bearer pressure

was wondering if bearer pressure between the plate and blanket cylinders effect print length.the 528 which i run has the bearer pressures set 2 increments below zero on all units and im having problems with the 1st unit printing long.all the blankets are packed the same and the plate cylinders have no packing on them.any ideas, cheers

 

if all units are set the same They should be ok When I ran a 528 I used to move the fit some times by increasing or decreasing the pressure on the unit with the dials Its surprising how much you can move the fit with the dials

 

Andy i have found that the "dials" whether digital or mechanical are often inaccurate and can usually be moved to reflect a true reading. As tim mentioned if the dials are accurate and all set the same you should print the same length on all units. If your not printing the same then i would suggest that your cylinder circumferences are not all the same and need to be adjusted with packing. Ive seen new presses from the factory with print length issues that required up to .003" packing to make it print the same.

 

mate I would check your blanket to impression cylinder pressure, to do this use a long 0.20mm feeler gauge between the bearers with impression on. Set your dials above 0.2 then bring the pressure down slowly until you can just feel the pressure on the feeler gauge, don't forget to rotate the machine after you change the pressure. Once you have equal pressure on both side see what your dials are reading and adjust if necessary then do the other units.
Changing the plate to blanket pressure will not alter the print length, although I have on occasion given a unit a bit more pressure to compensate for an old blanket.