--- title: 4 Causes of Flow Lines in Blown Film Extrusion (and One Easy Solution) description: Purging Expert Chris Melchiore talks about causes of flow lines in Blown Film Extrusion and how purging compounds solve all of your processing issues. image: https://www.asaclean.com/hubfs/Blown%20Film.png --- [ Order Online ](https://asaclean.my.site.com/b2bstore) [ Free Sample ](https://offers.asaclean.com/free-sample) ## [ Asaclean Blog ](https://www.asaclean.com/blog) Browse by Topic " aerospace asaclean asaclean news Asaclean® benefits asahi kasei automotive Best Practices black specks blisters blow molding blown-film extrusion buyers caps and closures carbon contamination cast-film extrusion Chemical Purging Compounds clear applications Color Changeovers Company News compounding consumer products contamination Cost savings custom molders Customer Success Story decreasing scrap defects electronics Energy Efficiency EX Grade extruder cleaning Extrusion fillament glass filled Glitter Grade Selection HDPE High and Low Temp Changeovers hold a bubble Hot Runners Injection Molding Injection Molding Tips LDPE Lightweight automotive components LLDPE low residue maintenance Material Changeovers Mechanical Purging Compounds medical Melt Flow Index NPE 24 nylons on the fly packaging PCR PEEK Polypropylene Post Consumer Resins preventative preventative purging processing tips profile extrusion Purge Program purge programs Purge Training Purge Trial purging purging compounds purging concentrates purging procedures Purging Tips quality recycled resins residue issues scrap reduction Screw Pulls sheet extrusion shutdown and sealing start-up super engineering resins Sustainability Tech Day technical support training trials Troubleshooting Twin Screw twin screw extrusion two step purging U Grade ULTEM venting Viscosity webinars wire extrusion - 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There are many possible causes, but these are the four "usual suspects": 1) Color Changes If going from a dark color to light or clear, color can hang up in negative flow areas. 2) Material Changes If performing a resin change from one polymer to another a difference in viscosity can cause flow lines or gels. 3) Poor Preventative Maintenance Over time polymer will degrade creating carbon (black specks). This carbon will hang up in areas and is difficult to remove. 4) Extended Shutdowns Shutting down the line for extended periods of time will create carbon or contamination due to residence time and the cool down and heat up process. Purging compounds help you address all of these causes and can dramatically improve your efficiency overnight. Chemical purge compounds are heat activated. More heat = increased chemical activity = better cleaning. Chemical purge’s foam, creates steam and carbon dioxide. These reactions generate an internal turbulence that gets into negative flow areas and dead spots effectively. That combined with mild abrasives can effectively clean the system without the need to manually clean.  When purging, it’s only necessary to raise heats in the areas where the problems are, commonly in the die. The rest of the system can be run at normal production temperatures. The purge process has two components. The purge has to clean the machine and be easily removed. This is accomplished by matching viscosity of the carrier resin of the purge and production material being displaced. **Ready to reduce your ****production downtime**** to protect your profits? Learn more about how ****purging compounds**** and process efficiency work in tandem.** ![Chris Melchiore](https://www.asaclean.com/hs-fs/hubfs/Head_Shots/Chris%20Head%20shot.jpg?width=150&name=Chris%20Head%20shot.jpg) #### [ Chris Melchiore ](https://www.asaclean.com/blog/author/chris-melchiore) Chris Melchiore, serving as Business Development Manager at Asaclean Purging Compounds, excels with his specialized knowledge in Chemical Purging Compounds and Concentrate Grades. His industry journey, extending over two decades, includes a notable 16-year stint at NOVACHEM before joining Asaclean in 2015. Beyond his core role, Chris is actively involved in speaking engagements at webinars and tradeshows, showcasing his expertise and contributing to the broader industry dialogue. His insights and experience make him a pivotal figure in both business development and educational outreach for Asaclean. - [Share On LinkedIn ](https://www.linkedin.com/in/christopher-melchiore-19abb2a1/) ## Related Posts [![Purging Expert Chris Melchiore talks about the benefits of chemical purging compounds. ](https://www.asaclean.com/hs-fs/hubfs/Blog%20Header-Chemical%20Sweet%20Spot.jpg?width=450&height=250&name=Blog%20Header-Chemical%20Sweet%20Spot.jpg) Finding the Sweet Spot With a Chemical Purge Chemical... / 3 min read / January 05, 2022 ](https://www.asaclean.com/blog/finding-the-sweet-spot-with-a-chemical-purge) [![The Hidden Value of Soak Time for Chemical Purging Compounds](https://www.asaclean.com/hs-fs/hubfs/AI-Generated%20Media/Images/This%20image%20depicts%20soap%20suds%20in%20a%20bath.jpeg?width=450&height=250&name=This%20image%20depicts%20soap%20suds%20in%20a%20bath.jpeg) The Hidden Value of Soak Time for Chemical Purging Compounds Troubleshooting / 2 min read / June 27, 2019 ](https://www.asaclean.com/blog/the-hidden-value-of-soak-time-for-chemical-purging-compounds) ## Comments Get Started ## Ready to start improving your efficiency and increasing your profitability? - [Request a Consultation](https://www.asaclean.com/blog/4-causes-of-flow-lines-in-blown-film-extrusion-and-one-easy-solution#) - [Contact Sales](https://www.asaclean.com/blog/4-causes-of-flow-lines-in-blown-film-extrusion-and-one-easy-solution#) ![](https://www.asaclean.com/hubfs/assets/images/icons/icon-layers.svg) #### Free Sample Request a free sample of Asaclean® Purging Compounds for your plant and start saving today. 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[See your savings](https://www.asaclean.com/cost-savings-calculator) [ Back to Top ](https://www.asaclean.com/blog/4-causes-of-flow-lines-in-blown-film-extrusion-and-one-easy-solution#top) ```json { "@context" : "https://schema.org", "@type" : "BlogPosting", "author" : { "@type" : "Person", "name" : "Chris Melchiore", "url" : "https://www.asaclean.com/blog/author/chris-melchiore" }, "dateModified" : "2021-03-02T21:05:42.034Z", "datePublished" : "2021-03-02T21:05:42.000Z", "headline" : "4 Causes of Flow Lines in Blown Film Extrusion (and One Easy Solution)", "image" : [ "https://www.asaclean.com/hubfs/Blown%20Film.png" ], "mainEntityOfPage" : { "@id" : "https://www.asaclean.com/blog/4-causes-of-flow-lines-in-blown-film-extrusion-and-one-easy-solution", "@type" : "WebPage" }, "publisher" : { "@type" : "Organization", "logo" : { "@type" : "ImageObject", "url" : "https://www.asaclean.com/hubfs/Asaclean%20Logo%20TM.jpg" }, "name" : "Asahi Kasei Plastics North America" } } ``` ```json { "@context" : "http://schema.org", "@type" : "Article", "articleBody" : "Flow lines are one of the most common processing issues faced by blown film extruders. There are many possible causes, but these are the four \"usual suspects\": 1) Color Changes If going from a dark color to light or clear, color can hang up in negative flow areas. 2) Material Changes If performing a resin change from one polymer to another a difference in viscosity can cause flow lines or gels. 3) Poor Preventative Maintenance Over time polymer will degrade creating carbon (black specks). This carbon will hang up in areas and is difficult to remove. 4) Extended Shutdowns Shutting down the line for extended periods of time will create carbon or contamination due to residence time and the cool down and heat up process. Purging compounds help you address all of these causes and can dramatically improve your efficiency overnight.", "author" : { "@type" : "Person", "name" : "Chris Melchiore" }, "datePublished" : "March 02, 2021", "headline" : "4 Causes of Flow Lines in Blown Film Extrusion (and One Easy Solution)", "image" : "https://f.hubspotusercontent20.net/hubfs/468726/Blown%20Film.png", "name" : "4 Causes of Flow Lines in Blown Film Extrusion (and One Easy Solution)", "url" : "https://www.asaclean.com/blog/4-causes-of-flow-lines-in-blown-film-extrusion-and-one-easy-solution" } ```