The plastic blending process allows one to combine properties of multiple components and generate blends for optimized performance.
For many processors, colored plastics are frequently used in an array of applications and settings, but it still can be a mystery as to how these colors are implemented.
In the past, resins have been blended with other components using manual open pour processes and loss of weight methods. This can prove to be wasteful and inefficient. The process requires hands-on labor, and difficult-to-trace batch history.
Like every other aspect of plastics processing, blending has become more high-tech.
On many shop floors, the largest gravimetric blenders process on the top end about 7,000 pounds to 8,000 pounds per hour. Beyond that, extruders would turn to other options.
Low-volume trends favor gravimetric blenders.
Current trends favor larger blenders, though it isn’t necessarily the result of higher throughput capacity or increased rates. Generally, it is because of an increase of components being added to the blend, such as multiple fillers, repalletized materials, additional regrinds and virgin materials.
The size of the blender is based on the throughput rate of the blender, and the time it takes to make the batch of a blend. If you have additional components that have slower flow characteristics, the cycle time extends. This can lead some shops to seek larger blenders.
On some shop floors, the time required to transport material from the grinder to the machine throat must be reduced to minutes. This can be done with low-volume blenders, feeders or loaders.
Many shops must be able to blend large amounts of material, which sometimes mean special equipment is needed.
Companies today offer large-volume blenders that can accommodate multiple components. They can be fabricated in a modular design. With a blender that is modular, shops can realize a cost savings that will quickly offer a positive return on investment.
The modular unit also can include metering devices and other controls, allowing operators to set the parameters for their blending specs. The end result is increased efficiencies for high-volume blending.