Project Background：
The factory operates 20 injection molding machines (160–300 tons) for automotive interior and structural components. The original cooling system used small open towers, leading to:
· High water temperature in summer (>32°C), uneven mold cooling, part warpage and sink marks, with a 6.5% defect rate;
· Hydraulic oil temperature often exceeding 60°C, rapid seal aging, 2–3 shutdowns/month for maintenance;
· High water consumption due to evaporation and blowdown, severe scaling, frequent mold cleaning.
To improve quality, reduce energy consumption and maintenance costs, the plant upgraded to a large counterflow open cooling tower for centralized cooling.
Solution：
1. Configuration
· 2 × Model DBNL3-200 open cooling towers (1 duty + 1 standby), each 200 m³/h flow rate;
· Cooling scope: all mold circuits + hydraulic oil coolers;
· Design: inlet ≤ 42°C, outlet ≤ 30°C (summer extreme).
1. Process Flow Injection mold / hydraulic oil cooler → Hot water header → Open tower (spray + counterflow heat exchange) → Cold water basin → Circulating pumps → Injection machine cooling loops.
Operation & Control
· Automatic temperature control: VFD fans based on outlet water temperature;
· Make-up water, blowdown, and softening pretreatment to minimize scaling.
Results & Benefits：
1. Product Quality
· Mold temperature stabilized at 25–30°C, temperature variation < ±1.5°C;
· Defect rate reduced from 6.5% to 1.2%, yield up to 98.8%.
1. Equipment Reliability
· Hydraulic oil temperature maintained at 40–55°C, no overheating alarms;
· Seal life doubled, maintenance downtime reduced by 70%.
1. Energy & Cost Savings
· Circulating water efficiency improved, ~40% annual water savings;
· VFD fans + high-efficiency fillings, ~25% power savings;
· Total annual cost (water + power + maintenance) reduced by ~$50000.
Customer Feedback：
“Since switching to centralized cooling with large open towers, our injection molding shop runs at stable temperatures, part quality is much better, downtime is down, and energy costs are lower. We saw clear ROI within half a year.”
