Coating

Proper maintenance maximizes ­benefits of fixed lip slot dies

By Ryan Anderson, Product Manager, Nordson Corporation

Slot dies provide important economic and productivity advantages over conventional roll coating, and fixed-lip slot dies are particularly valuable for their ability to apply very thin coatings with great precision at high speeds. One key to prolonging the working life of these dies and obtaining the full measure of their benefits is proper maintenance by technicians and operators. What follows are recommended procedures for servicing or repairing a fixed-lip slot die. For starters, it is important to understand the various die components. The two basic parts of slot dies are the upper and lower die bodies. These solid steel components serve as the two halves of a single-layer die. Fluid enters the die through an inlet or «throat» in the lower half, is distributed to target width by a manifold, flows toward the die exit via a slot between the upper and lower bodies, and exits the die at the lip (see Schematic 1). Two areas that play important roles in the precision and uniformity of the fluid coating are the land length, which is the portion of the slot surface prior to the lip exit, and the lip face, which affects the application of the fluid to a substrate.

Nordson BKG GmbH, D-48157 Münster, www.nordsonfluidcoating.com Nordson Corporation, Polymer Processing Systems, Chippewa Falls, WI 54729 USA www.nordsonpolymerprocessing.com, At ICE USA: Booth 711