Problem

In large rotomolding mold projects, many failures originate from early design and decision stages rather than production. For molds in the 0.2T–30T range, errors can result in costly rework and delays.

Common issues include failed trial runs, uneven wall thickness, deformation and low production efficiency. These problems are usually caused by multiple combined risks.

Risk 1 Machine Mismatch

One of the most common risks is mismatch between mold size and machine capacity.

If the mold diameter exceeds oven space or the weight exceeds arm capacity, production becomes impossible.

The solution is to verify machine limits during the design stage.

Risk 2 Structural Weakness

Large molds above 10T require strong structural support.

Without proper reinforcement, molds may deform during repeated heating cycles.

Reinforced frames and segmented design can improve stability.

Risk 3 Uneven Wall Thickness

Uneven thickness is a typical issue in rotomolding.

It is caused by poor mold design, incorrect rotation parameters or unstable temperature control.

Maintaining temperature within ±2°C and rotation speed at 3–6 rpm helps improve consistency.

Risk 4 Cooling and Internal Stress

Uneven cooling creates internal stress in thick-wall products.

Over time, this stress may cause deformation or cracking.

Uniform cooling is essential to reduce this risk.

Risk 5 Incomplete Customization

Late changes in openings or fittings increase cost and delay production.

All requirements should be confirmed before mold manufacturing.

Risk 6 Process Instability

Even with a good mold, unstable process parameters can affect product quality.

Temperature fluctuation and incorrect rotation speed lead to uneven material distribution.

Stable process control is necessary.

Conclusion

Risks in rotomolding mold production can be reduced through proper planning and control

Machine matching
Structural reinforcement
Process stability
Clear customization requirements