3D printing technology is on the rise, and there is increased use by professionals and laypersons. Someday soon, this amazing technology will give hand therapists a remarkable tool to make “in-house” assistive devices, hand exercise equipment, therapy tools, orthotic components and orthoses (formerly termed “splints”), and more.
What are 3D printers and how do they work?
There are different types of 3D printers that use various processes to create objects. The most common type of 3D printer in the consumer market uses plastic filament with a price range of about $500 to $4,000 (Figure 1). Think of it as a highly sophisticated hot glue gun, which melts plastic filament and deposits it in layers from the bottom up to form an object (like building a brick wall). A digital file provides the “virtual blueprint” for instructing a 3D printer where to lay the plastic to form an object. These digital files are created by persons with skill in using computer design/modeling software or from scans of objects (using scanning technologies and even data from MRI or CT scans).
How is a 3D Printed Wrist Orthosis (Splint) Made?
Briefly, the process of making a custom 3D printed wrist orthosis requires scanning technology to obtain a digital copy of a person’s hand and arm. Next, using special software, a digital wrist orthosis is created on the digital hand and arm, and then the digital hand and arm is removed, leaving a digital wrist orthosis ready for 3D printing. Printing of the orthosis takes some time. For example, one prototype of a wrist orthosis took more than seven hours to print using a filament-based 3D printer. As this technology evolves, the process will become more user-friendly and faster for use in hand therapy practice. The current method of making wrist orthoses in a hand therapy clinic consists of heating a thin sheet of low temperature thermoplastic and skillfully molding it directly upon the client. This process takes about 15 minutes.
A nice feature of 3D printing is that many of the digital 3D models (for a wide variety of objects) are available for free download from the Internet for anyone to print! These models are created and shared by laypersons and professionals with various levels of skill in 3D design. Included among these are assistive devices (Figure 2), simple hand orthoses and mechanical hands/digits. It is important to be aware that the majority of these models are not created by healthcare professionals, and there is no requirement/regulation to ensure functionality and safety of these devices.
Figure 2: An example of a 3D printable assistive device
When finger pain, weakness or limited range of motion make it difficult to twist open lids on plastic containers, a 3D printed assistive device such as a “Plastic Cap Wrench” can do the job with much less effort! The Plastic Cap Wrench (remix) Rounded was created by GiovaGio and is available for free download from http://www.thingiverse.com/thing:711671. It takes about 20-30 minutes to print, and the material cost is less than 50 cents. The tricky part is resizing, or scaling, the object prior to printing in order to fit a specific cap size.
In the near future, as 3D printing technology improves (and it is doing so at a very rapid pace), hand therapists will be able to use this technology to make custom assistive devices, equipment, therapeutic tools, orthoses and more within the clinic setting. The advanced technology will help clients return to the occupations and daily living skills that are important to them!
Robin Janson, MS, OTR, CHT is an occupational therapist, Certified Hand Therapist and is a member of the American Society of Hand Therapists (ASHT).
All of the photos provided were taken by Robin Janson.