When designing new electronic products, functionality and innovation are often prioritised. However, the exposed components that make up these devices remain highly vulnerable until properly enclosed. Without protection, electronics can quickly deteriorate when exposed to temperature extremes, dust, water or mechanical stress.

There are several methods available to protect electronic components, including potting and traditional injection moulding. While these approaches have their merits, they can also be complex, time-consuming or costly.

As electronics continue to shrink in size, overmoulding becomes even more valuable, allowing manufacturers to maintain high durability and performance without bulky housings or potting enclosures.

Originally used in the automotive industry to waterproof connectors and provide strain relief for wires, overmoulding services are now employed across a wide range of sectors — from consumer electronics and industrial automation to medical, military and marine applications.

This innovative encapsulation method has become an essential process for protecting sensitive electronics. Through overmoulding, a cable or PCB assembly can be encased within a robust, watertight compound that shields it from mechanical stress, moisture, vibration and other environmental hazards.

The result is an unbreakable, shock-resistant product with greater reliability and an extended lifespan.

Why is it important to overmould your components?

Protecting sensitive electronic components is critical to ensuring performance, safety and product longevity. Properly protected assemblies and electronics experience fewer failures, improving uptime and lowering repair costs.

Overmoulding offers a reliable way to encapsulate and protect PCB or cable assemblies against:

• Health and safety hazards. Encapsulating cables reduces the risks of trips, slips and electrical hazards. Overmoulded products are also protected from water damage and harmful chemicals that could lead to fires or short circuits.
• Extreme environments. Exposure to heat, sunlight, snow or rain can degrade unprotected cables and enclosures. Outdoor or exposed installations are often also vulnerable to damage from wildlife and rodents. Overmoulding helps to prevent such damage by ensuring components remain sealed and reliable, even in extreme environments.

In cable and harness assembly projects, overmoulding provides 360-degree strain relief and increased pull strength. The seamless encapsulation prevents ingress of moisture and contaminants while reducing mechanical fatigue at the connector interface.

For PCB assembly, overmoulding ensures boards and components remain protected from environmental stress without damaging delicate solder joints.

Overmoulding applications across industries

Overmoulding services are used across countless industries to improve durability, safety and product performance. Common applications include:

• Automotive — sealed connectors, sensors and strain relief solutions for wiring harnesses.
• Medical and healthcare — durable, hygienic protection for diagnostic and wearable devices.
• Military and security — tamper-proof, rugged encapsulation for mission-critical systems.
• Industrial and marine — resistance to vibration, saltwater and corrosive environments.
• IoT and consumer electronics — compact, sealed and aesthetically refined product designs.

A key advantage of overmoulding is the ability to achieve high levels of environmental protection defined by ingress protection (IP) ratings. The process can produce seals equivalent to IP67 and beyond — meaning the encapsulated components are completely protected from dust ingress and can withstand temporary immersion in water. By forming a continuous, watertight barrier around cable and PCB assemblies, overmoulding eliminates the need for separate enclosures or gaskets, delivering compact, fully sealed products that meet stringent performance requirements.

For applications in industrial automation, marine or outdoor environments, these IP-rated seals are essential to ensure long-term reliability and safety.

What’s the difference between high and low-pressure overmoulding?

Overmoulding offers many of the benefits of both potting and injection moulding without their disadvantages.

Both high-pressure and low-pressure overmoulding (LPO) achieve the same goal — encapsulating and protecting electronic components — but they do so in different ways.

In LPO, a PCB assembly or cable and harness assembly is placed into a specially manufactured aluminium mould. The mould is then filled with a molten thermoplastic compound, typically a polyamide-based hot melt, injected at a relatively low pressure of 50–200 psi. This low pressure prevents damage to delicate electronic components, while the material’s low viscosity allows it to flow easily and form a watertight, durable seal (often IP67-rated).

By contrast, high-pressure injection moulding operates at much higher pressures (up to several thousand psi) and temperatures of around 250°C. It allows for greater material versatility — including PU, TPU and PVC — and achieves more precise definition, surface finish and colour options. However, the higher forces involved make it less suitable for fragile PCB or cable assemblies.

Comparing performance and cost for high vs low-pressure overmoulding

Feature	High-pressure overmoulding	Low-pressure overmoulding
Injection pressure	1000–4000 psi	50–200 psi
Material types	PU, TPU, PVC	Polyamide hot melts
Temperature range	~250°C	~210°C
Tooling cost	£2,500+	£1,000–£2,000
Cycle time	Moderate	Fast (15–90 seconds)
Component sensitivity	Suitable for robust parts	Ideal for fragile electronics
Aesthetic finish	High precision, more colours	Functional, simple designs

While high-pressure overmoulding offers enhanced finish and material options, low-pressure overmoulding delivers superior protection for sensitive electronics and remains a more versatile, cost-efficient solution for many applications.

What are the benefits of low-pressure overmoulding?

The LPO process offers numerous technical and commercial advantages that make it the preferred encapsulation method for many electronics manufacturing projects.

1. Cost-effective production

LPO is highly efficient because it eliminates the need for secondary housings or additional parts. The tooling required is also simpler and less expensive than that used in high-pressure systems.

Once tooling is complete, the fast cycle times and reduced labour requirements make low-pressure overmoulding one of the most economical methods for encapsulating electronics like PCB and cable assemblies.

2. Speed and simplicity

Unlike potting, which requires long curing times, the LPO process allows products to be handled or shipped within minutes of moulding. Typical cycle times range between 15 and 90 seconds, depending on the complexity of the component.

This rapid turnaround allows electronics manufacturers to shorten production timelines and bring products to market faster — without compromising on quality or protection.

3. Low pressure for delicate components

With injection pressures as low as 5–8 bar, LPO is ideal for encapsulating assemblies that include very small surface-mount components (even as small as 0402). The gentle process ensures that sensitive electronics remain undamaged, making it a popular choice for PCB assembly and sensor encapsulation.

4. Environmental and mechanical protection

Once encapsulated, electronic parts become completely sealed against environmental threats. The polyamide adhesive forms a watertight barrier that protects components from humidity, dust, sand, heat and cold.

This protection ensures that custom cable assembly and PCB products can operate reliably in harsh environments — such as marine systems, outdoor infrastructure or industrial machinery.

The process also provides superior strain relief, offering 360-degree reinforcement and increased pull strength. This helps to prevent cable fatigue and ensures long-term reliability.

5. IP and tamper protection

LPO not only safeguards against environmental hazards but also helps to protect your intellectual property. The encapsulated design forms an almost unbreakable shell, concealing internal circuitry and preventing reverse engineering by competitors.

6. Enhanced aesthetics and branding

The process allows for customisation through 3D CAD mould design. Logos, part numbers and other identifying features can be directly moulded into the product. Electronics manufacturers can also select from different surface textures — from soft-touch to rugged finishes — to meet both functional and aesthetic requirements.

This makes low-pressure overmoulding ideal for companies seeking both protection and a polished, professional appearance for their products.

EC Electronics’ overmoulding services

EC Electronics offers both high- and low-pressure overmoulding services, delivering tailored encapsulation solutions for cable assemblies and PCB assemblies.

Our LPO process protects sensitive electronics from vibration, impact and moisture, while our advanced moulding technologies allow for fast turnaround and cost-effective production.

State-of-the-art equipment

Our advanced vertical moulding machine, the Schelhase ST1600 Dual Slide, produces high-quality, durable components for clients across automotive, medical, military, marine, industrial and IoT sectors.

The Schelhase machine provides:

• 1 or 2 melting units
• Single or dual injection options
• Clamping force of 1600 kg
• Injection pressure control from 10–40 bar
• Melting rate of 5 kg per hour
• Adjustable height for ergonomic operation
• PLC control panel and shuttle table

This advanced system allows us to deliver precise, repeatable results even for complex or large-scale projects. Its flexibility also enables us to perform intricate designs, dual injections and produce larger parts than many other systems on the market.

Reliable materials for superior results

We use Henkel Corporation’s renowned Technomelt (formerly ‘Macromelt’) thermoplastic hot-melt adhesives. Based on natural fatty acids, these polyamide-based materials are chosen for their outstanding performance, strong adhesion and environmental resistance.

Key material characteristics include:

• Excellent adhesion to plastics, such as PA6.6, ABS and PVC
• Good low-temperature flexibility
• Wide service temperature range
• Available in amber, black or bespoke colours

While most Technomelt grades offer good moisture and temperature resistance, EC Electronics’ experts carefully select the best formulation to suit each application’s mechanical and chemical requirements.

Tooling expertise and logistics

A high-quality overmoulded part depends heavily on the precision of its tooling. We invest in the design and production of robust aluminium moulds that ensure durability, cost efficiency and high repeatability.

Our engineers use advanced CAD/CAM systems and import 3D model data via the STEP (ISO 10303) standard to drive our four- and five-axis CNC mills. This enables extremely tight tolerances, even down to the micron level. We can also create bespoke tools for prototyping, development or full-scale production — and even work without drawings when required by reverse-engineering existing components.

We recognise that time to market is critical. EC Electronics manages tooling logistics from start to finish, ensuring your projects are delivered on schedule without compromising on quality. From concept to completion, we provide a total solution that integrates design, tooling, moulding and testing under one roof.

The EC Electronics advantage

With over 40 years of experience in electronics manufacturing services, EC Electronics has supported original equipment manufacturers across Europe with reliable, high-performance encapsulation, PCB and cable assembly manufacturer capabilities.

Our facilities in the UK, Netherlands and Romania are equipped to handle complex projects of any scale. Whether you need a simple connector encapsulation or a complex custom cable assembly, EC Electronics delivers results that combine protection, performance and precision.

From material selection to tool creation, we’re here to guide you through every stage of development — ensuring the finished product exceeds expectations.

To learn more about EC Electronics’ overmoulding services, or to discuss your next PCB or cable assembly project, get in touch with our team today. We’ll be happy to guide you through the process and help determine whether high or low-pressure overmoulding is the right solution for your application.