包覆成型服务
Bond soft rubber directly onto hard plastic parts. We deliver comfortable grips and waterproof seals that never peel off, crack, or leak.
- 50+ Validated Rigid-Soft Pairings
- Zero Delamination & Flash-Free Edges
- Shore A 30 to D 80 Custom Grips
Compatible Overmolding Applications
In product design, you often need to improve grip, add waterproofing, or enhance appearance by wrapping a soft material (like TPE, TPU, or silicone) around a rigid plastic base. This is exactly what overmolding achieves. You see this everyday in tool handles, toothbrush grips, and rugged phone cases.
Unlike manual assembly or gluing, overmolding is a multi-step injection process that permanently bonds the second material directly onto the hard plastic substrate. For your projects, this means instantly adding ergonomic or protective features with no assembly gaps and zero peeling.
Ergonomic Grips & Tactile Surfaces
Adds soft, non-slip TPE or TPU to hard plastic parts. Commonly used for power tool handles, wearables, and control knobs.
Integrated Seals & Gaskets
Bonds rubber directly to housings to replace separate O-rings. Creates reliable IP67/IP68 waterproof and dustproof seals.
Impact Protection & Insulation
Uses thick rubber layers to absorb shock or provide electrical insulation. Ideal for rugged device corners and cable strain reliefs.(
Two-Tone Aesthetics & Structure
Combines different colors or materials in one part to reduce assembly. Used for brand logos, cosmetic finishes, and soft hinges.
Case Study: Resolving Shrinkage in Thick-Walled Parts
Thick plastic components, such as cosmetic caps, often develop sink marks due to uneven cooling. In this video, our Engineering Director explains how splitting a thick section into a two-step overmolding process eliminates surface distortion while maintaining the required structural thickness.
Overmolding Equipment & Specifications At First Mold
Two-step overmolding runs on standard injection molding machines, meaning the true quality of the part is determined by the mold tooling. To machine exact shut-off surfaces and prevent liquid rubber from flashing, we build our molds using industry-leading equipment, including Haas 5-axis CNCs, GF+ high-precision CNCs, and Makino EDMs. The specifications below outline our production capabilities and key design parameters.
| 规格 | 能力 | 规格 | 能力 |
|---|---|---|---|
| Elastomer Hardness | Shore A 30 – Shore D 80 | Optimal Overmold Thickness | 1.5 – 2.5 mm (for ideal tactile feel); feasible down to 1.0 mm |
| Min. Substrate Thickness | ≥ 1.5 mm (general guide to withstand injection pressure) | Recommended Draft Angle | 1.0° – 2.0° standard; add 0.5° – 1.0° for textured surfaces |
| 粘接方法 | Chemical Adhesion & Mechanical Interlocking | Adhesion Testing Standard | ASTM D903 (Peel) / ASTM D3359 (Cross-Hatch) |
| Parts Standard Tolerance | ±0.1毫米（±0.004英寸） | Shut-off Precision (No Flash) | ±0.05毫米（±0.002英寸） |
| Custom Color Matching | Pantone, RAL, Masterbatch Compounding | 材料合规性 | RoHS, REACH, FDA Class VI, Biocompatible |
包覆成型技术的材料组合
Handling 2+ new overmolding production commissions every month, First Mold’s engineering team has mastered the practical application of diverse resins and elastomers. We know exactly how to achieve a permanent, glue-free bond and prevent delamination.
| Soft Overmold | Excellent Bond | Good Bond | Poor Bond | 应用示例 |
|---|---|---|---|---|
| TPE | 聚丙烯 | ABS, PC, PS | POM, Nylon | Automotive anti-rattle overmolds; strain-relief boots; diagnostic equipment grips |
| 热塑性聚氨酯 | ABS, PC, PC/ABS | 尼龙 (PA) | PP, PE | Valve spool encapsulation; robotic cable joints; rugged sensor housings |
| 冠捷 | 聚丙烯 | Nylon (special grade) | ABS, PC | Under-hood duct seals; EV charging weatherseals; outdoor equipment gaskets |
| TPR | PS, HIPS | 聚丙烯 | PC, Nylon | Precision instrument isolation pads; soft/soft suction cups; anti-vibration mounts |
| 生物基 TPE | PLA, PBAT | 聚丙烯 | – | Diagnostic device housings; personal-care grips; compostable closures |
Why Partner with First Mold for Overmolding?
Ask yourself about your current supplier: Are their molds built in-house or outsourced? What is their aging degradation data for peel strength? When production defects arise, do they solve the root cause, or just point fingers?
Overmolding is an unforgiving process. Here is how First Mold ensures absolute accountability, verifiable quality, and the lowest total cost of ownership.
Unified Tooling & Molding Team
Whether an overmolded bond holds and whether the shut-off stays clean are about 80% decided during mold design. Because our tooling makers and molding engineers work together under one roof, no one points fingers. You never have to act as the go-between for different vendors—if a problem comes up, we find the root cause and fix it ourselves.
Data-Backed Precision & Bonding
We measure adhesion and precision—and prove the numbers. Our parts consistently achieve 180° peel strengths of 1.5–3.0 N/mm (and 4.5 N/mm or higher with plasma activation). We hold flash at critical shut-offs to ≤0.05 mm, with parting line clearances under 0.01 mm, so we can guarantee zero delamination in 72-hour salt spray tests.
Deep DFM Intervention
这是示例文本，单击 “编辑” 按钮更改此文本。
Predictive Warpage Compensation
包覆成型与嵌入成型嵌入成型与双色成型双色模塑
包覆成型是将一种材料注入到现有的基底（如硬塑料或金属）上。这一过程分步骤完成，以形成保护层或功能层。在嵌件成型中，金属或电子元件等嵌件首先被放入注塑模具中。然后注入塑料以固定和整合嵌件。在两次注塑中，使用旋转模具在同一周期内注入两种不同的材料。
| 尺寸 | 包覆成型 | 插入成型 | 双色模塑 |
|---|---|---|---|
| 流程步骤 | 两步注塑硬模芯 → 软包覆 | 预插入 → 一次封装 | 双射注塑（旋转/滑动模具） |
| 材料组合 | 软硬结合（如 PP+TPE） | 塑料+金属/插件（如 PA66+铜） | 双色塑料（如 ABS+PC） |
| 设备要求 | 标准机器 + 兼容模具 | 标准机器 + 机器人/手动刀片放置 | 专用双色机 + 旋转模具（±0.02 毫米） |
| 材料互动 | 化学键（热力学兼容性） | 机械锁定（无化学键连接） | 物理分层（熔点同步） |
| 结构差异 | 分层封装（功能集成） | 插入式芯材（复合材料加固） | 无缝分层（美学融合） |
| 模具成本 | $$ | $ | $$$ |
| 生产周期 | 30-60 秒（两层之间需要冷却） | 45-90 秒（手动插入） | 20-40 秒（自动双拍） |
| 典型产品 | 工具手柄、医疗器械 | 汽车连接器、医用电极 | 双色尾灯、半透明键盘按键 |
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