wrist splint humanitarian action

WRIST SPLINT

UPDATE : addition of a more rigid version allowing the addition of velcro

Hello,

I'm sharing my splint design to hold a wrist.

Please feel free to give me feedback to improve it.

This product has not been tested by doctors yet, the stiffness and ergonomics values are not finalized yet.

You can print it for your own use or to offer it via associations in support of war victims. In short, do whatever you want with it as long as you don't sell it.

Manufacturing cost: 50cts (0,5€) with PLA at 20€/kg

I recommend using PLA for its ease of printing and thermoforming.

link to video

https://youtu.be/BzM1xrOE5Qc

The concept is inspired by this work:

https://www.thingiverse.com/thing:403001/files

https://www.printables.com/fr/model/154797-palm-brace-splint/files

personal criticism of the latter:

• Too long to print

• Too much material consumed

• Not very comfortable and sometimes not very breathable for the skin

Here, the design is certainly not the most complex, but the trick to economy and customization is this:

• To play with stiffness, vary the scale factor in Z and the part will be thicker. You can also play with the fill density. In my case, the value is 30%.

• To play on the size, use the X and Y scale factor

• Don't rely on the stiffness of the plate when it is flat, as it increases once the plate is formed due to the evolution of its squared moment.

• The system is ambidextrous, so it is valid for both right and left hand, you just need to respect the position of the "TOP" on the top of the palm of the hand

Slicer setting for optimal results

Not being a CURA fan, I use Prusa Slicer, the parameterization philosophy remains the same, but the terms used may vary

The nozzle size is not important, but has a real impact on the print time, with a 0.6 nozzle and my DOOD pro volcano, I'm at 20min print time.

The plastic must be extruded very hot for the mechanical strength of the whole (at home, PLA is extruded at 220 °)

The size of the nozzle plays a huge role on the printing time. The larger the diameter, the faster it will be and the less fine the mesh will be for the same density.

For use on the skin, which I do not recommend, it is preferable to use a 0.4mm diameter nozzle

Useless, or even deleterious, to make thick walls, as it can lead to hard areas that will result in unpleasant pressure points.

The plastic cooling fan must be active to keep the plastic in an amorphous, and therefore flexible, state.

Watch my setup on prusa slicer carefully to get the desired result. No solid layer on top or bottom, so the model is open.

Filling pattern: lines (the most efficient in time compromise, material used, comfort)

Procedure for use:

• Immerse the object in boiling water

• Form it directly on the patient. It will become rigid as it cools. Start by forming at the wrist, making sure it is in its natural position and not crooked.

• Finish the adjustments with a hair dryer

• Use a bandage to plate the splint and have an optimal fit.

Tips:

• Cover the patient's hand with a thin bandage and soak it in cold water before applying the warm splint

• Once formed, put a thick cloth or fleece between the skin and the splint. The plastic may become uncomfortable to wear next to the skin.

Once recovery is complete, the splint can be recycled by placing it back in warm water. It will soften and can be put back on for the next use.

Take care of yourself.

Yann VODABLE

Mechanical engineering teacher

Lafayette High School of Clermont-Ferrand

Vice-president of the association Visière Solidaire

read the PDF as a grown-up would