When we talk about mold temperature control on the floor, it always comes down to three heat transfer mechanisms: conduction, convection, and radiation. Conduction is the main path—heat moves from the melt or molten metal into the steel, then into the cooling channels. What matters here is the thermal conductivity of the mold steel and the contact between the part and the cavity surface. For injection molds, a common rule is to keep turbulent flow in the cooling channels, typically at a Reynolds number above 10,000, because turbulent convection pulls heat away far more efficiently than laminar flow. In die casting, the heat load is much higher, so die inserts often use materials like H13 with thermal conductivity around 25 W/m·K, and localized cooling (baffles, bubblers, or conformal channels) is placed right where hot spots form.
Convection is where most process adjustments happen. In injection molding, coolant temperature, flow rate, and channel diameter directly set the mold surface temperature and cycle time. A practical check: if the temperature difference between inlet and outlet water exceeds 3–5°C, flow is likely too low or the channel layout is unbalanced. For die casting dies, water or oil lines are often run at higher flow to handle the intense heat flux near the gate and runner. Radiation is usually the smallest contributor in closed molds, but it matters in die casting and large molds where hot surfaces face the platens or open air—surface emissivity and shielding can affect heat loss, so don't ignore it when balancing thermal profiles.
The takeaway for quoting and tooling design is simple: match the cooling layout to the heat load, keep convection turbulent, and place high-conductivity inserts at hot spots. These details drive cycle time and part quality more than most people expect. For more mold sourcing and technical references, visit MoldSo at www.moldso.com.