Session 7: “Understanding Strength: How Design Affects Durability”
Architect:
Syed Shayaan Haider - Markhor3D
Session Overview
Building on their observations from previous sessions, Grade 5 students will explore what makes a 3D printed object strong or weak. They will learn about structural strength and how different design elements like thickness, support structures, infill patterns, print orientation, ribs, trusses, fillets, and chamfers influence the durability of their models. The teacher will introduce DFAM (Design for Additive Manufacturing) principles, emphasizing the importance of designing efficiently to use optimal materials and time. Students will also participate in a design challenge to create the strongest possible 3×3×8 cm rectangle by removing unnecessary material and adding spars and ribs. Additionally, they will learn how to create fillets and chamfers in TinkerCad to enhance the strength of their designs. By relating these concepts to their own printed objects, students will identify areas for improvement and understand how thoughtful design contributes to the functionality and longevity of their creations.
Learning Objectives
By the end of the session, Grade 5 students will:
- Understand Structural Strength: Learn what makes an object strong or weak in 3D printing.
- Identify Design Elements Affecting Durability: Recognize how thickness, support structures, infill patterns, print orientation, ribs, trusses, fillets, chamfers, and shape influence the strength of their models.
- Evaluate Their Printed Objects: Apply the concepts learned to assess the durability of their own 3D printed creations.
- Design Efficiently: Understand the importance of using optimal materials and time by designing models that are both strong and efficient.
- Participate in Design Challenge: Engage in a hands-on activity to create the strongest possible 3×3×8 cm rectangle using design principles.
- Learn to Create Fillets and Chamfers in TinkerCad: Understand and apply simple techniques to add fillets and chamfers to their models, enhancing strength and aesthetics.
- Prepare for Future Projects: Gain foundational knowledge for future activities, such as designing and building a bridge.
Teaching Aids
Visual Aids:
- Demonstration Videos: Clips showing examples of strong vs. weak 3D printed objects and how different design elements affect durability.
- Step-by-Step Guides: Simple screenshots or slides outlining each concept of structural strength.
- Example Models: Display models with varying thicknesses, infill patterns, print orientations, ribs, trusses, fillets, and chamfers to illustrate different strengths.
- Infographics: Visual guides explaining how design elements like wall thickness, infill, print orientation, ribs, trusses, fillets, and chamfers impact durability.
Required Equipment:
-
Printed Objects:
- Each student’s 3D printed model for evaluation.
- Additional samples demonstrating different strengths and weaknesses.
-
Measuring Tools:
- Rulers or digital calipers suitable for measuring small dimensions.
-
Computers or Tablets:
- For accessing demonstration videos and digital guides.
-
Interactive Whiteboard or Projector:
- For live demonstrations and displaying examples.
-
Notebooks and Pens:
- For students to take notes on the concepts and evaluate their designs.
-
Assistants or Volunteers:
- Additional adults to help guide students through the evaluation process and explain concepts.
Structure and Lesson Plan (Total Time: 60 minutes)
1. Introduction and Linking to Previous Sessions (5 minutes)
-
Greet the Students:
- “Good morning, Grade 5! Today, we’re going to learn about what makes our 3D printed objects strong or weak.”
-
Recap Previous Sessions:
- “Last time, you finished your designs and prepared them for printing. Today, we’ll see how your designs hold up and learn how to make them even better.”
-
Present the Session Overview:
- “We’ll talk about things like thickness, support structures, infill patterns, print orientation, ribs, trusses, fillets, and chamfers. You’ll see how these elements affect the strength of your models and how to design efficiently.”
2. Understanding Structural Strength (10 minutes)
-
Explain Structural Strength:
- “Structural strength is how strong your object is. A strong object can hold up better and last longer without breaking.”
-
Show Real-World Examples:
- “Think about a pencil. If it’s too thin, it can break easily. But if it’s thick, it’s stronger and lasts longer.”
-
Discussion:
- “Why do you think some objects are stronger than others? What design features make them sturdy?”
3. Identifying Design Elements Affecting Durability (15 minutes)
-
Explain Key Concepts:
-
Thickness:
- “Thicker walls make your object stronger. Imagine a thick box vs. a thin box—the thick one is sturdier.”
-
Support Structures:
- “Supports help hold up parts of your model that hang in the air. Without them, those parts might break or sag.”
-
Infill Patterns and Density:
- “Infill is the inside of your model. Different patterns and densities can make your object stronger or lighter. Using 100% infill means filling the entire inside, but it uses a lot of material and takes more time to print. Instead, we use special designs like ribs or trusses and a reasonable infill density (like 20-30%) to make it strong without wasting material.”
-
Print Orientation:
- “The way you place your model in the printer affects its strength. Some directions make it stronger in certain ways.”
-
Shape:
- “Shapes like triangles and rectangles can add strength, while very thin or odd shapes might be weaker.”
-
Fillets and Chamfers:
- Fillets: “Fillets are smooth, rounded edges. They help spread out the stress on your object, making it less likely to crack.”
- Chamfers: “Chamfers are beveled edges, like cutting off the corner of a box. They also help reduce stress and make your design stronger.”
- Creating Fillets and Chamfers in TinkerCad:
- Fillets: “In TinkerCad, you can add fillets by using the fillet shape from the community shapes. Drag the fillet onto your model and adjust its size to round the edges.”
- Chamfers: “To create chamfers, use small triangles. Place a triangle on the edge where you want to bevel it and adjust its position to create a beveled edge.”
-
-
Show Example Models:
- “Here are two boxes. Notice how the thick box is stronger than the thin box. This phone holder has ribs to keep it sturdy. Also, see how adding rounded edges with fillets makes the object stronger.”
-
Hands-On Activity:
- “Examine the example models and identify the different design elements we talked about. How do they make the objects stronger?”
4. Design Challenge: Creating the Strongest 3×3×8 cm Rectangle (20minutes)
-
Explain the Design Challenge:
- “Now, let’s put what we’ve learned into action. Your challenge is to design the strongest possible rectangle that measures 3 cm wide, 3 cm deep, and 8 cm tall.”
-
Provide Instructions:
-
Step 1: Start with a Base Shape:
- “Begin by dragging a box onto the TinkerCad workplane and set its dimensions to 3 cm wide, 3 cm deep, and 8 cm tall.”
-
Step 2: Enhance Strength:
- "Think about how to make this rectangle strong. You can:
- Add Ribs or Trusses: “Use thin supports inside the rectangle to add strength without adding much material.”
- Use Fillets and Chamfers: “Round the edges with fillets or bevel them with chamfers to reduce stress points.”
- Optimize Infill: “Instead of using 100% infill, use a lower density and incorporate ribs or trusses to maintain strength.”
- "Think about how to make this rectangle strong. You can:
-
Step 3: Remove Unnecessary Material:
- “Remove any parts that aren’t needed to make your design efficient. This helps save material and reduces print time.”
-
-
Recommend Efficient Design:
- “Instead of filling the entire inside with infill, which uses a lot of material and takes more time to print, focus on adding ribs or trusses. These are special designs that make your object strong without using too much material.”
-
Hands-On Activity:
- “Take your computer or tablet and start designing your 3×3×8 cm rectangle in TinkerCad. Use ribs, trusses, fillets, and chamfers to make it as strong as possible while keeping it efficient.”
-
Teacher and Assistant Support:
- Circulate the room to assist students with their designs.
- Provide tips on where to add ribs or trusses and how to apply fillets and chamfers in TinkerCad.
- Encourage students to think critically about where strength is needed most in their rectangle.
5. Evaluating and Refining Designs (8 minutes)
-
Explain the Evaluation Process:
- “After designing your rectangle, let’s evaluate how strong it is by checking its structure and making any necessary improvements.”
-
Hands-On Activity:
-
Step 1: Review Design Elements:
- “Look at your design and ensure you’ve added ribs or trusses where needed and applied fillets or chamfers to the edges.”
-
Step 2: Measure and Adjust:
- “Double-check the dimensions to make sure your rectangle is exactly 3×3×8 cm. Make any adjustments if necessary.”
-
Step 3: Optimize Efficiency:
- “Ensure you’re using materials efficiently by removing any unnecessary parts and maintaining a reasonable infill density.”
-
-
Discussion:
- “How did adding ribs or trusses help your design? Did fillets or chamfers make your rectangle stronger?”
6. Sharing Observations and Feedback (7 minutes)
-
Invite Students to Share:
- “Would anyone like to share their rectangle design and explain how they made it strong?”
-
Provide Positive Feedback:
- “Great job on your rectangle! The ribs you added inside make it really sturdy.”
- “I love how you rounded the edges with fillets. It helps spread out the stress and prevents cracking.”
-
Encourage Peer Feedback:
- “Listen to your classmates’ designs and think about what you can learn from their designs to improve your own projects.”
7. Conclusion and Next Steps (3 minutes)
-
Summarize the Session:
- “Today, you learned what makes your 3D printed objects strong or weak. You saw how thickness, supports, infill patterns, print orientation, ribs, trusses, fillets, and chamfers affect durability. You also took on a design challenge to create the strongest 3×3×8 cm rectangle.”
-
Preview Next Session:
- “In our next class, we’ll start designing our bridge project. You’ll use everything you’ve learned about strength and efficiency to create a bridge that can hold weight and look great.”
-
Closing Encouragement:
- “Keep thinking about how to make your designs strong and efficient. Great work today, everyone!”
Glossary
- Structural Strength: How strong an object is and how well it can hold up without breaking.
- Thickness: The measurement of how thick the walls of your model are. Thicker walls are stronger.
- Support Structures: Extra pieces added to hold up parts of the model that hang in the air during printing.
- Infill Patterns: The internal structure of your model that affects its strength and weight.
- Infill Density: How much of the inside of your model is filled. Lower densities use less material but can be weaker unless special designs are used.
- Print Orientation: The way you position your model in the 3D printer, which can influence its strength.
- Ribs: Thin, sturdy supports added to the design to increase strength without using much material.
- Trusses: A network of small triangles added to the design to provide strength and stability.
- Fillets: Rounded edges that help spread out stress and prevent cracks.
- Chamfers: Beveled edges that also help spread out stress and add strength to parts.
- DFAM (Design for Additive Manufacturing): Guidelines to design 3D models that print successfully and are functional.
- Extrusion: The process of adding height to a 2D sketch to create a 3D object.
- Precision: The quality of being exact and accurate in measurements and design.
- Pivot Point: The fixed point around which a part rotates or moves.
- Rotational Motion: Movement in which an object rotates around an axis or pivot point.
- Layer Lines: The visible lines on a 3D printed object that show where each new layer of plastic was added.
- Top Layer: The very last layer printed on an object, which can affect its finish and appearance.
- Bottom Layer: The first layer printed that adheres to the print bed, important for the object’s stability.
- Scaling: Changing the size of an object while keeping its proportions the same.
For suggestions, improvements, and corrections, feel free to reach out at shayaanhaider@gmail.com