is it a small vertical? If so, you have to measure the length between the two cursor centers on the packaging paper first, and then set the bag length to the measured length. After wearing the packaging paper, go through the photoelectric position to make the light spot shine on the cursor. Then start the machine, pack three or four bags, and see where the knife cuts on the cursor. According to the up and down position, slightly adjust the position of the photoelectric head, and then pack until it shines on the appropriate position. In terms of packaging materials, if the color of the cursor on the packaging paper is darker than that in other places, turn the photoelectric head to the “dark movement”. If the color of the cursor on the packaging material is lighter than that in other places, turn it to the bright movement. In terms of electricity, when the light spot on your photoelectric head shines on the “cursor”, you must fine tune the photoelectric head and adjust it to the point with signal, If you have an indicator light on your photoelectric head, it is the critical point where the indicator light is just on or just dark.