# 17. Use a 3D printer to Manufacture a Mini Me doll

Students will use 3D printing technology to learn how to produce models of themselves at 1:10 scale.

Unit Conversion

### Standards for Mathematical Practice:

CCSS.MATH.PRACTICE.MP1 Make sense of problems and persevere in solving them.
CCSS.MATH.PRACTICE.MP2 Reason abstractly and quantitatively.
CCSS.MATH.PRACTICE.MP3 Construct viable arguments and critique the reasoning of others.
CCSS.MATH.PRACTICE.MP4 Model with mathematics
CCSS.MATH.PRACTICE.MP5 Use appropriate tools strategically
CCSS.MATH.PRACTICE.MP6 Attend to precision.
CCSS.MATH.PRACTICE.MP7 Look for and make use of structure
CCSS.MATH.PRACTICE.MP8 Look for and express regularity in repeated reasoning.

### Learning Objectives:

• Students will design a model and use a 3D printer to manufacture a doll with a 10:1 scale based on their own body measurements
• Students will work within set parameters to design an advertising campaign around their doll and its capabilities
• Students will work within set parameters to design the most impressive doll overall

### Recommendations:

Group Size: 2 to 3 students, depending on how many students are in the class, how many 3d printers are available, and how much time can be allotted for using a 3D printer to manufacture the dolls.

Class Size: up to 40 students

### Materials Required:

• At least one computer per group, loaded with Google Sketchup or Autodesk123 Design
• For this particular lesson, AutoDesk123 Design was a great tool with its ability to round the edges and customize the design.
• Paper and pencil for drafting
• Airwolf 3D Printer
• Compass
• Ruler
• Protractors (recommended, not necessary)
• Super Glue (or Gorilla Glue) to adhere the plastic pieces to each other
• Optional Materials (to facilitate conversation)
• dolls
• action figures
• mini dolls

## Using a 3D Printer to Manufacture a Mini Me Model of yourself.

### Introduction:

• students have a good understanding of 3D modeling. Prior to incorporating this lesson into a unit, it is recommended that students have had training on 3D design.
• Students have a good understanding of SAE (Imperial) and/or Metric units.
• Students have a good understanding of using a ruler

For a video on creating a basic 3D model of yourself, go to

Prior to the day’s lesson, have students bring a doll in to class and leave it in an available cabinet or storage space. Leaving the mystery of the doll’s purpose will add to the value of the reveal of the objectives when it comes up, so the less information to the students the better.

On the first day of the lesson, share the dolls out with the students and ask them how cool it would be to have a 3d printed doll that was a scale model of themselves.

The first pertinent pieces of information that students will need to have are going to be their measurements. See the attached data sheet for a sample of what measurements would be helpful.

Feel free to print this out if devices are not available or share via Google Drive if your classroom has been equipped.

*** Since this is a project about measurements and scale factor of students’ bodies, it will be crucial to be mindful of students in your class that are self-conscious of their body image. Grouping students up so that there is at least one person who is willing to be measured and printed will be a great start. Having students volunteer to be made into a 3d printed doll, then finding partners for them would also be helpful. However you choose to do this, keep the sensitivity of body image in mind. It will also be important to define the parameters of what gets measured. If you teach middle school, this should be obvious! ***

For the sake of ease, have students take their measurements in centimeters, then have them convert the measurements with a 10:1 ratio.

For more advanced students, have them use an obscure conversion, such as a 12:1 or 9.5:1. This would also be useful if you are limited by the number of printers you have or the number of students in the class that will need to use a 3D printer to manufacture their dolls.

For even more advanced students, have them use inches to take their measurements and convert them into millimeters for a 10:1 ratio.

Next, present students with their challenge:

## Design a model and use a 3D printer to manufacture a doll that is scaled to your measurements

The closer you can get to an accurate representation, the better the doll.

Using only paper, pencil, a straight edge, and a lot of imagination, have students design the 2-dimensional version of their doll. Encourage the use of collaboration on this, knowing that students will need to turn their drawings into a 3D rendering. While a natural looking arm would be ideal, substituting them for cylinders would reduce the time necessary to learn advanced 3D modeling skills and would move the project along much faster.

### The Meat:

Within a 3D modeling program, groups will need to design their doll. It is recommended that students use a program that is comfortable for them; if they haven’t spent much time with design, Autodesk 123D Design is a great place to start. As mentioned above, have students substitute cylinders with appropriate measurements for a more natural looking body part. This will save precious time in the process and reduce the stress of the project on the groups.

Something else to consider is printing time and variability in density. For the torso and thighs, a less dense print is advisable. Since we won’t be stress-testing any of the objects, having less density will speed up printing and lower the cost of each product. Also, if time permits, have students print out the pieces individually. If not, 3d printing multiple groups’ doll pieces on the same build plate will move the projects along just fine.

Prior to printing, groups must show their design to at least 2 other groups and have them confirm dimensions and review the doll’s parts for any possible issues that may arise. Once this has been done, groups will send their final .STL file to the instructor and prepare for printing.

When printing, it is advisable to print at least 3 perimeter layers thick, so take this into consideration during the design, especially for the parts being printed with a density less than or equal to 20% fill. Nobody wants to have a 3d printed doll with a droopy torso!

After the design has been printed, students will clean it up and verify all measurements for accuracy with a ruler and a protractor, then check those measurements against the handout data that they had collected.

To assemble the 3d printed doll, students will need to glue each piece together unless they find a way to build in connection components. In the .STL file that has been provided with this lesson, spheres were placed atop each connecting piece, but the stability of them didn’t merit a desirable result. Once again, time permitting, have students mess with the design, try out a couple sample prints of various connection styles, and pick something that works.

If time is an issue, simply printing out the pieces and gluing them together will suffice.

### Discussion:

How did you come up with your design?

What would you differently after seeing everyone else’s product?

Does the doll accurately represent you? Why or why not?

What did you like about someone else’s doll?

How could you market your design? (See below for ideas)

Each one of these questions can provoke thoughtful responses that are rich in mathematical reasoning.

Just like in a Research and Design lab for major companies, the feedback and reflection on these projects will be the best part. Give students an opportunity to talk within their group and among their classmates to seek advice on improvements.  After completing their print, groups will then proceed to:

• Reflect on what went well and what they would improve on if they had a chance to print again
• Create a marketing plan to sell your product to a specific group of people or industry
• Set a desired cost for the doll, including shipping, based on cost to create the product and cost of shipping

For the advertisement, students have the option of their medium.  Whether it is creating  a website, video commercial, radio commercial, magazine ad, billboard, or many others, the key is to be creative in the area that the students are comfortable.  During this portion of the project, students will need to work efficiently within a deadline provided by the instructor.

Following the creation, students will showcase their advertisement with the class. Students can vote on which one is the best to use as the model for the school.

### Desired Outcomes:

A desired outcome is a doll that adequately represents the students whose measurements are being used in a 10:1 scale, or one determined by the instructor.

Content & Instruction Developed by:

John Stevens – Airwolf 3D STEM Consultant
Instructional Coach – Technology
Chaffey Joint Union High School District
CUE Rockstar Faculty & Organizer