## Introduction: 3D Print Prosthetic Hands in the Classroom.

At my school, we have multiple 3D printers and I am always trying to bring real-life experiences to the classroom. When I learned about the e-NABLE the Future organization I found the perfect way to marry these two while at the same time teach my students about empathy and community engagement.

eNable the Future has all the necessary resources on how to find a recipient, select the appropriate device, resize it, 3D print it and assemble. In this tutorial, I will be explaining how I incorporate this project into the classroom using the engineering design process in order to customize the device to what the recipient likes. This project can be done in high and middle schools. Since I teach middle school, I will cover the Next Generation Science Standards for middle schools; however, you can easily find the matching standards at the NGSSS website.

Sometimes, after joining the eNable community, it could be difficult to find a recipient right away. If this is the case, you can slightly modify this lesson so students print and assemble a smaller version of a full working hand. In this way, students will gain experience for when you get a recipient.

**The Engineering Design Process**

There are many versions out there of the process, some call the steps with different names; however, the essence of the process is the same. In middle school, students are still learning the process, so I focus on it. I grade students for each of the steps as we complete them and I also assign them a reflection piece. This helps generate multiple grades for those teachers who need to have a minimum of grades per week. Regardless of the grade, from the point of view of the student, the biggest reward is when they deliver the hand.

In the first video, you can see 8 year old Chloe picking up her bookbag for the first time. The boy int he picture is Edward. Chloe lives in England very close to where Edward has family, so he was able to assemble and deliver the hand to Chloe. Both were featured in multiple TV news in England and various social media outlets here in the United States.

## Supplies

All materials for this project can be found in the eNable the Future website and they vary depending on the type of device you will be printing.

## Step 1: Define the Problem

**NGSS Standard: **MS-ETS1-1 Engineering Design

*Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions.*

If you already have a recipient, I recommend having some interaction with the kid and have your own students meet them. If a meeting in person can not be done, they can video chat. You need to make sure the students ask questions to understand what the kid likes. Do they have any favorite superheroes, do they have any favorite characters or movies, what is their favorite color... Interview the kid by asking as many questions as possible so your students have enough information to come up with ideas on how to customize the prosthetic hand.

After student students have met the kid (or if there is no recipient, you can create an imaginary recipient and come up with different likes the fictional recipient has), I ask the students what our constraints are, and make a list of these on the board. Make sure to steer the students' participation so the list includes items like the size of the hand/arm, material to be used, range of motion, time availability and any other constraints that apply to your specific class. I would also remind students of the likes of the kid.

For the purposes of this instructable, I will refer to hypothetical kid Peter. Peter is 7 years old was born with all his fingers missing on his right hand. He likes superheroes, especially Spiderman, and his favorite color is red.

Ask students to create a table where the label of each column is a constraint and is written as a question. This table will be called a Decision Matrix and will be used later in the selection of their design. More on this table on the next step. A grade can be given to the students for the creation of the table. This will assess the standard.

## Step 2: Generate Concepts / Brainstorm Solutions

**NGSS Standard: **MS-ETS1-2

Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.

Once students understand the constraints and what they need to do, ask them to brainstorm ideas on how they would like to customize the hand of the kid. It is very important to point out that there are no crazy ideas (100+ years ago many people called the Wright brothers crazy, now we take airplanes for granted). Any idea is allowed as long as it addressed the problem.

If you are pairing up students, you can ask each student to come up with an individual idea, or if you want students to work individually, you can ask them to come up with more than one idea.

Once students have their concepts, they will use the decision matrix they created in the previous step to assess each concept they came up with. The concept with the highest score will be developed.

In my example, I have a group of 3 students, Oscar, Stacey, and Steve.

Oscar came up with the idea of 3D printing a red hand and buying spiderman stickers to apply them all over the hand.

Stacey came up with the idea of using both, red and blue filament to print multiple parts of the hand. She wants to 3D print a 2" diameter spiderman logo so it can later be glued to the back of the prosthetic hand. After the hand is completed they can paint spiderwebs around the hand.

Steve wants to 3D print a completely pink 3D printed hand.

In this example, both Oscar and Stacey met all the constraints. This means that in the decision matrix their designs tie. When this happen students normally have a pretty good idea of which design they want to use. I ask them to explain the reason why they want to pick a specific design and then ask them to put that reason as a new column on the decision matrix. In my example, students thought that it would be more physically appealing to have a 3D printed spiderman logo rather than just stickers, so they added a new column asking if the design was physically appealing. This became the tiebreaker.

A new grade can be given to the students for completing the brainstorming and decision matrix.

## Step 3: Developing the Solution.

**NGSS Standard:** MS-ETS1-4

Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process such that an optimal design can be achieved.

At this point, students will design the solution they picked. Students can use any CAD program you use at your school. For example, my hypothetical students can use Tinkercad to create a spiderman logo that is 2" in diameter and which will later be glued to the back of the hand.

A new grade can be given to the students for this step.

You can also save time by starting to 3D print all parts of the prosthetic hand while the students work on their design.

## Step 4: Construct and Test the Prototype

Once all parts are 3D printed, you can start assembling the arm. Please remember all resources for this are at the e-NABLE the future website.

Another grade can be given here for the completion of the assembly.

## Step 5: Evaluate and Present the Solution

**NGSS Standard: **MS-ETS1-3.Analyze data from tests to determine similarities and differences among several design solutions to identify the best characteristics of each that can be combined into a new solution to better meet the criteria for success.

Most of the devices your students complete will be revealed to the recipient at the moment you meet them, so there is no much testing that can take place beforehand. One of the workarounds I do is that I find a student that resembles most of the measurements from the recipient and test the fit with that student.

At the reveal I have students interview the recipient in order to determine if the hand or arm fits comfortably. If you sized the files correctly, most adjustments can be done at this point.

## Step 6: Reflection

Every time I end a project, I asked students to answer some questions about their own experiences. Here students reflect on their project and I also take this opportunity to ask them for feedback about the project. Some of the questions I ask are,

What did you like about this project?

What was difficult about this project? How did you manage to work around this difficulty?

If you had more time to work on this project, what would you do?

How can we improve this overall assignment?

Is there any advice you would like to give to future students who work on a prosthetic hand?

For large projects like this, I ask students to create a meme that relates to the project. I end up posting the memes on my windows.