Mounting a 15-inch Panel PC in a cabinet door: what cutout size do we use, and how do we keep the front at IP65?

The cutout is always in the mechanical drawing for that exact model — never derived from screen size. Two 15-inch units from different vendors can differ by a few millimetres of bezel, which is enough for the gasket to miss. Get the drawing by model number and print it 1:1 to check before cutting. Three conditions for a front that really achieves IP65: 1. The door panel must be flat and thick enough (typically 1.5–3 mm). A thin door bows when the clamps are tightened and the gasket lifts in the middle of the long edges. 2. The supplied gasket must be intact, seated in its groove, not trimmed and not replaced with silicone. If the unit is removed and refitted repeatedly, use a new gasket. 3. Tighten the clamps evenly in a cross pattern to the torque given in the manual. Tightening one side first, or overtightening, warps the bezel and breaks the seal. Note the rear: IP65 covers the front only. Behind the door the cabinet keeps its own rating, and cables should drop below the gland and loop up (a drip loop) so water cannot run along them into the ports.