Case Study - Standardised WorkMajor Pipe Manufacturer - NSW, Australia
The Challenge
During the implementation of an improvement project focused on the reduction of the level of defects, it was found that the accuracy of the categorised defects used as the fundamental basis of the project was flawed.
Categorisation of the defects is one of the fundamental building blocks of the data collection system, for focusing of improvement work.
A Pareto analysis of the incidence of defects will guide the selection of areas for action.
The success of this technique is dependent on the accuracy of the categorisation process.
The Solution
The Lean Six Sigma tools for assessing categorisation of data, often called a ‘Kappa Study’ or ‘Attribute Agreement Analysis’ was used to quantify the degree of data accuracy. The accuracy of data was found to be low.
A process of simplification and standardisation of the methods for identification, categorisation and recording of defect data was undertaken.
This process involved operator feedback, assessment of failure modes with the existing methods of defect categorisation, a simple tiered decision system designed to reduce the possibilities for miss-categorisation of defect types, and a redesign of the methods for assessing and recording the defects.
The new methods were then introduced to the operators via a targeted training package, which was followed up with spot audits, to ensure that the new methods and training were appropriate.
The Results
The Kappa study was repeated to verify the effectiveness of the changes to the process of recording defects. The accuracy of the data achieved through implementation of the changes was very good.
Improving the accuracy allowed the Pareto style analysis to effectively guide the focus of improvement activities and the effect of changes to be clearly observed.