I think you can have a try with ‘fix aveforce’ which average a total force and evenly distribute to all rigid particles.
By the way, how did you set your rigid part(metal layers)? Previously I was doing a similar compression. I combined ‘fix rigid’ where I set force X,Y off Z on and all torque off and ‘fix aveforce’, which gave me pretty good results.
Hope this can help.
I think if you want to reach a specific pressure, you can simply try with an ‘if’ command, OR probably you can also have a look if PID can be used here, it can be used in mesh but I am not sure here.
For the ‘fix aveforce’, I do not know how did you set your rigid metal. My guess, continuing compression may mean the rigid part cannot feel the reaction force from the lubrication, OR the reaction force is so small that not enough to slow or stop the metal.
Hope this can help