Rotational Molding vs Injection Molding
Rotational molding (roto-molding) and injection molding are the two main processes for large plastic cases. Roto-molding produces seamless, uniform-wall cases ideal for large coolers and industrial cases. Injection molding is faster and more precise. This guide compares them.
Feature-by-Feature Comparison
| Feature | Option A | Option B |
|---|---|---|
| Process | Mold rotates in oven, plastic powder melts and coats inside | Molten plastic injected into closed mold |
| Tooling cost | $10,000-50,000 (low to medium) | $20,000-100,000+ (medium to high) |
| Per-piece cost (medium volume) | $30-80 | $5-30 |
| MOQ | 100-500 pieces | 1,000-5,000 pieces |
| Wall thickness | Uniform 3-12mm (excellent) | Variable 1-8mm (optimized) |
| Part complexity | Simple shapes (no undercuts) | Complex (undercuts, threads, hinges) |
| Surface finish | Matte to satin (one side) | High-gloss, textured, multi-finish |
| Material | PE (LLDPE, HDPE, cross-linked) | All thermoplastics + glass-filled, blends |
| Lead time (tooling) | 6-12 weeks | 8-16 weeks |
| Lead time (production) | 2-4 weeks | 2-4 weeks |
| Best for | Large cases (50L+), coolers, seamless construction | Standard cases (under 50L), high-volume, complex |
| Common products | YETI coolers, Pelican-style large cases, water tanks | Pelican, SKB, Nanuk, all major B2B brands |
Our Verdict
Choose roto-molding for: large cases (50L+), seamless construction, low MOQ, outdoor/industrial. Choose injection molding for: standard cases, high-volume, complex features, best finish. We operate both processes and recommend based on your case size, volume, and design.
Frequently Asked Questions
Is roto-molding cheaper than injection molding?
For low to medium volumes (100-5,000 pieces), yes. Tooling is 2-5x cheaper. For high volumes (10,000+ pieces), injection molding is cheaper per piece. Break-even is typically 5,000-10,000 pieces.
Why are YETI coolers so expensive?
YETI coolers are roto-molded with cross-linked polyethylene (XLPE) for superior insulation and impact resistance. The roto-molding process is slower and more expensive than injection molding, but the result is a near-indestructible cooler that lasts 10+ years. YETI is the gold standard for roto-molded coolers.
What is the maximum size for roto-molding?
Roto-molding can produce parts up to 5+ meters in any dimension. Common products: water tanks (5m+), kayaks (4-5m), large coolers (1-2m), and cases up to 1.5m. For protective cases, max practical size is 1.2m. We have roto-molding capacity up to 2m.
What is cross-linked polyethylene (XLPE)?
XLPE is polyethylene with cross-links between polymer chains, giving it higher strength, temperature resistance, and chemical resistance. XLPE is used in roto-molded cases for medical, military, and premium consumer applications (YETI, Pelican ProGear). Cost is 30-50% higher than standard PE.
Can roto-molded cases have custom foam?
Yes, but the foam is attached with adhesive or mechanical fasteners. Roto-molded cases have thicker walls and larger interior volume, so foam layouts are often simpler (less precise cuts). For complex foam layouts, injection-molded cases are preferred.
Is roto-molding environmentally friendly?
Mixed. Roto-molding uses more energy (longer cycle times, oven heating) and has more waste (trim, excess material). However, the products are 100% recyclable and last 10-30 years (vs 5-10 for injection-molded). Life-cycle analysis: roto-molded is more sustainable due to longer lifespan.
Need a custom quote?
Contact KeXinMaterials for OEM/ODM case manufacturing. 12h quote, 30-day delivery.