SEMESTER 2, WEEK 8

Initial Design Development & Material Selection

Description:

We finalized the decision to use high-elasticity silicone as the primary material for the lung model to better simulate the compliance of human lung tissue. We began designing a two-part mold system to produce a hollow, expandable structure with uniform wall thickness. Additionally, we discussed developing a custom airflow mechanism rather than relying on a commercial air pump to allow greater control over system integration.

PLTW STEP:

Define the Problem & Generate Concepts

Outcome:

First Silicone Mold Fabrication & Structural Analysis

Description:

We fabricated and cured our first silicone mold. Upon demolding, we observed structural failure due to inconsistent wall thickness and localized stress points. Thinner regions experienced tearing under minimal mechanical strain. We evaluated the mold geometry and identified the need for reinforced edges and more controlled material distribution.

PLTW STEP:

Develop Prototype

Outcome:

Mold Redesign & Pump Prototype Conceptualization

Description:

We redesigned the mold to improve structural consistency by increasing wall thickness and reinforcing high-stress regions. Concurrently, we began conceptualizing a custom pump prototype using a 3D printed impeller-style fan system. The goal was to convert rotational motor energy into directed airflow capable of inflating the silicone lung model.

PLTW STEP:

Redesign & Plan Testing

Outcome:

3D Printed Fan Prototype Testing

Description:

We printed and assembled the first impeller-style fan component and conducted airflow testing. While the system successfully generated directional airflow, measured output pressure was insufficient for full lung expansion. We hypothesized that blade pitch angle and motor torque may need adjustment to increase volumetric airflow and static pressure.

PLTW STEP:

Test & Evaluate

Outcome: