- EVA, PE, and PU foam are NOT interchangeable for tool case inserts — each has a different density, hardness, and cost profile that fits different equipment classes.
- The Meiqi protective box range covers all three foam types with custom cutting.
- The customizable foam equipment case is the standard reference for OEM spec sheets.
- Density (kg/m³) and Shore A hardness are the two structural specs that determine foam selection.
- Request foam samples with the OEM equipment weight and class for material selection guidance.
Most OEM protective case procurement teams specify foam inserts by a generic “foam” descriptor without distinguishing EVA, PE, and PU materials. The result is a procurement pattern where the case ships with the wrong foam density, the equipment vibrates in transit, and the OEM brand experiences a recall or warranty claim that the right foam specification would have prevented. The fix is to specify foam inserts by the three structural parameters: density (kg/m³), Shore A hardness, and the equipment load class.
The Meiqi protective box range covers all three foam types with custom cutting. The customizable foam equipment case is the standard reference for OEM spec sheets. The data table below compares the three foam families across density, hardness, cost, and application fit, with foam samples available for prototype qualification.
The kg/m³ data table and procurement guidance below help brand buyers specify the correct foam for the equipment load class.
MJ-1690 customizable foam protective equipment case — EVA, PE, or PU foam inserts available. View product →
The Camera Kit That Arrived With Water Damage After the Factory Specified the Wrong Foam
A photography equipment brand in Western Europe contacted us in early 2025 after a customer shipment arrived with water damage. The brand had been sourcing protective cases from a previous supplier with a generic foam specification, and the cases had performed adequately for the brand’s existing product line. When the brand launched a new camera kit with a higher IP rating and shipped the kits to a tropical climate, the cases performed poorly — the foam absorbed humidity in the tropical environment, the absorbent foam transferred moisture to the camera body, and the customer filed warranty claims for water damage.
The root cause was the foam specification. The previous supplier had used open-cell PU foam throughout the case, which has high water absorption because the open-cell structure absorbs water like a sponge. For the tropical climate shipping, the correct foam specification was closed-cell EVA or PE foam, which has minimal water absorption because the closed-cell structure resists water ingress. The wrong foam specification was the structural cause of the warranty failure.
The fix was to specify closed-cell foam for the camera kit case, with the foam selection based on the equipment class and the shipping environment. The new specification with [Meiqi](https://www.meiqicase.com/protective-box/) covered closed-cell EVA foam at 50 kg/m³ density for the camera body cavity and PU foam at 20 kg/m³ density for the lens cavity, with the closed-cell EVA providing the water resistance and the PU providing the lens cushioning. The brand has since shipped 800+ kits to tropical destinations without water damage warranty claims.
The structural insight: foam specification is not a generic procurement decision but a structural decision tied to the equipment class, the shipping environment, and the expected transit conditions.
The Three Foam Families: Why Tool Case Inserts Are Not Interchangeable
The three foam families used for protective case inserts are EVA (ethylene-vinyl acetate), PE (polyethylene), and PU (polyurethane). Foam standards are documented through ASTM D3576. Foam flammability standards are published through UL Standards for safety, including UL 94 foam flammability classification. Each foam has a different chemical structure, a different cell structure, and a different performance profile that fits a different equipment class.
EVA foam (closed-cell): made from ethylene-vinyl acetate copolymer, with closed-cell structure that resists water and air ingress. EVA foam has good resilience and recovery after compression, with moderate cost. The standard specification for general-purpose protective case inserts, with density range 30-280 kg/m³ and Shore A hardness 15-80. EVA is the most commonly used foam for OEM protective case programs because the combined structural support, chemical resistance, and cost profile fits the broadest range of applications.
PE foam (closed-cell): made from polyethylene polymer, with closed-cell structure that resists water and chemical ingress. PE foam has higher chemical resistance than EVA foam, with slightly lower cost. The standard specification for industrial and chemical-exposed applications, with density range 25-200 kg/m³ and Shore A hardness 20-70. PE foam is the better specification for tool cases that may be exposed to lubricants, solvents, and other industrial chemicals.
PU foam (open-cell): made from polyurethane polymer, with open-cell structure that absorbs water and air. PU foam has very soft feel and excellent cushioning properties, with lower structural support than EVA or PE. The standard specification for delicate equipment and cushioning applications, with density range 16-80 kg/m³ and Shore A hardness typically below 20. PU foam is the better specification for camera equipment, optical instruments, and measurement devices where the soft feel prevents surface scratches.
The three foam families are not interchangeable because the structural and chemical properties differ. Programs that specify foam by generic descriptor without distinguishing the three families encounter the equipment protection failure that the correct foam specification prevents.
The kg/m³ and Shore A Data Table: All Three Materials Side by Side
The table below compares the three foam families across density, hardness, cost, and application fit.
| Property | EVA Foam | PE Foam | PU Foam |
|---|---|---|---|
| Cell structure | Closed-cell | Closed-cell | Open-cell |
| Density range (kg/m³) | 30-280 | 25-200 | 16-80 |
| Shore A hardness | 15-80 | 20-70 | <20 |
| Water absorption | Low | Very low | High |
| Chemical resistance | Moderate | High | Low |
| Recovery after compression | High | Moderate | High |
| Relative cost (index) | Medium | Low | Medium |
| Typical application | General purpose, OEM | Industrial, tools | Delicate, cushioning |
| Custom cutting method | Waterjet, laser | Waterjet, CNC | Laser, knife |
The two structural specifications that determine foam selection are density (kg/m³) and Shore A hardness. Density determines the foam weight per unit volume and the structural support capacity; Shore A hardness determines the foam feel and the cushioning characteristic. Procurement specs should include both parameters, with the values matched to the equipment load class.
For OEM programs with high volume, the cost difference between the three materials is typically less significant than the performance difference. The foam selection should be based on the equipment protection requirements rather than the material cost alone. Programs that select foam based on cost alone consistently encounter the equipment protection failure that the correct foam specification prevents.
Pick the Right Foam for the Equipment Load Class
The equipment load class is the structural variable that determines foam specification, based on equipment weight per item, expected shock loading, and required vibration damping.
Light equipment (below 1 kg per item): PU foam at 16-30 kg/m³ density is the standard specification. The soft feel prevents surface scratches on delicate equipment, and the open-cell structure absorbs vibration. Examples: camera lenses, optical instruments, measurement devices.
Medium equipment (1-5 kg per item): EVA foam at 50-100 kg/m³ density is the standard specification. The EVA provides structural support for the medium weight combined with the cushioning for transit vibration. Examples: DSLR cameras, hand tools, medical devices.
Heavy equipment (5-20 kg per item): EVA foam at 100-200 kg/m³ density or PE foam at 80-150 kg/m³ density is the standard specification. The high density provides the structural support for the heavy weight, and the closed-cell structure provides the vibration damping for the transit conditions. Examples: power tools, rifle cases, drone cases.
Very heavy equipment (above 20 kg per item): PE foam at 150-200 kg/m³ density is the standard specification. The PE provides the highest structural support among the three foam families, and the closed-cell structure provides the vibration damping for the transit conditions. Examples: industrial equipment, military equipment, high-value instruments.
The load class selection is the structural decision that determines the foam specification. Programs that select foam without considering the equipment load class consistently encounter the equipment protection failure that the correct foam specification prevents.
The Fire/Static/Chemical Resistance Triangle
The three foam families have different performance profiles for fire, static, and chemical resistance. Foam selection should consider the application environment in addition to the equipment load class.
Fire resistance: EVA foam typically has moderate fire resistance and can be treated with fire retardant additives to meet UL 94 HF-1 or equivalent ratings. PE foam has similar fire resistance characteristics. PU foam typically has lower fire resistance and requires specific treatment for fire-critical applications. For programs requiring fire-critical certification, the foam supplier should provide the fire test report with the specific certification.
Static resistance: closed-cell EVA and PE foam have low static generation, which is the structural specification for electronics handling. Open-cell PU foam can generate static through the air movement in the open-cell structure, which is a concern for static-sensitive electronics. For programs handling static-sensitive electronics, closed-cell EVA or PE foam is the correct specification.
Chemical resistance: PE foam has the highest chemical resistance among the three families, with low reactivity to lubricants, solvents, fuels, and oils. EVA foam has moderate chemical resistance. PU foam has the lowest chemical resistance and is vulnerable to hydrocarbon exposure. For programs with industrial or chemical exposure, PE foam is the correct specification for chemical resistance.
Programs that select foam based on load class without considering the application environment encounter the fire, static, or chemical failure that the correct foam specification prevents.
Custom Foam Cutting at Meiqi: Laser, Waterjet, and CNC Routing
The custom foam cutting method is selected based on foam density and cut complexity. The three methods available at Meiqi cover the range of OEM protective case programs.
Laser cutting: standard for low-density PU foam and low-to-medium EVA foam. Cut width below 0.5 mm. Suitable for intricate cavity shapes and branding imprints.
Waterjet cutting: standard for high-density EVA foam and PE foam. Clean edges without heat-affected zone. Suitable for structural inserts where edge quality affects fit.
CNC routing: standard for thick foam blocks and complex 3D geometry foam inserts. Suitable for equipment requiring dimensional foam cavities.
The custom cutting method should be specified at the OEM spec sheet stage based on the foam density and the cut complexity. Programs that specify the custom cutting method at the procurement stage receive the structural foam insert that matches the equipment shape exactly.
Three Procurement Programs That Switched Foam Specs (and Why)
Three OEM procurement programs illustrate how the foam specification switch improved the equipment protection.
Program 1: Photography equipment brand, Western Europe, 800+ kits. Original foam: open-cell PU throughout. Switch: closed-cell EVA at 50 kg/m³ for camera body cavity + PU at 20 kg/m³ for lens cavity. Outcome: water damage warranty claims for tropical shipments dropped to zero. Lesson: foam selection must match the shipping environment, not just the equipment.
Program 2: Industrial tool brand, North America, 1,200+ cases. Original foam: low-density generic PU. Switch: PE foam at 80 kg/m³ for tool cavities. Outcome: tool shifting during transit dropped to zero, lubricant compatibility issues resolved. Lesson: chemical resistance is the structural specification for industrial tool cases.
Program 3: Medical device brand, North America, 500+ cases. Original foam: standard EVA at 40 kg/m³. Switch: EVA at 80 kg/m³ for main device cavity + PE at 100 kg/m³ for accessory cavity. Outcome: vibration damage during air transport dropped to zero. Lesson: density specification must match the expected transit shock loading.
The common thread across all three programs: foam specification is a structural decision tied to equipment class, shipping environment, and transit conditions.
Sourcing Custom Foam Protective Boxes From Meiqi
For OEM procurement teams sourcing custom foam protective boxes, six items should be covered before the PO is released.
- >
- Equipment specification: weight per item, dimensions, and quantity per case.
- Shipping environment: typical climate, expected shock loading, and humidity exposure.
- Foam specification: material type (EVA / PE / PU), density (kg/m³), and Shore A hardness.
- Custom cutting specification: laser, waterjet, or CNC routing based on foam density and cut complexity.
- Volume and packaging: foam cutting lead time, packaging, and OEM labeling.
- Quality assurance documentation: foam supplier batch certificates and density verification.
The [Meiqi protective box range](https://www.meiqicase.com/protective-box/) covers all three foam types with custom cutting. The [customizable foam equipment case](https://www.meiqicase.com/customizable-foam-protective-equipment-case-product/) is the standard reference for OEM spec sheets. [Foam samples](https://www.meiqicase.com/contact-us/) are available for prototype qualification with the OEM equipment weight and class for material selection guidance.
For OEM procurement teams new to foam specification, Meiqi provides technical guidance on material selection based on equipment weight, shipping environment, and budget.
Request Foam Samples for Your Equipment Class
Tell us your equipment weight, dimensions, and shipping environment. We will provide foam samples at the recommended density and Shore A hardness with the cost analysis for your OEM program.
Frequently Asked Questions
What is the difference between EVA, PE, and PU foam for protective case inserts?
EVA (ethylene-vinyl acetate) foam is a closed-cell foam with density 30-280 kg/m³ and Shore A hardness 15-80, offering good resilience and structural support at moderate cost. PE (polyethylene) foam is a closed-cell foam with density 25-200 kg/m³ and Shore A hardness 20-70, with higher chemical resistance and lower cost than EVA. PU (polyurethane) foam is an open-cell foam with density 16-80 kg/m³ and very soft feel, offering excellent cushioning for delicate equipment but less structural support. Each foam fits a different equipment load class and protection requirement. ESD protection standards for static-sensitive electronics are documented through IEC 61340.
What density of foam should I use for heavy equipment inserts?
Heavy equipment (above 5 kg per item) requires EVA at 100-200 kg/m³ or PE at 80-150 kg/m³, Shore A 40-60. Under-specified density causes bottom-out; over-specified adds weight and cost.
Is PU foam suitable for heavy equipment?
PU foam is generally not suitable for heavy equipment because the open-cell structure compresses easily under repeated loading. ISO 845 provides foam testing standards. PU foam is the standard specification for delicate equipment that needs cushioning (camera lenses, optical instruments, measurement devices) where the soft feel prevents surface scratches and the open-cell structure absorbs vibration. For heavy equipment above 5 kg per item, EVA or PE foam at higher density provides the structural support that PU foam cannot provide.
Which foam is best for camera equipment protection?
Camera protection typically uses PU at 16-30 kg/m³ for body cavity (soft cushioning) combined with EVA at 50-100 kg/m³ for lens cavity (structural support). The two-foam combination is the standard for camera case inserts.
Which foam is best for tool case inserts?
Tool case inserts typically use PE foam at 50-150 kg/m³ density, depending on tool weight and tools per case. PE foam is the standard for tool cases because chemical resistance protects against lubricants and solvents.
What is the difference between EVA and PE foam for protective case inserts?
EVA foam has higher resilience and better recovery after compression, slightly higher cost. PE foam has higher chemical resistance and lower cost. For frequent-opening cases, EVA is the better spec; for chemical exposure, PE.
Can foam inserts be custom cut for specific equipment shapes?
Yes, foam inserts are custom cut using laser, waterjet, or CNC routing based on foam density and cut complexity. Low-density PU is typically laser cut; high-density EVA is typically waterjet cut.
What is the cost difference between EVA, PE, and PU foam inserts?
The cost ordering from lowest to highest is generally PE < PU < EVA, but the actual cost depends on the density, the thickness, and the custom cutting complexity. Low-density PE foam is the lowest cost option, suitable for basic cushioning. PU foam is mid-cost with good cushioning. EVA foam is higher cost but offers the best resilience and structural support. For OEM programs with high volume, the cost difference between the three materials is typically less significant than the performance difference, and the foam selection should be based on the equipment protection requirements rather than the material cost alone.
Post time: Aug-20-2026