6YL-170 Cold Press Machine utilizes the screw that we set-up with different styles of screws and rotates when machines is running to push the materials into chamber. Owing to the spiral helical pitch of screws becomes shorter and the spiral depth of screw. Becomes shallower, in the chamber the volumes between screws and pressing ring inner is smaller, pressure produced from curve saw-tooth of pressing ring inner, which oil is separated out. Oil flowed out from the gaps between bars and oil slots between pressing rings.