How are PE and PU foam built?
PE foam has closed cells: each air bubble is sealed, so the material does not absorb water and springs back after impact. PU foam has open, connected cells, which makes it soft, breathable and very conformable, but it can absorb moisture. This single difference explains most of their behaviour in packaging.
When should you use PE foam?
Use PE foam for machined parts, automotive components, tools, electronics trays and returnable containers. It carries heavier loads, resists oils and moisture, and holds a precise CNC-cut cavity. Its firm surface keeps parts in fixed positions during repeated handling.
When should you use PU foam?
Use PU foam for light, fragile or high-gloss items: measuring instruments, medical devices, cosmetics, glass and presentation cases. The soft cells wrap around the product and spread pressure, which reduces the risk of scratches and pressure marks.
How do they compare side by side?
Structure: PE closed-cell, PU open-cell. Feel: PE firm, PU soft. Moisture: PE resistant, PU absorbs. Load: PE medium to heavy, PU light. Cut edge: PE sharp and precise, PU softer. Typical use: PE for industrial and automotive parts, PU for delicate and premium products.
Can the two foams be combined?
Yes. A common design laminates a firm PE base that carries the weight with a soft PU top layer that touches the surface. This gives both load support and scratch-free contact in one insert.