Importance of Rotomolded Tanks


Roto molding a tank, an electrical charge or shot quantity of material is inserted into a heated hollow. It is frequently rotated gently over the two parallel heating axes to distribute the pliable material and ensure it sticks to the mold walls.

The Usefulness of Rotomolded Tanks

Natural gas burners heat the oven, and the mold is fastened at the boundary before being placed within. It is mechanically rotated at speeds between 4 and 12 rpm. As the material melts, tiny layers of polyethylene are applied. After being heated in a mold, the plastic takes on its final shape before removal. The mold is broken from the tank when it has cooled to expose the final product. Expert manual labor is essential in a roto-molding system. For instance, having specialized personnel open and shut the molds in the roto-molding procedure is essential. Manual effort is needed to open and close the die.

Method of rotomolding

Components Found in Rotomolded Storage Tanks –

Rotationally molded tanks can be made from a wide range of thermoplastic materials, including polypropylene, Halar, & polyvinylidene fluoride. Plastic resin often has additive elements added to it to enhance properties, including strength, moisture, substance, & resistance to temperature, color, & flame retardancy, depending on the item’s intended use.

One of the most significant items created by rotational molding is plastic tanks. That’s why manufacturers employ the most potent roto molders possible. They require a large area, a source of intense heat, & a means of cooling down. The rotational molding machine may require space to rotate on two axes at all these points.

When producing tanks, the polymer resin is often ground into a fine powder for easy injection into the crevices of the tank-shaped mold. Low speeds and low pressure during the procedure can make evenly distributing the plastic difficult. However, complicated designs, including two-compartment tanks, become possible if the plastic grains are refined. Rotomolded tanks can be horizontal or vertical and hold a few quarts to several thousand gallons.

Rotomolded Tanks Benefits

  • Rotomold tooling can be made from low-cost materials like aluminum because of the low working pressures.
  • The mold rotates continuously throughout the heating and chilling processes, wall thickness is maintained consistently.
  • The double-wall construction can make complex container shapes with two walls without further processing.


By molding components together, weakening connection techniques like welding & joint fabrication are unnecessary.

Superior steadiness: 

Because of this, there is a reduced likelihood of defects in the final product and more excellent stability in the molding material.


Rotomolding results in thicker corners, less likely to fail in high-stress areas.


Rotomold tooling typically uses a soft metal, making it easy to accept surface finishes, including fine-detail surfaces, logos, emblems, & inscriptions.

Problems with Rotomolding

High repetition rates: 

Roto molding a single component at eight revolutions per minute can take as much as three hours. 

Restricted access to resources: 

Due to their high thermal stability & ease of conversion from granules to powder, poly-based polymers are the only supplies suitable for roto molding.

The inflated price of inputs: 

High prices result from several factors, including the price of the required additives, the cost of processing the material into a fine consistency, and stringent requirements for thermal stability.

Low consistency: 

Rotomold tooling is made of soft metal, which wears out every 3,000 rounds and requires fixing or replacing. This might cause quality issues.

Extremely high cost of labor: 

Since roto molding has not yet been mechanized or automated, it requires higher labor intensity than equivalent manufacturing. 


Continuous mold rotation is used during the cooling and heating systems phases to avoid sagging or distortion.




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