Best Practices for Reducing Warpage in Large Thin-Wall Injection Molded Parts

I don't think there is a 'one size fits all' solution to this. It would be helpful if you could share the drawing or, at least the size & general shape, and the current gating used.

On large thin-wall parts, warpage usually starts in the steel, not on the press screen. You can chase it with pack pressure for a week and move it maybe half a millimeter.

Cooling is where I would look first. Keep channels close to the big flat faces, and keep the layout mirrored on core and cavity. Baffles or bubblers help on tall cores where drilled lines cannot reach. A 5 °C gap between the two halves is enough to bow a 600 mm cover.

Gate position decides how the part packs, so it decides the shrink pattern too. For a long cover, I prefer two balanced drops over one end gate. End gating fills fine, then packs the near end harder than the far end. That shrink difference shows up as bow two days later, not at ejection.

Check wall thickness before you blame the process. A rib or boss on one face pulls that face as it cools. Holding mold temperature steady matters more than holding it high. Measure coolant in and out on both halves at T1, not after the parts warp.

Injection speed and pack settings are worth tuning, but only after the cooling layout is honest.