Mold thermal balance determines casting dimensional stability, cycle time and mold service life. Unbalanced mold temperature field increases part warpage rate by 35% after T6 heat treatment. This chapter introduces cooling channel layout rules, thermal monitoring parameters and temperature control strategy from Xinfeng mould project database.
Cooling channels arranged 12–18 mm away from cavity surface. Distance less than 10 mm risks mold cracking under thermal cycling; distance over 20 mm weakens cooling efficiency and enlarges mold temperature fluctuation.
Channel diameter commonly Φ8–Φ14 mm for automotive aluminum casting molds. Smaller diameter easily blocked by scale; oversized diameter reduces cooling uniformity at local hot spots.
Channel spacing below 39 mm for high heat flux zones such as bosses and ribs; spacing 40–50 mm for low heat flux flat areas.
Parallel cooling circuit layout for large mold inserts; independent cooling loops for hot spot zones to realize zoning temperature control. Zoned cooling reduces mold temperature difference below ±18℃.
Cooling water inlet temperature controlled at 32–42℃; water temperature difference between inlet and outlet limited ≤6℃. Larger temperature difference causes uneven contraction and part distortion.
Cooling water pressure maintained at 0.25–0.4 MPa to guarantee stable flow rate. Low water flow leads to local overheating and shrinkage porosity.
Forced air auxiliary cooling adopted for thin rib regions where drilling water channels is impossible. Air flow rate 12–18 m³/h reduces rib surface overheating.
Thermocouple embedded 5–8 mm below cavity surface at typical hot spots for real-time temperature monitoring. Temperature data feedback adjusts water flow and mold cycle parameters automatically.
Mold preheating realized by integrated electric heating rods inside mold base. Heating power configured 0.35–0.55 kW per 10 kg mold mass to reach target preheating temperature 280–370℃ uniformly.
Thermal stress simulation before mold machining to predict high thermal stress zones, optimize fillet and cooling hole position, lowering thermal crack risk by 38%.
Scale cleaning for cooling circuits every 6000 casting cycles to prevent channel blockage and cooling performance degradation.
Q1: What distance should cooling channels keep from mold cavity surface? A1: Keep 12–18 mm distance between cooling channel and cavity surface for balanced cooling. Q2: What is the allowed inlet-outlet temperature difference of cooling water? A2: Inlet and outlet cooling water temperature difference should be controlled ≤6℃. Q3: How to handle hot spots where water channels cannot be drilled? A3: Apply forced air auxiliary cooling to stabilize temperature at thin rib and narrow zones.
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