In the Nordson select system it is necessary to clean out the nozzles and tubing very well. If not, it builds a thin laminar coating on the sidewalls and in the nozzle aperture which tends to constrict the coating going thru. The coating is then meeting with a greater resistance to laminar flow then originally specified. This in turn can cause or produce bubbles due to what is an apparent increase in the elastic portion of the viscosity curve. You won't see these bubbles until they coalesce in the film. By then its too late to get them out if you heat too fast. *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************