The process of making high-density polyethylene (HDPE) sheets is mainly divided into the following key steps:
- Raw material preparation
Select HDPE raw materials:
Virgin HDPE resin (high purity, stable performance)
Or blend some recycled materials (reduce costs, but affect performance)
Add additives (optional):
UV stabilizer
Antioxidant (anti-aging)
Masterbatch (for color adjustment) - Melt extrusion (or molding) molding method
Method 1: Extrusion method (suitable for thin sheets and continuous production) - Extrusion molding equipment configuration:
Single screw or twin screw extruder
Sheet die head
Three-roll calender (leveling and cooling)
Traction device and cutting device - Process flow:
Raw materials enter the extruder → Heating to 190~230°C → Melting and plasticization
The melt is extruded through the die head to form a sheet
Three-roll calender → Cooling and shaping
Edge trimming → Cutting to size → Finished product stacking
Method 2: Molding method (suitable for thick plates and large-sized plates) - Molding equipment configuration:
Flat plate hot press (high pressure required)
Cooling press or cooling table - Process flow:
Fill HDPE powder or granules into the mold
Heat and press (usually 180220°C, pressure 515MPa, 30~60 minutes)
Pressure and cool to room temperature
Demolding → Trimming → Finished plate
III. Post-processing
Cutting to size
Surface treatment (polishing, frosting, typing, etc.)
Inspection and packaging