The surging trouble of PP Film

The process is T-die and base resin is PP. Temp. condition is 300 degree, Line speed is 100rpm. MIF is 15~18g/10min. The PP composite is including Recycling PP about 30%.
We can not reduce the recycling PP content. The surging problem is a real pain in the neck. Please help me.
And I confuse the surging with Melt fracture.. I am sure that that problem is surging trouble. But What is melt fracture? Are those same problems or Not ?
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Extrusion surging or melt fracture can be caused by feedstock, feeding, conveying and/or melting issues, which you may have to address step by step. I suggest you get your hands on books like the following, for troubleshooting advice: https://www.hansergardner.com/dp/hgweb/detail.cfm?isbn=1%2D56990%2D396%2D4%20%20&ctg=P -> sample page https://www.hansergardner.com/sample/1-56990-396-4.pdf
Go to "http://books.google.com " and search for "extrusion surging" to "surge suppression" to obtain book-links to: http://books.google.com/books?id=wwb22Q50C_MC&pg=PA445 http://books.google.de/books?id=2KSbTcdYv9QC&printsec=frontcover&source=gbs_summary_r&cad=0#PPA1496,M1
On melt fracture see: http://www.azom.com/Details.asp?ArticleID=3936 http://www.lorentz.leidenuniv.nl/~saarloos/Patternf/meltfracture.html http://www.thefreelibrary.com/Troubleshooting+Melt+Fracture-a080327160
Additives for eliminating melt fracture are suggested here: http://www.specialchem4polymers.com/tc/Polymer-Processing-Additives/?id=melt_fracture
In short: could your surging problem be related to: * "too large" differences in pellet shape and/or size between virgin and recycled PP * "wrong" feeding zone design * "wrong" screw design and/or screw vs barrel surfaces * "wrong" temperature profile * ...
canizaro wrote:

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