Grafisk Maskinfabrik DC330mini, Руководство по эксплуатации

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GM · CONVERTING UNIT
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12. Distortion and dispro factor
The dispro factor is defined as the percentage the die plate is shortened in order to have the correct length
when wrapped around the magnetic die. On figure 1 (right side) the distances D1 and D2 are the length of
the die plate measured from the top of the knife and the bottom of the plate. When flat, D1 is equal to D2.
When wrap around a cylinder D1 is longer than D2. This means that a plate measuring D2 when flat will
be longer when put on the cylinder. To have the correct repeat length the plate has to be shortened by a
certain percentage, the dispro factor.
If a plate does not have the optimal dispro factor it will show as a to small or large gab between the repeats.
This can occur if the plate is made for a 12” full rotary cylinder and used on a 25” digital die. It can also
occur when the plates are made for the 25” die – in this case the manufacture of the die plate has to change
the dispro factor slightly. Some die plate manufactures uses an experience constant that gives the best result
for a specific series of machines. The theoretical value is calculated on figure 1 (left side)
The machine can do a compensation for this problem – the distortion setting in the die cut parameters
menu. Doing a compensation will force the paper faster or slower under the die. The heavy compensation
on plates with many labels may not be possible and will cause deviations in the register.
Figure 1. Dispro calculation.