--- title: Purging Extrusion Sheet Applications & the Challenges with Hanger Dies description: Purging Expert Jeremy Cooley walks you through how to purge a hanger die in sheet extrusion. image: https://www.asaclean.com/hubfs/Sheet%20Die.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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They struggle with contamination near the edges due to lower flow.](https://www.asaclean.com/hs-fs/hubfs/Sheet%20Die.png?width=346&name=Sheet%20Die.png) In extrusion sheet production the first objective is to spread a continuous polymer melt stream coming from an extruder into a die, which ends in a rectangular and wide cross section of extruded sheet. Producing and maintaining a quality product can produce many challenges in itself, much less trying to keep the extruder and die clean from either material changes, color changes, or shutting down and starting up. Introducing and maintaining a proper purging procedure is extremely important in any plastics processing but sheet manufacturing can be of utmost importance in the grand scheme of processing. With sheet processing you are taking a polymer melt from a small (in comparison) diameter of a screw and barrel and extending that extrudite out to very wide dimensions. This is where the processing parameters and the design of the die (hanger type or otherwise) come into play. Molten plastic will always want to take the path of least resistance which is always center of the melt flow. The challenges to keep the same quality product consistent across the width can translate to the same type of challenges for choosing the correct purging compound for that process. General purpose mechanical grades of purge usually don’t work as well for sheet manufacturers because it takes time and product to get to the outer edges of a sheet die. For an effective purge, you want to run as little as possible but still get the job done so that you can quickly and efficiently move to the next color or material. [Chemical grades with expansion properties ](https://www.asaclean.com/purging-products/asaclean-chemical-purging-grades/ncr-grade-purging-compound-formerly-supernova-regular/)tend to work much better in these applications. The expansion of the purging agent will help get the purge to the areas that need cleaning the most which are usually the outer most edges of the die. If deckles are used to shorten the width of the sheet then it is recommended that they be removed before purging. That will always be an area where polymer can stagnate and degrade. The overall purpose for the purging compound is to clean the entire surface from one edge to the other and remove any contamination that may be present on the lip as well. An aggressive[ chemical grade of purge](https://www.asaclean.com/purging-products/asaclean-chemical-purging-grades/ncr-grade-purging-compound-formerly-supernova-regular/) can make a huge difference between a smooth controlled changeover or an impending headache every time there is a changeover looming. **Sealing with Purge isn't the only way to reduce downtime. Learn more about how to reduce production downtime and protect your profits with a purging compound.** ![Yoko Tanaka](https://www.asaclean.com/hs-fs/hubfs/Yoko%20Tanaka%20Headshot%203-25-16.jpg?width=150&name=Yoko%20Tanaka%20Headshot%203-25-16.jpg) #### [ Yoko Tanaka ](https://www.asaclean.com/blog/author/yoko-tanaka) Yoko Tanaka is the Marketing Manager at Asaclean. She has been helping molders and extruders learn about Asaclean purging and how to improve their processes for the past eight years. - [Share On LinkedIn ](https://www.linkedin.com/in/yokotanaka/) ## Related Posts [![Purging for Extrusion: Screw & Barrel vs. Downstream](https://www.asaclean.com/hs-fs/hubfs/Blog%20Header-extrusions%20screw%20vs%20downstream.jpg?width=450&height=250&name=Blog%20Header-extrusions%20screw%20vs%20downstream.jpg) Purging for Extrusion: Screw & Barrel vs. Downstream Chemical... / 4 min read / February 01, 2022 ](https://www.asaclean.com/blog/purging-for-extrusion-screw-barrel-vs.-downstream) [![Extrusion Defects–Pinstriping](https://www.asaclean.com/hs-fs/hubfs/AI-Generated%20Media/Images/This%20image%20shows%20navy%20blue%20vertical%20pinstripes%20on%20a%20white%20background.jpeg?width=450&height=250&name=This%20image%20shows%20navy%20blue%20vertical%20pinstripes%20on%20a%20white%20background.jpeg) Extrusion Defects–Pinstriping Troubleshooting / 2 min read / October 25, 2019 ](https://www.asaclean.com/blog/high-cavitation-injection-molding-0) ## Comments Get Started ## Ready to start improving your efficiency and increasing your profitability? - [Request a Consultation](https://www.asaclean.com/blog/purging-extrusion-sheet-applications-the-challenges-with-hanger-dies#) - [Contact Sales](https://www.asaclean.com/blog/purging-extrusion-sheet-applications-the-challenges-with-hanger-dies#) ![](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. [Request your free sample](https://offers.asaclean.com/en/free-sample?hsLang=en) ![](https://www.asaclean.com/hubfs/assets/images/icons/icon-calculator.svg) #### Cost Savings Calculator Use our free calculator to see how much you could be saving with Asaclean® Purging Compounds. [See your savings](https://www.asaclean.com/cost-savings-calculator) [ Back to Top ](https://www.asaclean.com/blog/purging-extrusion-sheet-applications-the-challenges-with-hanger-dies#top) ```json { "@context" : "https://schema.org", "@type" : "BlogPosting", "author" : { "@type" : "Person", "name" : "Yoko Tanaka", "url" : "https://www.asaclean.com/blog/author/yoko-tanaka" }, "dateModified" : "2021-03-23T12:45:00.485Z", "datePublished" : "2021-03-23T12:45:00.000Z", "headline" : "Purging Extrusion Sheet Applications & the Challenges with Hanger Dies", "image" : [ "https://www.asaclean.com/hubfs/Sheet%20Die.png" ], "mainEntityOfPage" : { "@id" : "https://www.asaclean.com/blog/purging-extrusion-sheet-applications-the-challenges-with-hanger-dies", "@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" : "In extrusion sheet production the first objective is to spread a continuous polymer melt stream coming from an extruder into a die, which ends in a rectangular and wide cross section of extruded sheet. Producing and maintaining a quality product can produce many challenges in itself, much less trying to keep the extruder and die clean from either material changes, color changes, or shutting down and starting up. Introducing and maintaining a proper purging procedure is extremely important in any plastics processing but sheet manufacturing can be of utmost importance in the grand scheme of processing. With sheet processing you are taking a polymer melt from a small (in comparison) diameter of a screw and barrel and extending that extrudite out to very wide dimensions. This is where the processing parameters and the design of the die (hanger type or otherwise) come into play. Molten plastic will always want to take the path of least resistance which is always center of the melt flow. The challenges to keep the same quality product consistent across the width can translate to the same type of challenges for choosing the correct purging compound for that process.", "author" : { "@type" : "Person", "name" : "Yoko Tanaka" }, "datePublished" : "March 23, 2021", "headline" : "Purging Extrusion Sheet Applications & the Challenges with Hanger Dies", "image" : "https://f.hubspotusercontent20.net/hubfs/468726/Sheet%20Die.png", "name" : "Purging Extrusion Sheet Applications & the Challenges with Hanger Dies", "url" : "https://www.asaclean.com/blog/purging-extrusion-sheet-applications-the-challenges-with-hanger-dies" } ```