Key Elements for HDPE Pipe Production Quality Control

Key factors in HDPE pipe production quality control involve the coordinated control of raw materials, process parameters, and equipment. The following are the key points:

1. Raw Material Selection and Pretreatment

• Resin Quality: High-purity HDPE resin should be selected, and modifiers such as antioxidants and UV stabilizers should be added to improve weather resistance.
• Drying: The raw material should be dried at 80–100°C for 2–3 hours, with the moisture content reduced to below 0.01% to prevent bubbles during extrusion.

2. Temperature Control

• Extrusion Temperature: Maintain a machine body temperature of 100–120°C, a die head temperature of 120–140°C, and a slightly lower die temperature to ensure stable melt viscosity.
• Cooling Temperature: Water or air cooling should be maintained at approximately 15°C to prevent internal stress from causing pipe deformation.

3. Process Parameter Optimization

• Screw Speed: Balance output and plasticization efficiency. Excessively high screw speeds will result in rough inner walls, while excessively low screw speeds will affect production efficiency.
• Pull-off Speed: Typically 1% to 10% faster than the extrusion speed to ensure uniform pipe shaping.

4. Online Monitoring and Equipment Accuracy

• Wall Thickness Control: Utilizes a gravity metering system (0.2% accuracy) and ultrasonic online detection for real-time adjustment of deviations.
• Pressure Management: Die head pressure must be maintained at a stable 0.02–0.05 MPa. Excessively high pressure will reduce output, while excessively low pressure will affect plasticizing quality.

5. Post-Processing and Inspection

• Cutting and Straightening: Ensure pipe straightness to avoid stress concentration during transportation and installation.
• Quality Testing