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Mixer Reduce Waste And Increase Productivity
- Oct 09, 2017 -

The application of static Mixer to extrusion processes not only increases throughput, but also improves product quality and, in some cases, shortens start-up times, improves performance, reduces waste and increases productivity.

Many extrusion processes are unable to achieve the maximum productivity specified by the manufacturer. The maximum production capacity depends on the quality requirements of the extrudate. The higher the productivity, the more likely the resulting uneven thickness, uneven surface or roughness, dent or other quality problems. As the quality requirements continue to increase and the difficulty of polymer processing continues to grow, the time required to start and adjust the optimal operating point is getting longer. These two factors have led to reduced productivity and increased costs, and in some cases will be bruised.

The extruder is used in molten polymers and is conveyed at a constant rate under high pressure conditions. The extruder itself should have high productivity and as compact as possible. In order to meet these requirements, the polymer needs to melt in a very short period of time, which is often accompanied by high temperature differences. According to the nature of the process, the high temperature difference in the melt can be achieved. The temperature difference between the highest and lowest melting temperatures measured at the outlet of the extruder is likely to be higher than 15 °C. Melt pumps and screen changers and other downstream equipment will produce temperature difference. The temperature change within the melt can lead to quality problems in many cases because the temperature change within the melt represents a change in flow and cooling behavior. Taking the layered plastic melt as an example,Mixer the flow pattern is parabolic, indicating that the melt center part of the flow faster than the boundary part. This also results in significant differences in melt residence time. The longer the residence time, the higher the temperature,Mixer the more the polymer degradation and sediment accumulation may have adverse effects.

A well-configured melt mixer can effectively balance the temperature difference. The melt mixer manufactured by Promix Solutions AG, based in Winterthur, Switzerland,Mixer reduces the temperature difference by 5-12 times depending on the configuration. Accordingly, it also reduces the temperature difference across the entire cross section of the channel from 15 °C to 1.25 °C. Figure 1 shows the temperature distribution of the melt at the outlet of the extruder equipped with and without the Promix Melt Mixer. The geometry of the melt mixer depends on its ability to achieve maximum benefit. The title chart shows the latest static mixer. This melt mixer continuously exchanges the center and boundary melt flow in an extremely efficient manner, resulting in a higher mixing performance with a shorter mounting length. In addition, the parabolic flow pattern near the exit of the extruder is effectively converted to piston flow. Correspondingly, the melt flowing from the melt mixer flows at a completely constant speed and temperature,Mixer which is a fundamental prerequisite for optimum process control. With a significantly enhanced process window, the process parameter setting becomes faster and easier. Even in high extruder productivity conditions, the thickness tolerance, surface quality and other quality characteristics can be maintained within the limits. In addition,Mixer the additives and pigments in the melt are even more homogeneous. It can improve the UV stabilizer to add the protective effect of bulk, and even reduce the amount. In order to maximize the advantages of the melt mixer, it should be placed as far as possible at the end of the production line, such as the front of the mold or feed mechanism.