This Phone Case Launches Pellets.


This project included:

- Rapid Prototyping

- SLA & Poly-jet 3D Printing

- Compliant Mechanism Design

- Materials Selection


Design Intent


I was inspired by Mark Rober, an engineer and designer who developed the world’s smallest nerf gun using a compliant mechanism.


I wanted to adapt this design for FDM 3D printing and make it portable, as part of an everyday object such as a phone case.


I have been researching compliant mechanisms for some time and loved the idea of having one as part of a phone case, additive manufacturing is the perfect way to do this.

Here’s a quick demo of the compliant mechanism!

First Prototype

This FDM prototype consists of just the backplate, to save material.

Last Prototype

This final Polyjet printed multi-material prototype includes mechanism + casing.

Here’s all the iterations of the design!

I printed the first 2 in PLA, then moved to the Formlabs SLA machines and then began to experiment with cool materials!

Mistakes = valuable learnings

3D Printing Challenges

FDM printing this part came with its caveats. The ratio of surface area to thickness made it lose adhesion. So, I had to adjust the nozzle temp and speed.

Prototyping Strategy

  • Prototyping a one-piece case from the get-go wasted time and material, which is why I started modular prototyping.

Material Failure

  • Although acrylic provided the sharpest spring back, it also had the shortest life of the materials I tried, so in my final I designed the case for multimaterial printing.

CONTACT

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646-987-2345


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Key Learning: Modular Prototyping


2 prototypes in, I finalized the dimensions and the fit of the inner and outer casing. This allowed me to implement modular prototyping, I tried three materials for the launching mechanism, and two for the phone casing.


This gave me 6 combinations of materials and allowed me to settle on a final material combination for the multi material print.

Materials Selection

Part I: Mechanism Material

Part II: Outer Bumper Material

Mechanism Material: PLA turned out to be the most cost-effective material that performed as desired, while acrylic had more spring back (Flexural Modulus) and performed the best but was too expensive.

Outer Bumper Material: Durable (SLA resin) stood out as a winner in all material attributes except for elongation at break and cost, which were trade-offs I was willing to make.

Material Choice

- Model for scale manufacturing: PLA + Durable Resin


- Model for performance: Vero (Polyjet Acrylic) + Elastic (Polyjet)

Key Features