Molding technology and quality estimation on the lipstick production scene

Abstract

In this paper, the optimization of a generic function of a lipstick manufacturing process is discussed. Traditionally, the quality of lipsticks has been measured by objective quality characteristics such as appearance. Sensory tests, which are not recommended in quality engineering, had been used to evaluate such quality characteristics. That is because these quality characteristics are not stable due to the changes of environmental conditions such as between‐lot variability and seasonal variation. When such quality problems occurred, manufacturing conditions were adjusted from time to time, which is known as fire fighting or ‘mole beating’ in Japanese. Among those objective quality characteristics, the ones such as scratches, colour uniformity or breaking during usage are manufacturing related. As a generic function, the stress/strain relationship was investigated and the results showed that the relationship has satisfied Hook's Law with a good improvement.