Learning Targets
- Describe what a CAD joint or relationship controls.
- Choose appropriate relationships for fixed or aligned parts.
- Test whether the assembly behaves as intended.
IED Unit 3 • Lesson 3.5
Joints and Assembly Relationships
Focus question: How do joints define relationships between parts?
Mission Briefing
Today’s Plan
Use this page with the lesson presentation, your engineering notebook, and the tools or evidence assigned for Define Assembly Relationships with Joints.
Success Looks Like
You can explain how a joint controls the relationship between two rocket parts.
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Opening Prompt
How do joints define relationships between parts?
Connect your response to the decision, evidence, or quality standard required for Define Assembly Relationships with Joints.
Reveal: useful engineering move
This lesson is ready to move forward when the evidence meets this standard: The joint holds the parts in the intended relationship without unintended freedom or misalignment.
Core Skill
What We Are Practicing
Joints define how parts relate to one another.
The wrong joint can create hidden alignment or motion errors.
Relationships should match the physical design intent.
Your Task
Define Assembly Relationships with Joints
Add appropriate joints so parts remain connected and behave according to the intended assembly relationship.
- Choose the two components and joint locations.
- Select the joint type that matches the intended relationship.
- Set alignment, orientation, and any required limits.
- Test the relationship and correct reversed or misplaced motion.
Quality check: The joint holds the parts in the intended relationship without unintended freedom or misalignment.
Lesson Interactive
Match Joints to Intended Motion
Choose the assembly relationship that allows exactly the motion each example requires.
| Assembly relationship | Required behavior | Joint |
|---|---|---|
| Fin to fin can | No relative motion | |
| Payload access door | Rotate about a hinge axis | |
| Removable payload tray | Translate along one axis |
A joint should constrain every motion except the movement the design intentionally allows.
What You Will Submit
Jointed Assembly Evidence
Submission standard: The joint holds the parts in the intended relationship without unintended freedom or misalignment.
Resources
Lesson Resources
Lesson 3.5 PowerPoint
Use the lesson slides for guided practice, interactive checks, and the exit ticket.
Introduction to Engineering Design
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