SM 52-5P2-H print problem on 4th tower

Dear all

I have I problem on my SM 52 machine. 5 color machine. the problem is on the 4th tower where there is a problem with the print out. Presetting for the thickness of the paper is normaly set, CPC 1,04, but when I actually run the machine I have to add about 0,08-0,10mm of pressure on this tower to recive a normal print out on the paper. All the blanket cylinders have the same amount of calibrated paper under them. If any one has any ideas please let me know.

Thank you, Ales

 

Have you recently exchanged pressure adjusting servo on that unit? Have you recently had a a paper jam in that unit? If you were to print a breakaway dry solid, would it breakaway evenly?

 

The pressure adjusting servo has not been changed recently. only if the servo is bad and does not pressure evenly or enough. we have changed the plate on the lower "print" cylinder with an original heidelberg plate. the print is not even its like it doesnt have enough pressure. when I add pressure then its ok but then the print becomes a bit longer then on other units.

 

Im guessing here that the "plate" you changed on lower print cylinder is an impression cylinder jacket for a perfecting press. If this is in fact the case then I would bet that the jacket was not installed at the correct height.

 

Yes the plate is on the impression cylinder. for the correct hight i am not sure. the plate was inserted with an input ruller that came along with the machine. i doubt that the plate was inserted incorectly because the plate would then be dameged at the begining where grippers and the plate meet on a impression cylinder.

 

Surely, the question that must be answered here is....Did this problem arise after you replaced the refined cylinder jacket? Also, why was the cylinder jacket replaced? Damaged? Or just worn? Was there a mylar underlayment adhered to the underside of the jacket? Did you remove it, thinking it was a "protective covering"?

 

The problem with the old jacket was that it was worn out. the probelm was there before but I had to add less presure then now. there was a cover under the jacket but it was not removed. the same jackets where replaced on other "towers" the same way and they work ok. would it be wise to call for a service to check the pressure on all impression cylinders? I run very different paper thickness on the machine. from 60gr up to 350 or 400 with thickness of 0,50.

 

Would be very wise to do so. There’s not much else that can be handled on a forum such as this.

 

If your shop has a packing gauge you can check the installed height of the jacket against other printing units. If the installed height is the same within a thousandth of an inch or so, then Im thinking you could just recalibrate the pots to read the same as the other units. This would only apply of course, if the running height of your blanket was consistent to the other units also. I would strongly suggest that you do NOT count on the stamps on the back of a blanket, or the stamps on each individual sheet of paper blanket packing to be accurate. The best way to check height is with a packing gauge as it gives you a true reading under rolling conditions. If you don't have a packing gauge a magnetic base dial indicator could also be used.

 

Hi all,
I suggest to print a "kiss printing test" and see the result, is the solid even or not, if yes you may adjust the bearers.
If not, you may have another problem like three points bearing.
Do the test and let us know.