They are different in principle and structure basically. The hammer stamps with ram's descending energy only while the ordinary press does with generating all power with action and reaction within the frame. However, typical screw press uses impact pressure rather than static pressure and this makes the best analogy forming of the hammer. This is the reason why the replacement of the hammer to the screw press is studied frequently for the benefit of no operational skill needed, easy for automation and little vibration pollution. Following is the popular and rough formula conducted from experiences

Therefore, replacement of the hammer with two to three tons can be considered to the screw press, however, it can't say practical if it surpasses this tonnage.

Another point is that the screw press can't accept eccentric load and it has difficulty in several stages stamping the way the hammer forges complicated shape. Quick repeated stamping operation the hammer can do is impossible for the screw press.

On the other hand, axial product the hammer conventionally stamps with laying rolled rod is a good candidate to produce big advantage for the screw press replacing it with the upsetting. We observe that the screw press is not good for complicated shape and large forging products for they are often out of the specification and that makes the both machines should cohabit.