With Unilever’s first single global aerosol design, manufactured in four sites at a billion units a year; and holding powerful new Bom Chicka Wah Wah filled fragrances, the job of developing the technical specification fell to me.

Bespoke statistical process control software (e.g. Minitab) was not available to support the thousands of vision system generated data and multiple, multi-million pound injection moulded tool sets.

The tolerance stack up was calculated on 3D CAD; based on consumer and functional requirements.

Then I coded a bespoke Visual Basic tool that enabled dimensional tolerances, histograms, CP and CPk statistics and deviations to be calculated and flagged from vision system data.

We even spotted an error in a world class tool; enabling us to modify the high speed assembly machine to hit launch targets.

Complemented with physical testing of components at top and bottom of specification, this “goldilocks” method of testing stack up is now part of the best practice design process for FMCG packs.