Date of Defense

4-21-2026

Date of Graduation

5-2026

Department

Industrial and Entrepreneurial Engineering and Engineering Management

First Advisor

Sang Hyeon Kang

Second Advisor

Audrey Brooks

Abstract

This project evaluated material handling inefficiencies and ergonomic concerns within Stryker’s Neptune medical device assembly line. Two primary issues were identified: lack of a standardized part-location system in the supermarket and excessive operator travel between subassembly and main assembly. These issues resulted in search waste, motion waste, lost production time, and increased ergonomic strain.

To address the labeling issue, a standardized bin labeling system was developed and tested. A time study comparing labeled and unlabeled conditions showed that average retrieval time decreased from approximately 120 seconds to 22 seconds, an 81% reduction. Statistical analysis confirmed that this improvement was significant and reduced variability in the process.

To address operator movement, a karakuri-based material handling system was designed to improve point-of-use delivery. The current process requires approximately 6,000 steps per day, while the proposed system reduces this to about 1,800 steps per day, representing a 70% reduction and recovering approximately 35 minutes per shift. Ergonomic evaluations using NIOSH, REBA, and RULA indicated that although lifting loads were acceptable, posture and reach height posed risks in the current system. Floor-level and overhead retrieval were identified as the highest-risk tasks, while mid-level access was the most favorable. The proposed system reduces these risks by presenting materials within an optimal reach zone.

Based on these findings, the team recommends implementing a standardized bin labeling system and continuing development of the karakuri material handling system. Together, these solutions improve efficiency, reduce operator movement, and enhance ergonomic conditions while supporting more consistent material flow.

Comments

Co-authored with:

Maria Laura Feliz

Erika Portorreal

Jack David Steines

Access Setting

Honors Thesis-Open Access

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