Accuracy of test methods
The QS 9000 MSA demands that the variance of a measurement shall not exceed 10% or 10% to <30% of product tolerance or total production process variation. The requirement cannot always be fulfilled by the test methods used for testing pressure sensitive adhesive products.
- Based on the product specifications agreed between producer and customer, measurement systems in the adhesive industry cannot always fulfil the QS 9000 MSA demand of R&R <= 10% or 10% to < 30% of tolerance, although they are “state of the art”.
- The high complexity of test methods for adhesive products (including sample preparation, environmental conditions, testing device parameters and others) results in a contribution of variation in addition to the tester and gauge variation.
- The majority of test methods for adhesive products are destructive tests. Therefore the measurement system variation, when carried out according to MSA, contains a significant portion coming from inherent differences between test samples.
Afera recommends that member companies consider these findings when evaluating their measurement systems. It is the collective view of industry experts that no better test methods are currently available. A suitable reference is the paper presented by P. Richardson at the 19th PSTC Technical Seminar in 1996: ‘Work on AFERA 4001 and its impact on Business’.