1. Raw material preparation
Raw material selection: PP resin with good UV resistance and weather resistance (color masterbatch, antioxidant and other modifying materials can be added).
Drying treatment: PP raw materials usually do not need to dry, if moisture needs to be dried at 80 ℃ for 1-2 hours.
2. Injection molding (core process)
Mold design: according to the structure of the planting box (such as drainage holes, reinforcement, etc.) to make steel molds.
Parameters of injection molding machine:
Temperature: 180-220℃ (segmented control)
Injection pressure: 60-100MPa
Cooling time: adjusted according to the thickness (usually 20-40 seconds).
Molding Steps:
1. Melt Plasticization: PP pellets are heated and melted in the barrel of the injection molding machine.
2. Injection Mold Filling: The melt is injected into the mold cavity under high pressure.
3. Pressure Holding and Cooling: Pressure is maintained to prevent shrinkage marks and to cool and finalize the molding.
4. Mold opening and ejecting: Eject the product after molding, and the robot picks up the parts automatically.
3. Post-treatment process
Deburring: Trimming the excess waste edges such as sprue and mold parting line.
Quality inspection:
- Dimensional accuracy (length/width/height, wall thickness uniformity).
- Surface defects (bubbles, shrink marks, missing material).
- Functionality test (drain hole patency, stacking stability).
4. Surface Treatment (Optional)
UV Coating: Spray UV resistant coating to extend outdoor life.
Silk-screen printing/labeling: Printing brand logo or instructions for use.
5. Assembly and Packaging
Accessory Assembly: such as installing casters, water traps, etc. (if it is a multi-functional grow box).
Packing: PE bag + carton, or stacked and fixed with winding film.
