| Quantity: | |
|---|---|
Thickness, creases and die-cut geometry: choosing corrugated PP for auto parts
 |  |  |
Most corrugated PP packaging that fails inside an automotive plant was specified from a thickness table alone. Thickness is the last variable, not the first. The flute direction decides whether a layer pad bows under a pallet, the crease line decides whether a folded tray still has a square corner after fifty trips, and the die-cut clearance decides whether a painted part arrives with a scuff. We quote sheet, grain and tooling in one pass, from a drawing of the part and the load it will carry.
Layer pads: 4 mm and 6 mm twin-wall cut to the pallet footprint, 400 kg static per pallet, stacked twenty high in a stillage and lifted by the top sheet.
Divider sets: 8 mm sheet slotted on the CNC router with 3 to 6 mm clearance per pocket, so painted, anodised and bead-blasted parts never touch a wall.
One-piece folded trays: creased, die-cut and shipped flat, then folded at the line side, where a single sheet replaces a base, four walls and eight staples.
Edge protectors and top frames: 2 to 3 mm strips riveted to a returnable frame, absorbing the abrasion that would otherwise reach the top layer of the stack.
What a sheet carries depends on the number of walls and the direction of the flutes. A 4 mm twin-wall pad spanning a 1200 x 1000 mm pallet deflects by a few millimetres under 400 kg when the flutes run across the short side, and by visibly more when they run the other way: same sheet, same load, different result. Above roughly 600 kg, or on any span past 1200 mm, the board buckles between the bearers whatever the thickness, and the honest answer is a PP honeycomb panel, a plywood deck or a moulded EPP insert rather than a heavier corrugated sheet. |
|
| Two limits matter in series production. An open flute edge takes in water and swarf, so every pad leaving the plant is ultrasonically sealed or taped on all four edges; unsealed board in a wash-down area fails within a season. And the surface is low-energy, so adhesives and most labels will not hold without corona treatment or mechanical fastening. Our print-grade sheet is treated to 46 dyne/cm and labels are specified with an acrylic adhesive. Both points are settled at the drawing stage, not on the shop floor. |
 | The 2025 Indonesia Industrial Exhibition was where several of these sheet specifications were argued out face to face: flute direction against pallet size, crease radius against expected fold count, edge sealing against the cleaning method in the customer's plant. Pads and folded trays leave us flat, so one 40HQ container holds about four times the volume of the same packaging assembled, and the folding happens wherever labour is cheapest. |  |
