Prevention and Cleaning Solutions for Blocked Cooling Water Channels of Chinese Injection Molds

Cooling water channels are the core temperature control system of Chinese injection molds, directly determining cooling uniformity, molding cycle, product warpage and mold service life. During long-term mass production of domestic plastic products, water channels inside molds easily accumulate limescale, rust, microbial slime, oil stains and mixed impurities, resulting in uneven mold temperature, prolonged cooling time, product shrinkage and sharp rise of mass defective rate. Severe blockage will cause domestic mold corrosion perforation and permanent scrap. Combined with the actual maintenance status of Chinese injection mold workshops, this paper puts forward complete blockage prevention and special cleaning solutions.

1. Root Causes of Cooling Water Channel Blockage on Chinese Injection Molds

1.1 Water Quality Impurities, Limescale and Rust Deposition

Most domestic molding workshops adopt factory circulating cooling water containing plenty of calcium and magnesium ions. Under long-time alternating hot and cold cycles inside Chinese injection molds, hard limescale forms and adheres tightly to channel inner walls, narrowing pipe diameter and slowing water flow. Most conventional domestic molds use common mold steel that is prone to oxidation and rust; rust debris sheds and accumulates at elbows and blind holes to form blockages, and continuous rusting further expands internal corrosion of Chinese injection molds.

1.2 Oil Stains, External Impurities and Lack of Regular Maintenance

Floating release agent oil stains generate oily mucosa inside water channels, adsorb polishing dust and form sticky sludge. During mold disassembly, grinding and repair of Chinese injection molds, iron filings, abrasive residues and sealant fragments easily fall into water channels and trigger local blockage. Most small and medium domestic molding factories only repair molds after complete blockage without periodic maintenance, leading to gradual accumulation of tiny deposits and serious water channel failure.

2. Production Losses Caused by Blocked Water Channels of Chinese Injection Molds

Uneven local cooling will trigger product shrinkage, bubbles, stress deformation, dimensional deviation and obvious weld lines for plastic parts produced by Chinese injection molds. Poor cooling efficiency forces extended cooling time, lengthening molding cycle and reducing machine output of domestic workshops. Local heat accumulation causes partial annealing of Chinese injection molds, cavity cracking and accelerated aging. Meanwhile, chillers and mold temperature machines run under long-time high load, leading to sharp rise of power and water consumption for domestic molding enterprises.

3. Hierarchical On-site Cleaning Solutions for Blocked Water Channels of Chinese Injection Molds

3.1 Mild Blockage: Online Circulating Chemical Cleaning

When water flow weakens and mold temperature rises slowly for Chinese injection molds, special descaling and bacteriostatic agents are mixed with water for closed circulation of mold temperature machine for 20 to 40 minutes, dissolving limescale and softening sludge. After circulation, high-pressure clean water flushing is carried out until the outlet water is clear and free of impurities.

3.2 Moderate Blockage: High-pressure Pulse Cleaning Machine Treatment

For Chinese injection molds with partial unobstructed water channels and obvious temperature difference, pulse water hammer vibration is used to strip hard limescale and thick rust that cannot be removed by ordinary flushing. This method is suitable for quarterly maintenance of mass production domestic molds.

3.3 Severe Blockage: Mold Disassembly and Segmented Dredging

For Chinese injection molds with almost fully blocked channels, remove water nozzles and plugs for segmented inspection. Flexible dredging strips and high-pressure air are used for cleaning; stubborn limescale is soaked with weak acid, then fully neutralized and flushed to avoid residual chemical corrosion on domestic mold steel. After all cleaning, measure water flow, water pressure and inlet-outlet temperature difference to ensure all channels of Chinese injection molds are smooth.

4. Normalized Long-term Prevention Mechanisms for Chinese Injection Molds

Install precision filters (50~100μm) at all chiller and mold temperature machine water inlets to intercept sediment and impurities, with regular filter element cleaning and replacement. Replace all circulating cooling water monthly (every 20 days in summer), and add corrosion inhibitors and bacteriostatic agents regularly to avoid sludge and rust on Chinese injection molds. Set fixed maintenance cycles: clean water channels every 2 months for ordinary domestic molds, every month for high-temperature Chinese injection molds producing PEEK and PC. Seal all water nozzles during mold polishing and maintenance to prevent sundries from entering water channels of Chinese injection molds; carry out shift inspection of water flow and pipeline temperature, and stop production for treatment once abnormal temperature difference is found.

5. Long-term Management Targets for Chinese Injection Mold Maintenance

Through source filtration, periodic cleaning and daily abnormality inspection, the blockage problem of cooling channels on Chinese injection molds can be fundamentally controlled. Stable and uniform mold temperature reduces product deformation and shrinkage defects, shortens molding cycle and improves production capacity of domestic molding workshops. Regular maintenance avoids internal corrosion of water channels, greatly extending the service life of Chinese injection molds, cutting unplanned shutdown time and reducing overall mold operation and maintenance costs for domestic plastic manufacturers.