Troubleshooting Web-Handling Problems and Dryer Related Coating Defects Inside Flotation Dryers

Presented by Dan Bemi & Steve Zagar, MEGTEC Systems

For many converting operations, a flotation drying system represents the longest web span between tension isolation points on the entire coating line. As such, web stability inside the dryer can be a concern. Current trends toward faster line speeds and lighter weight substrates only serve to compound dryer web handling challenges. Problems such as troughs, edge flutter, edge curl, web-weave and web shift are often attributable to dryer design or operation. This paper will explore the
various conditions that can create or contribute to such web-handling problems. In addition to web handling, we will also address common dryer-related coating defects such as blistering, pinholes, orange peel effect, and cratering. The author will discuss appropriate test methodology for identifying the root cause or causes of web handling problems and dryer induced coating defects, and will offer options for corrective action and process quality enhancement.