Production process for improving NVH performance of ceiling

The invention discloses a production process for improving NVH (Noise Vibration and Harshness) performance of a ceiling, which comprises the following steps of: adding a polyisocyanate raw material into a first feeding barrel, adding a liquid polyol material into a third material tank, driving a third stirring rod to rotate through a fourth motor to pre-mix and stir the liquid polyol material, adding the solid powdery polyol material into a conveying pipe through a hopper, and feeding the solid powdery polyol material into the conveying pipe; and under the action of a fifth motor, a polyhydric alcohol material of solid powder is fed through a second auger, and the polyhydric alcohol material is stirred while being fed. According to the production process for improving the NVH performance of the ceiling, after the PU plate is foamed, the thickness of the sliced PU foam sheet is increased to 7-9 mm, the propagation time of sound waves in the foam sheet is prolonged, when the automobile ceiling is subjected to c