𝐓𝐨𝐝𝐚𝐲'𝐬 𝐊𝐍𝐎𝐖𝐋𝐄𝐃𝐆𝐄 𝐒𝐡𝐚𝐫𝐞 : 𝗜𝗻𝗷𝗲𝗰𝘁𝗶𝗼𝗻 𝗠𝗼𝗹𝗱 𝗩𝗲𝗻𝘁 𝗗𝗲𝗽𝘁𝗵 𝗗𝗲𝘀𝗶𝗴𝗻: 𝗔 𝗖𝗼𝗺𝗺𝗼𝗻 𝗖𝗵𝗮𝗹𝗹𝗲𝗻𝗴𝗲 𝗪𝗲 𝗙𝗮𝗰𝗲

𝐓𝐨𝐝𝐚𝐲'𝐬 𝐊𝐍𝐎𝐖𝐋𝐄𝐃𝐆𝐄 𝐒𝐡𝐚𝐫𝐞

𝗜𝗻𝗷𝗲𝗰𝘁𝗶𝗼𝗻 𝗠𝗼𝗹𝗱 𝗩𝗲𝗻𝘁 𝗗𝗲𝗽𝘁𝗵 𝗗𝗲𝘀𝗶𝗴𝗻: 𝗔 𝗖𝗼𝗺𝗺𝗼𝗻 𝗖𝗵𝗮𝗹𝗹𝗲𝗻𝗴𝗲 𝗪𝗲 𝗙𝗮𝗰𝗲

🔍 A critical yet often overlooked challenge in injection molding: How to design mold vent depth correctly? This parameter directly impacts part quality—and striking the right balance is far from easy.

⚠️ Too deep, and you get part flash; too shallow, and trapped air causes burn marks. So, what’s the solution?

✅ Ideally, vent depth should align with material properties—following material data sheet (MDS) recommendations, accounting for melt viscosity and melt flow rate (MFR). A one-size-fits-all approach doesn’t work.

📌 Yet, in my observation, many factories (at least in China) commonly use a conservative 0.015mm depth for most molds—this standard is often adopted to avoid flash, but it overlooks its inadequacy for most materials and mold cavity geometries, which causes frequent venting-related defects. Adding to this, flash is more likely in thin-walled sections, as higher shear rates reduce plastic melt viscosity, increasing seepage.

🤝 This is not criticism, just an operational observation. I’m eager to hear peers’ thoughts: What guidelines do you use for vent depth? How do you balance air release and flash prevention?

source : Kevin Zou

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