3D Printed Grabbers - SCOPES Digital Fabrication

Lesson Details

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Author

Rich Lehrer
Rich Lehrer
K-12 teacher

Summary

This lesson will teach STEM and design concepts. It is adapted from an 8-module curriculum centering around the use of 3D printed prosthetics and other assistive devices. This curriculum is aimed at grades 7-10 and provides teachers with a mechanism for creating highly engaging and meaningful learning experiences for students through the creation, customization,and engineering of a tool intended to introduce 3D printed assistive devices.

What You'll Need

Key Concepts

Forces
http://www.innerbody.com/image/musc04.html
https://sites.google.com/a/cpsdigital.org/peraplegic/human-prosthetics

Friction
http://www.ck12.org/physical-science/Types-of-Friction-in-Physical-Science/lesson/Types-of-Friction-MS-P S/
https://www.youtube.com/watch?v=9XtGJXVnQxk

Elastic Potential Energy
https://www.khanacademy.org/science/physics/work-and-energy/hookes-law/a/what-is-elastic-potential-ene rgy
https://www.youtube.com/watch?v=9LB6JeW39kU

Energy Transformations
http://science.howstuffworks.com/prosthetic-limb4.htm
https://sites.google.com/a/cpsdigital.org/peraplegic/human-prosthetics http://www.upperlimbprosthetics.info/index.php?p=1_9_Body-Powered

Materials Science https://sites.google.com/a/cpsdigital.org/peraplegic/human-prosthetics http://science.howstuffworks.com/prosthetic-limb2.htm http://www.explainthatstuff.com/prosthetic-artificial-limbs.html
https://3dprintingindustry.com/3d-printing-basics-free-beginners-guide/materials/

Hand Biology
http://www.ncbi.nlm.nih.gov/books/NBK279362/ https://www.youtube.com/watch?v=zyl6eoU-3Rg

Key Vocabulary

amputation: The removal of an appendage due to trauma, bacterial infection or life-threatening cause. A traumatic amputation occurs when an appendage is removed as a result of the trauma without medical care, such as a bomb.

amputee: A person with an amputation.

components: The internal working parts of a prosthesis.

composite: A material that is a combination of multiple material components, designed to have specific properties, such as carbon fiber.

constraints: In engineering design, the limitations and requirements that must be considered when designing a workable solution to a problem.

cosmetic prosthesis: A prosthesis that enhances a person’s appearance or completeness, but has no functional purpose. For example, a replacement glass eyeball is a cosmetic prosthesis if it does not also restore vision.

cover: As relates to prostheses, material used to cover a prosthesis to make it appear more lifelike. criteria: In engineering design, the objectives that a final design solution is required to meet.

functionality: As relates to prostheses, the ability of a prosthesis to have a purpose or reason for designing it in a specific way. For example, a wood peg leg has less functionality than a modern prosthetic leg that enables an athlete to run competitively.

interface: The point where a prosthetic device meets a residual limb.

prosthesis: An artificial device, either external or implanted, that replaces or supplements a missing or defective body part, such as a tooth, eye, facial bone, palate, hip, knee joint, leg, arm, hand, etc. May be designed for functional or cosmetic reasons or both. (plural: prostheses)

prosthetics: The surgical, dental and/or engineering specialty concerned with the design, fabrication and fitting of prostheses.

regenerate: (biology) To renew or restore  a  lost,  removed  or  injured  part. residual limb: The remaining portion of a body’s appendage or limb after amputation.

tissue engineering: The use of cells, and biochemical and physiochemical factors to design new biomaterials to replace lost or damaged body materials that have specific biological functions. transfemoral: A prosthesis that replaces the leg from above the knee (includes the knee, angle, foot and toes).

transhumeral: A prosthesis that replaces the arm from above the elbow (includes the elbow, wrist, hand and fingers).

transradial: A prosthesis that replaces the arm from below the elbow (includes the wrist, hand and fingers). transtibial: A prosthesis that replaces the leg from below the knee (includes the ankle, foot and toes). trauma: An event causing severe damage to the body.

Materials List

(see also lists below in each step)

  • Various hand tools for assembly (screwdrivers, hammers, scissors, needle nose pliers, files, etc)
  • 1 lengths of PVC pipes with a hole drilled through
  • Elasticized cord (2 x 15cm pieces)
  • Fishing line (2 x 50cm pieces)

Digital Fabrication Equipment Details

Hardware

  • 3D Printer
  • 3D Printing Filament

Software

  • Tinkercad

Design Files: https://drive.google.com/drive/folders/0B3tPBZnliO7bSkljT0otc1l0S28?usp=sharing

The Instructions

Map of the Lessons

Steps:

  1. Define disability
  2. Science behind prosthetic performance
  3. Understanding a design process
  4. Hack a raptor
  5. Create design files for knuckles & fingers
  6. Build a Grap-tor
  7. “Animalize” your Grab-tor

Step One: Define disability

Essential Question: What do you think of when you hear the word “disability?

Bell Ringer (10 Minutes): In a full class discussion, have students generate a list (or Wordle) of words that answer the question: What do you think of when you hear the word “disability?

Show the video “We’re the Superheroes” – Rio Paralympics Trailer

Return to the list – are there any terms we would like to add, change, remove, etc. Have any students changed their concept of the term “disability”?

Teacher Talk (25 Minutes): Share “Upper Limb Differences” powerpoint with students

On Smartboard show the following videos:

  1. PBS Newshour: “Robotic arms”
  2. “Hands of the Future”
  3. “The DARPA Challenge”
  4. Tech Crunch: “The Future of 3D Printed Prosthetics”
  5. How 3D Printing Gave These Animals a New Life

In-class writing (20 Minutes): Using “Next Generation Assistive Devices” jigsaw activity – Have students write short responses (ungraded) on their preconceptions about disability and track their understanding of concepts.

Step Two: Science behind prosthetic performance

Essential Question: What are the areas of science that affect prosthetic performance?

  1. Bell Ringer: (10 Minutes): Show video: How It’s Made: Robot Arm
  2. Teacher and Student Talk (20 Minutes)Conduct a brainstorming session of questions relating to the different areas of scientific concepts that influence the performance of prosthetic devices: forces, friction, simple machines, elastic potential energy, energy transformations, materials science, and hand biology.
    Forces
    http://www.innerbody.com/image/musc04.html
    https://sites.google.com/a/cpsdigital.org/peraplegic/human-prostheticsFriction
    http://www.ck12.org/physical-science/Types-of-Friction-in-Physical-Science/lesson/Types-of-Friction-MS-P S/
    https://www.youtube.com/watch?v=9XtGJXVnQxk

    Elastic Potential Energy
    https://www.khanacademy.org/science/physics/work-and-nergy/hookes-law/a/what-is-elastic-potential-energy
    https://www.youtube.com/watch?v=9LB6JeW39kU

    Energy Transformations
    http://science.howstuffworks.com/prosthetic-limb4.htm
    https://sites.google.com/a/cpsdigital.org/peraplegic/human-prosthetics http://www.upperlimbprosthetics.info/index.php?p=1_9_Body-Powered

    Materials science https://sites.google.com/a/cpsdigital.org/peraplegic/human-prosthetics http://science.howstuffworks.com/prosthetic-limb2.htm http://www.explainthatstuff.com/prosthetic-artificial-limbs.html
    https://3dprintingindustry.com/3d-printing-basics-free-beginners-guide/materials/

    Hand biology
    http://www.ncbi.nlm.nih.gov/books/NBK279362/ https://www.youtube.com/watch?v=zyl6eoU-3Rg

  3. Transition ( 5 Minutes): Explain to students that they will learn about 3D Printed Assistive Devices. First, we will find out what they already know
  4. Pre-Assessment (15 Minutes)

Pre-assessment of student understanding based on responses on the know/want-to-know/learned (KWL) Chart

K: What do I know about 3D Printed Assistive Devices? W: What do I want to find out?

L: What have I learned?

Step Three: Understand a Design Process

Essential Question: What is the Design Process?

  1. Warm-Up (10 Minutes): Have students move through the steps of the Design Squad Designs, Design Process Sheet
  2. Divide students into groupsTEACHER’S NOTE: Consider these methods for grouping students: Count Off (eg. 1, 2, 3, 4, 1, 2, 3, 4…..)
    Popsicle Stick (Randomly select students for groups) Socio-emotional (Behavior, Independent, Processing skills) Ability Groups (homogenous or heterogeneous)
  3. Gallery Walk (30 Minutes) – Introduce concept of a gallery walk, including expectationsGallery Walk Activity (Student Engagement):
    1. Divide the class into groups and give each a large piece of poster paper
    2. Each group will receive a resource defining the Design Process (ex. handout, website) that they will research for 20 minutes. Once group has thoroughly investigated the resource they have been assigned, they will create a “gallery artifact” (i.e. informational poster) that gives the following information:
      1. Topic or title of Resource
      2. Brief (no more than 3 sentences) summary of resource
      3. Top 5 points that one should learn from this resource
      4. Reflection on the piece (choose one):
        1. “This was an important piece because…”
        2. “This resource made us think differently about because     
        3. “One thing that concerned us about this piece was because       
    3. Groups will post their “gallery artifacts” around the room
    4. Gallery walk – Students will silently walk around the room, focusing on
  4. Formative Assessment: Students write one-page (ungraded) on key concepts of Design

Step Four: Hack a Raptor

TEACHER NOTES:

  • Although the creating of the Grab-Tor files is presented as a single one-hour lesson, it is conceivable that it may take longer, depending on students familiarity with 3D designing and printing, the number of printers available at a school, etc. etc.. Consider needing some flexibility in terms of implementing this lesson.
  • Consider creating a class Tinkercad account – This will allow easy organization of and access to student designs. Please note that if multiple students are logged onto the same Tinkercad Account, when one logs off all are logged off. Each student (if creating individually) or group (if working in groups) will need a computer, calipers, PVC pipe, access to the class Tinkercad account, access to the Hack a Raptor Powerpoint
  • Time to print may be a limiting factor in this Allow for 6 or more hours to print each set of Grab-Tor materials. Consider planning other activities and lessons that will be implemented during the time it takes to print the class set of Grab-Tor materials.
  1. Bell Ringer (10 Minutes): Show Video: Raptor Hacking “The Beast vs Pig, https://www.youtube.com/watch?v=Kwh_mO5xMP4
  2. Show the video Creating the “Grab-Tor” – An introduction to “Raptor Hacking” and explain that this is what students will be building
  3. Review Rubrics and Student Assignments – 2.1-2.3 Grab-Tor Assessment Checklist

Step Five: Create Design Files for Knuckles & Fingers (40 Minutes)

A. Knuckle Ring

  1. Slides 1-29 of the Hack a Raptor Powerpoint contain all the information that students will need to turn a Raptor Reloaded STL file into a Grab-Tor knuckle ring.
  2. Have students work through these slides, providing assistance where necessary. It may be helpful to also have a completed Grab-Tor available that will give students a sense of what the completed product will look like.
  3. The larger the Grab-Tor, the easier it will be for students to build. This Powerpoint guides students to building a 120% scale Grabtor.
  4. Students will undoubtedly complete this section at different rates, depending on their designing abilities. Consider having students move to the “Animalizing your Grab-Tor” section (Slides 52-65 of the Hack a Raptor Powerpoint) if they finish early.B. Fingers
  5. Once the Grab-Tor knuckle ring has been created, consider having students also add fingertips, proximal phalanges, fingertip pins, and knuckle pins to the build plate so that these might print at the same time. Students can find these on slides 25-29 of the Hack a Raptor Powerpoint. Note: this Powerpoint recommends printing fingers and pins at 117% to reduce friction between the knuckle ring and proximal phalanges.
  6. In order to print files, have students follow slides 30-38 of the Hack a Raptor Powerpoint. Note: this Powerpoint guides students through the use of a MakerBot Replicator to print but these files may be printed on any model of printer.
  7. WRAP-UP
    • Discuss with students the schedule for printing all groups’ Grab-Tor pieces
    • Encourage students to regularly refer to Grab-Tor Assessment Checklist

Step Six: Build the Grab-tor (Grabbing Raptor)

  1. TEACHER Prep: Building a Grab-Tor is an activity that can be done individually or in groups of 2 or Teachers may find it difficult to have students equitably share the workload in groups larger than 3.A. For each individual/group building a Grab-tor, students will need materials including:
    • 1  length of PVC pipes with a hole drilled through
    • Elasticized cord (2 x 15cm pieces)
    • Fishing line (2 x 50cm pieces)
    • Scissors
    • Needle nose pliers
    • 3D printed Grab-Tor pieces
      • 1 knuckle ring w/120% knuckles
      • 2 fingertips @ 117%
      • 2 proximal phalanges @ 117%
      • 2 knuckle pins @ 117%
      • 2 finger pins @117%B. Print off enough “Building a Grab-Tor” packets from the Hack a Raptor Powerpoint
    • Depending on experience, it could take from 30-60 minutes for a youth or adult to build a Grab-Tor
    • Ensure that all parts are pre-printed and assembled into “building kits” including all 3D printed parts, bungees, cords, and PVC pipes
    • Ensure that you have enough pairs of scissors, needle nose pliers, tweezers, and PVC pipe cutters on hand and that you have plenty of
    • Pre cut and drill PVC pipes
  2. DESIGN PROCESS (20 Minutes)- Consider creating progressive “work stations” with support at each station:
    • Confirming parts, explaining overall approach and attaching knuckle ring
    • Proximal phalanges, and fingertips
    • Attaching bungees to both fingers
    • Attaching cords to both fingers and trouble-shooting your Grab-Tor
  3. Have students access slides 39 – 51 of the Hack a Raptor Powerpoint or print hard copies of these slides..
  4. WRAP-UP (10 Minutes):
    • Conduct a brief review of the status of each group’s Grab-Tor construction.
    • Assign completion work where appropriate.

Step Seven: “Animalize” your Grab-tor

TEACHER NOTE: Following design of “Animalized” Grab-Tor, teachers will need to decide on the printing schedule and construction of the devices

BELL RINGER: Show 10 Amazing Animal Predators or Bird Feeding Adaptations and discuss natural selection of claws, beaks, jaws, and talons

  1. Have students access slides 52-65 of the Hack a Raptor Powerpoint
  2. Teachers may choose to have students design or find fingertip attachments to fuse to the Raptor fingertips based on a number of criteria (“prey” they will be grabbing, specific form/function relationships to explore, nature of “natural selection lesson” being explored, etc. etc.). If designing, Tinkercad is an effective tool. If finding attachment STL files, Thingiverse is a good resource.
  3. The Hack a Raptor Powerpoint focuses on one of these possible adaptations: a bear Although the Hack a Raptor Powerpoint focuses on one of these possible adaptations: a bear claw, the Powerpoint also contains information on how to “Design Removable Claws for your Grab-Tor” on slides 74-96″ for any educators looking to extend this work with their students
  4. Share Grab-Tor Assessment Checklist with students and discuss the “functionality test” in which students will be Teachers may choose to develop this independently or with class, deciding on such things as:
    1. What will constitute the prey
    2. How effectiveness of Grab-Tor will be analyzed
    3. The role of “time to complete” task in the functionality test
    4. Other thoughts generated during discussion
  5. Have students follow the steps on slides 52-65 of Hack a Raptor Powerpoint.
  6. Complete the lesson/module by having all groups participate in the “functionality test”
  7. Have students assess the performance of their own and other groups’ “Animalized” Grab-Tors using the Grab-Tor Assessment Checklist

Lesson Feedback

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  1. SCOPES-DF March 8, 2019
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