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Engineering in Medicine

Goal: To learn about engineering in medicine through exploring 3D printed prosthetics

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Emma O’Shea

Breakout Development Team

Kristine Budill

College: Yale and MIT

Major: Electrical Engineering, BS & MS

Industry Experience: General Electric Aircraft Engines, ITT Fluid Technology, Haemonetics

Dylan Weber

College: Fairfield University

Major: Mechanical Engineering, BS

College: Bucknell University

Major: Biomedical Engineering

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Part One: Engineering in Medicine

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Engineering in Medicine

Engineering in medicine is also known as Biomedical engineering
Biomedical engineering is the application of engineering principles and design concepts to medicine and biology for healthcare purposes

Part One: Engineering in Medicine

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What does a Biomedical Engineer do?

Biomedical engineers design and analyze:

Prosthetics and braces
Surgical devices
Medical models
Dental devices
Medicine and treatments
Cells and tissue
And many more!

Part One: Engineering in Medicine

Biomedical engineers design and analyze, Prosthetics and braces, Surgical devices, Medical models, Dental devices, Medicine and treatments, Cells and tissue, And many more! (Can expand discussion using info below)
One field which has completely revolutionized Biomedical engineering is 3D Printing

Biomedical engineers work in a wide variety of settings and disciplines. There are opportunities in industry for innovating, designing, and developing new technologies; in academia furthering research and pushing the frontiers of what is medically possible as well as testing, implementing, and developing new diagnostic tools and medical equipment; and in government for establishing safety standards for medical devices. Many biomedical engineers find employment in cutting-edge start-up companies or as entrepreneurs themselves.

Tissue and stem cell engineers are working towards artificial recreation of human organs, aiding in transplants and helping millions around the world live better lives. Experts in medical devices develop new implantable and external devices such as pacemakers, coronary stents, orthopaedic implants, prosthetics, dental products, and ambulatory devices. Clinical engineers work to ensure that medical equipment is safe and reliable for use in clinical settings. Biomedical engineering is an extremely broad field with many opportunities for specialization.

Source: https://www.mtu.edu/biomedical/department/what-is/

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3D Printing in Medicine

Part One: Engineering in Medicine

3D printing has changed the world of Biomedical Engineering because it is cheap, products are customizable, and the printing process is fast

Some applications include dental implants, auditory devices, and bone implants

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Part One: Engineering in Medicine

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E-Nable

Some things to note about the design of most E-Nable prosthetics:

3D Printed Pieces act as the bones
Pins serve as joints, allowing the bones to move around
Elastic connects to different parts of the bones, providing tension and serving as muscles, tendons, or ligaments.
Attachment mechanisms include a socket where the limb can enter, and/or bands that extend past the prosthetic to the clients existing joints

Part One: Engineering in Medicine

Tension string attached to wrist joint, and socket at base of finger

Open socket for palm, when wrist bent inward tension strings are pulled and fingers close

Now that we have watched this video on E-Nable, let’s make some observations about their prosthetics.

Different pieces are printed to act as the bones. For example, the top right finger prosthetic has 3 “bones”
Pins are either bought or printed to serve as joints, allowing the bones to move around. You can place a pin between two bones allowing them to rotate around.
Different types of elastic or string wrap around the joints and connect to different parts of the bones, providing tension and serving as muscles, tendons, or ligaments. These are what allow the prosthetics to open and close in a controlled manner.
In order to attach a prosthetic to a client, there must be some sort of socket where their remaining limb can enter and push on tensioner strings. Additionally, bands may extend past the prosthetic to the clients remaining joints to provide even more control.
In the bottom right prosthetic, tension string run from the fingertips to the base of the wrist so that when the client bends their wrist, the fingers close.

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E-Nable

These sections are different printed pieces, or “bones” of the finger.

Part One: Engineering in Medicine

You may not be able to see them here, but pins or “joints” are running perpendicular through holes in the “bones” and connecting them.

Tension strings will run through the fingers and holes such as these to give the hand control.

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Part Two: 3D Printing in the Product Development Process

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Part Two: The Product Development Process

Where does 3D Printing fit into this process?

Define and Refine the Idea

Research and Design

Select and Purchase Materials

Create the product

Test the product and Market it

CAD Drawing

3D print the product

Product Manager

Design Engineer

Materials Engineer

Manufacturing Engineer

Quality Engineer

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Does anyone know what CAD stands for? What is the importance of a sketch/drawing in the design process?

CAD and Drawings

Part Two: The Product Development Process

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Computer Aided Design (CAD)

CAD allows for:

Efficient design and optimization
Saving time → Increase in productivity
Improvements in accuracy
Drawing and dimensioning
Creation of complex multi-part assemblies

TinkerCAD is a type of CAD software!

Part Two: The Product Development Process

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Drawings and Dimensioning

With CAD comes another step, and that is DRAWING!

Important for sending your designs to a manufacturer
Specify shape, size, materials, and assembly (if there are multiple parts)
Provide different views, including TOP, FRONT, and SIDE
All parts necessary in building are dimensioned (labeled with a specific measurement)

Drawings serve as a universal language among engineers!

Part Two: The Product Development Process

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Drawing Activity

Part Two: The Product Development Process

Now let’s practice with some simple engineering drawings. Using the images on the left, decide what the top, front, and side views are of the design on the right!

Side

Front

Top

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Drawing Activity

Part Two: The Product Development Process

Now it’s your turn to practice with some simple engineering drawings. Using the images on the left, decide what the top, front, and side views are of the design on the right! Drag these boxes to show your answer:

Side

Front

Top

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Part Three: It’s Your Turn to design a Prosthetic

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Your Prototype Design Constraints:

The maximum dimensions of your object are 10 cm x 10 cm
The height of your object should not exceed 2 cm

Familiarize yourself with different types of E-NABLE prosthetics.
Gain an understanding of how the E-NABLE prosthetic fingers work.
Choose a finger you would be interested in designing to be a prosthetic.
Start by drawing a 1:1 scale sketch of your chosen prosthetic finger.
Design your finger in TinkerCAD!
Resize finger to meet Client needs.
Have fun and be creative!

Your Task Today: Be a Design Engineer

Part Three: Design a Prosthetic

IMPORTANT NOTE:

Teachers can send student CAD files to Engineering Tomorrow for printing. Instructions are located in the Student Workbook and in the Teacher Guide.

Let me walk you through the design challenge that you will be documenting in your student interactive workbook.

Familiarize yourself with different types of E-NABLE prosthetics.
Gain an understanding of how the E-NABLE prosthetic fingers work.
Once you have an understanding, choose a finger you would be interested in designing to be a prosthetic, and follow the Engineering Design Process to effectively execute your idea.
Start by drawing a 1:1 scale sketch of your chosen prosthetic finger, and be sure to dimension the main parts of the finger (length, width, height).
Things to confirm when finished:

Make sure there’s a TOP, FRONT, and SIDE view of the prosthetic finger.
All parts are dimensioned.

Compare your dimensions to the given Client dimensions and resize finger to meet Client needs. Please note that teachers should collect the student CAD files and send them to ET for printing. Instructions for how to do this are located in the student workbook and the teacher guide.
Have fun and be creative!

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Different 3D Printed Prosthetics

Part Three: Design a Prosthetic

When 3D printing prosthetics, the possibilities are endless! E-Nable has designs for anything from a singular finger to an entire arm!

These prosthetics all provide different levels of functionality, depending on what the client needs.

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Observing 3D Printed Hands

Based on the observations made after watching the video, answer the following questions about this prosthetic hand:

How does the prosthetic attach to the body?

How many parts or “bones” of the finger are there?

How many pins or “joints” are there in the fingers?

How do the joints work to provide function?

Part Three: Design a Prosthetic

Attaches to the wrist, with a socket for remaining limb
2 bones, 2 joints
Tensioner strings pull down to wrist

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Brainstorm and Build

Part Three: Design a Prosthetic

The next step is for you to choose which finger you are going to design a prosthetic for.

Then, based on your answers to the questions about the design of 3D printed hands, answer these same questions about a singular finger:

How many bones and joints are you going to include?
How are you going to attach your finger to the client?

Make a to-scale engineering drawing of your design, showing TOP, FRONT, and SIDE views and the dimensions of three sides.

Design your finger in TinkerCAD.

Now that you have designed your prosthetic in TinkerCAD, it is time to fit it to a client!

To wrap up let’s look at the final steps of your project.

First you will want to make a plan, start this by deciding which finger you are going to design a prosthetic for. Let’s answer some questions to help you with your design:

How many bones and joints are you going to include?

Probably 2-3 bones, 2-3 joints

How are you going to attach your finger to the client?

Wrist band that attaches to finger tip with tensioner string

Using what you learned from the engineering drawings in the introduction, make a sketch of your design. This sketch should be to-scale, and you should dimension three different parts of your finger as is done in engineering drawings. You should also include TOP, FRONT, and SIDE views of your design.

Now it is time to model your finger on Tinkercad! (or your program of choice). You should take into account some of the design choices you will have to make. How might the client want their finger to look? What is the most practical? What type of materials would be best to prevent wear and tear?

Finally, lets fit your prosthetic to a client. Using these specs, you should resize your TinkerCAD design: Your client has a remaining portion of their finger that is 21 mm long with a circumference of 18 mm.

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If you liked today’s breakout, you may be interested in these topics:

Types of Engineering Relevant to today’s 3D Printing breakout:

Rapid Prototyping
3D Printing of COVID-19 PPE
Other Materials: 3D Printing with Wood and Metal here and here
Career in Biomedical Engineering
Free CAD Programs for 3D Printing

Materials Science
Computer Science
Mechanical Engineering
Civil Engineering
Mechatronics
Biomedical Engineering

Continue to Explore

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Student Interactive Workbook:

Zoom Session #2:

Watch all videos to reinforce key engineering concepts
Complete all activities to assess for understanding
COMPLETE EXIT TICKETS

You should be at least halfway through your workbook
College students provide feedback on your initial designs

Next Steps

Zoom Session #3:

Share your final design
Get feedback on your work from an engineer