Fixing the Flow: How Data-Driven Root Cause Analysis Increased Yield and Capacity

What Was Actually Happening

The line was losing product at several points at once, and no single loss was large enough on its own to have triggered an investigation. A DMAIC review of hold times, tank weights, filter flush volumes, sampling data and scrap rates – supported by statistical analysis and Monte Carlo simulation – identified four contributing causes.

The analysis revealed multiple root causes:

• Excessive vibration on conveyor belts caused vials to fall, break, and create glass debris, in the process, slowing down the line and also increasing product loss
• Gaps in equipment qualification and validation dating from initial commissioning left the line running with unaddressed performance variability
• Sampling practices were inconsistent and contributed to measurable yield loss
• Material variability in vial stoppers contributed to increased rejects and reduced efficiency

The problem wasn’t a single failure. It was a systemic issue spanning equipment, materials, and methods.

What We Changed

We developed and executed a comprehensive improvement plan:

• Planned Maintenance Program: Implemented equipment (especially, conveyor belt) vibration monitoring and preventive maintenance schedules to stabilize conveyor performance
• Update Line (and Related Equipment) Validation: Engaged Engineering, Manufacturing, and Quality to update validation of the line per current standards and to include conveyor belt vibration in validation studies
• Sampling Optimization: Updated the sampling plan based on data trends to reduce unnecessary product loss
• Supplier Collaboration: Partnered with Vendors and Supplier Quality to tighten stopper material specifications and implement improved testing protocols
• Implemented Total Productive Maintenance (TPM) across site leading to significantly fewer equipment breakdowns
• Trained current employees on the new process and updated SOPs and training material for sustaining best practices

What It Delivered

• 4.6% increase in product yield, restoring full production capacity
• Site began consistently meeting the manufacturing plan, eliminating backlog and delays
• Fewer deviations and improved process stability, reducing investigation workload
• Lower COGS through higher throughput, reduced scrap, and optimized sampling
• A sustainable system of preventive maintenance resulting in improved equipment reliability
• Established a process for improvement of supplier quality through continued performance monitoring