<?xml version="1.0" encoding="UTF-8"?><rss xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:atom="http://www.w3.org/2005/Atom" version="2.0"><channel><title><![CDATA[Mold Venting Design: Solving Gas Traps and Burn Marks]]></title><description><![CDATA[<p dir="auto">Proper venting is often overlooked but accounts for many molding defects.</p>
<p dir="auto"><strong>Types of Vents:</strong></p>
<ul>
<li>Parting line vents: shallow grooves 0.02-0.05mm deep</li>
<li>Ejector pin vents: clearance 0.02-0.04mm</li>
<li>Insert vents at gas trap locations</li>
<li>Vacuum venting: active cavity evacuation</li>
</ul>
<p dir="auto"><strong>Vent Depth by Material:</strong></p>
<ul>
<li>Amorphous (ABS, PC): 0.03-0.04mm</li>
<li>Semi-crystalline (PE, PP): 0.02-0.03mm</li>
<li>High-flow (LCP): 0.02mm max</li>
<li>Rubber: 0.02-0.05mm</li>
</ul>
<p dir="auto"><strong>Land Length:</strong> 3-10mm before opening to atmosphere</p>
<p dir="auto"><strong>Diagnosing Issues:</strong></p>
<ol>
<li>Burn marks at last fill area → insufficient venting</li>
<li>Short shots with no other defects → trapped gas</li>
<li>Glossy marks at weld line → gas trapped at melt front</li>
</ol>
<p dir="auto"><strong>Advanced Solutions:</strong></p>
<ul>
<li>Porous steel inserts (25-30% porosity)</li>
<li>Stepped vent grooves</li>
<li>Automated vent cleaning for high-production molds</li>
</ul>
<hr />
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<hr />
<p dir="auto">新手建议收藏，老手欢迎指点。</p>
]]></description><link>https://forum.mj7.cn/topic/2202/mold-venting-design-solving-gas-traps-and-burn-marks</link><generator>RSS for Node</generator><lastBuildDate>Mon, 10 Aug 2026 14:13:00 GMT</lastBuildDate><atom:link href="https://forum.mj7.cn/topic/2202.rss" rel="self" type="application/rss+xml"/><pubDate>Sat, 30 May 2026 22:38:28 GMT</pubDate><ttl>60</ttl></channel></rss>