When sourcing plastic products, manufacturers often compare rotational molding companies with injection molding specialists. Both processes produce hollow or complex plastic parts, but they differ significantly in tooling cost, part size, production volume, and design freedom.
What Is Rotational Molding?
Rotational molding (roto-molding) uses a heated mold that rotates on two axes, coating the interior with molten plastic powder. It is ideal for large, hollow, stress-free parts such as tanks, kayaks, and playground equipment. Rotational molding companies offer low tooling costs but slower cycle times.
What Is Injection Molding?
Injection molding forces molten plastic into a closed mold under high pressure. It delivers tight tolerances, excellent surface finish, and fast cycle times for high-volume production. Injection molding is the preferred choice for precision parts and complex geometries.
Key Differences
- Part size — rotational molding handles very large parts; injection molding is best below 1 meter
- Production volume — injection molding wins above 10,000 units; rotational suits lower volumes
- Cycle time — injection molding: seconds to minutes; rotational molding: 20-60 minutes
- Tolerances — injection molding achieves ±0.1mm; rotational molding is much looser
- Tooling cost — rotational molds are cheaper; injection molds cost more but last longer
Which Should You Choose?
If you need large, hollow, low-stress parts in modest volumes, rotational molding companies are the right choice. If you need precision, tight tolerances, high volumes, or complex features, injection molding is superior. For mixed requirements, many manufacturers combine both processes.
Partner With RCH Plastic for Injection Molding
RCH Plastic specializes in precision injection molding with in-house mold making. If your application demands the accuracy and efficiency of injection molding, contact us for a competitive quote and expert guidance.