Plate weak Problems

[ravindra]

dear all,

Nowadays we are facing a serious problems of image wear ,it started as early as on 45000 impression. the details are given below:
1.m/c = Hiline 45 ( web offset )
2.Blanket = vulcan
3.Packing underneath blanket= 0.25 mm
4. ink used = flint
5.paper= Solikama ( russian ) ,and uttai ( china ) ( web )
6. m/c configuration= 4 Hiline tower + folder + 3 Hiline tower.
7.Plate = thermosatar and viostar
8.Ctp= agfa and krause
9.pH= 4.4


after 60 000 impression its impossible for printer to runs further as the image wear problems are so severe that its hard to read the matter.
at most all plates of black and cyan got weak. ( the solid areas got weak very fast. )

So please guide as this is happening from last two weeks but hard to rectify the problem.

 

[VladCanada]

Not clear: do you have the same issue on thermal and violet plates?

 

[ravindra]

yes sir, weather its thermal or violet we are facing the plate weak problems.

 

[maxon]

All right then, you should focus on monitoring pH it's a bit low and work with Flint ink supplier to test/replace the ink batch. Do you see any sign of ink breakdown or emulsification in your dampening system, is your fountain solution clean ?

 

[Dieter Zang]

pH & paper

pH & paper

Hi.. if you have the plate wear, hwo do the blanket look at this momenmt? Is there a lot of build up? Is it ink or is paper?
I can imagine that such low pH will attack the paper and therefor you will get a lot of paper build up on the blanket. The pH should be around 5.0.

 

[alexmark73]

Fount solution

Fount solution

Did you change fount solution?

You can try to make a test with another plate... ;-)

 

[ravindra]

thanks 4 suggestions..

 

[maas]

some more suggestions.

- get a grind test done on the ink
- if you have ink filters on your tower check them for debris
- look at the worn plate under a 100x scope and see if the wear is mechanical i.e. grooves and metal being moved around on the plate
- record batch numbers of your plate and ask your suppler for a new set of plate with the batch number at least 5-10k different
- if you have a return system on your fount look for metal particles in the tank
- check your blankets clean them!! to ensure its not any lint build up, there is no substitute for good housekeeping
- check you blanket to plate clearances

best of luck

regards
Maas

 

[jithu.sreekuttan]

check wheather the pre heater of the processor(pre-press) is correct if it is low there is a chance for weakining the plate

 

[Dan Roll]

Do the plates show any physical sign of wear, such as polishing down the sides or at the lead edge?