Injection Mold Temperature Controller Power and Flow Calculation
Effective mold mass (M): Only the mass of heat-transferring parts (core, cavity, inserts), excluding non-heated components like mold bases. Calculated by mold volume × 7.85 g/cm³ (steel density), unit: kg.
Initial temperature (T1): Workshop ambient temperature, typically 20–25°C; adjust for low-temperature environments.
Target mold temperature (T2): Determined by plastic type (PP: 40–60°C; ABS: 60–80°C; PC: 80–120°C), unit: °C.
Heating time (t): 0.5–1 hour (standard for mass production); shorter time requires higher power.
A 10–15% safety margin is needed to compensate for heat loss (convection, radiation).
Basic power formula (no heat loss):
P_base = (M × C × ΔT) / (t × 3600)
Where: C = 0.46 kJ/kg·°C (specific heat capacity of mold steel); ΔT = T2 – T1 (temperature difference); 3600 = time conversion (1 hour = 3600 seconds).
Actual power (with heat loss):
P_real = P_base × (1 + K)
Where K = heat loss coefficient (0.1–0.3): 0.1–0.15 for closed workshops, 0.2–0.3 for high-temperature/open environments.
ΔT = 80 – 25 = 55°C
P_base = (80 × 0.46 × 55) / (0.5 × 3600) ≈ 1.13 kW
P_real = 1.13 × (1 + 0.15) ≈ 1.3 kW
Selection: Choose a 2 kW MTC (reserve 10–20% for adjustments).
Core formula:
Q = S × v × 3600 / 1000
Where: Q = flow rate (L/h); S = total cross-sectional area of mold cooling channels (cm²); v = medium flow velocity (m/s); 3600/1000 = unit conversion.
Key parameters:
Channel diameter (d): 8–12 mm (0.8–1.2 cm), based on mold design.
Channel number (n): Total independent channels (excluding spares).
Velocity (v): 0.8–1.5 m/s (water); 0.6–1.0 m/s (oil, lower due to high viscosity).
Practical Flow Calculation Example
Single channel area: S_single = π × (0.1/2)² ≈ 0.00785 cm²
Total area: S_total = 0.00785 × 14 ≈ 0.1099 cm²
Q = 0.1099 × 1.2 × 3600 / 1000 ≈ 0.47 L/h
Selection: Choose 1–2 L/h MTC (add 20% for complex channels).
Water MTC: 1 kW power ≥ 0.5 L/h flow rate (e.g., 5 kW → ≥2.5 L/h).
Oil MTC: 1 kW power ≥ 0.8 L/h flow rate (e.g., 5 kW → ≥4 L/h).
High-precision molds (optical/medical): Increase flow by 20–30% for ±1°C temperature uniformity.
Only calculate heat-transferring mold parts; avoid overestimating mass.
Do not ignore heat loss (K); insufficient margin causes power shortage.
Match velocity to medium type (oil vs. water) to avoid circulation issues.
Reserve 10–20% for selection; adjust for material type and mold complexity.
Common mistakes: Overlooking channel length/bends, using wrong specific heat capacity, or ignoring ambient temperature.
