Slot die stripe coating of low viscous fluids
Slot die coating is applied to deposit thin and homogenous films in roll-to-roll and sheet-to-sheet applications. The critical step in operation is to choose suitable process parameters within the process window. In a new work, scientists investigate an upper limit for stripe coatings. This maximum film thickness is characterised by stripe merging which needs to be avoided in a stable process. It is shown that the upper limit reduces the process window for stripe coatings to a major extent. As a result, stripe coatings at large coating gaps and low viscosities are only possible for relatively thick films. Explaining the upper limit, a theory of balancing the side pressure in the gap region in the cross-web direction has been developed.
The study is published in: Journal of Coatings Technology and Research September 2018, Volume 15, Issue 5, pp 899–911.