That's an excellent question for anyone specifying commercial or public space bins. The core difference lies in the manufacturing process, which drastically impacts the final product's characteristics.
Injection Molding involves injecting molten plastic (like HDPE) into a rigid, detailed mold under high pressure. This creates products with sharp details, smooth surfaces, and very consistent, thin walls. The process is fast and efficient for high volumes. However, the thin walls can make the cans lighter and potentially less impact-resistant. Seams are often present where mold halves meet.
Rotation Molding (Rotomolding) uses a powdered plastic (typically polyethylene) in a closed mold. The mold is heated and rotated on multiple axes, causing the plastic to evenly coat the interior and melt into a single piece. The result is a seamless, one-piece construction with thicker, more uniform walls. This makes rotomolded cans exceptionally durable, impact-resistant, and better at insulating contents. The process allows for more complex, double-walled designs but is slower and often more costly per unit.
Key Differences Summary:
* Durability: Rotation-molded cans are generally more robust and resistant to dents, impacts, and vandalism.
* Wall Construction: Injection-molded has thin, consistent walls; rotation-molded has thick, seamless, often double walls.
* Design & Detail: Injection molding allows for intricate graphics and sharper details. Rotomolding excels at large, simple shapes and complex hollow forms.
* Weight & Feel: Rotomolded bins are heavier and feel more substantial.
* Cost & Volume: Injection molding is cheaper at very high volumes. Rotomolding is cost-effective for medium runs of durable, large items.
Best Applications:
* Choose Injection-Molded for high-volume, cost-sensitive needs where detailed branding is key, and extreme durability is less critical.
* Choose Rotation-Molded for harsh environments (parks, beaches, city streets), where superior impact resistance, insulation, and long-term durability are paramount, justifying a higher initial investment.
In short, for most demanding outdoor public applications, rotation-molded trash cans are the preferred choice for longevity, while injection-molded suits high-volume commercial needs with specific aesthetic details.