New extrusion coating die eliminates edge bead and enhances coat weight uniformity

When Korea Aluminium Installed Nordson Extrusion Dies Industries EPC™ Die on an Existing Coating Line, Thickness Tolerances Were Narrowed by 50 to 60%

An advanced extrusion coating die designed to reduce edge bead has enabled one leading producer of aluminum foil and foil-laminate flexible packaging to actually eliminate edge bead, as well as reducing coat width variation by half or more, it was announced today by Nordson Corporation.

After a die for applying LDPE on an existing production line for flexible food packaging had been causing problems with die lines and leakage, Korea Aluminium Co. Ltd. recently replaced it with the Nordson Extrusion Dies Industries Edge Profile Control (EPC™) die. The new die has not only eliminated the previous problems but has also made it possible to address the issue of edge bead and the waste of coating and substrate material that results from it, according to Mr. Jeonghyeon Heo, senior manager of Korea Aluminium's headquarters facility in Chungbuk.

While the degree of edge bead reduction achievable with the EPC die depends on a number of factors, the reduction in the Korea Aluminium coating line was 100%. "We are now manufacturing product with zero edge bead," said Mr. Heo.

In addition, he noted, the EPC die reduced coat weight variation by 50 to 60%: "Thickness uniformity was +/- 2 or 2.5 microns with the old die, but with Nordson's EPC die uniformity has been improved to almost +/- 1 micron."

The EPC unit installed on Korea Aluminium's coating line was a manual die, noted Sam G. Iuliano, Nordson Extrusion Dies Industries chief technologist. "The 4 to 5% range of variation from target coat weight is very good indeed for a manual die," he said. "With an automatic die, the range could easily be cut in half."