Comparing the placement time of Stop-Motion and Moving-Motion

We calculated the time taken from the feeder to the PCB for the existing stop-motion. And we proposed moving-motion faster than stop-motion and compared the placement time of them.

In the stop-motion method, the gantry stops in front of the camera. Therefore, the travel time can be calculated through the velocity graph. But the moving-motion method does not stop in front of the camera. The travel time to the camera can be calculated when distance and the final velocity are given. Also, the velocity to the placement position can be calculated when distance, travel time, and acceleration is given.

This study developed an algorithm that calculates the time of routes traveled for the existing stop-motion method, and the proposed moving-motion method. The stop-motion method takes 175ms(millisecond) to move from the pick-up position to the camera position. Meanwhile, the moving-motion method has a Y axis velocity of 1.325m/sec, and is faster by 43ms than the stop-motion method, with a time of 132ms. Both methods take 302ms from the camera to placement because of the X-axis. The results show that the movingmotion method, which minimizes operating time by maximizing the velocity of the X-axis and Y-axis, is able to complete placement with a 9% shorter time. From a rough conversion of the number of components placed per hour to an entire day or a year, we expect the moving-motion method to significantly enhance productivity. While productivity can be improved by reducing time, this study did not take into account the reliability of the proposed visual inspection for moving components.

In the future, we will develop an algorithm for calculating the travel time for a total of 16 paths(combined with 4 pick-up positions, 4 placement positions).