Tips for blown film processors

Dow Plastics’ Jeffrey Wooster has two basic recommendations for processors looking for optimal productivity, one technical and one administrative:

“Use a variable-step thermocouple to monitor melt temperature and melt temperature uniformity. This allows the processor to see the true melt temperature coming off the extruder before the material goes through the die. Older extrusion systems may not give you the true melt temperature”.

Wooster warns that a false low reading may cause bubble instability, while a false high temperature can lead to melt fracture or poor die output due to pressure limitation.

The administrative tip is somewhat simpler:

“Ask your supplier for technical assistance. Sometimes people want to take a data sheet and a box of material and figure it out on their own. While it’s possible to do that, it will probably waste a lot of effort. If you simply ask for technical assistance, frequently you can avoid some of the pains of starting up a new material and avoid those pitfalls.”