Customized tools for people with physical disabilities using 3D printing

 

Have you ever been in a situation when you need a very specific tool (or a tool adaptation) that doesn’t exist, but its existence would make your task easier? Probably you would think about that tool’s specs, and if you were really into it, probably you would create a prototype with some materials available in your house. Nowadays there is another alternative: print it.

 

I use this idea in my former work where I designed customized tools for people with physical disabilities, principally for people with fingers amputations or reduced mobility due spinal cord injury. This work started as a project which objetive was searching for applications of 3D printing in a clinical environment.

The idea of designing tools for people with disabilities already existed inside the hospital, occupational therapist created tools by hand with different materials like thermoplastics, fabric and metal pieces. But the usage of 3D printing could allow to occupational therapist focus more on rehabilitation, while leaving the fabrication of the tool to the printer.

 

 

I worked with a physiatrist, an orthoprotesist and an occupational therapist, and continuous patient’s feedback. Each one of us contributed from our own fields to the design, creating a unique solution that mixed knowledge and experiences from each of us. I was in charge to transform these ideas in a CAD design and finally, in a product. As a mechanical engineer this was a good opportunity to  put in practice all the knowledge I have about design. Among the most important things that were always in my mind:

  • Before start, identify the problem and possible solutions. You should correctly identify the problem and determine if the creation of a tool is the best solution. Sometimes patients can achieve a task that couldn’t perform after the accident with therapy. Furthermore, if it’s decided that a tool is the best solution, you should compare the advantages and disadvantages with other options different to 3D printing.
  • You will need to iterate, even in some cases starting all over again.

  • You will need to address patient expectations. Because you are going to be designing something new, there is a risk of not being able to find a proper solution.
  • Think about using other materials. For example in the case of the thumb prosthesis, the main structure was 3D printed, but I also added silicone on the tips, and metal pins on the joins. You can also use a 3D printed mold to shape other materials as resine or silicone.

 

 

I designed tools for the patients, but there are also a lot of models of several tools and assistive technology available for free on internet on webpages like Thingiverse  (search keywords like AssistiveTech, disability, occupational therapy). I also search for inspiration on hackaday.io, a website with different projects and ideas.

I really love the idea of having the opportunity to help others with my designs, and is great to see how knowledge can grow if you share it. You can find my designs on Thingiverse (link).

 

 

 

 

I truly believe that 3D printers offer the opportunity to find solutions to necessities so specific that there are no companies that create exactly what you need. Nowadays you can buy at accesible prices a 3D printer on websites like Aliexpress or Ebay, or you can just search on Google if in your city there is a place where you can print, like a makerspace or company that offer 3D printing services.

Advantages of  3D printed tools
  • Good looking product
  • Easy replication
  • Washable, since it can be clean with soap or bleach
  • Highly customizable (You can resize a .STL file, or you can design it with CAD software)

 

Disadvantages  and how to address them

 

 

Software I used
CAD

I developed my designs in Inventor and Solidworks, because those where the CAD software that I learned to use in my university, but there are several free software that you can use, some of my recommendations are:

 

Fusion 360
It has the same tools of a typical CAD software. I found particularly useful the option of “create forms”, that allow me to create more organic shapes.
It’s free for hobbyists and students.

 

 

Meshmixer
This is not a software for drawing as in a CAD program, but it is still useful for 3D printing. It allows you to modify the “Mesh”, that is, customize .STL files (the ones you download)  through operations like Drag-and-Drop, cut, etc.

 

 

 

 

Printing

If you download or you create your own design, you will end with a .STL file. It must be loaded in a printing software that tells the printer where to move, temperature and speed.

Simplify 3D
This is a non-free software, but is the one I used. What I like is the option of customized supports.

As a free option you can use “Makerbot print”

Printer I used

I used a FDM printer. This is the cheapest technology that allow you print different kind of polymers. I printed everything using just PLA.