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3D Printing vs. Transfer Molding Comparative Analysis

Grades: 10-12
Author: David B. Helmick II
Source: This material is based upon work supported by the National Science Foundation under Grant No. EEC- 1542358.


Abstract

Students are completing a comparative analysis to test the physical properties of a given material using two different devices: a 3D printer & transfer mold machine. In technical terms: students using an extruder will make their own filaments and 3D print Izod Impact Resistance Bars and Tensile Bars to test the material & production-process strength against the same material/shaped bar for Izod & Tensile Bars made using a transfer mold machine. Students will complete a comparative analysis of two tests: Izod Impact Resistance ASTM D-256 & Tensile Strength ASTM D-638M. (Again, optional 3-point bend test could be conducted in place of these two tests). Students will evaluate their data to provide a solution to a real-world problem in industry/society that they determine to answer. Students will need to conduct research to determine a real-world problem. Students’ data must be used to support their claim to their answer of the real-world problem based on prioritized criteria and trade-offs that account for a range of constraints, including cost, safety, reliability, and aesthetics as well as possible social, cultural, and environmental impacts.

*Note* This lesson is written for Engineering Students completing a Polymer Testing Course; but the research aspect can be adapted to fit the research/report needs of a chemistry or physics class with an optional modified 3-point bend testing version with different directionally printed 3-D samples in the worksheets section for those without the proper equipment.


Objectives

What should students know as a result of this lesson?

Through completion of the comparative analysis students should:

  • Define and describe a polymer
  • Compare and contrast a thermoplastic to a thermoset
  • Describe at least two different physical properties of polymers
  • Describe at least two different production processes used to form polymers into end-user forms
  • Define force, stress, and strain
  • Perform the testing procedures for standardized ASTM D-256 & D-638
  • Describe polymer production criteria such as but not limited to: cost, availability, reliability, safety, aesthetics, and environmental aspects.

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

Through completion of the comparative analysis students will be able to:

  • Compare and contrast the advantages and disadvantages of polymers, based on physical properties
  • Determine the production processes used to create products from categories of materials
  • Evaluate the types and magnitude of stresses and forces
  • Analyze material properties by destructive and nondestructive tests
  • Select materials for a given application based on specified criteria (e.g., cost, availability, manufacturability)
  • Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a range of constraints, including cost, safety, reliability, and aeasthetics, as well as possible social, cultural, and environmental impacts.

Materials

  • Desktop Extruder to make 3D printer filament (or store bought filament).
  • 3D Printer with accompanying computer and software to run printer.
  • Transfer Mold Machine
  • Pellet form of polymers for testing such as Acrylonitrile Butadiene Styrene (ABS),Polylactic Acid (PLA), High Impact Polystyrene (HIPS), Polycarbonate (PC), High Density Polypropylene (HDPE), or Low Density Polypropylene (LDPE), etc.

Procedures

Engagement

Engage students by demonstrating how to use the Izod Impact Tester and the Tensile Machine. Both are destructive tests and the students are fully engaged in destroying parts!

Assessment: Student completion of the safety test for using the machines and the accurate execution of using the machines. Students notes in their Engineering Notebooks on proper machine usage and safety procedures.

Exploration

Students can explore on their own by conducting the ASTM tests for each machine and reporting their findings using the standardized report format.

Assessment: Students lab report with reported data collected from the testing machines

Explanation

Students may need further explanation of the testing procedures or trouble shooting while performing the actual test. The instructor needs to be ready to provide just-in-time instruction to the students on an as needed basis for each machine. Only one student can be using a machine at a time, thus allowing the instructor to provide one-to-one instruction.

Verbal interaction between the instructor and student provides great formative assessment to help further instruction. Students final findings will be reported on their lab report, so before students data is collected incorrectly, misconceptions can be addressed and data collection corrected during this time. Students can use their Engineering Notebooks to record data and analyze the consistency of their results. If outliers are present they need to think about what errors they may have made and possible re-test to see if their findings are conclusive or not.

Elaboration

After learning how to use each of these machines to conduct tests on and report their findings, students will begin their comparative analysis of 3D printed vs Transfer Molded Parts. Students will be given the 3D Printed vs Transfer Molded Comparative Analysis Checklist & Rubric to begin their research (see attached rubric in Worksheets section). Students will work individually to research and select a real-world problem or issue in the field of polymer packaging or manufacturing. Students will select an associated material with this problem. Students will then devise their experiment and testing procedures to collect data to validate a conclusion to answer their identified problem based upon the conditions outline in the checklist & rubric.


Prerequisites

This lesson is specifically written for second year students in a two-year career technical education Engineering Program. Students have background in using the associated machines to perform these tests with and some introductory knowledge of polymers. With frontloading and additional resources this lesson could be adapted to use with students that have zero background in polymers. The teacher would need to provide adequate readings or lessons to the students about polymers and their use in industry. Additionally the research aspect of this assignment could be made a group project so that the workload is divided up into content-specialist areas.


Best Teaching Practices

  • Scientific Literacy
  • Metacognition
  • Hands-on/Minds-on Learning
  • Authentic Problem-based or Issue-based Learning
  • Real-life Situations and Problem Solving

Alignment with Standards

NGSS Standards:

Engineering Design

  • HS-ETS1-3. Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a range of constraints, including cost, safety, reliability, and aesthetics as well as possible social, cultural, and environmental impacts.

Ohio Standards:

Engineering and Science Technologies and Manufacturing Technologies Career Field Teachnical Content Standards

  • 5.5.1. Compare and contrast the advantages and disadvantages of organic materials, metals, polymers, ceramics and composites based on physical properties.
  • 5.5.2. Determine the production processes used to create products from categories of materials.
  • 5.5.3. Evaluate the types and magnitude of stresses and forces.
  • 5.5.4. Analyze material properties by destructive and nondestructive tests.
  • 5.5.5. Select materials for a given application based on specified criteria (e.g., cost, availability, manufacturability).

Content Knowledge

ODE Table 2: Expectations for TECHNOLOGICAL AND ENGINEERING DESIGN GRADES 9-12

  • Identify a problem or need, consider design criteria and constraints.
  • Integrate multiple disciplines when problem solving.
  • Synthesize technological and engineering knowledge and design in problem solving.
  • Apply research, development, experimentation and redesign based on feedback to problem solving.

Safety

Engineering and Science Technologies and Manufacturing Technologies Career Field Technical Content Standards

  • Safety, Tools and Equipment
  • Learners apply principles of protection, prevention and mitigation to create and maintain safe working conditions at manufacturing sites. Knowledge and skills may be applied in all aspects of personal and site safety, including handling materials, using tools and equipment, working with and around electricity and using personal protective equipment.

Applications

Polymer Testing, Production Manufacturing, Packaging Industry, and any consumer product production industry.


Assessment

3D Printing vs Transfer Molding Comparative Analysis Final Report.

A typed lab report following the rubric detailed in the Worksheets section.


Other Considerations

Grouping Suggestions:

  • N/A

Pacing/Suggested Time:

  • Students in this class work in an asynchronous classroom environment. Each student develops their own schedule for completing lab work.
  • Suggested time frame for entire completion: 2 weeks, 90 minute class periods, 5 days per week.

Printable PDF Worksheets


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