How to Select the Right Composite Material: A Practical Guide for Engineers & OEMs
Key Takeaways
- Composite material performance depends on matching the right resin, reinforcement, and manufacturing process to the application.
- Thermoset composites often outperform thermoplastics in high-heat, high-load, and electrical insulation environments.o
- Engineers should evaluate strength, temperature resistance, electrical properties, wear behavior, and manufacturability—not just cost.
- Many failures stem from overlooked trade-offs like creep resistance, chemical exposure, or dimensional stability.
- Spaulding Composites helps engineers make informed decisions through engineering review, CAD support, and prototype validation.
Choosing the right composite material is one of the most critical decisions in product design. The challenge? Composites vary widely in strength, thermal performance, electrical insulation, chemical resistance, and manufacturability. For engineers and OEMs, understanding these differences early prevents costly redesigns, delays, and part failures.
This practical guide breaks down the essential factors to consider—and explains how Spaulding Composites supports customers from concept through production.
Why Material Selection Matters
Composite materials combine resin systems and reinforcements to achieve properties not possible with metals or plastics alone. However, each composite family behaves differently under stress, heat, or electrical load. Selecting the right one impacts:
- Performance and reliability
- Tooling and production costs
- Long-term durability
- Regulatory or environmental compliance
- Total cost of ownership
A thoughtful material selection process helps engineers avoid overspecifying or underspecifying their solution—and ensures the design performs as intended.
Key Factors to Consider When Choosing a Composite Material
1. Mechanical Strength Requirements
Ask: What loads will this part endure?
Consider tensile strength, flexural strength, modulus, and fatigue resistance.
For high-load, structural components:
- Glass-reinforced thermosets (e.g., epoxy or polyester laminates) offer excellent stiffness and long-term dimensional stability.
- Woven or filament-wound glass systems provide oriented strength for tubes, rods, and cylindrical components.
2. Temperature Resistance
Evaluate both continuous operating temperatures and peak exposure.
Thermosets excel when:
- Temperatures exceed 250°F
- Thermal cycling is intense
- Dimensional stability is critical
Thermoplastics may deform or creep under prolonged heat, while thermosets maintain stability due to crosslinked molecular structure.
3. Electrical & Thermal Insulation
If your application requires insulating, shielding, or dielectric performance, material selection becomes even more important.
Thermoset composites provide:
- High dielectric strength
- Excellent arc and track resistance
- Low thermal conductivity
- Stable performance in high-voltage environments
Spaulding produces custom insulators, circuit board substrates, and tube components for electrical OEMs nationwide.
4. Wear, Friction & Chemical Exposure
For moving parts, sliding interfaces, or harsh chemicals:
- Look for reinforced thermosets with high wear resistance.
- Evaluate exposure to oils, solvents, acids, or moisture.
- Consider surface treatments or resin blends that enhance friction performance.
Wear failures often appear years into a product’s life—making early material choice essential.
5. Manufacturability
A common oversight: choosing a composite based solely on performance, without considering how it will be manufactured.
Factors to account for:
- Wall thickness and part geometry
- Tooling method (compression molding, injection molding, filament winding, CNC machining)
- Production volume
- Tolerances and secondary machining
Spaulding’s engineering team frequently helps adjust designs to reduce costs or improve manufacturability without sacrificing performance.
Thermosets vs. Thermoplastics: When Each Makes Sense
Best for applications requiring:
- High heat resistance
- Dimensional stability
- Electrical insulation
- Structural strength
- Chemical resistance
- Low creep under load
Examples:
Glass-epoxy sheets, filament-wound tubes, convolute-wound cylinders, molded electrical components, high-temperature insulators.
Thermoplastic Composites
Best when you need:
- High-volume production via injection molding
- Low cost
- Recyclability
- Flexibility or ductility
However, thermoplastics may soften under heat, deform under long-term loads, or lose stability in electrical or chemical environments.
Common Material Trade-Offs Engineers Often Overlook
- Creep vs. strength: A material may test well initially but deform under sustained loads.
- Thermal cycling: Repeated expansion and contraction can cause cracking or delamination.
- Moisture absorption: Some composites swell or lose dielectric performance when exposed to humidity.
- Machining requirements: Not all composites tolerate tight tolerances or sharp internal corners.
- Chemical compatibility: Even “resistant” materials can degrade under specific solvents or pH levels.
Early engineering review prevents these issues from turning into redesigns or field failures.
How Spaulding Composites Supports Material Selection
Spaulding works with engineers and OEMs throughout the design and development process. Our support includes:
• Engineering & Materials Review
We help identify the optimal composite for structural, electrical, or environmental demands.
• CAD + Drawing Support
Our team assists with geometry, tolerances, and manufacturability improvements.
• Prototype Development
Validate your design with real materials before committing to full-scale production.
• Advanced Manufacturing
Including filament winding, convolute winding, compression molding, CNC machining, and custom material formulation.
• Application-Specific Recommendations
We tailor solutions based on mechanical, thermal, electrical, or wear requirements unique to your application.
Material Selection Checklist
Provide your audience with a simple, scannable tool:
Checklist Includes:
- Mechanical loads
- Temperature range
- Electrical requirements
- Environmental exposure
- Expected lifespan
- Preferred manufacturing process
- Budget and volume
- Tolerance requirements
Frequently Asked Questions
1. What’s the biggest mistake engineers make when choosing a composite material?
Focusing only on strength and ignoring environmental factors like temperature, moisture, chemical exposure, or electrical requirements.
2. How early should material selection occur in the design process?
Ideally in the concept phase. Early decisions prevent costly tooling changes or redesigns later.
3. Are thermoset composites always better than thermoplastics?
Not always—but thermosets significantly outperform in heat, load, and insulation applications. Thermoplastics are better for high-volume, low-cost parts.
4. Can Spaulding help modify an existing design?
Absolutely. Our engineering team frequently reviews or revises customer designs to improve manufacturability or performance.
5. How do I know if a prototype is necessary?
If the part is new, complex, or mission-critical, prototyping is highly recommended—and often accelerates time-to-market.
Why Engineers Choose Spaulding Composites
For decades, Spaulding has been a trusted partner for OEMs needing high-performance thermoset composite parts. Our engineering-first approach ensures every design is validated for strength, insulation, heat resistance, and manufacturability.
Whether you’re evaluating materials, developing a prototype, or scaling production, our team is ready to help you make the best decision for your application.
Ready to Choose the Right Composite Material?
Request a consultation or engineering review today. Your composite solution starts here.