Custom Overmolded Cable Assembly
Injection-molded thermoplastic encapsulation for rugged, sealed, and branded cable assemblies. From IP68 waterproof connectors to EMI-shielded industrial harnesses — engineered for performance in demanding environments.
Why Choose Overmolded Cable Assemblies?
Overmolding transforms standard cable assemblies into sealed, strain-relieved, and branded products that outperform conventional approaches in durability, reliability, and aesthetics.
Complete Environmental Sealing
Achieve IP67/IP68 protection without separate seals or gaskets. The overmold creates a monolithic barrier against moisture, dust, and contaminants at the most vulnerable point — the cable-to-connector interface.
360° Integrated Strain Relief
Eliminate boot and gland components. The overmold geometry provides engineered strain relief that distributes pull forces evenly around the cable circumference, exceeding 35 lbs pull-force requirements.
Chemical & Abrasion Resistance
TPU and Nylon overmolds resist oils, solvents, fuels, and hydraulic fluids. Abrasion resistance exceeds 100,000 cycles in DIN abrasion testing — critical for drag-chain and robotics applications.
Professional Aesthetics & Branding
Custom color, texture, and logo branding transform commodity cables into branded products. Consistent finish quality across thousands of units with injection molding precision.
Lower Total Assembly Cost
Eliminate 3–5 separate components (boots, shrink tubing, adhesive, labor) with a single overmold operation. At 500+ units, overmolding is typically 30–40% cheaper than manual sealing methods.
Extended Product Lifecycle
Overmolded connections last 3–5× longer than heat-shrink terminated assemblies in harsh environments. Reduced field failures mean lower warranty costs and higher customer satisfaction.
Overmold Material Options
We stock and process six families of injection-grade thermoplastics. Our engineers help you select the right material based on your environmental, mechanical, and regulatory requirements.
TPU (Thermoplastic Polyurethane)
Properties: Excellent abrasion resistance, oil resistance, flexibility
Best For: Industrial, automotive, robotics cable assemblies
PVC (Polyvinyl Chloride)
Properties: Cost-effective, flame retardant, chemical resistant
Best For: Consumer electronics, appliances, general purpose
TPE (Thermoplastic Elastomer)
Properties: Soft-touch feel, recyclable, halogen-free available
Best For: Medical devices, consumer electronics, wearables
Nylon (PA6/PA66)
Properties: High strength, superior chemical resistance, rigid
Best For: Automotive under-hood, heavy machinery, military
Silicone Rubber
Properties: Extreme temperature tolerance, biocompatible, flexible
Best For: Medical, aerospace, high-temperature environments
Santoprene (TPV)
Properties: UV resistant, weatherproof, excellent sealing
Best For: Outdoor equipment, marine, agricultural machinery
Overmolding Capabilities & Services
From single-shot strain relief to multi-material insert molding — our nine overmolding presses and dedicated tooling shop deliver the capabilities your project demands.
Custom Mold Design & Tooling
In-house CNC-machined steel and aluminum molds designed for your exact connector geometry. Custom dies include logo branding, part numbers, and ergonomic grip features.
Multi-Shot Overmolding
Two-shot and multi-material overmolding for complex assemblies requiring different durometers or colors in a single part. Rigid-to-soft material bonding.
IP67/IP68 Sealed Overmolds
Hermetically sealed overmolded connections that pass submersion testing. Ideal for outdoor, marine, and wash-down environments requiring complete moisture protection.
360° Strain Relief Integration
Engineered strain relief built directly into the overmold geometry, eliminating the need for separate boot or gland components while providing superior pull-force resistance.
Color Matching & Branding
RAL/Pantone color matching for brand consistency. Custom color compounds with UV stabilizers for long-term color retention in outdoor applications.
Optical Inspection & QC
Automated vision inspection for flash, short-shots, and dimensional accuracy. 100% visual inspection on all overmolded terminations before shipment.
Precision Pressure Control
Servo-controlled injection pressure from 5 to 85 tons ensures consistent fill without wire damage. Real-time pressure monitoring with SPC data logging.
Insert Molding
Metal contact pins, PCB boards, and electronic components molded directly into the overmold structure for integrated connector assemblies.
EMI/RFI Shielded Overmolds
Conductive overmold compounds and shielded cable integration providing EMI/RFI protection with 360° shielding continuity through the connector interface.
Manufacturing Infrastructure
- 9 injection overmolding presses (5-ton to 85-ton clamping force)
- In-house CNC mold shop for rapid tooling
- Multi-cavity molds for batch production efficiency
- Servo-controlled injection with SPC monitoring
- Temperature-controlled material dryers and feeders
- Cleanroom overmolding cells for medical-grade assemblies
Connector Compatibility
We overmold virtually any connector type. Common families include:
Technical Specifications
| Injection Press Range | 5-ton to 85-ton clamping force |
| Maximum Mold Size | 400mm × 400mm |
| Material Temperature Range | 150°C to 280°C (material dependent) |
| Wall Thickness Range | 1.0mm to 15mm |
| Dimensional Tolerance | ±0.1mm standard, ±0.05mm precision |
| Wire Gauge Compatibility | 30 AWG to 8 AWG |
| Cable OD Range | 1.5mm to 25mm outer diameter |
| Multi-Conductor Support | Up to 64 conductors per assembly |
| Overmold Length | 15mm to 150mm per termination |
| Color Options | RAL/Pantone matched, 500+ standard colors |
| Surface Finish | Smooth, matte, textured, or custom patterns |
| Marking Options | Laser, pad print, in-mold embossing |
| Pull-Force Rating | ≥35 lbs per IPC/WHMA-A-620 (typical 50+ lbs) |
| IP Rating Capability | IP65 / IP67 / IP68 (application dependent) |
| Flammability Rating | UL 94 V-0, V-1, V-2, HB (material dependent) |
Overmolding Process: Design to Delivery
Our six-step process ensures consistent quality from initial concept through volume production.
Design Review & DFM Analysis
Our engineering team reviews your cable assembly drawings and 3D models. We analyze connector geometry, cable routing, and environmental requirements to recommend the optimal overmold material, wall thickness, and tooling approach.
Custom Mold Tooling
CNC-machined steel or aluminum molds are designed and manufactured in-house. Mold flow analysis ensures complete cavity fill without voids. Typical tooling lead time: 7–14 days for production molds.
Cable Assembly Preparation
Wire cutting, stripping, crimping, and connector termination performed to IPC/WHMA-A-620 Class II or III standards. Pre-molding electrical continuity test verifies all circuits before overmolding.
Injection Overmolding
Cable assemblies are placed into the mold cavity, and thermoplastic material is injected under controlled temperature and pressure. Multi-cavity molds enable batch production of 2–8 pieces per cycle.
Post-Mold Processing
Flash trimming, gate removal, and surface finishing. Laser marking for part numbers, date codes, and UL file numbers. Optional pad printing for logos and safety labels.
Final Testing & Certification
Post-mold electrical continuity and hi-pot testing. Pull-force testing per UL specifications. IP rating verification through submersion and pressure testing. Full dimensional inspection report.
Industries & Applications
Our overmolded cable assemblies serve mission-critical applications across six major industries where connection reliability and environmental protection are non-negotiable.
Medical Devices
- Patient monitoring cable assemblies
- Surgical instrument cables with autoclave-resistant overmolds
- Diagnostic equipment sensor harnesses
- Biocompatible silicone overmolded patient leads
Automotive & EV
- Engine bay harnesses with under-hood temperature resistance
- EV battery management system cables
- ADAS sensor wiring with sealed connections
- Charging port cable assemblies
Industrial Automation
- Robot arm drag-chain cables with flex-life overmolds
- Sensor cables for harsh factory environments
- PLC and I/O module connection harnesses
- Servo motor power and encoder cables
Marine & Offshore
- Navigation and communication system cables
- Submersible sensor harnesses
- Deck equipment power cables with UV protection
- Salt-spray resistant engine control harnesses
Military & Aerospace
- Avionics interconnect assemblies
- Field-deployable communication cables
- Ruggedized sensor harnesses
- MIL-SPEC overmolded connector assemblies
Consumer Electronics
- USB and charging cables with branded overmolds
- Audio equipment interconnect cables
- Gaming peripheral cables with strain relief
- Smart home device power harnesses
Explore our industry-specific wire harness solutions:
"Overmolding is where cable assembly engineering meets material science. The right combination of mold geometry, material selection, and process parameters turns a commodity cable into a ruggedized, branded product that performs reliably for years in the harshest environments. We've invested heavily in multi-material overmolding capabilities because our customers in automotive and medical demand sealed, strain-relieved connections that simply cannot fail."
Hommer Zhao
Founder & Technical Director, WellPCB
Quality Assurance & Testing
Every overmolded cable assembly undergoes rigorous testing to ensure it meets your performance specifications and industry standards.
ISO 9001:2015
Quality management system certified for consistent manufacturing processes and continuous improvement across all overmolding operations.
IATF 16949
Automotive quality standard ensuring defect prevention, variation reduction, and waste elimination in automotive-grade overmolded assemblies.
IPC/WHMA-A-620
Workmanship standard for cable and wire harness assemblies, with Class III acceptance criteria for high-reliability overmolded connections.
UL Recognized
UL-listed overmold compounds with flammability ratings (UL 94 V-0). Traceable material certifications for every production lot.
IP67/IP68 Testing
In-house submersion testing chamber for validating ingress protection ratings. Salt spray testing per ASTM B117 for marine applications.
RoHS & REACH Compliant
All overmold materials certified RoHS 3 and REACH compliant. Halogen-free and low-smoke formulations available for enclosed environments.
Testing Procedures
| Test | Standard |
|---|---|
| Pull-Force Testing | UL 486A-486B, minimum 35 lbs per IPC/WHMA-A-620 |
| Flex-Life Testing | 10,000+ cycles at 90° bend radius, no electrical discontinuity |
| Submersion Testing (IP Rating) | IP67: 1m/30min, IP68: 3m/continuous per IEC 60529 |
| Thermal Shock Testing | -40°C to +85°C, 100 cycles minimum per MIL-STD-202 |
| Hi-Pot (Dielectric) Testing | 1000V AC or 1500V DC for 60 seconds, no breakdown |
| Chemical Resistance Testing | ASTM D543, material-specific test protocols |
Overmolding Production Tiers
From prototype validation to high-volume manufacturing — choose the production tier that matches your project phase and volume requirements.
Prototype Overmolded Assemblies
- Aluminum prototype molds (lower tooling cost)
- Material sampling with 2–3 durometer options
- First article inspection report included
- Design optimization recommendations
- Suitable for functional testing and validation
Low-Volume Production
- Production-grade steel molds (10,000+ shot life)
- SPC-monitored injection parameters
- Batch traceability with lot coding
- PPAP documentation available
- Ideal for specialized or seasonal demand
High-Volume Production
- Multi-cavity hardened steel molds (100,000+ shots)
- Automated insert loading for cycle time reduction
- Kanban and VMI inventory programs
- Dedicated production cells
- Volume pricing with annual contract discounts
What We Don't Do
Transparency builds trust. Here are our current limitations so you can make an informed decision.
No Thermoset Overmolding
We specialize in thermoplastic injection overmolding. Thermoset (epoxy, polyurethane cast) potting is available but quoted separately as a different process.
Maximum Mold Size: 400mm
Our injection presses accommodate molds up to 400mm × 400mm. Larger overmolded components may require partner facilities.
Wire Gauge Limitations
Overmolding works best with 30 AWG to 8 AWG conductors. Extremely fine or heavy-gauge cables may require special fixturing and mold design.
Minimum Order for Custom Tooling
Custom steel mold tooling is a one-time investment. We recommend minimum 50-piece initial orders to justify production mold costs.
Overmolding Design Tips
Follow these engineering guidelines to optimize your overmolded cable assembly design for manufacturability, performance, and cost.
Specify Adequate Wall Thickness
Minimum 1.5mm wall thickness around cables and connectors ensures complete encapsulation and reliable sealing. Thinner walls risk voids and short-shots.
Design for Strain Relief Geometry
Include a tapered transition zone (15–30° taper angle) between the overmold body and cable jacket. This distributes bending stress and extends flex life.
Consider Material Bonding Compatibility
Not all overmold materials bond to all cable jackets. TPU bonds well to PVC and PUR jackets. Silicone cables may need primer treatment before overmolding.
Allow for Shrinkage
Thermoplastic materials shrink 0.5–2% during cooling. Factor shrinkage into critical dimensions, especially for snap-fit features and panel cutout interfaces.
Include Draft Angles
Add 1–3° draft angles on all perpendicular surfaces to ensure clean mold release. Textured surfaces require additional draft (1° per 0.025mm texture depth).
Plan Connector Orientation
Position connectors with parting line along a non-critical surface. Avoid parting lines across sealing faces or contact areas that affect IP rating or mating.
"The most common mistake I see is specifying overmolding without considering material bonding compatibility. Not every thermoplastic bonds to every cable jacket. When a customer sends us a silicone-jacketed cable and expects a PVC overmold to seal perfectly, we have to explain the chemistry. That's why our DFM review is free — catching these issues before tooling saves thousands of dollars and weeks of delay."
Hommer Zhao
Founder & Technical Director, WellPCB
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Custom Molex cable assemblies with genuine connectors. Mini-Fit Jr., Micro-Fit 3.0, and Pico-Blade series available.
Rapid Prototyping
Fast-turn prototype wire harness and cable assembly manufacturing. 7–10 day turnaround for 1–50 unit validation builds.
Frequently Asked Questions
Common questions about our overmolded cable assembly manufacturing services.
Request Your Overmolding Quote
Share your overmolded cable assembly requirements and receive a detailed quotation with DFM feedback within 24 hours.