What Are Rotational Molding Plastic Tanks? Advantages & Disadvantages

Although rotational molding has a lot of advantages, it is not the optimal production method for every product. So, how can you know if it’s the right fit for you? Understanding the benefits and drawbacks of the process is the first step toward making an informed decision.

What is Rotational Molding?

Rotational molding, commonly known as rotomolding, is a thermoplastic molding technique that is best suited for big, one-piece hollow objects and double-walled open containers like tanks, kayaks, and coolers. It’s best for inventors, start-ups, and small businesses because it’s most cost-effective for smaller production volumes.

The rotational molding procedure is straightforward:

  • Powdered plastic resin is poured into a hollow mold.
  • The mold is rotated bi-axially before being placed in an oven.
  • As the resin melts and coats the mold’s walls, the mold continues to rotate.
  • The resin is cooled until it hardens into the appropriate shape in the mold.
  • The mold is opened and the rotation is stopped, allowing the finished part to be removed.

The resin is distributed and fuses on the interior surfaces of the mold due to the simultaneous heating and rotating. As a result, the finished product has seamless components with consistent wall thickness and additional material in the corners to absorb shocks and stresses where they occur most frequently.

Rotational Molding Uses

Rotomolding is frequently used to create parts with high-quality finishes, homogeneous wall thicknesses, and great stability. Inserts and spin weld attachments can be directly included into the rotomold, and foaming can be employed to provide thermal insulation and rigidity. Rotomolding, unlike competing methods such as blow molding and thermoforming, creates no pinch-off seams or weld lines, resulting in a finished product that does not require extra processing.

Advantages of Using the Roto-Molding Process

Rotational molding differs from other competitive molding techniques in that the resin melts into the mold walls rather than being driven by pressure. This differentiation provides a number of benefits over other manufacturing methods including:

  • Low Cost: Because of the low operating pressures, rotomold tooling may be made of low-cost metals like aluminum.
  • Fast Manufacturing: This process saves a lot of manufacturing time, making it perfect for large orders. This also enables manufacturers to produce many tanks within a short period of time without compromising quality.
  • Stable: Because the molding material isn’t exposed to external pressure, it’s more stable and less likely to have faults in the end product.
  • Durable: Rotomolding provides thicker corners, which reduces the chance of failure in certain stress-concentration areas.
  • Better Control Over Plastic Thickness: Since the mold is in a continual rotation, it gets coated with materials equally during the heating and cooling cycles, resulting in more consistent thickness.
  • Double Wall Construction: Complex double-walled open containers can be manufactured without the need for further processing.

Disadvantages of Using the Roto-Molding Process

Although rotomolding boasts a number of advantages over comparable molding methods, there are some drawbacks as well. Rotomolding plastic tanks does have some disadvantages as well which include:

  • High Processing Times: rotomolding can take up to three hours to complete one part at eight rotations per minute.
  • Limited Material Options: rotomolding raw materials must be easily transformed from granules to fine powder and have excellent thermal stability, which limits material selection to poly-based resins.
  • High Raw Material & Work Costs: due to high thermal stability requirements, the cost of needed additives, and the expense of grinding the material into a powder, raw material costs are high.

Is a Rotomolded Tank Right For You?

At Tank-Depot, we offer a wide variety of rotomolded tanks for you to browse through! Rotomolded tanks are one of the best options to consider when it comes to getting plastic water storage tanks. Tank-Depot is your one-stop shop for many different types of rotational mold plastic storage tanks. Unlike most other wholesalers, Tank-Depot also accepts custom orders.

The plastic molding experts at Tank-Depot can help answer all of your questions.

To contact us, please call our sales team at (866) 926-5603 or email us at info@tank-depot.com.