We are often asked for the formulas to determine plate distortions. Below are these formulas.
The plate cylinder repeat must be known for both distortion formulas. If the K-Factor is known than you can determine both the distorted repeat and the distortion percentage. The distorted repeat is simply the plate cylinder repeat minus the K-Factor. The distortion percentage can then be calculated as the distorted repeat divided by the plate cylinder repeat times 100 (to convert to a percentage).
Formula for Distorted Repeat
cyl. - K = distorted repeat
Formula for Distortion Percentage
(cyl. - K) / cyl. x 100 = % distortion
To determine the K-Factor, subtract 0.005 from the plate thickness. Multiply the resulting number by 3.142 times 2.
Formula for K-Factor
(Thickness - 0.005) x 3.142 x 2 = K
Following are K-Factors for some common plate thicknesses.
K-Factors
0.030 = 0.16
0.045 = 0.25
0.067 = 0.39
0.107 = 0.64
0.112 = 0.67
0.187 = 1.14
0.250 = 1.54