Need a running start

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homicidalbrainiac
Posts: 13
Joined: Wed Jun 22, 2022 6:04 pm

Need a running start

Post by homicidalbrainiac »

Hello,

I am designing a special PAPR mask which might help protect frontline medical workers in future pandemics. I would like to make the design entirely opensource, using opensource tools (instead of Autodesk, etc.) Existing PAPRs have some drawbacks I would like to address.

I have all the systems engineering and integration knowledge necessary, I could even take the design through the NIOSH approval process. What I lack is advanced knowledge of FreeCAD. I know the basics, like making a sketch, using constraints, parametric design concepts. I made a few basic designs, like a special camera for photogrammetry. I just never imported something like a human body and then tried to make something ergonomic. I'm a quick study, I would just like some direction for a running start.

I have a 3D model of a person, obtained by a 3D scanner, it's in the STEP file format. I have my own 3D scanner and will be also making models of me and my kiddos so I can test the mask for various sizes. I would like to import it and then be able to make the equipment conformal to the imported model as possible. The mask will basically be a sort of collar, supported on the shoulders and chest that attaches with a vest around the torso. It will also have a protective polycarbonate dome that goes over the head, attaches to the collar.

I would imagine being able to get cross sections from the imported scan, create segments from the curves, integrate it into the actual hardware, then turn them into a coherent STL for 3D printing. Are there existing tutorials I could take a look at? Could anyone suggest a more suitable approach to the FreeCAD workflow?

Thanks in advance for you consideration.
Last edited by homicidalbrainiac on Wed Jun 29, 2022 2:04 am, edited 1 time in total.
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thomas-neemann
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Re: Need a running start

Post by thomas-neemann »

homicidalbrainiac wrote: Wed Jun 22, 2022 6:22 pm ..
this workflow might fit

https://www.youtube.com/watch?v=kUf2Uk_Yry0

phpBB [video]
Gruß Dipl.-Ing. (FH) Thomas Neemann

https://www.youtube.com/@thomasneemann5 ... ry=freecad
homicidalbrainiac
Posts: 13
Joined: Wed Jun 22, 2022 6:04 pm

Re: Need a running start making a Canopy

Post by homicidalbrainiac »

Thanks for the suggestion! I'm slightly further along. I am wondering if someone can take a look at what I have so far.

I have two curved profiles, one along the horizontal axis, the other along the vertical. The idea is to form a canopy of sorts. I tried using datum planes so I could keep the canopy along an axis that would allow vacuum forming. I will make the back half of the canopy in a separate part and plastic weld them together. I figured with angle I chose, it also keeps the resulting seams outside the field of vision.

I am wondering how to make the canopy's surface. I have seen people make multiple sketches, space them apart and trace the individual profiles along the canopy before lofting them. I don't know how to make a series of sketches that track along the intersection of the datum planes.

Is this the best way? Is there a way that can let me play with the horizontal and vertical curve sections to parametrically tweak the canopy?
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