Survey of Current Bead Reduction Die Technology, 1997 Polymers, Laminations & Coatings Conference Proceedings

Bead reduction dies have been in use for many years. Early designs provided bead reduction via a single deckle rod in close proximity to the final die land. The next innovation to this technology came from Japan in the way of a rigid-lipped die with no adjusting bolts, very short die land length, and several internal deckles to drastically reduce edge bead thickness, primarily for extrusion coating applications. The benefits of this die design extend far beyond reduced polymer consumption and waste, also providing reduced substrate waste, reduced downtime, and a significant overall cost reduction. Several new bead reduction die designs have emerged in the current era of technology for both extrusion coating and cast film applications. These dies vary dramatically from each other, and offer the converter a wide variety of choices and options when either purchasing new equipment or upgrading existing equipment. This paper will review the bead reduction technologies currently available, as well as the pros and cons associated with each.