Perfect direct cut
It is easy to cut cardboard along the ruler, but you may have issues with the backside of cardboard it has a tendency to jam and to become torn on edges. To avoid that cut in 2-3 light cuts. If you have thick cardboard you need to make more cuts. If you want to cut in one move put your cardboard near the table edge and cut with a long blade all way through the cardboard surface sawing up and down.