

Wow! That is going to be fun to get off the support. Too bad you couldn’t have printed molds for those.


#27

Yeah, that’s step 2. But I need to ask E3D’s chemist (Sanjay) how you pour Scaffold. That is tricky stuff to work with.


#28

Truly impressive print job. Can’t imagine you’re going to have an easy time of it getting that support off, but if you do manage it, that will be something else!


#29

So the fun thing about doing this in a group of uber-nerds, is someone always makes that super amazing spark like off hand comment. So one of the guys who was sort of peaking in as we were planning, muttered, “too bad you can’t just heat the filament and bend it to your shape since it’s about the same size.” Total dead silence in room. So plan B is to use this as a guide and use the filament heated to 215C and with kevlar gloves reshape it (it’s fairly linear) and see how that goes. If that works we will work on a “bending model” which will allow rapid shaping (say using nails or printed pins). I the future the GF will make a great tool for making bending jigs.

Clearly for larger arteries (we are working on a pelvic artery simulator for the femoral artery, but that’s the size of your finger) we can print them, but this is on the ragged edge of what the slicer will allow…


#30

If that’s PVA, you should easily be able to heat it to bending shape with literally a few seconds in a 245°F oven.

Might even be able to do it with a hot hairdryer. (Heat gun’s gonna be too much.) :relaxed:


#31

You can bend PLA in hot water because it has a glass transition around 55C.


#32

Yes, but this is pVa not pLa. Trying to bend PVA in water looks like this


#33

My heat gun (from Amazon) has digital temp controls and starts at 150F.

Easier to manage the heat gun than trying to use an oven I think!


#34

Thanks! Didn’t know they made variable temp ones, and I can use it for a lot of things. Just picked one up. :relaxed:


#35

They’re good for lasered acrylic projects. You can set the heat (350 for 1/8", 500 for 1/4") for the material and not risk bubbling.


#36

Femoral is the size of a finger?? Learn something new every day. I had no idea it was that big.


#37

Happy cakeday @jamesdhatch! Enjoy the day!

The funky perspective thing of weather it is the positive or the negative of the mold since it is all greys. Cool beans. The knowledge and technology this all represents. Gives me goosebumps.


#38

I am sure this morning one of you woke up and said, hey what does a femoral artery 3D printed in PVA look like?:

And now you know! Just a little cleanup near the pipe connection at the superior end, and this baby is ready for enrobing in silicone. I have to reprint the pelvic bones, as I ran out of filament on the first time after 60 hours!!! Ugh.


#39

By golly…how did you know? Seriously, though…that’s fascinating and amazing. Thanks for all you are doing to advance medical science…and for sharing it with all of us.


#40

Yeah, that’s bugged me for a long time…but it’s hard to tell the scale from that photograph…size? - Rich