The workers are inspecting the ball operation of the trapezoidal screw to check whether the balls are running smoothly on the trapezoidal screw and whether there are any jamming, abnormal noise, etc. During the quality inspection process, trapezoidal screw that do not meet the requirements need to be reworked or scrapped to ensure product quality and reliability. At the same time, qualified trapezoidal screw need to be packaged and protected to prevent them from being damaged during transportation and storage.