A 1/2 inch drive torque wrench, three sockets, a charger brick and a bit set arrived in the sample room inside a taped-up carton that had already split along one edge. That carton was the real benchmark. Whatever we drew had to survive the same courier route that had torn it, and the buyer, a power tool importer in Ohio, wanted six colourways without paying for six separate tooling runs.
Tool cases run heavier than most of what we build. We start at 0.20-0.24 g/cm3 EVA sheet with a 4-5 mm wall and a Shore C of 60-65, then pull the corner radii in tight enough that a dropped case lands on material rather than on a seam. A 600D Oxford laminate covers the outside because it shrugs off oil and jobsite grit; PU leather goes on when the case doubles as a retail package.
The cavity is the product
Nobody buys a tool case for the shell. The layout has to hold each item at the right depth so a socket does not walk into the wrench handle, and the foam has to be dense enough to keep its edge after a few hundred removals. We use die-cut foam around 25-30 kg/m3 for tools, cut to roughly +/-1 mm on load-bearing walls, and we keep at least 8 mm of material between any cavity and the outer wall. Cheap foam tears at the top lip first, then the tool starts moving.
Freight testing before the first container
The Ohio order was quoted against ISTA 2A, and for heavier shipments we run ASTM D4169 instead. On the bench that means a 1.5 m drop on six faces, three drops per face, with the case loaded to its real weight, followed by vibration and a stack check. Webbing handles get pulled to roughly three times the loaded case weight, and zippers are cycled to about 5,000 opens. The zipper is usually the first thing to go, so we specify YKK or an equivalent and add a storm flap over the teeth when the case will live in a truck bed.
Six colourways, one tool
Colour, logo and surface finish all move without touching the mold. An embossed or screen printed logo, a swap from Oxford to PU leather, a different zipper tape and puller, a printed interior label: none of those need new tooling, which is why our customization program separates shell tooling from trim. What does need tooling is a cavity change, so we tell buyers to settle the layout first and the colours second. Minimum order starts at 500 pieces with tiers at 1,000 and 3,000, and a first sample usually comes off the bench in about three days.
Our EVA case lines cover everything from small meter pouches to 20 inch tool boxes, and the EVA tool case range is where most of this testing happens. The Ohio buyer signed off after the third 1.5 m drop with a 6 kg load inside. The first 1,000 units went into production the following Monday, a black shell with six trim colours split across two shipments out of Yantian.