--- title: Thickness Control for Sheet Extrusion description: This talks how to fix defects in sheet extrusion. Asaclean Technical Sales Reps have a combined 200+ years of processing experience. image: https://www.asaclean.com/hubfs/Sheet%20Extrusion%20-%20Photo%204-1.jpg --- [ 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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[LinkedIn Share ](https://www.linkedin.com/shareArticle?mini=true&url=https%3A%2F%2Fwww.asaclean.com%2Fblog%2Fthickness-control-for-sheet-extrusion&title=Thickness%20Control%20for%20Sheet%20Extrusion&summary=This+talks+how+to+fix+defects+in+sheet+extrusion.+Asaclean+Technical+Sales+Reps+have+a+combined+200%2B+years+of+processing+experience.&source=) - [Pinterest Pin ](https://pinterest.com/pin/create/button/?url=https%3A%2F%2Fwww.asaclean.com%2Fblog%2Fthickness-control-for-sheet-extrusion) - [Email Email ](mailto:?subject=Thickness%20Control%20for%20Sheet%20Extrusion&body=https%3A%2F%2Fwww.asaclean.com%2Fblog%2Fthickness-control-for-sheet-extrusion) ![Thickness Control for Sheet Extrusion](https://www.asaclean.com/hs-fs/hubfs/Sheet%20Extrusion%20-%20Photo%204-1.jpg?width=640&height=500&name=Sheet%20Extrusion%20-%20Photo%204-1.jpg) ![Sheet Die](https://www.asaclean.com/hs-fs/hubfs/Sheet%20Die.png?width=294&name=Sheet%20Die.png) When extruding a flat sheet on a die we can have variations in thickness. Some variations can be eliminated with good process control. Some determining parameters are: - Variations in extrusion flow - Temperature in the different zones of the die - Die opening - Opening of the rollers - Variations in the geometry of the rollers and control of their temperature. - Speed with which the rubber rollers stretch, excessive time between the gripper and cutting. Now we know some of the variables, the first step is to control them: - The cooling and heating system in the zones must work properly. The higher the temperature, the greater the flow and therefore the greater the thickness. The middle of the die tends to flow more and the edges of the die tend to cool faster so the zones do not always need to be adjusted to the same temperature. - Monitor the torque or amperage on the extruder. If we have the same RPM and the same material, the effort of the engine should not drastically increase or decrease. Otherwise something is blocking the flow or changing the viscosity of the material. - The calibration of the rod and the lips is important, as is the adjustment given by each screw. At a very detailed level, it helps in the adjustment up to number of threads per distance that the screws have. - This blog doesn’t discuss the relationship between the polymer and the distance of the calender and the opening of the rollers with each polymer, but there are tables that show some of this information. - The rollers will always print their geometry onto the sheet, so any variation in their shape will cause indentations or protrusions. It is important to keep them clean, take care of the finish, and take care of the parallelism between the rollers and their surface dimensions. - If there are differences between the speed at which the material flows, this can cause transversal lines of varying thicknesses. **Ready to reduce your ****production downtime**** to protect your profits? Learn more about how ****purging compounds**** and process efficiency work in tandem.** ![Tom Hanvey](https://www.asaclean.com/hs-fs/hubfs/Tom%20Headshot.jpg?width=150&name=Tom%20Headshot.jpg) #### [ Tom Hanvey ](https://www.asaclean.com/blog/author/tom-hanvey) Tom Hanvey is the Associate Director of Marketing & Sustainability at Asahi Kasei Plastics North America. Before joining APNA, he worked as the Senior Marketing Manager for Asaclean Purging Compounds. He's worked in the plastics industry for over 10 years and focuses on recyclable resins and on the inbound marketing side, providing easy-to-digest content to processors looking for an edge on their competition. - [Share On LinkedIn ](https://www.linkedin.com/in/thomashanvey/) ## Related Posts [![](https://www.asaclean.com/hs-fs/hubfs/iStock-614446642.jpg?width=450&height=250&name=iStock-614446642.jpg) Purging Options for Blow Molding Machines Have Come a Long Way Purging Tips / 3 min read / August 17, 2021 ](https://www.asaclean.com/blog/purging-options-for-blow-molding-machines-have-come-a-long-way) [![Tool Maintenance](https://www.asaclean.com/hs-fs/hubfs/Tool%20Maintenance.png?width=450&height=250&name=Tool%20Maintenance.png) Injection Molding Tips: Mold Preventative Maintenance Troubleshooting / 2 min read / June 20, 2019 ](https://www.asaclean.com/blog/injection-molding-tips-mold-preventative-maintenance) ## Comments Get Started ## Ready to start improving your efficiency and increasing your profitability? - [Request a Consultation](https://www.asaclean.com/blog/thickness-control-for-sheet-extrusion#) - [Contact Sales](https://www.asaclean.com/blog/thickness-control-for-sheet-extrusion#) ![](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/thickness-control-for-sheet-extrusion#top) ```json { "@context" : "https://schema.org", "@type" : "BlogPosting", "author" : { "@type" : "Person", "name" : "Tom Hanvey", "url" : "https://www.asaclean.com/blog/author/tom-hanvey" }, "dateModified" : "2025-07-07T15:12:19.533Z", "datePublished" : "2020-01-08T18:32:39.000Z", "headline" : "Thickness Control for Sheet Extrusion", "image" : [ "https://www.asaclean.com/hubfs/Sheet%20Extrusion%20-%20Photo%204-1.jpg" ], "mainEntityOfPage" : { "@id" : "https://www.asaclean.com/blog/thickness-control-for-sheet-extrusion", "@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" : "When extruding a flat sheet on a die we can have variations in thickness. Some variations can be eliminated with good process control. Some determining parameters are: Variations in extrusion flow Temperature in the different zones of the die Die opening Opening of the rollers Variations in the geometry of the rollers and control of their temperature. Speed with which the rubber rollers stretch, excessive time between the gripper and cutting.", "author" : { "@type" : "Person", "name" : "Tom Hanvey" }, "datePublished" : "January 08, 2020", "headline" : "Thickness Control for Sheet Extrusion", "image" : "https://468726.fs1.hubspotusercontent-na1.net/hubfs/468726/Sheet%20Extrusion%20-%20Photo%204-1.jpg", "name" : "Thickness Control for Sheet Extrusion", "url" : "https://www.asaclean.com/blog/thickness-control-for-sheet-extrusion" } ```