The repeat length (R) is normally specified with the print job. If repeat length is not known, you can determine it by measuring a printed sheet. (See How is distortion compensation applied? for an illustration of repeat length.) If this is not possible, you can calculate it by adding the radius of the printing cylinder, the thickness of the polyester adhesive, and the plate thickness, then inserting the results into the following equation:
R= 2πx
where π = 3.142, and x = (cylinder radius + adhesive + plate thickness)
Example :
Plate mounted on a 8" diameter cylinder (radius of 4"),
Polyester adhesive is 0.005", plate thickness is 0.067"
R= 2π(cylinder radius + adhesive + plate thickness)
= 2 x 3.142 x (4 + 0.005 + 0.067)
= 2 x 3.142 x 4.072
= 25.59"