As we said before, a swing arm robot is simple pick and place device which is applied to 40-400 ton injection machine. Since last year our factory quitted producing the double arm swing arms robot, and only have two strokes of 550,650. About the whole stroke, it was like: The arm stay on the top of injection machine, ready for picking up the products, after receiving a mold opening signal from injection machine, then take it out, and then robot arm will send back a signal to injection machine after it took out the finished products, then injection machine close mold to inject another product in the mean time robot arm rotate a specified angle, drop off the product. After gripper dorp off product, robot arm back to starting position, and be ready for the next cycle. That the theory of the swing arm robots' work.