Problem

Choosing the right manufacturing process for large hollow plastic products can be difficult. For tanks in the 0.2T–30T range, selecting the wrong process may lead to high cost, unstable structure or poor durability.

Common mistakes include using blow molding for large tanks or considering injection molding for hollow structures, both of which have limitations.

Process Logic

Rotomolding is a low-pressure process where material is heated and rotated to form a hollow structure

Blow molding uses air pressure to expand material

Injection molding uses high pressure for solid parts

Each process is designed for different applications

Size Capability

Rotomolding can produce structures with diameters over 3000mm

Blow molding is limited in large sizes

Injection molding is not suitable for large hollow products

For ton-scale tanks, rotomolding is often the only practical solution

Structural Advantage

Rotomolding produces seamless structures

No welding joints
Wall thickness between 6–15mm
Strong resistance to hydrostatic pressure

Blow molding produces thinner walls
Injection molding is not suitable for large hollow shapes

Thickness Control

Rotomolding allows relatively uniform wall thickness

Large tanks typically use 8–15mm thickness

Blow molding struggles with uniformity in large structures

Cost Efficiency

Lower mold cost than injection

No high-pressure equipment required

Suitable for customized production

Application Fit

Water tanks
Industrial containers
Chemical tanks
Hollow structural products

Limitations

Longer cycle time
Lower surface precision
Not suitable for thin-wall parts

Conclusion

Rotomolding is not universally better
It is simply the best choice for large hollow products