Double-surface preheating device of hard box packing machine

The invention discloses a double-surface preheating device of a hard box packing machine. The double-surface preheating device comprises an upper electric heating plate, a lower electric heating plate and cylinders, and is characterized in that the upper electric heating plate and the lower electric heating plate are parallel to each other and horizontally placed; four cylinders are uniformly distributed on the bottom surface of the lower electric heating plate; and a cylinder shaft is arranged in the center position of the upper surface of each cylinder. Through the settings, the double-surface preheating device improves the preheating uniformity and accuracy, and greatly reduces the reject ratio of hard boxes. The double-surface preheating device reduces the production cost, and greatly improves the production efficiency.