Auto-Iris: Airflow Restrictor Automation 

Overview

Role and Ownership

In end-of-line test, operators were required to manually swap airflow restrictors to simulate different patient conditions (adult vs child). Missed swaps created false failures and retests, reducing first-time yield and increasing cycle time. I removed this failure mode by developing an automated “auto-iris” restrictor: a sealed mechanism that adjusts opening to hit the required back-pressure specification at a given flow. The solution converted a human-dependent step into a repeatable, calibrated process.

•	Owned mechanism concept → prototype → integration into final test workflow
•	Designed a sealed rotating actuation mechanism driving an iris-style restrictor
•	Developed calibration procedure mapping position to back-pressure specification
•	Implemented error-proofing logic and override modes to support production operations
•	Delivered integration details and documentation supporting repeatable test execution

Approach 

 Requirements: hit back-pressure targets, eliminate manual swaps, maintain clean/robust operation
	Architecture tradeoffs: iris mechanism to decouple “hole size” from functional spec (pressure vs flow)
 CAD + tolerance strategy: sealed interfaces, repeatable actuation geometry, robust stops/homing strategy
 Prototype iterations: refine sealing, friction, and repeatability; tune actuation and response
 Characterization / validation: calibrate and verify position-to-spec mapping; confirm repeatability over cycles
 DFM + release readiness: robust integration into line test with operator-safe workflow and documented procedures

results

•	Removed a frequent human-error failure mode by eliminating manual restrictor swaps
•	Reduced retests and stabilized operational flow during end-of-line testing
•	Sustained first-time yield in the high-80% range by preventing false failures tied to setup mistakes