Ultrasonic Welding Process Improvement for the Scrap Reduction of a Medical Device

Abstract

A medical device company in Puerto Rico aims to improve an Ultrasonic Welding Process of a high-volume bone shredding medical device. The current process yield is 93% and must be at least 95% to meet the manufacturing site Key Performance Indicators. Six Sigma methodology was used as the improvement project framework. Tools such as Process Failure Mode and Effect Analysis, Cause and Effect Analysis and Tool Life Studies were used to evaluate the root cause of the underperforming yield. The root cause for the incomplete and over-welding defects was confirmed to be wear in the ultrasonic welding holding fixture which allowed parts to vibrate during welding. Improvements to reduce wear to the fixture were implemented. Process yield monitoring after the implementation of changes consistently show an increase in yield of over 95% and a cost avoidance of over $12,000 dollars a month. Key Terms ⎯ Polymer Chemistry, Six Sigma Methodology, Tool Life, Ultrasonic welding.