Intensification Ratio

Though it has been discussed previously in '95, it may be time to revisit.

The intensification ratio is the relationship of the working area of the hydraulic cylinder / cylinders diameter to the area of the screw diameter. If we go back to some basics;
Pascal's principle states:
When additional pressure is put on a confined liquid, the pressure is transmitted equally to all parts of the liquid.

       A                                                                                             B

In the above, if A were to equal 8 in weight, the weight of B would than equal 24. The basics' break down to Weight dividied by area or 8/10 = 0.8 and since the pressure is equal we now take the 0.8 X 30 = 24.  It is further stated that the ratio of area is the same as the ratio of weight, in this example 1:3.  This is the basic principle of a hydraulic jack.
Now in the molding machine we have this in regards to the pump set pressure and our cylinder. When we apply the pressure at 1000 psi, it means that each square inch of space sees 1000 psi. If we now mechanically attach a rod to this cylinder, we can now multiply the force as the following illustration shows.

If the small end has an area of 1 square inch and the larger area has an area of 10 square inches, the relationship is 10:1.
 
 

Now given that we have applied 1000 psi to the large end, the force on the small end is now 10,000 psi.

This is the relationship in the molding press but not all presses have the same intensification ratio, thus the hydraulic pressure used on press A may not be what we want or need in press B.

How to calculate next time, thanks for the time.

Steven L Silvey
Sr. Technical Service
General Polymers Division
Ashland Distribution