Plate Cylinders

The plate cylinder must be very accurate.

Its TIR (Total Indicated Runout) should be in the range .0002-.0005" for good process color printing.

TIR is a combined measure of both roundness and concentricity of a cylinder.

It is the difference between the maximum and minimum radius of the rotating cylinder.

Plate cylinders may be integral construction (part of the press) or demountable.

There are several ways to attach a demountable cylinder to the shafts.

One type mounts with its end wall heated so that it will expand and slide over the shaft. After it cools it shrinks into position and fits tightly.

Another type has a threaded opening on the end wall.

The shaft is threaded and they lock together when tightened with a spanner wrench.

Another type locks into position with a pressure system using a grease gun fitting.

Still another type is fastened with screws which activate a hydraulic system.