The Engineering Behind the Rotational Molding Process
Rotational Molding is an industrial process for transforming thermoplastic materials, used in the manufacturing of different types of parts. It involves placing a mold shaped like the desired part inside a preheated machine.
The process develops in five phases. The first is loading, which consists of placing the raw material inside the mold. Next is the transformation phase, during which the mold rotates inside the oven on two axes — vertical and horizontal — so that the melted material adheres uniformly to the inner surface. Then comes cooling, with continued rotation until the end, ensuring a homogeneous wall thickness.
In the demolding phase, the part is removed from the mold. Finally, the finishing stage eliminates any excess material, especially around the mold joints.
The molds, made of cast aluminum or metal sheet, are essential elements in the process. The quality of the parts largely depends on how these molds are designed.
Efficiency, durability and precision
Rotational molding offers economic advantages over other processes such as injection molding, blow molding or vacuum forming, allowing lower mold production costs — especially for medium or small series.
In addition, it enables the creation of large-scale parts with more sophisticated designs.
With a well-planned project, multiple parts can be combined into a single piece, reducing costs and increasing the strength of the final product.
This technique has been gaining more relevance due to its versatility. It is used in diverse sectors such as decoration, toys, technical parts, and also in the production of tanks, reservoirs, and containers.
The growing demand for more eco-friendly solutions, innovative design, and greater adaptability has been a key factor in the expanding use of rotomolding.