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Akron Global Polymer Academy Lesson Plans

Mechanical Properties of 3D Printed Parts in Fused Deposition Modeling

Grades: 9-12
Author: Todd Alkire
Source: Original - This material is based upon work supported by the National Science Foundation under Grant No. EEC- 1542358.


Abstract

Today's students are not aware of the many uses of polymers in their daily life. In this experiment, students will examine the mechanical properties of 3D parts to solve a real world problem. Students will determine the optimal mechanical properties of components fabricated with 3D printers. Students will create 3D printed parts with various print specifications such as orientation, temperature, infill, layer thickness, etc. This research, testing and analysis will then be used by the students to create a DIY assistive technology (DIY-AT), "which is any device or system that allows an individual to perform a task that they would otherwise be unable to do, or increases the ease and safety with which the task can be performed"�� [1]. Once the students have created their 3D printed parts, they will conduct a tensile test. The data collected will be graphed and analyzed with the conclusion of the experiment to be a collaborative discussion of the Students will use data gathered from the tensile testing to determine optimal properties for use in assistive technology.

[1] Cowen,D. & Turner-Smith,A. The role of assistive technology in alternative models of care for older people. In Sutherland,I. (ed.) With Respect To Old Age:The Royal Commission for the Long Term Care of the Elderly (1999), Stationary Office, 325-346


Objectives

What should students know as a result of this lesson?

What should the students be able to do as a result of this lesson?


Materials

Testing Apparatus


Procedures

Engagement Part 1: Checking Student’s Past Knowledge of Polymers

  1. Teacher will ask students to make a list with their partner of polymers they come into contact with in a day. Students are not to use their phones or electronic devices.
  2. Teacher will then ask the students to report out (expecting answers like plastic water bottles, pens, computers, baggies, etc) Teacher will then point out some of the less obvious polymers that students that they come in contact with daily.
  3. Teacher will take this opportunity to "define" a polymer.
  4. Students will then have the opportunity to "play" with polymers (this is teacher's' choice-silly putty, diaper magician, etc)

Engagement Part 2: Real Life Example of Polymers Used for Service

  1. Teacher will lead a discussion with the students explaining the application of polymers in additive manufacturing.
  2. Teacher will then narrow that discussion by showing a video on fused deposition modeling. https://www.youtube.com/watch?v=WHO6G67GJbM
  3. Teacher will then demonstrate actual 3D printing in operation. Students will be able to walk around the lab and watch the printing as well as handle the parts produced.
  4. Teacher will play a video on prosthetics. https://www.youtube.com/watch?v=3ZyDLGgSj60
  5. Teacher will discuss with the students that the goal of this lesson is to use their knowledge for service. Teacher will explain what assistive technology is and how it will relate to this lesson. "Our typical mechanical projects are not necessarily impactful on the world." "Now that you have seen this video you can see how easy it would be for us to help".
  6. Teacher will direct students to a think-pair-share brainstorming different uses of polymers for assistive technology. (expected answers are to align with the definition of AT). If there is time remaining students will report out their list.

Exploration Part 1: Create the part in Computer Aided Design (CAD) software

The use of Computer Aided Design (CAD) software must be used to create the part file to eventually be tested. Software such as SolidWorks and Autodesk Inventor are common but can be costly for a normal classroom environment. OpenSource programs such as OpenScad, FreeCAD, and Google SketchUp are free, easy to learn, and will be more than sufficient for this project. This procedure assumes students have access to and are fluent in some sort of CAD software.

3D Printer Parts

3D Printer Parts

3D Printer Parts

Exploration Part 2: Strength Test Procedure of 3D Printed Filament

In engineering, flexure or bending describes the behavior of a structural element subjected to an external load. The load is applied perpendicular to the longitudinal axis of the test specimen. In this experiment we will conduct a destructive test to determine the maximum weight capacity of the printed test beam. Essentially adding weight until the part breaks.

3D Printer Parts

Materials:

Testing Apparatus:

3D Printer Parts

Testing the Part:

Explanation

Teams will share the results of their experiment by creating a poster to include the following items. The poster is to be 24" x 24" and include the following items.

Elaboration


Prerequisites

Students will need previous experience with some sort of CAD software. For the inexperienced user most software websites have extensive videos/tutorials to create the test specimens for this activity. The level of CAD knowledge necessary is relatively basic.


Best Teaching Practices


Alignment with Standards

NGSS Standards:

Ohio Standards:

Ohio Career Field Content Standards
Strand 5. Pre-Engineering: Design and Development Learners apply principles of design and development related to the design process, sketching and visualization, modeling, drafting, materials and production and process design.


Content Knowledge

N/A


Safety


Applications

Polymeric materials such as plastics are used in a wide variety of items on a daily basis and many of these materials are being used in structural capacity. It is important to understand the mechanical properties of these materials for the proper application.

The use of assistive technology can be prohibitive for the end user due to cost, generic design, and the complexity of ever changing needs of the individual. The need for DIY-assistive technology is constantly growing.


Assessment

Teams will share the results of their experiment by creating a poster to include the following items. The poster is to be 24" x 24" and include the following items.


Other Considerations

Grouping Suggestions: Groups of no more than 2-3 students is suggested.

Pacing/Suggested Time: This lesson was written under the assumption of a lack of technical equipment to conduct a true tensile or flexure test. The apparatus as demonstrated cost less than $11. The ability to create stress-strain curves and derive the modulus of the specimen can be conducted with commercially made equipment and software from companies such as Vernier, PASCO, Pitsco and AMT Stress Analyzer 1000. This project can easily stretch into weeks if necessary. To save time one can omit the CAD lesson and print all the test specimens prior and focus only on the strength test.


Printable PDF Worksheets


Safety Disclaimer