4 Crucial Steps in the Process of Rotational Molding

With an increasing market share, rotomolding, or rotational molding process is applicable to many industries. It is a specialized process of plastic transformation to produce hollow parts with high structural strength. 

4 Crucial Steps in the Process of Rotational Molding

The rotational molding process has evolved in the past few years due to lower costs and higher durability. Whether you want a standard product or a custom design for a specific part, the rotomolding process serves every need. The main steps in this process are:


If you need custom roto-molded parts, the job will start with proper consultation with the client. It includes an understanding of product features, aesthetics, and specifications. 

The designers conceive the parts with the help of 2D and 3D renderings that give realistic touches to the ideas. It helps to bridge the communicative gaps between designers and consumers as well. 

Mold Designing

In this stage of rotational molding, the designers create CAD models using conceptual ideas or drawings. The 3D models help to identify parting lines and other specific design features. Parting lines are the areas where various sections of the mold tool meet and create the design. They establish the complexity of tools and draft angles. 

Also, you may find small blemishes on the outer surfaces where parting lines trace the mold surface. Hence, designers have to consider the parting lines and materials to be used for the molds. Based on the structural strength and thermal characteristics of the materials, you may choose the right shape and size of the mold. 

Tool Fabricating or Casting

For proper manufacturing of the products as per client expectations, you need a precisely fabricated tool or mold. This phase involves four main steps- mold preparation, mold heating, cooling, and mold unloading.

Mold preparation refers to filling the hollow mold with the right mixture. The frame is preheated according to the material properties and moved to the heating section. 

The process of heating requires holding the mold and rotating them on two axes inside the preheated oven. This ensures even distribution and melting of the material inside the mold. Here, it is also essential to maintain the right speed to avoid centrifugal forces and ensure excellent material coverage. 

Cooling the mold is also an essential part of the process. After removing the molds from the oven, engineers position them in a cooling station to remove the heat by air or sprinkling water.

Lastly, the unloading of mold requires attention to detail to apply for mold release with care. It includes stopping the rotary movements and opening the molds to separate them from mold cavities. 

The entire process of tooling may take anywhere from a few weeks to a few months to execute the perfect design.

Starting the Production

After completing the process of tooling, the engineers move on to the stage of production. It requires experience and expertise to create a fine-tuned product with impeccable design, surface area, wall thickness, and perfect angles. The process may involve trial and error until you get the desired results.

If you want to achieve precision and control in your products, find an experienced rotational molder that can handle all these steps with precision to save costs.