Why does the WPC door panel production line increase the length of the cooling and shaping table, but instead add a cooling system to ensure the door panel forming process？

When making WPC door panels, surface flatness and dimensional stability are the most critical factors in producing quality products. At Jiangsu Xinhe Intelligent Equipment Co., Ltd., we have continuously refined the WPC door panel extrusion line design with experience of actual customer feedback from Vietnam, Indonesia, Saudi Arabia, etc. Among these, a typical improvement is the elongation of the cooling and shaping table length and additionally installation of a cooling system. From initial view, the above two measures seems overlapping, but in reality, they are playing different roles for perfecting door panel formation.

Extended Shaping Table Provides Gradual Calibration

A longer shaping table is intended to provide longer contact duration between the extruded profile and the calibration tool. As is known, compared to plastic/pure wood, WPC has higher coefficient of thermal expansion and contraction. Once out from the die, the WPC is still soft enough to be calibrated precisely along the wider range of length in order to keep it stable, to minimize internal stress that could result in distortion in later stage. It could better guarantee the dimension consistency of width, thickness, and surface flatness in a slow and uniform way, which might not happen to the short shape length where initial tiny error might get magnified in final dimension.

Added Cooling System Accelerates Heat Removal from the Core

Although the longer table alone does not actively remove heat from the profile, it merely relies on the passage of time. WPC has a poor thermal conductivity. Although the surface cools quickly, the inside of a thick door panel may still be hot and can shrink slowly and unevenly, leading to distortion that will appear only when the panel is cut or stored. Adding an additional cooling system which utilizes temperature controlled air or water circulation can absorb the heat of WPC at a controlled rate. By this way, internal voids, surface defects and thermal stresses can be reduced.

Synergy Between Longer Table and Active Cooling Prevents Deformation

As is known, WPC is a low thermal conductivity material, so that an additional cooling system is very helpful to control the rate of cooling. A longer shaping table can accommodate more cooling stages—or more independent cooling stages—allowing us to achieve higher production speeds within a limited length. With the help of a certain cooling mechanism of additional cooling system, more heat can be extracted from the WPC by the controlled airflow in this longer shaping table, and internal stresses formed can be avoided, surface defects can also be avoided. At Jiangsu Xinhe Intelligent Equipment Co., Ltd. We have already made many tests, long shaping table alone will still have a tiny camber in the door panel, and while additional cooling system with a short shaping table the surface marking could be an issue since the profile is not stable enough for a relatively large force during the initial calibration. They both play an active role and cannot replace each other.

Impact on Production Speed and Material Consistency

Additional cooling system with long shape table ensures faster production speeds as the heat of the WPC panel is quickly removed, without need for a correspondingly longer cooling tunnel or extended extrusion lines, thereby increase the output efficiency. For many factories in Turkey, Mexico, this is a very good news and could obviously reduce cost per panel. With better cooling system for a longer table, crystallization and the mechanical properties will be more steady across the WPC compound batch and between production cycles.

Reduced Reject Rates and Post-Processing Costs

A perfectly flat door panel as it comes off the line would require less or even no subsequent straightening and finishing. Labor costs and rejection rates will dramatically decrease. Many clients of Jiangsu Xinhe Intelligent Equipment Co., Ltd. have stated that their rejection rates dropped more than 30 percent after installation of a longer table plus an additional cooling system on the WPC door panel extrusion line.