Basic Components of a Flexible PU Foam Production Line: Conveyor Belt and Chain Plate

Small foaming machines typically use an endless rubber belt as a conveyor, whereas large foaming machines often employ a metal chain plate conveyor. Compared to rubber belts, metal chain plates are more expensive but offer easier adjustments, stable operation, no slipping or deviation issues, resistance to aging, and easier cleaning.

Conveyor belts are usually driven by sprockets and allow stepless speed regulation through a motor or a variable-speed drive. The adjustable speed range generally falls between 3 to 10 m/s. In horizontal foaming machines, the conveyor system typically consists of a main conveyor belt and an auxiliary conveyor belt. The main conveyor belt is equipped with side wall link chains on both sides. In some foaming machines, these side chains are made of metal plates that synchronize with the conveyor belt (see Figure 1). This synchronization ensures that the side liner paper advances with the chain plate, preventing misalignment that could lead to foam surface defects such as material stripping or even cracks. The auxiliary conveyor mainly transports the formed foam blocks.

Figure 1: Metal Chain Plate Conveyor and Side Wall Link Chain Diagram

To ensure proper foaming and achieve a greater foam thickness, the conveyor belt requires a tilt angle of 3 to 6 degrees. This tilt can be adjusted using a hydraulic lift, manual or motorized screw lifts, or a fixed incline of around 4 degrees.

Vertical foaming machines use a track-type conveyor belt to lift and transport foam blocks in a vertical direction. When producing rectangular foam blocks, the conveyor itself serves as the molding chain plate, eliminating the need for additional configuration. However, for cylindrical foam blocks, a cylindrical shaping mold is installed above the foaming trough.