{"id":12694,"date":"2026-05-20T03:18:14","date_gmt":"2026-05-20T03:18:14","guid":{"rendered":"https:\/\/ideal-pro.com\/?p=12694"},"modified":"2026-05-20T05:09:30","modified_gmt":"2026-05-20T05:09:30","slug":"injection-molding-plastic-degradation-causes-solutions","status":"publish","type":"post","link":"https:\/\/ideal-pro.com\/de\/injection-molding-plastic-degradation-causes-solutions\/","title":{"rendered":"Why Do Injection Molded Parts Degrade? Causes and Effective Solutions"},"content":{"rendered":"<p>Plastic degradation is a common headache in the\n<a href=\"https:\/\/ideal-pro.com\/de\/kunststoff-spritzguss\/\" target=\"_blank\" rel=\"noopener noreferrer\">Spritzgie\u00dfen<\/a>\nindustry. Whether it appears as burn marks, discoloration, or brittleness, degraded plastic compromises the quality and strength of your final product.<\/p>\n<p>But what exactly causes this issue? Usually, the culprits fall into three categories: <strong>The Machine<\/strong>, <strong>The Mold<\/strong>, oder <strong>The Material<\/strong>.<\/p>\n<p>In this guide, we break down the root causes of plastic degradation and provide actionable solutions to help you optimize your production process.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/ideal-pro.com\/wp-content\/uploads\/2026\/05\/1-18.jpg\" alt=\"Why Do Injection Molded Parts Degrade? Causes and Effective Solutions\"><\/p>\n<hr>\n<h2>Issues Related to the Injection Molding Machine<\/h2>\n<p>Often, degradation happens because the plastic is subjected to excessive heat or stays in the barrel for too long. Here is how to troubleshoot machine-related problems:<\/p>\n<p><strong>A. Excessive Heating in the Barrel<\/strong><\/p>\n<ul>\n<li><strong>Das Problem:<\/strong> The plastic melt temperature is set too high, causing the polymer chains to break down.<\/li>\n<li><strong>The Solution:<\/strong> Lower the melt temperature settings. Ensure the temperature profile matches the specific requirements of the resin you are using.<\/li>\n<\/ul>\n<p><strong>B. Malfunctioning Temperature Controllers<\/strong><\/p>\n<ul>\n<li><strong>Das Problem:<\/strong> The temperature controller may be reading incorrectly or failing to regulate the heat properly.<\/li>\n<li><strong>The Solution:<\/strong> Verify that the controller is monitoring the correct zone of the barrel. Recalibrate the temperature controller and inspect the heating bands for stuck relays or loose connections.<\/li>\n<\/ul>\n<p><strong>C. Incorrect Thermocouple Type<\/strong><\/p>\n<ul>\n<li><strong>Das Problem:<\/strong> Using a thermocouple type (e.g., J-type vs. K-type) that does not match the controller's configuration leads to false temperature readings.<\/li>\n<li><strong>The Solution:<\/strong> Check that the installed thermocouples match the type specified by the controller manufacturer (e.g., FECON). Test all thermocouples to ensure they are functioning accurately.<\/li>\n<\/ul>\n<p><strong>D. Excessive Residence Time<\/strong><\/p>\n<ul>\n<li><strong>Das Problem:<\/strong> If the shot weight is too small for the machine size, plastic sits in the barrel too long and degrades.<\/li>\n<li><strong>The Solution:<\/strong> Check your shot weight. If it is less than <strong>25% of the machine's maximum injection capacity<\/strong>, move the mold to a smaller machine.\n<ul>\n<li><em>Anmerkung:<\/em> If a smaller machine is unavailable, reduce the barrel temperatures to the minimum viable limit to produce acceptable parts.<\/li>\n<\/ul><\/li>\n<\/ul>\n<p><strong>E. Material Stagnation During Stops<\/strong><\/p>\n<ul>\n<li><strong>Das Problem:<\/strong> Leaving plastic inside the barrel during production pauses or shutdowns allows it to bake and degrade.<\/li>\n<li><strong>The Solution:<\/strong> Always purge and clean the barrel before stopping production. Leave the screw in the <strong>forward position<\/strong> to prevent material from sitting in the heating zones.<\/li>\n<\/ul>\n<p><strong>F. Material \"Hang-ups\" in the Barrel<\/strong><\/p>\n<ul>\n<li><strong>Das Problem:<\/strong> Plastic can get trapped in scratches or damaged areas inside the barrel (often near the non-return valve), eventually degrading and breaking off into the shot.<\/li>\n<li><strong>The Solution:<\/strong> Inspect the barrel interior thoroughly. Remove any residue or buildup on the mating surfaces and check for mechanical damage.<\/li>\n<\/ul>\n<hr>\n<h2>Issues Related to the Mold<\/h2>\n<p>While less common, mold specifications can indirectly contribute to degradation issues.<\/p>\n<p><strong>A. Mold Capacity Mismatch<\/strong><\/p>\n<ul>\n<li><strong>Das Problem:<\/strong> Similar to the machine issue, if the mold requires a shot size that is too small for the available machine, it leads to long residence times.<\/li>\n<li><strong>The Solution:<\/strong> Relocate the mold to an injection molding machine with a smaller shot capacity that better matches the part weight.<\/li>\n<\/ul>\n<hr>\n<h2>Issues Related to the <a href=\"https:\/\/ideal-pro.com\/de\/verbundwerkstoff-spritzgiesmaterialien\/\" target=\"_blank\" rel=\"noopener noreferrer\">Plastik Material<\/a><\/h2>\n<p>Sometimes the defect starts before the plastic even enters the machine.<\/p>\n<p><strong>A. Excessive Moisture Content<\/strong><\/p>\n<ul>\n<li><strong>Das Problem:<\/strong> Many engineering plastics (like Nylon, PET, PC) are hygroscopic. High moisture content causes hydrolysis, leading to degradation and splay marks.<\/li>\n<li><strong>The Solution:<\/strong> Implement a strict drying regimen. Use the correct hopper dryer settings (temperature and time) recommended by the material supplier.<\/li>\n<\/ul>\n<p><strong>B. Poor Quality or Contaminated Regrind<\/strong><\/p>\n<ul>\n<li><strong>Das Problem:<\/strong> Using regrind (recycled scrap) that contains dust, metal contaminants, or has been heat-damaged previously will ruin the new batch.<\/li>\n<li><strong>The Solution:<\/strong> Strictly separate and inspect regrind materials. Filter out impurities and limit the percentage of regrind mixed with virgin material.<\/li>\n<\/ul>\n<hr>\n<h2>Summary Checklist<\/h2>\n<p>To prevent plastic degradation, remember these key takeaways:<\/p>\n<ol>\n<li><strong>Monitor Temperatures:<\/strong> Ensure controllers and thermocouples are accurate.<\/li>\n<li><strong>Match Machine to Part:<\/strong> Avoid running small parts on massive machines.<\/li>\n<li><strong>Cleanliness is Key:<\/strong> Purge the barrel when stopping and keep regrind clean.<\/li>\n<li><strong>Dry Your Material:<\/strong> Never skip the drying process for hygroscopic resins.<\/li>\n<\/ol>\n<p>By systematically checking these areas, you can eliminate degradation defects and improve your overall yield.<\/p>","protected":false},"excerpt":{"rendered":"<p>Plastic degradation is a common headache in the injection molding industry. Whether it appears as burn marks, discoloration, or brittleness, [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":12696,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_seopress_robots_primary_cat":"","_seopress_titles_title":"","_seopress_titles_desc":"re your injection molded parts showing signs of degradation? Discover the common causes\u2014from machine settings to material moisture\u2014and learn practical solutions to fix plastic burn marks and discoloration.","_seopress_robots_index":"","_seopress_analysis_target_kw":"","site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"default","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[21],"tags":[36,119,232],"class_list":["post-12694","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","tag-injection-molding","tag-plastic-defects","tag-quality-control"],"acf":[],"_links":{"self":[{"href":"https:\/\/ideal-pro.com\/de\/wp-json\/wp\/v2\/posts\/12694","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ideal-pro.com\/de\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ideal-pro.com\/de\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ideal-pro.com\/de\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/ideal-pro.com\/de\/wp-json\/wp\/v2\/comments?post=12694"}],"version-history":[{"count":6,"href":"https:\/\/ideal-pro.com\/de\/wp-json\/wp\/v2\/posts\/12694\/revisions"}],"predecessor-version":[{"id":12701,"href":"https:\/\/ideal-pro.com\/de\/wp-json\/wp\/v2\/posts\/12694\/revisions\/12701"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ideal-pro.com\/de\/wp-json\/wp\/v2\/media\/12696"}],"wp:attachment":[{"href":"https:\/\/ideal-pro.com\/de\/wp-json\/wp\/v2\/media?parent=12694"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ideal-pro.com\/de\/wp-json\/wp\/v2\/categories?post=12694"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ideal-pro.com\/de\/wp-json\/wp\/v2\/tags?post=12694"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}