Coating Plate Distortion

[aqazi81]

How do you calculate the distortion factor for polymer coating plates for offset presses?
We are supplying plates to the flexo industry but some of our customers who have offset setup as well, require coating plates.
I need to know the plate thickness and the way to calculate distortion for the coating unit.
Currently, we have a demand for a 1.14 mm coating plate for KBA 106 and CD102.

Any help in this regard would be much appreciated.

 

[johnny_jay]

We have a coater on one of our web presses that uses flexo plates. Our partner that creates the flexo plates had us run a grid with coating and they measured to get the distortion. We had to run a second test then a third to get it just right. We have done this with two different web widths, the distortion is slightly different for each.

 

[chriscozi]

Math -

Specific cylinder dimension - diameter OR circumference - which your Press manufacturer MUST supply - and surface height above the cylinder of your 'plate'. (1.14 mm)

#1. Circumference of the plate cylinder alone C = Pi * Diameter.
#2. Circumference of Plate + Cylinder = Pi * ( The diameter of the plate cylinder + (2 * 1.14 mm) coating plate )
#3. Subtract #1 from #2. This is total change in circumference ie length of image.
Divide #2 by #3 and multiply by 100
This is the PERCENT OF CHANGE required - in your case this will be a negative distortion in one axis.

Blanket and printing area size do not matter. Image start location will be affected but should be console adjustable.

Should be straightforward to get it close.
And as Johnny_jay notes sometimes adjustments are necessary.

YMMV.