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Improving Output and Yield: Intraocular Lenses

Yield of intraocular lenses increased by > 40% in 3-months. End-of-year output targets hit in Q1.


Healthcare Supplies - Intraocular Lenses

Project length

3 months - 1 Consultant + Senior Support


  • Increase yield of 2 main lens types from 60% to 85%
  • Achieve stable output to meet end-of-year production target


  • Yield increased by > 40%, narrowly missing 85% target
  • One year after project end, yield had reached 89%
  • End-of-year production targets hit by end of Q1
  • Sales in Q1 87% higher than forecast

Why was Chartwell brought on board?

Production demand had increased sharply due to growing sales of a newly-launched product. In addition, a factory move necessitated stock to be rebuilt.

Core Project Workstreams

Output increase and productivity improvement

The output was increased to meet end-of-year targets using the following strategies:

  • Maximum and actual speeds for each sub-process were identified. Constraints on run speed were better understood and systematically broken. 
  • Shop floor productivity measurement tools gave front line teams accountability for performance and empowered them to identify and action opportunities for improvement. 

Yield improvement - Dry dimension rejects 

Dry dimension rejects were the top cause of yield loss. Focussed improvement actions reduced rejection rates at this stage from 20% to 4%.

  • Parameter testing protocols were updated to minimise rejects. Any changes to setup parameters were tested with only a few lenses instead of an entire batch.
  • Best practices were defined for machine set-up and operation to reduce variability in output quality.
  • A new machine was validated, enabling more accurate measurement of the dry dimension and reducing the number of false rejections. 

Sustainability of results and embedding improvement structures

Effective structures were implemented to enable the team to maintain and build upon the results achieved during the project.

  • Meeting structures facilitated inter-department communication, removing project roadblocks.
  • Tools to identify, prioritise and monitor the progress of projects allowed a successful handover of workstreams to the client.
  • Sustainable structures for day-to-day management such as KPIs and operations manuals increased visibility of performance and created a culture of improvement.