Session 8: “Designing with Moving Parts”
Architect:
Syed Shayaan Haider - Markhor3D
Learning Objectives
By the end of the session, Grade 4 students will:
- Understand Moving Assemblies: Learn the basics of designing simple assemblies with moving parts, such as hinges, pinwheels, and toy cars.
- Design with Clearances: Comprehend the importance of clearances to ensure moving parts fit and operate smoothly without fusing during printing.
- Create Functional Components: Use TinkerCad to design components that can move independently within a single assembly.
- Apply Mechanical Concepts: Explore basic mechanical principles like pivot points and rotational motion through hands-on design.
- Enhance Precision and Detail: Develop skills in precise alignment and grouping to create functional and aesthetically pleasing moving assemblies.
Teaching Aids
Visual Aids:
- Demonstration Videos: Short clips showing the design and printing of a hinge, pinwheel, and toy car.
- Step-by-Step Guides: Screenshots or slides illustrating the design process for each assembly in TinkerCad.
- Example Models: Display pre-designed models with moving parts to inspire students.
- Infographics: Visual representations of clearances and how moving parts interact.
Required Equipment:
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Computers or Tablets:
- One per student or pair, with TinkerCad logged in and ready to use.
- Internet access for referencing tutorials and downloading SVG files if needed.
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Interactive Whiteboard or Projector:
- For live demonstrations of designing moving parts.
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Access to Online Image Libraries:
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Assistants or Volunteers:
- Additional adults to help guide students through complex design steps.
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Safety Equipment:
- Ensure students understand safe computer usage practices and the importance of handling printed objects carefully.
Structure and Lesson Plan (Total Time: 60 minutes)
1. Introduction and Recap (5 minutes)
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Greet the Students:
- “Good morning, everyone! Today, we’re going to take our 3D design skills even further by creating objects with moving parts.”
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Recap Previous Sessions:
- “Last time, you finalized your functional objects and prepared them for printing. How did your prints turn out?”
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Introduce Today’s Theme:
- “Today, we’ll learn how to design simple assemblies with moving parts, like hinges, pinwheels, and toy cars. We’ll also discover how to ensure these parts can move smoothly without sticking together when printed.”
2. Understanding Moving Assemblies and Clearances (10 minutes)
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Explain Moving Assemblies:
- “Moving assemblies are groups of parts that can move relative to each other, like the hinges on a door or the wheels on a toy car.”
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Introduce Clearances:
- “Clearance is the small gap between moving parts. It’s important to have enough space so that parts can move freely without sticking together.”
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Show Examples:
- Basic Hinge:
- Display a simple hinge model.
- “This hinge allows the lid of a box to open and close smoothly.”
- Pinwheel:
- Display a pinwheel model.
- “This pinwheel spins when you blow on it or when exposed to wind.”
- Toy Car:
- Display a toy car model with rotating wheels.
- “These wheels rotate around the axles, allowing the car to move.”
- Basic Hinge:
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Discussion:
- “Why do you think having a little space between parts is important for moving assemblies?”
3. Designing Moving Assemblies in TinkerCad (40 minutes)
A. Designing a Basic Hinge
1. Create the First Hinge Part
- Drag a Cylinder from the Shapes menu onto the workplane.
- Size: Change its dimensions to 10mm diameter and 20mm height using the white corner squares.
- Add a hole for the hinge pin:
- Drag another Cylinder to the workplane.
- Change its size to 5mm diameter and 20mm height.
- Switch it to Hole using the Shape Properties menu.
- Align the smaller cylinder to the center of the larger one using the Align tool.
- Group the two shapes together by selecting both and clicking Group (Ctrl+G).
2. Create the Second Hinge Part
- Drag another Cylinder onto the workplane.
- Size: Change its dimensions to 10mm diameter and 15mm height.
- Make a slot for the first hinge part to fit into:
- Drag a Box shape onto the workplane.
- Resize the box to 12mm wide, 10mm deep, and 15mm high.
- Switch it to Hole using the Shape Properties menu.
- Position the box to overlap the cylinder slightly and create a U-shaped cutout.
- Group the shapes to form the slot.
3. Add the Hinge Pin
- Drag another Cylinder onto the workplane.
- Size: Change its dimensions to 4.8mm diameter and 25mm height.
- Position the pin:
- Align it with the holes in both hinge parts so it fits snugly.
4. Test the Fit
- Encourage students to check if the pin fits through the holes without gaps.
- The pin should be slightly smaller than the holes for smooth rotation.
5. Final Touches
- Adjust sizes if necessary using the Scale tool to ensure all parts align properly.
- Make the hinge visually appealing by rounding edges or adding custom designs.
6. Prepare for 3D Printing
- Select each part (first hinge, second hinge, and pin) and export them as STL files.
- Ensure they are separate files so they can be printed individually.
7. Print and Assemble
- Once printed, have students:
- Slide the pin through the holes in both hinge parts.
- Test the hinge by rotating it and observing how it moves.
- Highlight Clearances:
- “Notice the small gaps around the hinge pins. These clearances allow the hinge to move freely.”
- Hands-On Practice:
- “Now, try designing your own basic hinge. Follow the steps we just went through and adjust the clearances as needed.”
B. Designing a Pinwheel (15 minutes)
1. Create the Pinwheel Blades
- Drag a Box shape onto the workplane.
- Size: Change its dimensions to 40mm wide, 5mm deep, and 1mm thick.
- This will form one blade of the pinwheel.
- Rotate the blade:
- Use the rotation handles to tilt the blade 45 degrees.
- Duplicate the blade:
- Click the blade and press Ctrl+D (Duplicate).
- Rotate the duplicate blade 90 degrees.
- Repeat this step two more times so you have four blades in total, forming a cross shape.
- Align the blades:
- Select all four blades and use the Align tool to center them on the workplane.
2. Add a Center Hole
- Drag a Cylinder shape onto the workplane.
- Size: Change its dimensions to 5mm diameter and 1mm height.
- Set it as a Hole using the Shape Properties menu.
- Align the cylinder to the center of the blades using the Align tool.
- Group the blades and the cylinder (Ctrl+G) to create a hole in the middle of the pinwheel.
3. Create the Handle
- Drag another Cylinder onto the workplane.
- Size: Change its dimensions to 5mm diameter and 80mm height.
- This will be the pinwheel’s stick or handle.
- Add a stopper for the pinwheel:
- Drag a Torus (donut) shape onto the workplane.
- Resize it to 10mm outer diameter and 4mm thickness.
- Align the torus near the top of the handle to act as a stopper.
4. Add the Pin for Spinning
- Drag another Cylinder onto the workplane.
- Size: Change its dimensions to 4.5mm diameter and 10mm height.
- Position the pin above the stopper and ensure it lines up with the hole in the pinwheel.
5. Assemble the Pinwheel for Testing
- Move the blades above the pin:
- Place the pinwheel blades over the pin so the hole fits perfectly around it.
- Leave a small gap between the blades and the stopper to allow free spinning.
6. Test the Design
- Check that the pinwheel can rotate freely around the pin in Tinkercad by visualizing the gaps.
- Encourage students to experiment with the number of blades, their size, or even add decorations!
7. Prepare for 3D Printing
- Export the parts:
- Blades, handle, and pin should be saved as separate STL files.
- Make sure all parts are aligned and fit together before printing.
8. Assemble the Printed Pinwheel
- After 3D printing:
- Slide the blades onto the pin.
- Attach the pin to the handle.
- Blow or spin the blades to watch them move!
C. Designing a Car (20 minutes)
1. Create the Car Body
- Drag a Box shape onto the workplane.
- Size: Change its dimensions to 70mm long, 40mm wide, and 20mm high.
- This will form the base of the car.
- Round the edges for a smoother design:
- Use the Radius slider in the Shape Properties menu to round the edges slightly.
2. Add the Wheel Axles
- Drag a Cylinder shape onto the workplane.
- Size: Change its dimensions to 5mm diameter and 50mm length.
- This will be the axle that connects the wheels.
- Duplicate the axle:
- Press Ctrl+D to make a copy and position the second axle near the back of the car.
- Align the axles with the car body:
- Move the axles so they are evenly spaced under the car body (about 10mm from each end).
3. Create the Wheels
- Drag another Cylinder onto the workplane.
- Size: Change its dimensions to 20mm diameter and 5mm thickness.
- This will form one wheel.
- Duplicate the wheel:
- Press Ctrl+D to make three copies.
- Position the wheels:
- Align one wheel to each end of both axles using the Align tool.
- Ensure the wheels are centered and flush with the axles.
4. Add a Hole in the Wheels for the Axles
- Drag a Cylinder onto the workplane.
- Size: Change its dimensions to 5.5mm diameter and 5mm height.
- Set it as a Hole using the Shape Properties menu.
- Center the hole:
- Align it with the center of the wheel using the Align tool.
- Group the wheel and hole:
- Select both and press Ctrl+G to make the hole a part of the wheel.
- Repeat for the other three wheels.
5. Secure the Wheels to the Axles
- Add stoppers for the wheels:
- Drag a Torus (donut) shape onto the workplane.
- Resize it to 6mm outer diameter and 2mm thickness.
- Duplicate the torus and place one on the inside of each wheel along the axle.
- Ensure the toruses hold the wheels in place but still allow them to spin freely.
6. Add a Cabin or Design Features
- Drag another Box shape onto the workplane.
- Size: Change its dimensions to 40mm long, 30mm wide, and 20mm high.
- Position it on top of the car body to create a cabin.
- Decorate the car:
- Add shapes like cones, cylinders, or text to make headlights, a spoiler, or a custom license plate.
7. Test the Design
- Ensure all parts are aligned and securely connected.
- Verify that the wheels are able to rotate freely on the axles.
8. Prepare for 3D Printing
- Export the parts:
- Car body, axles, and wheels should be saved as separate STL files.
- Check that all parts are properly aligned and printable.
9. Assemble the Printed Car
- After 3D printing:
- Attach the wheels to the axles.
- Slide the axles into the car body.
- Secure the wheels with the toruses or by gluing, if necessary.
- Decorate the car with paint or stickers for a personalized touch.
4. Sharing and Feedback (5 minutes)
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Invite Students to Share:
- “Would anyone like to show their moving assembly design and explain how they ensured the parts can move freely?”
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Provide Positive Feedback:
- “Your hinge design is perfect with just the right amount of clearance for smooth movement!”
- “Great job on your pinwheel! It looks like it will spin beautifully without any issues.”
- “I love how your toy car’s wheels rotate smoothly around the axles. Excellent work!”
Glossary
- Scribble Tool: A feature in TinkerCad that allows users to draw custom shapes and turn them into 3D objects.
- SVG File: A scalable vector graphic file format that TinkerCad can import to create 3D models.
- Importing: Bringing in 2D images or designs into TinkerCad to convert them into 3D models.
- Clearance: The small gap between moving parts to ensure they can move freely without sticking together.
- Moving Assemblies: Groups of parts that can move relative to each other, such as hinges, pinwheels, and toy cars.
- Grouping: Combining multiple shapes into a single, unified model to simplify manipulation and design.
- Alignment: Positioning shapes accurately relative to each other to ensure proper functionality and aesthetics.
- 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.
- Hinge: A mechanical bearing that connects two solid objects, allowing only a limited angle of rotation between them.
- Spinner: The part of a spinning top that remains stationary while the body spins around it.
- Axle: A rod or spindle passing through the center of a wheel or group of wheels.
- Chassis: The base frame of a vehicle, to which various components are attached.
For suggestions, improvements, and corrections, feel free to reach out at shayaanhaider@gmail.com