The Impact of Product Variety on Quality Conformance in Continuous Process Manufacturing: A Quantitative Investigation in a Chemical Industry Context.

Product variety in manufacturing has increased significantly, driven by technological advancements
and growing demand for customisation. To meet diverse customer preferences,
companies often overextend their portfolios without fully considering the resulting
impact on manufacturing effectiveness. This study investigates how product variety is
associated with quality conformance in continuous process manufacturing, an area underexplored
in the existing literature, which predominantly focuses on discrete or assembly-
based operations. Utilising production data from a large chemical manufacturer, logistic
regression analysis was applied to examine how variety-related engineering parameters
relate to the probability of non-conformance at the big-bag level. The analysis shows
that ramp-ups, especially those associated with major changeovers, and short production
uptimes are correlated with an increased likelihood of quality issues. Very infrequent production
also appears to increase quality risks. Contrary to learning-curve expectations,
products with medium and low production intensity showed lower odds of non-conformance
than high-intensity products. These findings indicate the implications of product variety
in continuous manufacturing environments. By identifying variety parameters that
appear to contribute to quality risks, this study offers initial guidance for production planners
and product portfolio managers aiming to balance product variety with quality conformance
and overall manufacturing effectiveness.