The PP Hollow Grid Board Production Line is a complete set of automated equipment designed to extrude and mold polypropylene (PP) granules into hollow grid sheets. It is capable of producing hollow boards ranging from 2 to 12 mm in thickness and 1220 to 3500 mm in width, finding widespread application in fields such as packaging, advertising, construction, and logistics.

I. Core Components (From Raw Material to Finished Product)

Feeding and Mixing System

Comprising a spiral feeder and a high-speed mixer, this system ensures the uniform blending of PP granules with color masterbatches, anti-static agents, and flame retardants.

Single-Screw Extruder (Main Unit)

Specifications: SJ90/120/150 series; L/D ratio: 33–36; Power output: 75–160 kW.

Features a specialized screw design and precise temperature control (200–250°C) to ensure uniform plasticization, high output, and stable operation.

Hydraulic Screen Changer

Dual-station rapid screen-changing mechanism with reliable sealing, allowing for screen replacement without halting production, thereby ensuring continuous operation.

Dedicated Hollow Board Die

Constructed from alloy steel with precision-machined flow channels; equipped with throttling and differential adjustment capabilities to guarantee uniform wall thickness and a regular cross-sectional profile.

Vacuum Calibration Table

Utilizes a combination of vacuum suction and water-circulation cooling (≤20°C) to facilitate rapid shaping and precisely control the board's thickness and flatness.

Haul-off Unit (Multi-Roller)

Features a 6-roller plus 2-roller configuration to maintain constant tension, preventing deformation of the sheet material; linear speed ranges from 5 to 15 m/min.

Oven (Stress Relief)

Employs low-temperature, zone-controlled heating to eliminate internal stresses within the material, thereby preventing warping or deformation in the finished product over time.

Collection/Stacking Table

Enables automatic stacking and counting of finished boards, facilitating convenient packaging and warehousing.

II. Process Flow

Raw Material Mixing → Extrusion & Plasticization → Screen Changing & Filtration → Die Forming → Vacuum Calibration → Haul-off → Oven Treatment → Cooling → Fixed-Length Cutting → Finished Product Stacking

III. Key Technologies and Advantages

High Efficiency & Stability: Features full automatic control via PLC, with real-time monitoring of temperature, pressure, and speed. Achieves an output capacity of 200–500 kg/h, characterized by high linear speeds and a low scrap rate. Superior Product Performance: Lightweight (0.3–0.8 g/cm³), high strength, water- and moisture-resistant, corrosion-resistant, anti-aging, and recyclable; serves as an ideal substitute for cardboard, wood, or aluminum panels.

Customizable Functionality: Can be compounded with anti-static, conductive, flame-retardant, or anti-bacterial masterbatches to produce specialized hollow boards.

Flexible Specifications: Board thickness ranges from 2–12 mm, width from 1220–3500 mm, and length can be customized according to specific requirements.

IV. Common Products and Applications

Standard Hollow Boards: Packaging boxes, dividers, backing pads, and turnover boxes.