{"id":15050,"date":"2026-09-21T09:38:39","date_gmt":"2026-09-21T09:38:39","guid":{"rendered":"https:\/\/kenddg.tw\/enblog\/?p=15050"},"modified":"2026-10-04T14:05:14","modified_gmt":"2026-10-04T14:05:14","slug":"injection-molding-wall-thickness","status":"publish","type":"post","link":"https:\/\/kenddg.tw\/enblog\/injection-molding-wall-thickness\/","title":{"rendered":"Plastic Part Wall Thickness Design Guide\uff1a Thickness Range, Flow Length, and Shrinkage Control"},"content":{"rendered":"\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_88 ez-toc-wrap-center counter-flat ez-toc-counter ez-toc-light-blue ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/kenddg.tw\/enblog\/injection-molding-wall-thickness\/#1-key-takeaways\" >1. Key Takeaways<\/a><\/li><li class='ez-toc-page-1'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/kenddg.tw\/enblog\/injection-molding-wall-thickness\/#2-why-is-wall-thickness-important\" >2. Why Is Wall Thickness Important?<\/a><\/li><li class='ez-toc-page-1'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/kenddg.tw\/enblog\/injection-molding-wall-thickness\/#3-basic-wall-thickness-design-guidelines\" >3. Basic Wall Thickness Design Guidelines<\/a><\/li><li class='ez-toc-page-1'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/kenddg.tw\/enblog\/injection-molding-wall-thickness\/#4-wall-thickness-and-flow-length\" >4. Wall Thickness and Flow Length<\/a><\/li><li class='ez-toc-page-1'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/kenddg.tw\/enblog\/injection-molding-wall-thickness\/#5-what-if-the-flow-length-is-too-long\" >5. What If the Flow Length Is Too Long?<\/a><\/li><li class='ez-toc-page-1'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/kenddg.tw\/enblog\/injection-molding-wall-thickness\/#6-wall-thickness-design-comparison\" >6. Wall Thickness Design Comparison<\/a><\/li><li class='ez-toc-page-1'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/kenddg.tw\/enblog\/injection-molding-wall-thickness\/#7-further-reading\" >7. Further Reading<\/a><\/li><li class='ez-toc-page-1'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/kenddg.tw\/enblog\/injection-molding-wall-thickness\/#8-references-and-additional-resources\" >8. References and Additional Resources<\/a><\/li><\/ul><\/nav><\/div>\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"1-key-takeaways\"><\/span>1. Key Takeaways<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">When designing wall thickness for an injection-molded plastic part, consider\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>(a) Product strength and stiffness<\/li>\n\n\n\n<li>(b) Weight and material cost<\/li>\n\n\n\n<li>(c) Electrical and assembly requirements<\/li>\n\n\n\n<li>(d) Dimensional stability<\/li>\n\n\n\n<li>(e) Melt flow and filling capability<\/li>\n\n\n\n<li>(f) Sink marks, voids, shrinkage, and warpage<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Wall thickness should also be evaluated together with material properties, flow length, gate location, and overall part size.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"2-why-is-wall-thickness-important\"><\/span>2. Why Is Wall Thickness Important?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Wall thickness directly affects both product performance and molding quality. Walls that are too thin may increase flow resistance, reduce strength, or cause incomplete filling.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Walls that are too thick increase material usage and cooling time. They may also create uneven shrinkage, sink marks, internal voids, or warpage.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For this reason, wall thickness should be determined according to product function, structural requirements, and molding conditions rather than appearance alone.<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260917-03-en-a-1024x576.jpg\" alt=\"Wall thickness design considerations\" class=\"wp-image-15196\" srcset=\"https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260917-03-en-a-1024x576.jpg 1024w, https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260917-03-en-a-300x169.jpg 300w, https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260917-03-en-a-768x432.jpg 768w, https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260917-03-en-a-1536x864.jpg 1536w, https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260917-03-en-a-2048x1152.jpg 2048w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/>\r\n\r\n<\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"3-basic-wall-thickness-design-guidelines\"><\/span>3. Basic Wall Thickness Design Guidelines<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">(3-1) Typical Wall Thickness Range<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">General plastic parts commonly use wall thicknesses of approximately 1\u20136 mm, with 2\u20133 mm being common in many applications. However, there is no universal value. The final wall thickness depends on:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>(a) Plastic material<\/li>\n\n\n\n<li>(b) Part size<\/li>\n\n\n\n<li>(c) Structural requirements<\/li>\n\n\n\n<li>(d) Molding conditions<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Large plastic parts may require walls thicker than 6 mm when additional structural support is needed. Recommended values for thermoplastic and thermoset parts also vary with material and overall part dimensions (Table 1) (Table 2).<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">(3-2) Keep Wall Thickness Uniform<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Uniform wall thickness is a basic rule in injection-molded part design. Large thickness variations can cause:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>(a) Uneven cooling<\/li>\n\n\n\n<li>(b) Differential shrinkage<\/li>\n\n\n\n<li>(c) Sink marks<\/li>\n\n\n\n<li>(d) Voids<\/li>\n\n\n\n<li>(e) Warpage<\/li>\n\n\n\n<li>(f) Dimensional instability<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">If a thickness change is necessary, avoid abrupt transitions. Use gradual transitions to improve melt flow and cooling consistency.<\/p>\n\n\n\n<div style=\"width:100%;overflow-x:auto;margin:20px 0;\">\n<table style=\"font-family:Arial,'Noto Sans TC','Microsoft JhengHei',sans-serif;border-collapse:collapse;table-layout:fixed;width:100%;text-align:center;line-height:1.35;color:#111;min-width:900px;\">\n<colgroup>\n<col style=\"width:45.625%\">\n<col style=\"width:9.0625%\"><col style=\"width:9.0625%\">\n<col style=\"width:9.0625%\"><col style=\"width:9.0625%\">\n<col style=\"width:9.0625%\"><col style=\"width:9.0625%\">\n<\/colgroup>\n<tbody>\n<tr>\n<td rowspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;font-weight:700;background:#d9e2f3;\">Plastic Material<\/td>\n<td colspan=\"6\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;font-weight:700;background:#d9e2f3;\">Molded Part Height<\/td>\n<\/tr>\n<tr>\n<td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">\uff1c50<\/td>\n<td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">50\uff5e100<\/td>\n<td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">\uff1e100<\/td>\n<\/tr>\n<tr><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">Phenolic Plastic with Powdered Filler<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1\uff5e2<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">2\uff5e3<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">5\uff5e6.5<\/td><\/tr>\n<tr><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">Phenolic Plastic with Fibrous Filler<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.5\uff5e2<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">2.5\uff5e3.5<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">6\uff5e8<\/td><\/tr>\n<tr><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">Amino Plastic<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.3\uff5e2<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">3\uff5e4<\/td><\/tr>\n<tr><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">Polyester Plastic with Glass-Fiber Filler<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1\uff5e2<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">2.4\uff5e3.2<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">\uff1e4.8<\/td><\/tr>\n<tr><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">Polyester Plastic with Inorganic Filler<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1\uff5e2<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">3.2\uff5e4.8<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">\uff1e4.8<\/td><\/tr>\n<tr><td colspan=\"6\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;font-weight:400;\">(Table 1)  Recommended Wall Thickness Values for Thermosetting Plastic Parts<\/td><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;font-weight:400;white-space:nowrap;\">Unit\uff1amm<\/td><\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n\n\n\n<div style=\"width:100%;overflow-x:auto;margin:20px 0;\">\n<table style=\"font-family:Arial,'Noto Sans TC','Microsoft JhengHei',sans-serif;border-collapse:collapse;table-layout:fixed;width:100%;text-align:center;line-height:1.35;color:#111;min-width:1100px;\">\n<colgroup>\n<col style=\"width:40.625%\">\n<col style=\"width:12.625%\"><col style=\"width:12.625%\">\n<col style=\"width:12.625%\"><col style=\"width:12.625%\">\n<col style=\"width:12.625%\"><col style=\"width:12.625%\">\n<col style=\"width:12.625%\"><col style=\"width:12.625%\">\n<\/colgroup>\n<tbody>\n<tr><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;font-weight:700;background:#d9d9d9;\">Plastic Material<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;font-weight:700;background:#fce4d6;\">Minimum<br>Wall Thickness<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;font-weight:700;background:#ddebf7;\">Recommended Wall<br>Thickness for Small Parts<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;font-weight:700;background:#e4dfec;\">Recommended Wall<br>Thickness for Medium Parts<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;font-weight:700;background:#d9e2f3;\">Recommended Wall<br>Thickness for Large Parts<\/td><\/tr>\n<tr><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">Nylon<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">0.45<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">0.75<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.60<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">2.4\uff5e3.2<\/td><\/tr>\n<tr><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">Polyethylene<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">0.6<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.25<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.6<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">2.4\uff5e3.2<\/td><\/tr>\n<tr><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">Polystyrene<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">0.75<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.25<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.6<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">3.2\uff5e4.5<\/td><\/tr>\n<tr><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">Modified Polystyrene<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">0.75<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.25<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.6<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">3.2\uff5e5.4<\/td><\/tr>\n<tr><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">Acrylic (372)<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">0.8<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.5<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">2.2<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">4\uff5e6.5<\/td><\/tr>\n<tr><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">Rigid Polyvinyl Chloride<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.15<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.6<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.8<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">3.2\uff5e5.8<\/td><\/tr>\n<tr><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">Polypropylene<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">0.85<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.45<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.75<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">2.4\uff5e3.2<\/td><\/tr>\n<tr><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">Chlorinated Polyether<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">0.85<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.35<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.8<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">2.5\uff5e3.4<\/td><\/tr>\n<tr><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">Polycarbonate<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">0.95<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.8<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">2.3<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">3\uff5e4.5<\/td><\/tr>\n<tr><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">Polyphenylene Oxide<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.2<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.75<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">2.5<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">3.5\uff5e6.4<\/td><\/tr>\n<tr><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">Cellulose Acetate<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">0.7<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.25<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.9<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">3.2\uff5e4.8<\/td><\/tr>\n<tr><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">Ethyl Cellulose<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">0.9<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.25<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.6<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">2.4\uff5e3.2<\/td><\/tr>\n<tr><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">Acrylics<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">0.7<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">0.9<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">2.4<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">3\uff5e6<\/td><\/tr>\n<tr><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">Polyoxymethylene<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">0.8<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.4<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.6<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">3.2\uff5e5.4<\/td><\/tr>\n<tr><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">Polysulfone<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">0.95<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">1.8<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">2.3<\/td><td colspan=\"2\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;\">3\uff5e4.5<\/td><\/tr>\n<tr><td colspan=\"8\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;background:#d9d9d9;text-align:left;\">Note: The minimum wall thickness may vary depending on molding conditions<\/td><td style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;background:#d9d9d9;white-space:nowrap;\">Unit\uff1amm<\/td><\/tr>\n<tr><td colspan=\"9\" style=\"border:1px solid #222;padding:8px 6px;vertical-align:middle;font-weight:400;\">(Table 2) Recommended Minimum and Common Wall Thicknesses for Thermoplastic Plastic Parts<\/td><\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"4-wall-thickness-and-flow-length\"><\/span>4. Wall Thickness and Flow Length<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Wall thickness strongly affects how far molten plastic can flow through the mold cavity. In general\uff1a<\/p><div class=\"c0dfe75489dd6130bcab6314dcbf1b7e\" data-index=\"6\" style=\"float: none; margin:0px 0 0px 0; text-align:center;\">\n<script async src=\"https:\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js?client=ca-pub-9493520551675557\"\r\n     crossorigin=\"anonymous\"><\/script>\r\n<ins class=\"adsbygoogle\"\r\n     style=\"display:block\"\r\n     data-ad-format=\"fluid\"\r\n     data-ad-layout-key=\"+43+p6-21-7u+128\"\r\n     data-ad-client=\"ca-pub-9493520551675557\"\r\n     data-ad-slot=\"3408999682\"><\/ins>\r\n<script>\r\n     (adsbygoogle = window.adsbygoogle || []).push({});\r\n<\/script>\n<\/div>\n\n\n\n\n<ul class=\"wp-block-list\">\n<li>(a) Thicker walls allow longer flow distances.<\/li>\n\n\n\n<li>(b) Thinner walls create greater flow resistance.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The relationship between wall thickness t and flow length L can therefore be used to evaluate filling feasibility (Table 3 and Figure 2).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For example, when the wall thickness is 2.5 mm, the corresponding t-L relationship can be used to estimate whether the required flow distance is practical under normal molding conditions.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Wall thickness should therefore be checked together with gate location and the distance from the gate to the end of fill.<\/p>\n\n\n\n<div style=\"width:100%;overflow-x:auto;margin:20px 0;text-align:center;\">\n<table style=\"border-collapse:collapse;border-spacing:0;table-layout:fixed;width:772px;min-width:772px;margin:0 auto;font-family:Arial,sans-serif;font-size:12pt;color:#000000;\">\n<colgroup>\n  <col style=\"width:285px;\">\n  <col style=\"width:101px;\">\n  <col style=\"width:285px;\">\n  <col style=\"width:101px;\">\n<\/colgroup>\n<tbody>\n<tr style=\"height:40px;\">\n  <td colspan=\"2\" style=\"border:1px solid #000000;padding:0 8px;text-align:center;vertical-align:middle;box-sizing:border-box;white-space:normal;background:#DDEBF7;font-weight:bold;\">Plastic Type<\/td>\n  <td colspan=\"2\" style=\"border:1px solid #000000;padding:0 8px;text-align:center;vertical-align:middle;box-sizing:border-box;white-space:normal;background:#DDEBF7;font-weight:bold;\">t &#8211; L Relationship<\/td>\n<\/tr>\n<tr style=\"height:53.4px;\">\n  <td colspan=\"2\" style=\"border:1px solid #000000;padding:0 8px;text-align:center;vertical-align:middle;box-sizing:border-box;white-space:normal;\">Good Flowability<br>(e.g., Polyethylene, Nylon, etc.)<\/td>\n  <td colspan=\"2\" style=\"border:1px solid #000000;padding:0 8px;text-align:center;vertical-align:middle;box-sizing:border-box;white-space:normal;\">5\uff5e6.5<\/td>\n<\/tr>\n<tr style=\"height:53.4px;\">\n  <td colspan=\"2\" style=\"border:1px solid #000000;padding:0 8px;text-align:center;vertical-align:middle;box-sizing:border-box;white-space:normal;\">Medium Flowability<br>(e.g., Acrylic, Polyoxymethylene)<\/td>\n  <td colspan=\"2\" style=\"border:1px solid #000000;padding:0 8px;text-align:center;vertical-align:middle;box-sizing:border-box;white-space:normal;\">6\uff5e8<\/td>\n<\/tr>\n<tr style=\"height:53.4px;\">\n  <td colspan=\"2\" style=\"border:1px solid #000000;padding:0 8px;text-align:center;vertical-align:middle;box-sizing:border-box;white-space:normal;\">Poor Flowability<br>(e.g., Polycarbonate, Polysulfone, etc.)<\/td>\n  <td colspan=\"2\" style=\"border:1px solid #000000;padding:0 8px;text-align:center;vertical-align:middle;box-sizing:border-box;white-space:normal;\">3\uff5e4<\/td>\n<\/tr>\n<tr style=\"height:26.6px;\">\n  <td colspan=\"4\" style=\"border:1px solid #000000;padding:0 8px;text-align:center;vertical-align:middle;box-sizing:border-box;white-space:normal;\">(Table 3)&nbsp;&nbsp;Relationship Between Wall Thickness t and Flow Length L<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260922-01-1024x576.jpg\" alt=\"Relationship between wall thickness and flow length\" class=\"wp-image-15226\" srcset=\"https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260922-01-1024x576.jpg 1024w, https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260922-01-300x169.jpg 300w, https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260922-01-768x432.jpg 768w, https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260922-01-1536x864.jpg 1536w, https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260922-01-2048x1152.jpg 2048w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"5-what-if-the-flow-length-is-too-long\"><\/span>5. What If the Flow Length Is Too Long?<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">If the required flow distance exceeds the material&#8217;s practical filling capability, several design changes may be considered\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>(a) Increase the wall thickness<\/li>\n\n\n\n<li>(b) Add additional gates<\/li>\n\n\n\n<li>(c) Change the gate location<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Increasing wall thickness can improve flow, but it may also increase weight, cooling time, shrinkage, and material cost.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Adding or relocating gates can reduce the required flow distance without significantly increasing the wall thickness.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The objective is to achieve reliable filling while maintaining product structure, appearance, and dimensional stability.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"6-wall-thickness-design-comparison\"><\/span>6. Wall Thickness Design Comparison<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Good wall thickness design should minimize unnecessary thick sections and avoid sudden changes in section thickness. During DFM review, engineers should identify areas that may cause\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>(a) Excessive material buildup<\/li>\n\n\n\n<li>(b) Difficult filling<\/li>\n\n\n\n<li>(c) Uneven cooling<\/li>\n\n\n\n<li>(d) Sink marks<\/li>\n\n\n\n<li>(e) Warpage<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Recommended and less desirable wall thickness designs are shown in (Figure 3-1) and (Figure 3-2).<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260922-04c-1024x576.jpg\" alt=\"Wall thickness design comparison\" class=\"wp-image-15235\" srcset=\"https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260922-04c-1024x576.jpg 1024w, https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260922-04c-300x169.jpg 300w, https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260922-04c-768x432.jpg 768w, https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260922-04c-1536x864.jpg 1536w, https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260922-04c-2048x1152.jpg 2048w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<figure class=\"wp-block-image aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260922-05c-1024x576.jpg\" alt=\"Wall thickness design comparison\" class=\"wp-image-15236\" srcset=\"https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260922-05c-1024x576.jpg 1024w, https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260922-05c-300x169.jpg 300w, https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260922-05c-768x432.jpg 768w, https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260922-05c-1536x864.jpg 1536w, https:\/\/kenddg.tw\/enblog\/wp-content\/uploads\/2026\/09\/20260922-05c-2048x1152.jpg 2048w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"7-further-reading\"><\/span>7. Further Reading<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">(7-1) Uniform Wall Thickness in Plastic Part Design<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Uniform wall thickness helps prevent uneven cooling and shrinkage, reducing the risk of sink marks, voids, warpage, and dimensional variation. Use gradual transitions to maintain smooth material flow and a consistent appearance. <\/p>\n\n\n\n<figure class=\"wp-block-embed aligncenter is-type-wp-embed is-provider-kens-engineering-design-knowledge-base wp-block-embed-kens-engineering-design-knowledge-base\"><div class=\"wp-block-embed__wrapper\">\n<blockquote class=\"wp-embedded-content\" data-secret=\"Dgcl4QosvO\"><a href=\"https:\/\/kenddg.tw\/enblog\/uniform-wall-thickness-plastic-part-design\/\">Uniform Wall Thickness in Plastic Part Design<\/a><\/blockquote><iframe loading=\"lazy\" class=\"wp-embedded-content\" sandbox=\"allow-scripts\" security=\"restricted\" style=\"position: absolute; visibility: hidden;\" title=\"\u201cUniform Wall Thickness in Plastic Part Design\u201d \u2014 Ken\u2019s Engineering Design Knowledge Base\" src=\"https:\/\/kenddg.tw\/enblog\/uniform-wall-thickness-plastic-part-design\/embed\/#?secret=ClOuvNLwPE#?secret=Dgcl4QosvO\" data-secret=\"Dgcl4QosvO\" width=\"600\" height=\"338\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\"><\/iframe>\n<\/div><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">(7-2) Plastic Part Wall Thickness and Flow Length Ratio (FLR) Design<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Wall thickness and Flow Length Ratio (FLR) are key factors in injection-molded part design. Proper control of wall thickness, transitions, and flow length helps reduce sink marks, voids, warpage, and cracking while improving molding stability and production efficiency.<\/p>\n\n\n\n<figure class=\"wp-block-embed aligncenter is-type-wp-embed is-provider-kens-engineering-design-knowledge-base wp-block-embed-kens-engineering-design-knowledge-base\"><div class=\"wp-block-embed__wrapper\">\n<blockquote class=\"wp-embedded-content\" data-secret=\"wPN6kaIvHj\"><a href=\"https:\/\/kenddg.tw\/enblog\/plastic-part-wall-thickness-flow-length-ratio\/\">Plastic Part Wall Thickness and Flow Length Ratio (FLR) Design<\/a><\/blockquote><iframe loading=\"lazy\" class=\"wp-embedded-content\" sandbox=\"allow-scripts\" security=\"restricted\" style=\"position: absolute; visibility: hidden;\" title=\"\u201cPlastic Part Wall Thickness and Flow Length Ratio (FLR) Design\u201d \u2014 Ken\u2019s Engineering Design Knowledge Base\" src=\"https:\/\/kenddg.tw\/enblog\/plastic-part-wall-thickness-flow-length-ratio\/embed\/#?secret=tjI62VH0I0#?secret=wPN6kaIvHj\" data-secret=\"wPN6kaIvHj\" width=\"600\" height=\"338\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\"><\/iframe>\n<\/div><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"8-references-and-additional-resources\"><\/span>8. References and Additional Resources<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">This article draws on relevant technical books, literature, research materials, and publicly available sources. The primary references have been compiled in the \u201cReferences and Book Sources\u201d video for readers who wish to explore the subject in greater depth.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Any images, charts, technical data, or published materials cited or reproduced in this article remain the property of their respective authors, publishers, or other rights holders.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">[1] Zhao, Longzhi, Zhao, Mingjuan, and Fu, Wei. <em>Practical Handbook of Modern Injection Mold Design<\/em>. China Machine Press, October 2012.<br>[2] Li, Huilai. <em>Practical Examples of Product Structural Design<\/em>. Publishing House of Electronics Industry, July 2013.<br>[3] Zhong, Yuan. <em>Product Design Guidelines for Manufacturing and Assembly<\/em>. China Machine Press, October 2011.<br>\u25b6 Complete References and Source Materials \u2014 For more details, please watch the following video.<\/p>\n\n\n\n<figure class=\"wp-block-embed aligncenter is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe loading=\"lazy\" title=\"\u90e8\u843d\u683c\u6587\u7ae0\u53c3\u8003\u6587\u737b \/ Blog Article References and Source Materials\" width=\"1290\" height=\"726\" src=\"https:\/\/www.youtube.com\/embed\/DCAipnsaZmw?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n<\/div><\/figure>\n\n<div style=\"font-size: 0px; height: 0px; line-height: 0px; margin: 0; padding: 0; clear: both;\"><\/div>","protected":false},"excerpt":{"rendered":"<p>Wall thickness is one of the most important factors in plastic part design. It affects part strength, weight, dimensional stability, appearance, material usage, and injection moldability.<br \/>\nThe main design goal is not simply to make a part thicker or thinner. A good design balances structural requirements with material flow, cooling, shrinkage, and manufacturing feasibility.<\/p>\n","protected":false},"author":1,"featured_media":15195,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"footnotes":""},"categories":[21],"tags":[51,56,48,52,49,55,53,50,54],"class_list":["post-15050","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-02-1-subcategory","tag-dfm","tag-gate-design","tag-injection-molding","tag-mold-design","tag-plastic-part-design","tag-rib-design","tag-sink-marks","tag-wall-thickness-design","tag-warpage"],"blocksy_meta":{"styles_descriptor":{"styles":{"desktop":"","tablet":"","mobile":""},"google_fonts":[],"version":8}},"_links":{"self":[{"href":"https:\/\/kenddg.tw\/enblog\/wp-json\/wp\/v2\/posts\/15050","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kenddg.tw\/enblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kenddg.tw\/enblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kenddg.tw\/enblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/kenddg.tw\/enblog\/wp-json\/wp\/v2\/comments?post=15050"}],"version-history":[{"count":48,"href":"https:\/\/kenddg.tw\/enblog\/wp-json\/wp\/v2\/posts\/15050\/revisions"}],"predecessor-version":[{"id":15310,"href":"https:\/\/kenddg.tw\/enblog\/wp-json\/wp\/v2\/posts\/15050\/revisions\/15310"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/kenddg.tw\/enblog\/wp-json\/wp\/v2\/media\/15195"}],"wp:attachment":[{"href":"https:\/\/kenddg.tw\/enblog\/wp-json\/wp\/v2\/media?parent=15050"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kenddg.tw\/enblog\/wp-json\/wp\/v2\/categories?post=15050"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kenddg.tw\/enblog\/wp-json\/wp\/v2\/tags?post=15050"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}