Rotomolding Process

Rotational Molding is a manufacturing process, it’s working principle is:The plastic material is evenly distributed on the surface of the mold through high-temperature and rotational methods, and then cooled and solidified to form a hollow plastic product.By using this process, the rotational molding factory can produce high-quality hollow products, such as toys, storage boxes, kayaks, etc.

    In short,it can be divided into the following four steps:

Step One: Load materials into the mold.

The first step is loading the resin in the mold. Pulverized material in a fine powder form is loaded into the prepared mold. The mold is then secured closed and rotated to ensure no powder is able to escape.

Step Two: Heating

Mold moves into the heating chamber of the oven while rotating on two axes at a low speed.

StepThree: Cooling

Mold moves into the cooling chamber and is cooled by air or water spray or a combination of both, while still rotating.

Step Four: Demolding

Mold is unloaded revealing the molded part. 

The distinct advantage of rotomolding is that it is an easier process than any other when producing large, hollow parts, such as oil tanks or chairs. Also, the molds used in rotomolding are significantly less expensive than different types of molds. Rotomolding generates much less wasted material; excess material can often serve for another usage, making it economical and ecological. 

Another advantage lies in the molds themselves; they necessitate less tooling. Consequently, companies could put into production much faster than other molding processes. This is especially valuable for complex parts. Rotational molding is also the choice process for short runs and rush deliveries. The operator can exchange the molds quickly or use different colors without purging the mold. With other processes, purging may be necessary to swap colors.

The article is quote from：

https://www.rotomolding.com/rotomolding/rotationalmolding-process.html 

https://www.3ds.com/make/guide/process/rotomolding