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.
Application Context
Overmolding uses injection-molded thermoplastic to encapsulate a terminated connection, transforming a standard cable assembly into a sealed, strain-relieved, and branded product that outperforms heat-shrink or boot-and-gland approaches in durability, reliability, and aesthetics. A single overmold operation can replace three to five separate components — boots, shrink tubing, adhesive, and the labor to assemble them — while delivering IP67/IP68 environmental sealing and 360° integrated strain relief right at the cable-to-connector interface.
We stock and process six families of injection-grade thermoplastics — TPU, PVC, TPE, Nylon (PA6/PA66), silicone rubber, and Santoprene (TPV) — and our engineers help select the right material for your environmental, mechanical, and regulatory requirements. Every assembly is manufactured under our ISO 9001 quality system to IPC/WHMA-A-620 workmanship, with in-house submersion testing to validate the IP rating before shipment.
Applications
Our overmolded cable assemblies serve mission-critical applications across six major industries where connection reliability and environmental protection are non-negotiable.
Biocompatible, autoclave-resistant overmolded assemblies for patient monitoring, surgical instruments, and diagnostic equipment.
Under-hood, EV battery, ADAS, and charging-port cable assemblies engineered for heat, vibration, and sealed connections.
Flex-life drag-chain, sensor, PLC/I-O, and servo cables built for harsh factory and automation environments.
UV- and salt-spray-resistant navigation, communication, submersible, and deck-equipment harnesses.
Ruggedized MIL-SPEC avionics, field-communication, and sensor harness assemblies.
Branded, strain-relieved USB, audio, gaming-peripheral, and smart-home cable assemblies.
Explore our industry-specific wire harness solutions: Automotive, Medical, Marine, Robotics, Industrial, and all industries.
Engineering Challenges
Not every thermoplastic bonds to every cable jacket — TPU bonds well to PVC and PUR jackets, while silicone cables may need primer treatment. Our free DFM review catches incompatibilities before mold tooling is committed.
A minimum 1.5 mm wall around cables and connectors ensures full encapsulation and reliable sealing; thinner walls risk voids and short-shots, so fill is validated before molds are machined.
A tapered 15–30° transition zone between the overmold body and cable jacket distributes bending stress and extends flex life at the exit point.
Thermoplastics shrink 0.5–2% on cooling and need 1–3° draft angles for clean release, so critical dimensions and mold release are accounted for at the design stage.
Technical Capabilities
Servo-controlled injection presses, in-house CNC tooling, and SPC monitoring across a broad material and wire-gauge envelope.
Manufacturing Process
Quality & Testing
Every overmolded cable assembly undergoes a rigorous inspection protocol — pull-force, flex-life, submersion (IP), thermal-shock, hi-pot, and chemical-resistance testing — with in-house submersion chambers validating IP67/IP68 ratings and 100% optical inspection on all overmolded terminations before shipment.
Why WHP
Overmolding transforms commodity cables into sealed, strain-relieved, and branded products that outperform conventional approaches in durability, reliability, and aesthetics.
Achieve IP67/IP68 protection without separate seals or gaskets. The overmold creates a monolithic barrier against moisture, dust, and contaminants.
Eliminate boot and gland components. The overmold geometry provides engineered strain relief that distributes pull forces evenly around the cable.
TPU and Nylon overmolds resist oils, solvents, fuels, and hydraulic fluids. Abrasion resistance exceeds 100,000 cycles in DIN abrasion testing.
Custom color, texture, and logo branding transform commodity cables into branded products, with consistent finish quality across thousands of units.
Eliminate 3–5 separate components (boots, shrink tubing, adhesive, labor) with a single overmold operation. At 500+ units, overmolding typically lowers total assembly cost by 30–40%.
Overmolded connections last 3–5× longer than heat-shrink terminated assemblies in harsh environments. Reduced field failures mean lower warranty costs.
Overmolded assemblies are built to IPC/WHMA-A-620 Class III workmanship under our ISO 9001 and IATF 16949 quality systems, with UL-recognized, RoHS 3 and REACH-compliant overmold compounds.
FAQ
OEM Program Entry
Share your overmolded cable assembly requirements — connector types, cable specifications, IP-rating needs, environmental conditions, and certifications — and receive a detailed quotation with DFM feedback within 24 hours.
Related Capabilities
Cable assembly and harness services that pair with overmolded programs.
Materials
We stock and process six families of injection-grade thermoplastics — our engineers help you select the right material for your environmental, mechanical, and regulatory requirements.
Properties: Excellent abrasion resistance, oil resistance, flexibility
Best for: Industrial, automotive, robotics cable assemblies
Properties: Cost-effective, flame retardant, chemical resistant
Best for: Consumer electronics, appliances, general purpose
Properties: Soft-touch feel, recyclable, halogen-free available
Best for: Medical devices, consumer electronics, wearables
Properties: High strength, superior chemical resistance, rigid
Best for: Automotive under-hood, heavy machinery, military
Properties: Extreme temperature tolerance, biocompatible, flexible
Best for: Medical, aerospace, high-temperature environments
Properties: UV resistant, weatherproof, excellent sealing
Best for: Outdoor equipment, marine, agricultural machinery
Capabilities
From single-shot strain relief to multi-material insert molding — nine overmolding presses and a dedicated tooling shop.
In-house CNC-machined steel and aluminum molds designed for your exact connector geometry. Custom dies include logo branding and part numbers.
Two-shot and multi-material overmolding for complex assemblies requiring different durometers or colors in a single part. Rigid-to-soft material bonding.
Hermetically sealed overmolded connections that pass submersion testing. Ideal for outdoor, marine, and wash-down environments.
Engineered strain relief built directly into the overmold geometry, eliminating the need for separate boot or gland components.
RAL/Pantone color matching for brand consistency. Custom color compounds with UV stabilizers for long-term color retention in outdoor applications.
Automated vision inspection for flash, short-shots, and dimensional accuracy. 100% visual inspection on all overmolded terminations before shipment.
Servo-controlled injection pressure from 5 to 85 tons ensures consistent fill without wire damage. Real-time pressure monitoring with SPC data logging.
Metal contact pins, PCB boards, and electronic components molded directly into the overmold structure for integrated connector assemblies.
Conductive overmold compounds and shielded cable integration providing EMI/RFI protection with 360° shielding continuity through the connector interface.
Manufacturing
We overmold virtually any connector type. Common families include:
Production Tiers
From prototype validation to high-volume manufacturing — choose the tier that matches your project phase and volume.
Testing
Every overmolded cable assembly is validated against defined mechanical, electrical, and environmental standards.
Measures the force required to separate the overmold from the cable jacket
Cyclic bend testing at the overmold transition zone to validate strain relief performance
Complete submersion under controlled pressure to verify seal integrity
Rapid temperature cycling between extreme high and low temperatures
High-voltage insulation resistance testing of the overmolded interface
Exposure to oils, solvents, and cleaning agents per application requirements
Design Guidance
Engineering guidelines to optimize your overmolded cable assembly for manufacturability, performance, and cost.
Minimum 1.5mm wall thickness around cables and connectors ensures complete encapsulation and reliable sealing. Thinner walls risk voids and short-shots.
Include a tapered transition zone (15–30° taper angle) between the overmold body and cable jacket. This distributes bending stress and extends flex life.
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.
Thermoplastic materials shrink 0.5–2% during cooling. Factor shrinkage into critical dimensions, especially for snap-fit features and panel cutout interfaces.
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).
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. 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
Transparency
Transparency builds trust. Here are our current limitations so you can make an informed decision.
We specialize in thermoplastic injection overmolding. Thermoset (epoxy, polyurethane cast) potting is available but quoted separately as a different process.
Our injection presses accommodate molds up to 400mm × 400mm. Larger overmolded components may require partner facilities.
Overmolding works best with 30 AWG to 8 AWG conductors. Extremely fine or heavy-gauge cables may require special fixturing and mold design.
Custom steel mold tooling is a one-time investment. We recommend minimum 50-piece initial orders to justify production mold costs.