2026-09-21 · KeXinMaterials 编辑团队

滚塑 vs 注塑 防护箱工艺对比:B2B 制造选择 (2026)

滚塑和注塑生产了全球大部分防护箱。两种工艺提供不同的箱体几何形状、表面处理、模具经济和单价。B2B 采购方应根据采购画像匹配工艺。

两种工艺,两种采购画像

Rotomolding and injection molding are not interchangeable. Each suits specific case geometries and order volumes.

Rotational molding (rotomolding) uses a heated mould rotated on two axes. Powder resin coats the inside of the mould as it rotates, then fuses into a hollow shell. Suits large, complex geometries with uniform wall thickness. Lower tooling cost (USD 5,000-15,000) but longer cycle time (30-90 minutes per part).

Injection molding injects molten plastic into a closed mould under high pressure (1,000-2,000 PSI). Cycle time 30-120 seconds. Suits high-precision, small-to-medium geometries with tight tolerances. Higher tooling cost (USD 8,000-30,000) but very fast cycle time.

The economic crossover: rotomolding wins for low-volume large cases; injection molding wins for high-volume small-to-medium cases.

模具成本与交期

Tooling cost is the dominant upfront decision. Rotomolding tools are cheaper but slower; injection tools are expensive but faster.

For B2B buyers below 500 pieces per SKU, rotomolding is cost-competitive with injection molding at low volumes because tooling cost is lower. Above 2,000 pieces, injection molding wins on cycle time and unit cost.

For complex large cases (>1.5m length), rotomolding is the only practical process. Injection molding cannot produce such large parts in a single shot due to platen size limits.

按工艺选材料

Rotomolding is dominated by polyethylene (PE). Injection molding works with a wider material portfolio.

Rotomolding: 95%+ of cases are polyethylene (PE). PE offers excellent impact resistance, low temperature brittleness resistance, and chemical resistance. PE rotomolded cases are the classic "Peli-style" protective case shell. Material cost USD 1.50-3.00/kg. Wall thickness 3-8mm typical.

Injection molding: works with PP, ABS, PC (polycarbonate), PA (nylon), POM (acetal), and glass-filled variants. PP is the workhorse for protective cases (similar to PE but stiffer). ABS for high-gloss surface finish. PC for high-impact clarity. PA for high-temperature applications.

For most B2B protective case applications (drone, military, medical, instrument), either PE rotomolding or PP/ABS injection molding works. The choice is usually driven by tooling cost and order volume, not material performance.

At KeXinMaterials we run 60+ injection moulding machines. PE rotomolding available via partner factories for large cases. PP + glass-filled PP + ABS standard for injection. PC + PA for premium SKUs.

箱体强度与防护等级

Both processes can achieve IP67 / MIL-STD-810G. The process choice does not determine the certification.

IP67 rating depends on shell sealing design (O-ring groove + latch compression), not moulding process. Both rotomolded PE and injection-molded PP / ABS can be designed to IP67 spec.

MIL-STD-810G drop test depends on case geometry, wall thickness, and corner radius. Rotomolded cases typically have thicker walls (5-8mm) and uniform corner geometry. Injection-molded cases can have thinner walls (3-4mm) with strategic ribs for stiffness.

In practice, both processes can pass MIL-STD-810G with proper design. The 2010-2020 industry trend has been migration from rotomolding to injection molding for cases < 1.5m, due to lower per-part cost at high volumes and better surface finish for retail branding.

表面处理与品牌美学

Surface finish is the most visible difference. Rotomolding gives a matte "orange peel" texture; injection molding gives a smooth glossy or textured finish.

Rotomolding surface: matte, slightly rough, "orange peel" texture. Functional but not premium-looking. Difficult to add gloss or fine detail. Hot stamp logos work but silk-screen printing requires special surface prep.

Injection molding surface: smooth, glossy, can be moulded with texture (leather grain, brushed metal, etc.). Silk-screen printing and hot stamping both work well. UV-cured logos can be in-mould decorated. Higher perceived quality for consumer-facing brands.

For B2B programmes targeting industrial / defence / field service users, rotomolding's matte finish is acceptable and may even be preferred (less glare in field use). For consumer-facing brands (retail, photography, lifestyle), injection-moulding finish delivers premium aesthetics.

单价对比

Unit cost varies with size, material, order volume, and process. Here is a real comparison for representative case sizes.

Small case (300mm × 200mm × 150mm, IP67, 500-piece MOQ): rotomolding USD 65-95, injection molding USD 55-85. Injection wins slightly due to lower cycle time even at low volume.

Medium case (500mm × 350mm × 200mm, IP67, 1,000-piece MOQ): rotomolding USD 95-140, injection molding USD 85-130. Injection wins on cycle time.

Large case (1,200mm × 600mm × 400mm, IP67, 200-piece MOQ): rotomolding USD 250-380, injection molding N/A (too large for platen). Rotomolding wins by default.

Very large case (2,000mm × 1,000mm × 800mm, 100-piece MOQ): rotomolding USD 800-1,400, injection molding N/A. Rotomolding only option.

For 90% of protective cases (drone, military, medical, instrument, camera, tool, trolley), injection molding is the process of choice at volume. Rotomolding dominates large industrial and military cases.

B2B 采购决策

Match the process to your case size, order volume, and brand requirement.

• Small case (under 500mm length), 1,000+ piece MOQ: Injection molding wins. Faster cycle, lower unit cost, premium surface finish.
• Medium case (500-1,200mm length), 500+ piece MOQ: Injection molding if platen size supports it. Otherwise rotomolding.
• Large case (1,200-2,000mm length), any volume: Rotomolding only option. Tooling cost USD 5,000-15,000.
• Very large case (over 2,000mm length), any volume: Rotomolding only. Custom industrial case for military / aerospace / marine.
• Defence / industrial priority (matte finish OK): Rotomolding or injection molding both acceptable.
• Consumer / retail priority (premium finish needed): Injection molding preferred for surface finish and moulded texture options.

为什么选择 KeXinMaterials

KeXinMaterials operates 60+ injection moulding machines for cases < 1.2m. We partner with rotomolding factories for larger cases.

For 90% of protective case sizes (under 1.2m), injection molding is our primary process. 60+ machines, 20+ patents, ISO 9001:2015 certified. 100-piece MOQ for custom OEM / ODM, 30-45 day lead time.

For large industrial cases (1.2m+), we partner with rotomolding factories in our supply chain. We handle mould design, project management, quality control, and export shipping. Single-point accountability for B2B buyers.

Material options: PP (workhorse), PE (rotomolding only), ABS (high-gloss), PC (clarity), PA (high-temp), glass-filled PP (stiffness), flame-retardant variants (UL94 V-0 for some applications).

Trade terms: EXW Shenzhen / FOB Shenzhen / FOB Ningbo. No DDP, no EU warehouse, no US warehouse. Every shipment direct from our 13,000 m² Guangdong facility or partner rotomolding facilities.

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