Rotational molding process
Rotational molding is one of the plastic forming methods used by about 2500 companies around the world. This molding started in the late 1950s with the molding of liquid PVC, and later, the volume of polyethylene consumption increased, which is the most widely used polymer in this industry. Despite its relatively small share in the plastics market, its growth is higher than the average of similar industries.The flexibility in the design and volume of products, which includes from simple storage tanks to complex parts with applications in the automotive, medical and aerospace industries, has caused increasing attention to this shaping method; So that the process method for forming the pipette bubble with medical use is exactly the same as the forming of seven-meter big boats. Because of these advantages, the favor of engineers and designers to produce complex parts such as fuel tanks and ducts related to airplanes has increased day by day. Also, the increasing attention to this forming process has attracted the opinion of raw material suppliers who play an effective role in the development of this industry.
The apparent simplicity of the molding process has caused some people to have a technical view of it and ignore its more scientific aspects. However, making more complex parts with better properties as well as shortening the production cycle time to increase productivity requires special and more scientific attention to this industry. Behind the simple appearance of rotational molding process steps, complex interactions of heat transfer and material distribution that occur during the process inside the mold are hidden. Until recently, our knowledge was limited about what happens inside the mold after it enters the furnace, melts the powder, and then cools it to form the part.But today, it is possible to measure the temperature inside the mold during the cycle, continuously scan the surface of the mold to read the temperature, and even place a camera inside the mold to observe the formation of the part. Rotational molding is unique among plastic molding methods because all the steps of heating, forming and cooling of the part are done inside the mold without using pressure.
The products produced by rotary molding have a wide range, which can be mentioned as follows:
• Agriculture (storage tanks, spraying tanks)
• Automotive (internal panels, fuel tanks, air intake systems)
Building and road construction (water tanks, septic tanks, traffic barriers)
• Household appliances (vacuum cleaner parts, tables and chairs)
• Industrial (chemical tanks, chambers, pollution and corrosion control parts)
• Gardening (protection and fuel tank of the lawnmower)
• Marine industries (floating platforms, buoys, fuel tanks)
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What is polyethylene and what types of polyethylene tanks are there?
