A return rate around 3 percent on a handheld diagnostic device is what brought a Dutch customer to us last year. The units arrived with cracked housings while the shipping carton looked untouched. The problem was the case: a soft pouch that let the device move about 6 mm inside its own packaging, which is enough to break a connector at the board edge.
Fit Is the First Benefit, Not the Shell
The most useful thing a molded EVA case does for electronics is stop movement. A die-cut foam cavity holds the product on all six faces with roughly 1-2 mm of interference, so the load path during a drop goes into the foam instead of the device. Foam selection follows the product: closed-cell EVA die-cut for general use, egg-crate foam as lid padding for anything with a screen, and anti-static grades where a bare PCB or a module is involved. Surface resistance is verified against the limits in IEC 61340-5-1 before the insert goes into production.
Shell construction matters second. Wall thickness of 1.5-2.5 mm at a density of 0.18-0.22 g/cm3 gives enough stiffness to resist a point load without adding much weight, and hardness around Shore C 55-65 keeps the corners from collapsing. Heavier items - a drone body, a power tool, a battery pack - justify going to about 0.25 g/cm3.
What the Testing Actually Covers
Most electronics programs we run now quote drop testing at 1.0-1.5 m across six faces, three drops per face, with the device inside and the case inside the customer's shipper. Distribution testing for parcel networks follows ISTA 2A or 3A, or ASTM D4169 when the buyer's protocol says so. Neither test guarantees zero returns; what they do is move the failure point out of the range that normal handling produces.
Sealing is the third area. IP54 is achievable on a molded EVA shell with a formed lip and a covered zipper track, and it is enough for workshop dust and light rain. IP65 is a different build - gasketed, usually with a different closure - and buyers should ask which one is actually being quoted, because the two are frequently confused in supplier copy.
Materials compliance closes the list. Every compound on our lines carries RoHS and REACH declarations from the sheet supplier, with CTI reports on file, and CA Prop 65 statements are available for US retail portals. Velvet or flocked linings are used where a screen or a polished surface would otherwise be scuffed by foam.
Our game console case range and earphone and headphone cases sit at the light end of this work, where screen protection and pocketability drive the design. Larger builds, such as the electronic accessories cases for chargers, cables and adapters, are usually about organizing several items in one foam layout rather than protecting a single device.
The Dutch customer's return rate dropped below 1 percent after the change, and the foam drawing for that insert is still the reference we send to anyone with a similar device geometry.