Responsible for 2% of the transformation of polymeric compounds, rotomolding is a widely used process because of its low cost. Its main function is to model plastic materials, changing them to thermoplastics. In this type of processing, the most common resins are polyethylene, polyvinyl chloride, and polypropylene.
Knowing how does rotomolding work, many companies can create the simplest and the most complex materials. In addition, depending on the purpose of the plastic material, it may be more usual than options such as injection, blowing, and vacuum. To learn more, keep following us!
What is rotomolding?
After all, what is rotomolding? As we said earlier, this is a process that allows the production of simple and high-level complexity materials. In general, such pieces are hollow and hermetic, as small as a coin, or as large as 25,000 liters tanks.
In this type of piece, the residual stresses tend to be small, due to the absence of pressure on the resin. This system also molds products with threads, inserts, double walls, reinforcements, openings, and holes, allowing easy replacement of colors and materials.
The molds used by the rotomolding industry are cheaper compared to other processes such as vacuum, blowing, and injection. This is because it has low-cost materials such as copper, aluminum, steel, or nickel, and the pieces produced do not require an excellent finish.
As the weight of the rotomolding materials is monitored during the process, it is common to have few leftovers. Although the cost is low, it is worth remembering that the rotomolding has a high cycle. This means that long periods of heating and cooling can increase the risk of thermal degradation.
How is the rotomolding process done?
So, what is rotomolding process? For the processing to generate high-quality products, the first step is to fill the mold with the raw material, which may be liquid or powder. These options are recommended as they help to give greater homogeneity to the pieces that will be manufactured.
However, if the choice is the powder option, the company must make sure that it was micronized. Doing so will facilitate the flow into the mold, accelerating the plasticization of the resin and reducing the air insulation. Once filling, the mold is covered and taken to the oven.
In the oven, the material undergoes transfusion and rotation movements, which make it fill all the walls as it was inserted. Still in this stage, the polyethylene for rotomolding undergoes cooling and demolding. Then, it is extracted to receive some finishes.
Among the main advantages of this procedure are the production of unique pieces, without welds or seams, the diversity of colors, models, and formats, as well as resistance to weather and impacts. Another noteworthy point is the obtaining of anti-corrosive, recyclable, light, durable, and safe materials.
Main applications of rotomolding
In general, this system is widely used in industrial sectors to manufacture large or small hollow parts. With it, it is possible to produce different thermoplastics, giving shapes to the product. This option can be used in the production of porcelain molds, decorative candles, etc.
Besides the thermoplastic resins that we have already mentioned, some thermosets can be used, such as rubber, for example. However, as they do not take on new shapes when they are melted, the first option turns out to be more viable.
Benefits of rotomolded plastic
One of the biggest advantages of this type of processing is the fact that the rotomolded polyethylene can create pieces more resistant and with longer service life. It is no coincidence that this raw material is used by around 90% of the rotomolding market in the world.
Now that you know what is rotomolded plastic, another advantage of it is the ease of cleaning in parts with rough surfaces. However, this effect may vary according to the shape of cavity, fluidity, and granulometry of the resin used, in addition to rotational speeds, manufacturing temperatures, among others.
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