Capping or lamination is an unsolved common problem in tablet manufacturing. Knowledge gaps remain despite an enormous amount of effort made in the past to better understand the tablet capping/lamination phenomenon. Using acetaminophen – containing formulations, we examined the potential use of a compaction simulator as a material-sparing tool to predict capping occurrence under commercial tableting conditions. Systematical analyses of the in-die compaction data led to insight on the potential mechanism of tablet capping/lamination. In general, capping strongly correlates with high in-die elastic recovery, high Poisson's ratio, low tensile strength, and radial die-wall pressure. Such insight can be used to guide the formulation design of high quality tablet products that are free from capping problems for challenging active pharmaceutical ingredients.