Packaging engineers are tasked with solving a complex challenge: how to prevent shock, vibration, and impact damage while also providing enough structural support to keep components stable and secure. Too much cushioning, and the product may shift or deform. Too much rigidity, and impact forces may transfer directly to the item being protected.
The key to solving this challenge lies in understanding how different foam materials behave, and how to strike the ideal balance between cushioning and support. This involves understanding the material science behind foam mechanics, comparing the properties of common packaging foam types, and choosing the best foam material based on what you are shipping.
Cushioning vs. Support: What’s the Difference?
In foam engineering, “cushioning” refers to a material’s ability to absorb energy and reduce the transmission of shock or vibration. It’s typically associated with:
- Low to moderate density
- Softer compression characteristics
- High deflection under load
On the other hand, “support” refers to a material’s resistance to deformation under pressure, its ability to maintain shape, and its capacity to prevent movement or collapse under weight.
While cushioning and support are often in tension with one another, they’re not mutually exclusive. The right foam application offers a controlled combination of both, at least enough give to absorb impact, and enough structure to hold form and position.
Foam Types: Cushioning vs. Supportive Properties
Polyurethane (PU) Foam
Polyurethane foam is one of the most commonly used materials in protective packaging because of the high cushioning and light to moderate support it provides. It’s an open-cell foam that compresses easily and recovers well, making it ideal for:
- Delicate electronics
- Fragile instruments
- Lightweight retail products
Pros:
- Excellent energy absorption
- Lightweight and flexible
- Available in a wide range of firmness levels
Cons:
- Lower structural support
- Not ideal for heavy or high-load items
Expanded Polyethylene (EPE) Foam
EPE is a semi-rigid, closed-cell foam that provides a good balance between impact absorption and structural rigidity. Use cases include:
- Packaging, appliances, electronics, medical device, commercial equipment, and so on …
- Case inserts; military, commercial, retail, contractor
- Industrial parts
- Cold chain packaging
- Returnable packaging systems & dunnage
Pros:
- High impact resistance
- Omni directional compressive strength and creep resistance
- Class A surface
- Variable density range allows for a range of diverse applications
- Excellent strength to weight ratio
- Recyclable and reusable
- Low water absorption
Cons:
- Less compressible than polyurethane
Polyethylene Foam (PE):
PE is extruded from polyethylene resin pellets, is closed cell, and it is well suited for a wide range of packaging applications.
Pros:
- Good impact resistance
- Variable density allows for a diverse product offering and application range
- Recyclable
- Excellent recycled product options with economical pricing
- Fire retardant and anti static alternatives
Cons:
- Less durable compared to EPE and/or XLPE
Cross-Linked Polyethylene (XLPE) Foam
XLPE foam is a high-performance, closed-cell foam known for its smooth surface finish, superior durability, and structural integrity. While firmer than EPE or PU, it still offers shock absorption properties—just with a higher compression modulus.
Use cases include:
- Medical device packaging
- Military-grade transport cases
- Automotive or aerospace assemblies
Pros:
- Resists deformation and retains shape
- Excellent chemical and water resistance
- Ideal for high-value or high-precision parts
Cons:
- More rigid—less cushioning feel than open-cell foams
- Higher cost than basic PU or EPE
Expanded Polypropylene (EPP) Foam
EPP foam is a bead foam like EPE but with higher structural resilience and superior multi-impact performance. It is often used where both cushioning and support are needed over repeated cycles, such as in:
- Reusable shipping containers
- Floater pallets and crates
- Automotive interior components
- Robotics and drone packaging
Pros:
- High strength-to-weight ratio
- Excellent for dynamic loads and returnable systems
- Great compression recovery
Cons:
- Can be more difficult to fabricate due to material rigidity in higher densities
How to Balance Cushioning and Support in Protective Packaging
The ideal foam solution is rarely about choosing the softest or firmest material. Instead, it’s about tailoring the foam density, thickness, and structure to meet the protection requirements of your specific product. How should you approach it?
Understand Your Product’s Fragility and Weight
- Lightweight + fragile items (e.g., cameras, sensors, glassware):
- Use low-density polyurethane or EPE for high shock absorption with gentle compression.
- Heavy + durable items (e.g., metal parts, tools, batteries):
- Use firmer, high-density foams like XLPE or EPP to maintain support and prevent movement.
- Medium-weight + semi-fragile items (e.g., electronics, enclosures):
- Use a blend of cushioning and rigid layers (e.g., PU insert inside a PE shell).
Evaluate the Shipping Environment
- Will the product face long-distance transit, rough handling, or frequent stacking?
- Consider multi-layer constructions where outer layers provide support and inner cavities offer cushioning.
- Amcon Foam offers custom lamination, allowing you to combine different foam types for optimized performance.
Factor in Compression and Recovery Needs
- Foams like PU compress easily but may experience permanent deformation under sustained pressure (high compression set).
- EPD, EPP and XLPE retain their shape better under static and dynamic loads, making them ideal for longer-term use and multi-trip shipping.
Consider Custom Fabrication and Fit
Foam only performs as well as it fits. Precision-cut, custom-fitted foam ensures:
- Even distribution of pressure
- No unwanted shifting during transit
- No excess void space that reduces cushioning effectiveness
At Amcon Foam, we provide CNC routing, waterjet cutting, and die cutting to deliver exact-fit foam solutions that match your product’s geometry, weight, and protection needs.
Choose the Right Foam with Amcon
Cushioning and support aren’t opposites; they’re two sides of the same performance coin. The most effective protective foam packaging balances both by choosing the right material, the right thickness, and the right cut for the job.
At Amcon Foam, we help OEMs, manufacturers, and packaging engineers find that balance with a wide selection of engineered foam materials, advanced fabrication capabilities, and expert design assistance to tailor every insert, cavity, or pad to your product’s exact needs.
Need help finding the sweet spot between softness and strength? Contact the Amcon Foam team today to talk custom packaging foam solutions.