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Overmolding Service
We specialize in high-precision, high-reliability overmolding services, precisely coating plastics and other materials onto metal or electronic components to significantly improve product durability, sealing, and tactile experience. Whether it’s precision assembly of automotive parts, insulation protection for consumer electronics, or comfortable design for medical devices, our customized services strictly adhere to international standards, helping your products stand out in the market.
What is Overmolding?
Overmolding is a process in injection molding that involves completely encapsulating a base material (metal/plastic/ceramic) with molten plastic, creating a molecular-level interface fusion structure to achieve functional integration.
Why is Professional Overmolding Service Needed?
73% of encapsulation project failures stem from interface design flaws.We offer
- Pre-validation service: Input product drawings, and we’ll deliver a comprehensive “Encapsulation Feasibility Report” within 48 hours.
- Risk transfer guarantee: If the initial mass production yield is <98%, we’ll optimize the mold free of charge until it meets the standard.
What is Overmolding?
Overmolding is a process in injection molding that involves completely encapsulating a base material (metal/plastic/ceramic) with molten plastic, creating a molecular-level interface fusion structure to achieve functional integration.
Why is Professional Overmolding Service Needed?
73% of encapsulation project failures stem from interface design flaws.We offer
- Pre-validation service: Input product drawings, and we’ll deliver a comprehensive “Encapsulation Feasibility Report” within 48 hours.
- Risk transfer guarantee: If the initial mass production yield is <98%, we’ll optimize the mold free of charge until it meets the standard.
Our Professional Overmolding Services
The value of overmolding lies not in the technology itself, but in how it eliminates mass production risks, accelerates time-to-market, and protects your brand reputation.In over 200 mass production projects over 10 years, we’ve found that 90% of our clients don’t truly need the “overmolding process” itself, but rather the certainty of “zero recalls” and the control over “on-time delivery.”
Full-process Professional Services
01.Requirements Validation
Pre-validation Services
– Material compatibility scanning
– Thermal expansion coefficient ratio analysis
Risk assessment report
Key requirements for industry customization
02.Process Assurance
Pre-validation Services
– Simultaneous mold flow analysis and mold manufacturing
– Three rounds of parameter optimization (temperature/pressure/ cooling rate)
Quickly validate test data
Industry-specific testing
03.Mass production guarantee
Triple Protection System
– Automatic random inspection every 2 hours
– Real-time monitoring by in-mold sensors
– Dedicated quality team
Rapid Risk Response
Industry-customized reports
Technology-based Differentiated Services
Materials Database Advantages → Solving Material Incompatibility Issues
200+ validated material combinations (not theoretical data), covering automotive (VDA 238-11) / medical (ISO 10993) / industrial (UL 746C) certification requirements, matching special needs within 3 days.
Failure Analysis Capabilities → Solving interface delamination issues
Our in-house laboratory is equipped with a thermomechanical analyzer to quickly pinpoint the root cause of delamination:
1. Interfacial molecular bonding analysis (XPS spectroscopy)
2. Thermal stress distribution mapping (infrared thermal imager)
3. Vibration fatigue curves (ISO 16750-3)
Mass Production Assurance → Resolves product yield fluctuation issues
Strict service standards:
1. Orders with unverified material combinations will not be accepted.
2. Mass production batches with a first-article yield of <98% (IATF 16949) will not be delivered.
3. No test data will be concealed.
Service improvement effectiveness (average of 66 projects in 2024)
|
Standards
|
Industry Average
|
Our Service
|
|---|---|---|
|
Mass Production Pass Rate
|
85%
|
99.6%
|
|
Design to Mass Production Cycle
|
45 DAYS
|
28 DAYS
|
|
Total Cost of Ownership (TCO) Per Unit
|
$1.25
|
$0.52
|
|
Product Recall Rate
|
2.7%
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0%
|
How To Choose The Right Molding Service?
68% of mass production failures stem from incorrect process selection, and our pre-validation service can reduce selection risk by 90%. Wontech provides detailed comparisons of injection molding, insert molding, and overmolding processes, and helps you make the precise selection.
The differences between injection molding, insert molding and overmolding
|
Difference
|
Standard Injection Molding
|
Insert Molding
|
Overmolding
|
|---|---|---|---|
|
The essence of the process
|
Melting and molding a single material
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Embedding metal/plastic components
|
Completely encapsulating metal/plastic
|
|
Interface characteristics
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No interface issues
|
Mechanical interlocking (strength 15-20 MPa)
|
Molecular adhesion (strength ≥3.5 MPa)
|
|
Core Applications
|
Casing/Bracket/Container
|
Nuts/Conductive Terminals/Load-bearing Inserts
|
Sealing Rings/Buttons/Shock-damping Handles
|
|
Product yield in mass production
|
98-99.5%
|
99%+ (after optimization)
|
99.2%+ (after optimization)
|
|
Key Failure Modes
|
Sink marks/burst (repairable)
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Insert misalignment/interface delamination (irreversible)
|
Interface delamination (temperature-sensitive/vibration-sensitive)
|
|
Verification Standards
|
ISO 2768-1 (Dimensional Tolerances)
|
ISO 13379-2022 (Insert Positioning)
|
ISO 527-2 (Interfacial Shear Strength)
|
|
Material Requirements
|
No special requirements
|
Insert dimensional stability (ΔL < 0.01 mm)
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Coefficient of thermal expansion ratio < 2.0:1
|
|
Technical complexity
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Low (Standardized process)
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Medium (Requires positioning accuracy control)
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High (Requires molecular-level interface control)
|
3 Steps to determine your optimal process,we provide corresponding verification support
1.Does the product contain an internal substrate (metal/hard plastic)?
No
Is a plastic-only structural component required?
Yes
Standard Injection Molding
Verification:
1.Wall thickness uniformity > 0.8
2.Shrinkage rate consistency
No
Is soft-hard material combination required?
Yes,it’s Overmolding
Yes
Does the substrate require complete encapsulation?
Yes
Overmolding
Verification:
1.CTE ratio <2.0:1
2.Surface energy >30 mN/m
No
Is the substrate only partially embedded?
Yes
Insert Molding
Verification:
1.Positioning tolerance ≤0.01mm
2.Mechanical interlocking structure
* If none of the above requirements are met, the product design needs to be re-evaluated. Please contact our engineers for a professional assessment.
Material Combinations for Overmolding
The core of overmolding lies in the ability of two materials to bond firmly and stably. The choice of materials directly determines the final product. Based on extensive material testing and practical project experience, we clarify the characteristics and matching principles of various materials for you. From the most reliable classic combinations to innovative solutions that meet specific needs.
Core Screening Criteria
- Thermal expansion coefficient ratio Δα ≤ 2.0, controlling thermal stress
- Surface energy of the substrate≥30 mN/m, controlling wettability
- Melt viscosity ≤500 Pa·s, control of filling properties
Failure to meet any of these three technical requirements will result in interfacial failure in 87% of cases.
Core Screening Criteria
- Thermal expansion coefficient ratio Δα ≤ 2.0, controlling thermal stress
- Surface energy of the substrate≥30 mN/m, controlling wettability
- Melt viscosity ≤500 Pa·s, control of filling properties
Failure to meet any of these three technical requirements will result in interfacial failure in 87% of cases.
|
Substrate Material
|
Overmolding Material
|
Industry Standard
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Application
|
|---|---|---|---|
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304 Stainless Steel
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Silicone
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ISO 10993
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Automotive Electronic Buttons
|
|
Metal Insert (Copper)
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BMC
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UL 94 V-0,IEC 60664
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Motor Insulation End Cap
|
|
Aluminum Base
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BMC
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GB/T 11026.1,UL 1446
|
HV Connector Housing
|
|
PC
|
TPU
|
IEC 60529 IP68
|
Wireless Earphone Charging Case
|
|
Medical Titanium Alloy
|
TPE
|
ISO 10993-5
|
Surgical Instrument Handle
|
|
Aluminum Alloy
|
Conductive Rubber
|
SAE J1211
|
Motor Protective Cover
|
|
Carbon Fiber Reinforced Plastic
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TPU
|
ISO 13485
|
Medical Endoscope Handle
|
|
Glass Fiber Reinforced PA
|
TPU
|
ISO 16750-3
|
Automotive Sensor Housing
|
|
Magnesium Alloy
|
Conductive Silicone
|
UL 746B
|
EV Battery Connector
|
|
Ceramic Substrate
|
LCP
|
IPC-A-610
|
5G Antenna Bracket
|
Wide Applications of Overmolding Across Industries
Learn how Wontech’s overmolding technology addresses real-world challenges in consumer electronics, medical devices, automotive parts, and industrial tools.
Automotive Parts
Typical components: Touch buttons, knobs, sensor housings
Production scale: 1-5M units per year
Our solution: For vehicles operating under long-term vibration and extreme temperature variations, we provide full-cycle vibration reliability verification and tactile consistency process control. From optimizing material interface adhesion strength to solidifying mass production parameters, we ensure accurate and stable feedback with every press.
Medical Devices
Typical Components: Surgical instrument handles, endoscope assemblies
Production Scale: 0.5-2M units/year
Our Solution: We provide pre-screening of biocompatible materials, optimization of sterilization adaptability processes, and assurance of aseptic environment production. This ensures that the coating layer maintains structural integrity and functional reliability even after repeated high-temperature and high-pressure sterilization.
Industrial Equipment
Typical components: Motor Protective Covers, Control Panel Seals
Production scale: 0.8-3M units per year
Our solution: For complex industrial environments with oil, dust, and extreme temperatures, we provide accelerated oil and temperature resistance verification and interface anti-aging process solutions. This ensures the coating does not delaminate or become brittle during long-term service, protecting the equipment for stable operation.
Consumer Electronics
Typical components: Smartwatch straps, waterproof interface modules
Production scale: 3-10M units per year
Our solution: We provide IP68-level sealing structure design support and drop impact optimization services. Through elastic cushioning of the coating layer and interface reinforcement technology, our products can easily withstand daily bumps and humid environments, extending product lifespan.
Wide Applications of Overmolding Across Industries
Learn how Wontech’s overmolding technology addresses real-world challenges in consumer electronics, medical devices, automotive parts, and industrial tools.
Automotive Parts
Typical parts:Touch buttons, knobs, sensor housings
Production scale: 1-5M units per year
Our solution: For vehicles operating under long-term vibration and extreme temperature variations, we provide full-cycle vibration reliability verification and tactile consistency process control. From optimizing material interface adhesion strength to solidifying mass production parameters, we ensure accurate and stable feedback with every press.
Medical Devices
Typical parts: Surgical instrument handles, endoscope assemblies
Production Scale: 0.5-2M units/year
Our Solution: We provide pre-screening of biocompatible materials, optimization of sterilization adaptability processes, and assurance of aseptic environment production. This ensures that the coating layer maintains structural integrity and functional reliability even after repeated high-temperature and high-pressure sterilization.
Industrial Equipment
Parts: Motor Protective Covers, Control Panel Seals
Production scale: 0.8-3M units per year
Our solution: For complex industrial environments with oil, dust, and extreme temperatures, we provide accelerated oil and temperature resistance verification and interface anti-aging process solutions. This ensures the coating does not delaminate or become brittle during long-term service, protecting the equipment for stable operation.
Consumer Electronics
Typical parts: Smartwatch straps, waterproof interface modules
Production scale: 3-10M units per year
Our solution: We provide IP68-level sealing structure design support and drop impact optimization services. Through elastic cushioning of the coating layer and interface reinforcement technology, our products can easily withstand daily bumps and humid environments, extending product lifespan.
Partner with Us. Engineer Your Success.
- Get A Quote for Your Overmolding Project
- Learn More About Real-world Cases
- Talk to a Molding Expert
- No.2, South Huatai East Road, Caosan PioneerPark,ZhongShan,Guangdong,China
- +86 13326981626
- ocean.h@wanglai.cn
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