High-Performance Materials for Wiring Harnesses

Introduction to High-Performance Materials in Wiring Harnesses

What Are High-Performance Materials?

High-performance materials are conductors and insulators capable of withstanding extreme conditions, such as hot temperatures, chemical and acid exposure, vibration, and abrasion, without failure. Therefore, they are commonly used in applications requiring high durability and reliability, such as aerospace.

In comparison, standard materials cannot withstand these conditions, so you’ll most likely find them in household appliances like fridges and washing machines, where the conditions are not extreme.

These high-performance materials cover the entire construction of the harness, so we’re talking about the insulation, shielding, conductors, terminals, connectors, and sheaths. With cable insulation, for instance, typical high-performance materials include Teflon and polyurethane.

Importance of Material Selection

Each material has different properties that determine its performance. Therefore, material selection is critical, and picking the most suitable high-performance material for the job will ensure you get benefits like better resistance to environmental factors, heat, and chemicals, as well as enhanced electrical properties.

In airplanes, for instance, polymers like PTFE are usually used as insulators in wire harnesses, connectors, and housings to increase corrosion and chemical tolerance.

Types of High-Performance Materials Used in Wiring Harnesses

Insulation Materials

Typical high-performance insulation materials in wire harnesses include:

• PTFE/Teflon: Teflon is a branded name for PTFE, so the two are the same. PTFE is known for its low friction and high-temperature resistance properties, as well as resistance to water, oil, and chemicals.
• Nylon: Nylon is almost at par with PTFE in terms of performance but has one flaw; it is hygroscopic. However, the material is cheaper.
• Polyurethane: This material is not as resistant to extreme temperatures as PTFE (both hot and cold) and doesn’t match its chemical resistance. So PTFE is best suited for demanding applications, such as aerospace, while polyurethane is better for jacketing due to its flexibility and UV resistance.

Conductors and Cables

The common conductor materials are copper and aluminum. Copper is more widely used because it is highly conductive, flexible, and durable. However, this metal’s properties can vary depending on its purity. For instance, high-purity copper (such as oxygen-free) provides the best conductivity, but the material is soft and not as durable. Specialty alloys, on the other hand, have better material strength but sacrifice conductivity performance.

Moving away from copper, aluminum is lighter and cheaper, making it a better option for weight-sensitive wire harness applications, such as aerospace. However, it is less conductive and flexible, meaning it can break easily.

Shielding Materials

Shielding materials protect the conductors from electromagnetic interference emanating from internal or external sources. The two common shielding techniques are braided and foil.

• Foil: This technique provides 100% shielding, making it ideal for high-frequency applications. It is also thinner and cheaper to produce but doesn’t provide better overall EMI defense due to its less dense characteristic.
• Braided: Braided shielding provides 70–95% shielding coverage, making it suitable for low to medium-frequency applications. Although the shielding is difficult to produce, it is flexible, has superb mechanical strength, and is denser than foil, making it better at providing overall protection against EMI. Metal braids are also easier to terminate than foils.

Connectors and Terminals

Some of the terminals and connectors used in high-performance wire harnesses include:

• Blade Connectors: Feature flat metal blades/tabs that fit into female connectors of the same type.
• Pin Connectors: Have cylindrical metal pins that fit into sockets/female connectors.
• Circular Connectors: With a round housing and multiple pins/sockets arranged in a circular pattern, this connector is ideal for aerospace, military, and industrial equipment applications.
• Rectangular Connectors: These are the rectangular versions of circular connectors. Molex connectors fall in this category.
• Terminal Blocks: Terminal blocks allow several wires to be connected at once. They have a modular design and feature an insulating body with metal terminals/screws to secure the conductors.

These connectors usually have gold-plated connectors to enhance their corrosion and wear resistance during plugging and unplugging.

Protective Sheathing

A protective sheath provides an extra insulation layer that safeguards the wires inside from hazards and damage resulting from heat, corrosion, abrasion, and impact. Therefore, this layer must be made of abrasion-resistant and flame-retardant materials, such as silicones, polyurethanes, chloroprene rubber, polypropylene, and PVC.

Benefits of High-Performance Materials in Wiring Harnesses

Enhanced Durability and Longevity

High-performance wiring harness materials provide the required resilience to withstand harsh and extreme conditions, which means the wire harness will last longer. For instance, protective outer jackets form the first line of defense, keeping the conductors safe from chemicals, flames, corrosion, etc. Even if this layer wears out, the wire insulation is present to provide the same type of protection.

Improved Reliability and Safety

Safety is non-negotiable in electrical systems and reliability is a key requirement in high-performance wiring harnesses. Because it is difficult to spot issues in wiring harnesses until it’s too late, high-performance materials are necessary to mitigate these issues or risks.

Superior Electrical Performance

High-performance wiring harness materials also include conductors, which enhance the electrical performance of the harness by reducing electrical resistance. The conductor’s design is also carefully considered because braided wires have a higher electrical resistance than their solid core counterparts, which reduces issues like voltage drops across long transmission lines. There’s also the inclusion of shielding, which minimizes signal interference.

Adaptability to Extreme Conditions

The insulators and jackets/sheaths used to protect conductors inside the wires enable the harnesses to perform optimally under normal conditions, as well as when exposed to moisture, extreme temperatures, or vibrations.

Factors to Consider When Selecting High-Performance Materials for Wiring Harnesses

Application Requirements

The entire harness can’t be made using the same materials because it handles different functions in the application area. In aerospace, for instance, planes need flexible wires running to the landing gear, which means the cable should have braided copper or aluminum wires. At the same time, this harness should have a flexible sheath that can withstand the freezing temperatures in the wheel wells. But such characteristics are not necessary for the harnesses in the cabin that power lights, charging ports, and other components.

Compliance and Standards

While selecting these materials, it is important to adhere to relevant industry standards and regulations to ensure the harnesses are durable, safe, reliable, and high quality. For instance, IPC/WHMA-A-620 describes the materials acceptability criteria for cable and harness assemblies, setting expectations between WHMA members and customers on what is considered acceptable quality workmanship.

Cost vs. Performance

Although using the best materials will result in superior performance, this will come at a cost. So it is necessary to do a requirements analysis to determine the most suitable materials to use for each section of the harness for cost optimization.

Supplier Reliability and Material Quality

A material’s quality is only as good as the supplier who provides it. For instance, if a supplier hasn’t waterproofed the nylon storage unit, then the integrity of the material will be compromised. Therefore, supplier reliability is a key factor to consider when selecting these materials. If you don’t have a reliable nylon insulation material supplier, it is better to use the more expensive PTFE than substandard nylon.

WellPCB’s Expertise in Utilizing High-Performance Materials

Proprietary Material Selection Process

At WellPCB, we have material scientists and experts in-house who advise the team on the most suitable materials to use for the harness at the lowest cost. We consider the application requirements and compliance with standards, then list the usable materials for the project. After that, we narrow it down using the cost vs. performance factor to get the best materials at a sweet price point, which ensures optimal performance, reliability, and low input costs.

Also, we consider the requirements for each section of the harness and use different materials as needed. As for suppliers and material quality, we have a strong supply chain and have built long-term strategic partnerships with component suppliers to ensure we get the specific materials we need for each project.

Advanced Testing and Validation

WellPCB employs these tests to evaluate the harnesses built and assembled in our plant.

• Short circuit testing using a multimeter
• High-voltage/dielectric strength testing using a hi-pot testing machine
• Continuity testing using a multimeter
• Resistance measurement using a milliohm meter
• Pull testing using a motorized pull tester
• Flex/bend testing using a flex/bend testing machine
• IP66/IP67 water ingress testing
• Fungal resilience testing

This rigorous testing ensures the harnesses are capable of withstanding the harsh environments in their application area without failing.

Custom Material Solutions

In addition to using the standard materials and components sourced from our suppliers, we can customize materials to make tailor-made harnesses that meet the performance and cost requirements of our clients. Our overall goal is to make harnesses that meet high-performance requirements, so we blend materials to enhance their oil, chemical, heat, water, and abrasion resistance. 

Commitment to Sustainability

WellPCB is committed to building and assembling high-performance wire harnesses using environmentally friendly materials, including lead-free solder, to ensure the products leaving our plants have a minimal impact on the environment. Using these materials is also beneficial to our clients because it ensures the harnesses meet the relevant international standards, such as RoHS, to access global markets.

Real-World-Applications of High-Performance Materials in Wiring Harnesses

Automotive Industry

With ICE cars, high-performance materials improve their wiring harnesses by ensuring the cables can withstand the intense vibrations associated with car movement and heat around the drivetrain.

But the performance demands are higher in EVs because the harnesses associated with the battery must withstand high voltage and current levels. In such cases, copper is the material of choice for the conductor, while the insulation should be materials like XLPE, silicone rubber, and thermoplastic elastomers.

Aerospace Sector

Lightweight performance is the most important factor to consider when assembling aerospace wiring harnesses, so materials like aluminum are critical for making both the conductors and shields. Shielding is particularly important in this application because aircraft harnesses are exposed to numerous EMI noise sources, including lightning, and require maximum reliability to ensure the systems exchange data accurately.

Medical Equipment

Wiring harnesses in medical applications are primarily exposed to sterilization using methods like steam, liquid chemicals, and dry heat. Therefore, they must withstand exposure to these elements to ensure maximum reliability and comply with the required medical standards to avoid negative incidents like contamination.

Industrial Equipment

Like in automotive and aerospace applications, wiring harnesses in industrial equipment need high-performance materials to withstand intense vibrations, heat, chemicals, and mechanical stresses.

Best Practices for Selecting and Utilizing High-Performance Materials

Conduct Thorough Material Research

It is important to understand the specific properties of each material to identify its suitability for specific projects or applications, and this is only possible by doing thorough material research. You can find this data in authoritative sources, such as academic journals and research papers, then purchase some of the narrowed-down materials to do some tests if possible to verify the gathered data.

Collaborate with Experts

Even though doing thorough material research will reveal critical data, it is important to engage material scientists because you might miss out on some crucial information. Also, bring in engineering experts in wire harness design to help optimize the harness from these two angles.

Implement Rigorous Quality Control

Quality control covers two aspects, the first being adhering to standards during material selection. These standards contain the criteria that define the quality, properties, composition, and performance of the wire harness materials.

The second aspect is testing. It is vital to implement stringent internal testing or quality control measures to ensure the harness meets the required performance standards.

Stay Updated with Material Innovations

Like technology, materials are evolving and new ones keep emerging quickly in the market, so it is critical to stay updated on the latest trends and developments. Remember, some of the key factors to consider when building high-performance wire harnesses are weight, cost, performance, and environmental resistance, all of which materials have a critical role to play. Emerging materials can help make the harness more lightweight, efficient, resistant to external factors, or cost less, which are beneficial to specific applications.

Conclusion

To conclude, selecting high-performance materials for wiring harnesses used in specific applications like aerospace is critical to ensuring that connecting cables are reliable, safe, efficient, and durable. There are several factors to consider when picking the best material, and WellPCB has the expertise to determine the most suitable conductors, insulators, protective sheath, shielding, and connector materials to use in your project.

We adhere to RoHS, UL, IPC, ISO, and REACH standards when selecting these materials and follow the steps laid out earlier to find the sweet spot between performance and cost. All we need are your project needs, so contact us to get started on the requirements analysis or for personalized support on using high-performance materials for wiring harnesses.

FAQs

What are high-performance materials used in wiring harnesses?

High-performance materials include insulators, conductors, protective sheaths, terminals, and shielding materials that are capable of withstanding extreme conditions without failure. They feature properties like flame, chemical, abrasion, and water resistance.

How do high-performance materials improve wiring harness performance?

High-performance materials enhance the performance of wiring harnesses by increasing the cable’s resilience against harsh external factors like chemicals, oil, abrasion, EMI (noise), and water to protect the conductors inside. They also minimize the occurrence of internal faults like shorting and open circuits, which ensures power and signal transmission are reliable, the harness is durable, and the overall electrical performance is better.

What factors should be considered when selecting materials for wiring harnesses?

The key factors to consider include:

• Application requirements
• Compliance to standards
• Cost-effectiveness vs. material performance/properties
• Material quality and supplier reliability

What are the common types of high-performance materials in wiring harnesses?

The common types of high-performance materials include the following.

• PTFE, nylon, and polyurethane for the insulation
• Copper alloys, high-purity copper, and aluminum for the conductor and shielding, which can be stranded or solid for the former and foil or braided for the latter
• Silicones, polyurethanes, chloroprene rubber, polypropylene, or PVC for the protective sheathing

How does WellPCB ensure the quality of high-performance materials in their wiring harnesses?

WellPCB employs rigorous testing procedures for internal quality control and assurance to ensure the materials and harnesses meet the required performance standards. These include short circuit, high-voltage, continuity, resistance, pull, flex, water ingress, and fungal resilience testing. On top of that, we adhere to the relevant ISO, UL, RoHS, REACH, and IPC standards for high-performance material selection for wire harnesses.