PVC profiles are produced by extrusion – continuous extrusion of softened material through a hole of a certain cross-section determined by the type of die (a part of the machine for forming chemical fibers in the form of a cap or a plate) at a temperature of 80-120 Co. The extruder consists of a drive with motor and gearbox, as well as a cylinder with screws and an inlet hopper inside it. The material loaded through the inlet hopper is mixed in the heating zone of the cylinder by two screws to a homogeneous melt, which is fed to the die. The molten extruded material acquires the required shape and dimensions in the die and in the vacuum gauge, where the initial cooling of the profile takes place.
At the next stage, the profile enters the secondary cooling section, where cold water is applied to the profile. Next, there is a unit that pulls the profile evenly out of the cooling section and feeds it to the labeling section, where a protective film is also applied.
At the end of the line there is a saw that cuts the profile of the required size, after which it is packed into pallets. During extrusion it is necessary to strictly observe the modes of mixture heating and profile cooling. Since PVC profile has a complex spatial structure with horizontal and vertical walls of different thickness, uneven temperature regime leads to profile distortion right at the extrusion stage.
For this reason, VEKA carries out complex, multi-stage quality control of the extrusion process. All of the Group’s plants are connected via satellite to the central control room of VEKA AG, where the operation of each extruder is monitored – from Germany to the USA. Every hour, control samples of the finished profiles are subjected to rigorous laboratory testing using state-of-the-art equipment.