A 3D-printed mechanical clamp with multiple functions: bag hook, phone stand, and bottle opener. Designed and prototyped as a hackathon solution to solve real-world canteen problems at GTU (Gujarat Technological University).
Status: Designed & prototyped | Material: PLA | Tool: Autodesk Fusion 360 | Year: September 2019
At the GTU canteen, students faced a recurring challenge: nowhere clean to store personal items while eating. The floor was dirty, and leaving a bag on it meant it would get soiled. A simple hook or attachment point on the table could solve this — but why make it single-function?
A compact C-clamp that mounts to any table edge and serves three purposes:
- Bag Hook — Hangs bags, watches, and personal items off the table surface (keeping them off dirty floors)
- Phone Stand — Notch holds a smartphone upright at a comfortable viewing angle
- Bottle Opener — Horseshoe-shaped hook at the bottom can open bottles
All in one compact, printed part.
The clamp demonstrates intentional DfAM principles:
- Printed threads: The clamp bolt and nut are designed with integrated threads, printed as a single assembly. This eliminates the need for metal hardware and showcases the capability of FDM printing to create functional mechanical interfaces.
- Compact geometry: All three functions fit within 60 × 50 mm, optimized for efficient print time and material use.
- Strength through design: Strategic thickness variations in the clamp body and jaw distribute stress without unnecessary bulk.
- Clamp body (yellow/gold) — C-clamp profile with notch for phone mounting
- Sliding jaw (grey) — Movable lower arm tightens against the table edge
- Printed bolt & nut (black) — Tightening mechanism with integrated threads
- Bag hook (red horseshoe) — Mounted at the bottom via connector
- Phone slot notch — Integrated into upper body design
| Parameter | Value |
|---|---|
| Footprint | 60 × 50 mm approx. |
| Material | PLA |
| Printer | Prusa Tarantula |
| Wall thickness | 2-3 mm |
| Number of parts | 3 (body, jaw, bolt/nut assembly) |
| Team size | 3 |
Isometric views of the fully assembled design showing all functional components:
Full assembly — C-clamp profile with phone slot and hook attachment points visible
Front view — hook position clearly shown for bag hanging
Top view — phone slot notch and bottle opener hook placement
The design was successfully printed on a Prusa Tarantula printer and tested in real-world conditions:
Prusa Tarantula in action — printing the clamp on PLA material
Completed print showing the threaded bolt and overall assembly
Close-up of the screw mechanism and hook connector
Functional test — smartphone mounted securely in the clamp notch
This project applies three key principles:
- Real-world problem-solving — Identified a genuine need in the canteen and designed a practical solution
- Multi-functionality — Maximized utility in minimal form factor; one device, three uses
- Additive manufacturing optimization — Leveraged 3D printing to create a single-piece assembly with integrated mechanical features (printed threads) that would be difficult or impossible to manufacture traditionally
clamp_assembly.step— Complete CAD assembly (Fusion 360 export)
- View the design: Open the STEP file in Fusion 360, FreeCAD, or any STEP viewer
- Print: Export to STL format and slice on your preferred slicer (Cura, PrusaSlicer). Recommended settings:
- Layer height: 0.2 mm
- Infill: 20% (gyroid or grid)
- Support: Required for the hook arm and notch
- Print time: ~4–6 hours depending on scale
- Assemble: Print as separate parts (body, jaw, bolt assembly) and press-fit together
- Test: Clamp to table edge and verify all three functions
Designed and prototyped by a team of three mechanical engineering students at GTU during a hackathon event, September 2019. All team members contributed across CAD modeling, design iteration, and physical testing.
MIT License — feel free to modify and reprint
This project was completed as part of a hackathon focused on practical product design. It represents the intersection of real-world observation, creative problem-solving, and hands-on prototyping. The emphasis on DfAM principles reflects an understanding that 3D printing enables designs that traditional manufacturing cannot easily achieve.
Possible improvements for future iterations:
- Refined print orientation for strength
- Tolerance testing on various table thicknesses
- Ergonomic redesign of the phone slot
- Alternative materials (PETG for improved strength)