Pencil Cup with a Twist
Design a pencil cup that integrates a dedicated, form-fitting compartment for one specific classroom tool while maintaining structural balance.
Engineering Context & Goal
Classroom workspaces frequently suffer from cluttered desktops where bulky tools like scissors, glue sticks, and rulers get buried under pens and pencils. Standard cylindrical cups fail to keep asymmetric tools upright, leading to tip-overs and inefficient retrieval during timed hands-on assignments.
This challenge tasks designers with engineering a compact desktop organizer that holds standard writing utensils while integrating a custom, form-fitted secondary dock. Designers must account for tool weight distribution, base surface area, and clean boolean subtractions to maintain stability without relying on extra ballast.
Key Learning Outcomes
- Calculate footprint dimensions and center-of-mass balance to prevent tipping under uneven tool loading.
- Apply negative-space boolean operations in CAD with 1.0mm tolerance clearance offsets.
- Design self-supporting vertical chambers that print cleanly without internal support structures.
Mandatory 2–4 Design Constraints
Each student must verify full compliance with all parameters below before exporting STL files for production.
Bounding Box Envelope
The complete organizer must fit strictly within an 80mm x 80mm x 110mm bounding box volume, including both tool cavities.
Dedicated Auxiliary Tool Dock
The design must contain a custom secondary chamber tailored specifically to one tool geometry (scissors, 15cm ruler, or glue stick) rather than a generic open pocket.
Flat Base & Zero Support Printing
The model must rest on a completely flat base with wall draft angles exceeding 45 degrees, printing 100% support-free.
Evaluation & Physical Verification
Assess the model against physical tolerance standards using the structured verification table.
| Evaluation Metric | Tolerance Target | Passing Criteria |
|---|---|---|
| Desk Interface Fit | +1.0 mm Clearance | Holds 25mm thickness without slipping or permanent deformation. |
| Primitive Solid Count | Max 4 Primitives | Constructed strictly with allowed boolean combinations. |
| Load Capacity | 12 Pencils + 1 Tool | Supports test weight for 60 seconds without joint cracking. |
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