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This thumb splint for broken or sprained thumbs was designed to be an durable but affordable parametric brace. The design prints in two flat parts requiring three size measurements and thermoforming to customize to wearer's precice hand shape. The main structure of the design is all 3d-printed material but an internal padding is recommended for comfort in areas of direct contact.
Bill of Materials
- PLA or other thermoformable filament
- Anytype of fabric to use as padding.
- Thumb Splint main body
- Wrist Strap for thumb splint:
- Use customizer to generate STLs based on measurements taken.
Tools needed for fabrication of the OSAT
- MOST Delta RepRap or similar RepRap 3-D printer
- Thermoforming tools
- Hot air gun (blow drier) or heated water will booth work on PLA material. See link below.
- Some type of fabric or cloth to act as padding between the hand
Skills and Knowledge Necessary
- How to thermoform 3d printed parts (https://www.inov3d.net/thermoform)
Technical Specifications and Assembly Instructions
- Step 1: Take measurements of wrist circumference, thumb circumference, and length from tip of thumb to base of wrist.
- Enter variables into parametric customizer 
- Follow Thermoforming procedure
- Option 1: Boiling Water
- Heat a small pot of water to near boiling then remove from heat for approximately 20 seconds.
- Place printed component in water until malleable. ~ 3 seconds
- Shake of water and form around hand.
- This processes can be repeated until desired fit is found for both parts.
- Option 2: Heat Gun
- Place part on heat resistant surface.
- Heat part until malleable, being careful not to melt plastic beyond this.
- Place on hand and form to fit.
- Heat gun can be used to fit the mold while it is on the hand as well as long as care is taken not to burn hands.
- If both options are available, use Option 1 for first fit and Option 2 for small changes .
- Option 1: Boiling Water
- Assembly time may vary but should take <10min once printed
Common Problems and Solutions
- A common printing error is the circular holes are difficult to print due to bed adhision. Be sure to print first layer slow or use an additive/heated bed. Part was able to be printed on plain glass bed.
- If any issues occur during thermoforming, just repeat the heating and molding process.
- Was able to print for $0.38 + cost of padding.
- Total fillimant used was around 25 grams for smallish hand.
- A more padded comparable commercial equivalent can be found for around $25.95 
- Assuming a total price of $1.38, there is a saving of 95%
Benefited Internet Communities
- Name and add links to at least 5 using single brackets around [url name]
- Digital Resource Foundation for the Orthotic and Prosthetic Community 
- Open source community 
- International Medical Corp 
- Doctors Without Borders 
- Doctors of the World 
Project developed by Travis W.