{"id":51666,"date":"2026-01-28T16:09:07","date_gmt":"2026-01-28T08:09:07","guid":{"rendered":"https:\/\/zetarmold.com\/?p=51666"},"modified":"2026-04-04T10:16:56","modified_gmt":"2026-04-04T02:16:56","slug":"yan-aksiyon-kaldiricilar-ve-katlanabilir-cekirdekler","status":"publish","type":"post","link":"https:\/\/zetarmold.com\/tr\/yan-aksiyon-kaldiricilar-ve-katlanabilir-cekirdekler\/","title":{"rendered":"How Do You Manage Injection Molding Undercuts Using Side-Actions, Lifters, and Collapsible Cores?"},"content":{"rendered":"<div class=\"callout-key\" style=\"background:#f0f7ff; border-left:4px solid #2563eb; padding:1em 1.2em; border-radius:6px; margin:1.5em 0;\"> <strong>\u00d6nemli \u00c7\u0131kar\u0131mlar<\/strong><br \/>\nUndercut'lar hakk\u0131nda bilgi edinmek, kal\u0131p tasar\u0131m\u0131nda olu\u015fturduklar\u0131 zorluklar\u0131 ve \u00f6zel mekanizmalara duyulan ihtiyac\u0131 anlamaya yard\u0131mc\u0131 olur.<br \/>\n\u2013 Side-actions are best for external features, while lifters and collapsible cores handle internal geometries.<br \/>\n\u2013 Utilizing \u201cbump-offs\u201d with flexible materials can eliminate the need for expensive mechanical actions.<br \/>\n\u2013 Proper maintenance of moving mold components is critical to prevent flash and seizing. <\/div>\n<h2>What Is the Definition of an Undercut in Injection Molding?<\/h2>\n<p>Bu ba\u011flamda <strong><a href=\"https:\/\/zetarmold.com\/tr\/enjeksiyon-kaliplama-sureci\/\">Enjeksiyon Kal\u0131plama (IM)<\/a><sup id=\"fnref1:1\"><a href=\"#fn:1\" class=\"footnote-ref\">1<\/a><\/sup><\/strong>, an <strong>undercut<\/strong> is a specific feature in the part geometry that prevents the mold from opening or the part from being ejected along the primary \"line of draw\" (the direction in which the mold halves separate).<\/p>\n<p>Without a specialized mechanism to release the feature, the steel of the mold cavity would physically trap the solidified plastic, causing damage to the part or the tool upon ejection. Solving this challenge is the core of <strong>complex mold design<\/strong>.<\/p>\n<p>Common mechanisms used to resolve undercuts include:<\/p>\n<ul>\n<li><strong><a href=\"https:\/\/www.moldall.com\/understanding-side-actions-in-injection-molding-a-comprehensive-guide\/\">Side-Actions (Slides)<\/a><sup id=\"fnref1:2\"><a href=\"#fn:2\" class=\"footnote-ref\">2<\/a><\/sup>:<\/strong> Cam-driven blocks that move perpendicular to the mold opening.<\/li>\n<li><strong><a href=\"https:\/\/www.moldall.com\/mold-release-angle\/\">Lifters<\/a><sup id=\"fnref1:3\"><a href=\"#fn:3\" class=\"footnote-ref\">3<\/a><\/sup>:<\/strong> Internal cores that move on an angle during ejection to release internal features.<\/li>\n<li><strong><a href=\"https:\/\/www.youtube.com\/watch?v=Zg8a0jEE77g\">Collapsible Cores<\/a><sup id=\"fnref1:4\"><a href=\"#fn:4\" class=\"footnote-ref\">4<\/a><\/sup>:<\/strong> Segmented cores that shrink inward to release threads or deep internal undercuts.<\/li>\n<\/ul>\n<div class=\"claim claim-false\" style=\"background-color: #f7efef; border-color: #f7efef; color: #db6f85;\">\n<p><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"24\" height=\"24\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M20 13c0 5-3.5 7.5-7.66 8.95a1 1 0 0 1-.67-.01C7.5 20.5 4 18 4 13V6a1 1 0 0 1 1-1c2 0 4.5-1.2 6.24-2.72a1.17 1.17 0 0 1 1.52 0C14.51 3.81 17 5 19 5a1 1 0 0 1 1 1z\"\/><path d=\"m14.5 9.5-5 5\"\/><path d=\"m9.5 9.5 5 5\"\/><\/svg> <b>All undercuts in part design require expensive mechanical side-actions or lifters to be molded successfully.<\/b><span class='claim-true-or-false'>Yanl\u0131\u015f<\/span><\/p>\n<p class='claim-explanation'>This is a misconception. Many minor undercuts can be resolved using 'bump-offs' (stripping) if the material is flexible, or by redesigning the part with slot-throughs or shut-offs to eliminate the undercut entirely.<\/p>\n<\/div>\n<div class=\"claim claim-true\" style=\"background-color: #eff2ef; border-color: #eff2ef; color: #5b8c70;\">\n<p><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"24\" height=\"24\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M20 13c0 5-3.5 7.5-7.66 8.95a1 1 0 0 1-.67-.01C7.5 20.5 4 18 4 13V6a1 1 0 0 1 1-1c2 0 4.5-1.2 6.24-2.72a1.17 1.17 0 0 1 1.52 0C14.51 3.81 17 5 19 5a1 1 0 0 1 1 1z\"\/><path d=\"m9 12 2 2 4-4\"\/><\/svg> <b>Incorporating slight draft angles on undercut features significantly reduces the force required for side-actions and lifters to disengage.<\/b><span class='claim-true-or-false'>Do\u011fru<\/span><\/p>\n<p class='claim-explanation'>Adding draft to the undercut feature reduces friction and drag during the retraction of the metal component, extending tool life and reducing the risk of part deformation.<\/p>\n<\/div>\n<h2>What Are the Key Parameters for Side-Action Cam Definition?<\/h2>\n<p>A <strong>side-action<\/strong> (often called a slide or cam action) is the most robust method for handling external <strong>injection molding undercuts<\/strong>. It typically consists of a cam pin (angle pin), a sliding body, and a locking block.<\/p>\n<p>When the mold opens, the angle pin forces the slide to retract away from the part. When the mold closes, the locking block (heel block) holds the slide firmly in place against injection pressure.<\/p>\n<p><strong>Table 1: Critical Design Parameters for Side-Actions<\/strong><\/p>\n<table>\n<thead>\n<tr>\n<th style=\"text-align: left;\">Parametre<\/th>\n<th style=\"text-align: left;\">Tipik De\u011fer \/ Aral\u0131k<\/th>\n<th style=\"text-align: left;\">Notlar<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"text-align: left;\"><strong>Angle Pin Angle<\/strong><\/td>\n<td style=\"text-align: left;\">10\u00b0 \u2013 25\u00b0<\/td>\n<td style=\"text-align: left;\">The angle of the pin determines the travel distance. Steeper angles provide more travel but less mechanical advantage.<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><strong>Heel Block Angle<\/strong><\/td>\n<td style=\"text-align: left;\">Pin Angle + (2\u00b0 to 5\u00b0)<\/td>\n<td style=\"text-align: left;\">The locking angle must be steeper than the pin angle to prevent the slide from backing up during injection.<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><strong>Slide Material<\/strong><\/td>\n<td style=\"text-align: left;\">H13, P20, or S7 Tool Steel<\/td>\n<td style=\"text-align: left;\">Moving components require hardened steel (48\u201352 HRC) to resist wear and galling.<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><strong>Wear Plates<\/strong><\/td>\n<td style=\"text-align: left;\">Aluminum Bronze \/ Graphitic Steel<\/td>\n<td style=\"text-align: left;\">Used under the slide to prevent steel-on-steel seizing; typically self-lubricating.<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><strong>Clearance<\/strong><\/td>\n<td style=\"text-align: left;\">0.012 \u2013 0.025 mm (0.0005\" \u2013 0.001\")<\/td>\n<td style=\"text-align: left;\">Tight tolerances are required to prevent \"flash\" (excess plastic leakage) at the parting line.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"457\" class=\"wp-image-53140\" src=\"https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/hdpe-injection-molding-process-v2.webp\" alt=\"Injection molding production process\" srcset=\"https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/hdpe-injection-molding-process-v2.webp 1200w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/hdpe-injection-molding-process-v2-300x171.webp 300w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/hdpe-injection-molding-process-v2-1024x585.webp 1024w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/hdpe-injection-molding-process-v2-768x438.webp 768w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/hdpe-injection-molding-process-v2-18x10.webp 18w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/hdpe-injection-molding-process-v2-600x343.webp 600w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><figcaption class=\"wp-element-caption\">Injection molding machine in production<\/figcaption><\/figure>\n<\/p>\n<h2>How Do You Design Lifters for Molds?<\/h2>\n<p><strong>Designing lifters for molds<\/strong> is necessary when the undercut is located on the <em>Slaytlarda So\u011futmay\u0131 \u00d6nceliklendir:<\/em> of the part, where a side-action cannot reach. A lifter is part of the ejection system. As the ejector plates push forward, the lifter moves upward and inward (laterally) on an angle, releasing the undercut feature.<\/p>\n<p><strong>Step-by-Step Lifter Function:<\/strong><\/p>\n<ol>\n<li><strong>Enjeksiyon:<\/strong> The lifter forms a portion of the internal wall or clip detail.<\/li>\n<li><strong>Mold Opening:<\/strong> The A-side (cavity) separates from the B-side (core). The part stays on the core.<\/li>\n<li><strong>Ejection Start:<\/strong> The ejector plate pushes the lifter rod.<\/li>\n<li><strong>Lateral Movement:<\/strong> Because the lifter rod is angled, the vertical ejection force translates into lateral movement, pulling the steel detail out of the plastic undercut.<\/li>\n<li><strong>Release:<\/strong> Once the lifter clears the undercut, the part falls or is picked by a robot.<\/li>\n<\/ol>\n<p><strong>Engineering Constraint:<\/strong> Cooling lifters is notoriously difficult because they are thin, moving rods. This can lead to longer cycle times compared to side-actions, which can be water-cooled easily.<\/p>\n<hr \/>\n<div class=\"claim claim-false\" style=\"background-color: #f7efef; border-color: #f7efef; color: #db6f85;\">\n<p><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"24\" height=\"24\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M20 13c0 5-3.5 7.5-7.66 8.95a1 1 0 0 1-.67-.01C7.5 20.5 4 18 4 13V6a1 1 0 0 1 1-1c2 0 4.5-1.2 6.24-2.72a1.17 1.17 0 0 1 1.52 0C14.51 3.81 17 5 19 5a1 1 0 0 1 1 1z\"\/><path d=\"m14.5 9.5-5 5\"\/><path d=\"m9.5 9.5 5 5\"\/><\/svg> <b>Lifters are generally less expensive and easier to maintain than external side-action slides.<\/b><span class='claim-true-or-false'>Yanl\u0131\u015f<\/span><\/p>\n<p class='claim-explanation'>Lifters are often more prone to mechanical failure and galling due to the complex stresses during ejection. They are also much harder to cool, which can extend cycle times and increase part cost compared to externally cooled slides.<\/p>\n<\/div>\n<div class=\"claim claim-true\" style=\"background-color: #eff2ef; border-color: #eff2ef; color: #5b8c70;\">\n<p><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"24\" height=\"24\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M20 13c0 5-3.5 7.5-7.66 8.95a1 1 0 0 1-.67-.01C7.5 20.5 4 18 4 13V6a1 1 0 0 1 1-1c2 0 4.5-1.2 6.24-2.72a1.17 1.17 0 0 1 1.52 0C14.51 3.81 17 5 19 5a1 1 0 0 1 1 1z\"\/><path d=\"m9 12 2 2 4-4\"\/><\/svg> <b>Using 'shut-offs' or 'pass-throughs' allows engineers to mold features that look like undercuts without using any moving mechanisms.<\/b><span class='claim-true-or-false'>Do\u011fru<\/span><\/p>\n<p class='claim-explanation'>By designing a hole in the part floor directly below a clip or snap-fit, the core and cavity steel can 'kiss' (shut off) to form the feature, eliminating the need for side-actions.<\/p>\n<\/div>\n<p><figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"457\" class=\"wp-image-53133\" src=\"https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/low-volume-mold-tooling-inspection-1.webp\" alt=\"Mold tooling inspection with depth gauge\" srcset=\"https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/low-volume-mold-tooling-inspection-1.webp 1200w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/low-volume-mold-tooling-inspection-1-300x171.webp 300w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/low-volume-mold-tooling-inspection-1-1024x585.webp 1024w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/low-volume-mold-tooling-inspection-1-768x438.webp 768w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/low-volume-mold-tooling-inspection-1-18x10.webp 18w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/low-volume-mold-tooling-inspection-1-600x343.webp 600w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><figcaption class=\"wp-element-caption\">Precision mold tooling inspection and measurement<\/figcaption><\/figure>\n<\/p>\n<h2>What Are the Advantages and Disadvantages of Undercut Solutions?<\/h2>\n<p>Choosing the right mechanism is essential for <strong>avoiding <a href=\"https:\/\/zetarmold.com\/tr\/enjeksiyon-kaliplamada-alttan-kesme-cozumleri\/\">undercut<\/a><sup id=\"fnref1:5\"><a href=\"#fn:5\" class=\"footnote-ref\">5<\/a><\/sup> costs<\/strong> and ensuring tool longevity.<\/p>\n<p><strong>Table 2: Comparison of Undercut Mechanisms<\/strong><\/p>\n<table>\n<thead>\n<tr>\n<th style=\"text-align: left;\">Mechanism<\/th>\n<th style=\"text-align: left;\">\u0130\u00e7in En \u0130yisi<\/th>\n<th style=\"text-align: left;\">Pros<\/th>\n<th style=\"text-align: left;\">Cons<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"text-align: left;\"><strong>Side-Action (Slide)<\/strong><\/td>\n<td style=\"text-align: left;\">External undercuts, ports, holes on side walls.<\/td>\n<td style=\"text-align: left;\">Robust; easy to cool; high pressure resistance; reliable.<\/td>\n<td style=\"text-align: left;\">Increases mold footprint (requires wider mold base); expensive to machine.<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><strong>Lifter<\/strong><\/td>\n<td style=\"text-align: left;\">Internal snap-fits, internal threads, internal barbs.<\/td>\n<td style=\"text-align: left;\">Solves internal trapped geometry; activates automatically with ejection.<\/td>\n<td style=\"text-align: left;\">Difficult to cool (hot spots); prone to breaking\/galling; complex maintenance.<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><strong>Collapsible Core<\/strong><\/td>\n<td style=\"text-align: left;\">Full circumference internal threads (e.g., bottle caps).<\/td>\n<td style=\"text-align: left;\">Allows ejection of 360\u00b0 internal undercuts; fast cycle times.<\/td>\n<td style=\"text-align: left;\">Extremely expensive; high maintenance; size limitations.<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><strong>Bump-off (Stripping)<\/strong><\/td>\n<td style=\"text-align: left;\">Shallow undercuts in flexible materials (PP, PE, TPE).<\/td>\n<td style=\"text-align: left;\">Zero mechanism cost; simplest mold design.<\/td>\n<td style=\"text-align: left;\">Limited to specific geometry constraints; requires material elasticity; part distortion risk.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"457\" class=\"wp-image-53134\" src=\"https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/prototype-plastic-parts-batch-1.webp\" alt=\"Prototype plastic parts batch\" srcset=\"https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/prototype-plastic-parts-batch-1.webp 1200w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/prototype-plastic-parts-batch-1-300x171.webp 300w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/prototype-plastic-parts-batch-1-1024x585.webp 1024w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/prototype-plastic-parts-batch-1-768x438.webp 768w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/prototype-plastic-parts-batch-1-18x10.webp 18w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/prototype-plastic-parts-batch-1-600x343.webp 600w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><figcaption class=\"wp-element-caption\">Batch of injection molded plastic parts<\/figcaption><\/figure>\n<\/p>\n<h2>What Are Practical Tips for Reducing Complexity and Cost?<\/h2>\n<p>In my experience on the factory floor, the best way to handle an undercut is to eliminate it during the Design for Manufacturing (DfM) phase. If that is not possible, follow these practical insights:<\/p>\n<ol>\n<li><strong>Use Sliding Shut-Offs:<\/strong> Instead of a side-action for a hole in a vertical wall, see if you can draft the wall and use a \"telescoping\" shut-off where the cavity and core slide past each other to form the hole.<\/li>\n<li><strong>Limit Side-Action Travel:<\/strong> Keep the undercut depth shallow. A deeper undercut requires a longer side-action travel, which forces a larger mold base, significantly increasing tooling costs.<\/li>\n<li><strong>Material Selection for Bump-Offs:<\/strong> If <strong>avoiding undercut costs<\/strong> is the priority, use materials like Polypropylene (PP) or Polyethylene (PE). Design the undercut with a lead-out angle (30\u00b0 to 45\u00b0) so the plastic can stretch over the steel bump during ejection without shearing.<\/li>\n<li><strong>Prioritize Cooling in Slides:<\/strong> Yan hareketler, kald\u0131r\u0131c\u0131lar ve katlanabilir \u00e7ekirdekler kullanarak enjeksiyon kal\u0131plama alt kesimlerini nas\u0131l ele alaca\u011f\u0131n\u0131z\u0131, optimum par\u00e7a \u00e7\u0131karma ve kal\u0131p bak\u0131m\u0131 i\u00e7in \u00f6\u011frenin.<\/li>\n<\/ol>\n<p><figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"457\" class=\"wp-image-53108\" src=\"https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/injection-molding-quality-testing.webp\" alt=\"Quality inspection of injection molded parts\" srcset=\"https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/injection-molding-quality-testing.webp 1200w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/injection-molding-quality-testing-300x171.webp 300w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/injection-molding-quality-testing-1024x585.webp 1024w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/injection-molding-quality-testing-768x438.webp 768w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/injection-molding-quality-testing-18x10.webp 18w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/injection-molding-quality-testing-600x343.webp 600w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><figcaption class=\"wp-element-caption\">Quality inspection of injection molded plastic parts<\/figcaption><\/figure>\n<\/p>\n<h2>What Are the Common Application Scenarios?<\/h2>\n<ul>\n<li><strong>Automotive Interior Trim:<\/strong> Uses <strong>lifters<\/strong> extensively for internal snap-fits that mount door panels to the chassis.<\/li>\n<li><strong>Consumer Electronics (Housings):<\/strong> Uses <strong>side-actions<\/strong> for USB ports, power buttons, and HDMI slots located on the sidewalls of the device casing.<\/li>\n<li><strong>Plumbing Fittings:<\/strong> Uses <strong>collapsible cores<\/strong> or unscrewing racks for internal threads that cannot be stripped.<\/li>\n<li><strong>Medical Vials:<\/strong> Often utilizes <strong>bump-offs<\/strong> for cap retention rings, relying on the medical-grade Polypropylene\u2019s flexibility.<\/li>\n<\/ul>\n<hr \/>\n<div class=\"claim claim-false\" style=\"background-color: #f7efef; border-color: #f7efef; color: #db6f85;\">\n<p><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"24\" height=\"24\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M20 13c0 5-3.5 7.5-7.66 8.95a1 1 0 0 1-.67-.01C7.5 20.5 4 18 4 13V6a1 1 0 0 1 1-1c2 0 4.5-1.2 6.24-2.72a1.17 1.17 0 0 1 1.52 0C14.51 3.81 17 5 19 5a1 1 0 0 1 1 1z\"\/><path d=\"m14.5 9.5-5 5\"\/><path d=\"m9.5 9.5 5 5\"\/><\/svg> <b>Collapsible cores are the standard industry solution for molding all types of internal threads.<\/b><span class='claim-true-or-false'>Yanl\u0131\u015f<\/span><\/p>\n<p class='claim-explanation'>Collapsible cores are complex and costly. For many standard internal threads, automatic unscrewing molds (using rotational gears) are preferred, or simple bump-offs if the thread profile is rounded and the material is flexible.<\/p>\n<\/div>\n<div class=\"claim claim-true\" style=\"background-color: #eff2ef; border-color: #eff2ef; color: #5b8c70;\">\n<p><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"24\" height=\"24\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M20 13c0 5-3.5 7.5-7.66 8.95a1 1 0 0 1-.67-.01C7.5 20.5 4 18 4 13V6a1 1 0 0 1 1-1c2 0 4.5-1.2 6.24-2.72a1.17 1.17 0 0 1 1.52 0C14.51 3.81 17 5 19 5a1 1 0 0 1 1 1z\"\/><path d=\"m9 12 2 2 4-4\"\/><\/svg> <b>Standardizing the angle of side-action pins to 15\u00b0 or 20\u00b0 simplifies mold design and replacement part procurement.<\/b><span class='claim-true-or-false'>Do\u011fru<\/span><\/p>\n<p class='claim-explanation'>Adhering to standard angles allows mold makers to use off-the-shelf components from suppliers like DME or Hasco, reducing design time and maintenance costs.<\/p>\n<\/div>\n<h2>What Steps Are Recommended for Selecting the Right Mechanism?<\/h2>\n<ol>\n<li><strong>Analyze Geometry:<\/strong> Is the undercut internal or external? (External \u2192 Side-Action; Internal \u2192 Lifter\/Core).<\/li>\n<li><strong>Check Material Properties:<\/strong> Is the material flexible (TPU, PP) or rigid (PC, Glass-Filled Nylon)? Flexible materials may allow bump-offs.<\/li>\n<li><strong>Calculate Stroke Required:<\/strong> How far must the steel move to clear the plastic? Ensure the mold base can accommodate this travel.<\/li>\n<li><strong>Evaluate Volume:<\/strong> For low volume (1,000 units), consider hand-loaded inserts. For high volume (100,000+ units), invest in hardened, automatic slides with wear plates.<\/li>\n<li><strong>Simulate:<\/strong> Use Moldflow analysis to ensure the moving components do not impede cooling or create air traps (gas burns).<\/li>\n<\/ol>\n<p><figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"457\" class=\"wp-image-53145\" src=\"https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/injection-molding-australia-plastic-parts-v2-1.webp\" alt=\"Injection molded plastic parts variety\" srcset=\"https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/injection-molding-australia-plastic-parts-v2-1.webp 1200w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/injection-molding-australia-plastic-parts-v2-1-300x171.webp 300w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/injection-molding-australia-plastic-parts-v2-1-1024x585.webp 1024w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/injection-molding-australia-plastic-parts-v2-1-768x438.webp 768w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/injection-molding-australia-plastic-parts-v2-1-18x10.webp 18w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/injection-molding-australia-plastic-parts-v2-1-600x343.webp 600w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><figcaption class=\"wp-element-caption\">Various injection molded plastic parts<\/figcaption><\/figure>\n<\/p>\n<h2>S\u0131k\u00e7a Sorulan Sorular (SSS)<\/h2>\n<p><strong>Q1: Can I mold undercuts without any moving parts?<\/strong><br \/>\nYes, through a method called \"bump-off\" or stripping. This works only if the plastic is flexible (e.g., Polypropylene (PP) or Thermoplastic Elastomer (TPE)), the undercut is shallow, and the feature has a radiused edge to slide over the steel.<\/p>\n<p><strong>Q2: What is the difference between a slider and a lifter?<\/strong><br \/>\nA slider (side-action) typically handles external undercuts and is actuated by an angle pin when the mold opens. A lifter handles internal undercuts and is actuated by the ejector plate system pushing the part out.<\/p>\n<p><strong>Q3: How much does adding a side-action increase mold cost?<\/strong><br \/>\nAdding a simple side-action can increase tooling cost by $1,500 to $5,000 USD depending on complexity, size, and cooling requirements. It adds design time, machining time, and component costs.<\/p>\n<p><strong>Q4: What is the maximum angle for an angle pin in a side-action?<\/strong><br \/>\nWhile 25\u00b0 is generally the recommended maximum to prevent locking or bending the pin, some designs push to 30\u00b0 in extreme cases. However, exceeding 20-25\u00b0 significantly increases wear and friction.<\/p>\n<p><strong>Q5: Why are lifters prone to breaking?<\/strong><br \/>\nLifters are long, slender steel rods subjected to bending moments and friction during every cycle. They also heat up significantly because they are hard to cool. The combination of thermal expansion and mechanical stress often leads to seizing or fatigue failure.<\/p>\n<p><figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"457\" class=\"wp-image-53105\" src=\"https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/hdpe-plastic-resin-pellets.webp\" alt=\"Plastic resin pellets for injection molding\" srcset=\"https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/hdpe-plastic-resin-pellets.webp 1200w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/hdpe-plastic-resin-pellets-300x171.webp 300w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/hdpe-plastic-resin-pellets-1024x585.webp 1024w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/hdpe-plastic-resin-pellets-768x438.webp 768w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/hdpe-plastic-resin-pellets-18x10.webp 18w, https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/03\/hdpe-plastic-resin-pellets-600x343.webp 600w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><figcaption class=\"wp-element-caption\">Plastic resin pellets used in injection molding<\/figcaption><\/figure>\n<\/p>\n<h2>\u00d6zet<\/h2>\n<p>Dealing with <strong>injection molding undercuts<\/strong> requires a balance between part functionality and tool complexity. While <strong>side-actions<\/strong> are the standard for external features and <strong>lifters<\/strong> for internal ones, they add significant capital cost and maintenance requirements. Strategies like <strong>complex mold design<\/strong> simplification\u2014using shut-offs or material flexibility for bump-offs\u2014are essential for <strong>avoiding undercut costs<\/strong>. By understanding the mechanical constraints of slides, lifters, and <strong>collapsible cores<\/strong>, engineers can design robust parts that are manufacturable at scale. See our <a href=\"https:\/\/zetarmold.com\/tr\/injection-molding-complete-guide\/\">Injection Molding Complete Guide<\/a> for a comprehensive overview.<\/p>\n<hr \/>\n<div class=\"footnotes\">\n<hr \/>\n<ol>\n<li id=\"fn:1\">\n<p>Understanding the basics of Injection Molding is crucial for grasping how undercuts and their solutions fit into the manufacturing process.\u00a0<a href=\"#fnref1:1\" rev=\"footnote\" class=\"footnote-backref\">&#8617;<\/a><\/p>\n<\/li>\n<li id=\"fn:2\">\n<p>Side-Actions are essential for handling external undercuts, making them a key component in mold design.\u00a0<a href=\"#fnref1:2\" rev=\"footnote\" class=\"footnote-backref\">&#8617;<\/a><\/p>\n<\/li>\n<li id=\"fn:3\">\n<p>Lifters are crucial for releasing internal undercuts, and understanding their function is vital for mold design.\u00a0<a href=\"#fnref1:3\" rev=\"footnote\" class=\"footnote-backref\">&#8617;<\/a><\/p>\n<\/li>\n<li id=\"fn:4\">\n<p>Collapsible Cores are used for complex internal geometries, making them an advanced solution in mold design.\u00a0<a href=\"#fnref1:4\" rev=\"footnote\" class=\"footnote-backref\">&#8617;<\/a><\/p>\n<\/li>\n<li id=\"fn:5\">\n<p>Learning about undercuts helps in understanding the challenges they pose in mold design and the need for specialized mechanisms.\u00a0<a href=\"#fnref1:5\" rev=\"footnote\" class=\"footnote-backref\">&#8617;<\/a><\/p>\n<\/li>\n<\/ol>\n<\/div>\n<div style=\"background:#f0f4f8;padding:20px;border-radius:8px;margin-top:30px;\">\n<p style=\"margin:0 0 10px;font-size:18px;\"><strong>Need a Quote for Your Injection Molding Project?<\/strong><\/p>\n<p style=\"margin:0 0 10px;\">Get competitive pricing, DFM feedback, and production timeline from ZetarMold&#8217;s engineering team.<\/p>\n<p style=\"margin:0;\"><a href=\"https:\/\/zetarmold.com\/tr\/bize-ulasin\/\" style=\"background:#2563eb;color:white;padding:12px 24px;border-radius:6px;text-decoration:none;font-weight:bold;\">Request a Free Quote \u2192<\/a><\/p>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>Anahtar \u00c7\u0131kar\u0131mlar \u2013 Alt kesimler do\u011frudan par\u00e7a \u00e7\u0131karmay\u0131 engeller ve yan hareketler, kald\u0131r\u0131c\u0131lar veya katlanabilir \u00e7ekirdekler gibi yard\u0131mc\u0131 mekanizmalar gerektirir. \u2013 Yan hareketler d\u0131\u015f \u00f6zellikler i\u00e7in en iyisiyken, kald\u0131r\u0131c\u0131lar ve katlanabilir \u00e7ekirdekler i\u00e7 geometrileri y\u00f6netir. \u2013 Esnek malzemelerle \u201c\u00e7arpma \u00e7\u0131k\u0131nt\u0131lar\u0131\u201d kullanmak, pahal\u0131 mekanik hareketlere olan ihtiyac\u0131 ortadan kald\u0131rabilir. \u2013 Hareketli kal\u0131p bile\u015fenlerinin uygun bak\u0131m\u0131 [\u2026]<\/p>","protected":false},"author":1,"featured_media":34914,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_seopress_robots_primary_cat":"none","_seopress_titles_title":"Undercuts in Injection Molding: Solutions Explained","_seopress_titles_desc":"Learn how to tackle injection molding undercuts using side-actions, lifters, and collapsible cores for optimal part ejection and mold maintenance.","_seopress_robots_index":"","_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[73],"tags":[205,206,89,190],"meta_box":{"post-to-quiz_to":[]},"_links":{"self":[{"href":"https:\/\/zetarmold.com\/tr\/wp-json\/wp\/v2\/posts\/51666"}],"collection":[{"href":"https:\/\/zetarmold.com\/tr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/zetarmold.com\/tr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/zetarmold.com\/tr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/zetarmold.com\/tr\/wp-json\/wp\/v2\/comments?post=51666"}],"version-history":[{"count":0,"href":"https:\/\/zetarmold.com\/tr\/wp-json\/wp\/v2\/posts\/51666\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/zetarmold.com\/tr\/wp-json\/wp\/v2\/media\/34914"}],"wp:attachment":[{"href":"https:\/\/zetarmold.com\/tr\/wp-json\/wp\/v2\/media?parent=51666"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/zetarmold.com\/tr\/wp-json\/wp\/v2\/categories?post=51666"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/zetarmold.com\/tr\/wp-json\/wp\/v2\/tags?post=51666"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}