Rotational molding is a production technique that is used to manufacture hollow parts of limitless sizes. Large plastic parts can be manufactured in a cost-effective manner using rotational molding. Resins or plastics (in a powder form) are poured into a hollow-shaped mold at first. Then, the mold is heated and rotated slowly in vertical and horizontal planes. The constant heating and rotating makes the resin melt and distribute evenly along the inner surface of the mold.
Injection molding is a forming process using molds. Materials such as synthetic resins (plastics) are heated and melted and then sent to the mold where they are cooled to form the designed shape. Due to the resemblance to the process of injecting fluids using a syringe, this process is called injection molding.
Compared with the above two molding way, rotational molding has the following advantages:
Low cost in mold making
For example, if one product can be made in both in two ways, the rotational mold cost is only half of the injection mold cost or even more.
Consistent wall thickness
In rotational molding, it is easy to make the same product in different thicknesses, so the customer can find a suitable thickness based on actual use, but injection is hard to make it.
Short lead time
On average, it only takes 4 weeks to finish one rotational mold making, even when more rotational molds come, they can still be finished within 8 weeks. But for injection mold may take up to 6 months to get your product from design to sale stage.