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# Mold Venting System Design, Calculation & Maintenance Schedule Venting system directly discharges trapped air, release agent decomposition gas and hydrogen.

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  • Release time: 2026-09-29

Mold Venting System Design, Calculation & Maintenance Schedule

Venting system directly discharges trapped air, release agent decomposition gas and hydrogen. Insufficient venting creates cold shut, gas pores and oxide defects. This article defines vent dimension calculation rules, layout principles and maintenance plan for LPDC and gravity casting molds.

Total vent area calculation rule: total vent cross-sectional area equals 0.8–1.2% of casting projected area. Below 0.8% easily leads to gas trapping; over 1.2% increases flash risk.

Vent slot depth classification:

  • Thin wall casting: 0.10–0.14 mm
  • Medium wall structural casting:0.12–0.16 mm
  • Thick boss region:0.14–0.18 mm

Vent slot width 8–15 mm per vent segment. Vent length controlled within 6–10 mm, followed by expanded exhaust cavity 2–4 mm deep to collect aluminum residue.

Vents placed at melt end filling positions, top of ribs and high point of cavity. Avoid placing vents directly at high speed melt impact zone.

Vent inserts are adopted for high wear vent locations. Replaceable vent inserts reduce maintenance time by 42% and avoid reworking whole cavity.

Vent cleaning cycle: gravity mold every 110–130 cycles; LPDC mold every 180–210 cycles. For high oxide alloy A206, shorten cleaning cycle to 100 cycles.

Vent inspection items during maintenance: slot depth, aluminum residue blockage, surface soldering and crack. Replace insert if vent depth wears over 0.03 mm.

CPC mold vent design needs to match argon flow field. Excessive vent area causes argon leakage and damages inert gas protection.

Debris from vent clogging may be pressed into casting surface and form foreign inclusion defects.

FAQ

Q1: What is the recommended total vent area ratio for aluminum casting mold? A1: Total vent cross-sectional area should be 0.8–1.2% of casting projected area. Q2: Where should mold vents be arranged? A2: Vents are arranged at melt final filling positions, rib tops and cavity highest points. Q3: How often to clean vents for A206 alloy casting? A3: Vent cleaning cycle shortened to every 100 casting cycles for A206 alloy.

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