Trouble with registration. Lack of consistency.

[Andrei83]

hello, we've got a problem with image register on Hiedelberg Speedmaster 102 5+l.
I start new job KCMY, mounting plates, print 4 sheets, move registers to register plates (in some cases use wrench to correct plate) print 5 other sheets to confirm register is ok and then pass sheets to corrector for approval. In the meantime i wash blankets. After approval ('bout 5 min) i starting to print full run. Print 5 sheets — register on M and Y drift diagonally or radially. Sometimes it's y only or m only. I have to move registers again and once more during the run.
The press done 57 mln impressions, everything was ok until 40 mln. Now it's getting worse.
We print mostly silk and gloss paper 130-200 gsm

Any ideas where to look?

 

[DeltaE]

Tell me how can you print 5 sheets in one shoot? Do you know there is vibration when impression is turned on and off?
In my opinion, you need to print more sheets to make machine in stable and then you take the sample for reference!

Regards,
DeltaE

 

[turbotom1052]

Delta is correct. 5 sheets are insufficient for the purpose of registration on a multicolor job. It takes at least 10 to 15 sheets, just to sheet off the previous image position. Then there is the issue of registration variance as the press speed changes from start up speed to running speed. I prefer to do BOTH registration and color makeready at the same time. For example.... 1. initial fountain settings for each plate, or load CIP data, 2. hang plates, 3. print 75 to 100 sheets, 4. inspect printed sheet and make registration corrections, AND color corrections, 4. repeat step 3 until job has salable registration and color.
Even with really accurate CIP data, and the press in the hands of a competent pressman, with a brand new press, this procedure will have you wasting at least a couple of hundred sheets unless of course your companies quality standards are really low.
Id also skip the washing of blanket part unless absolutely needed, as a blanket wash will often result in movement of registration. If you start the MR with clean blankets and you don't run really dirty waste through the press when trying to get color, a blanket wash will USUALLY not be needed before starting the press run.

 

[Andrei83]

Yes, you are right if more sheets for example 10-12, then it will be more accurate than at 5 I agree, and I do if the coverage area of ​​the form is large. If it is insignificant then 5 sheets is enough. After I move the printing plates twice, my rubber is sure to have no residual image. Nevertheless, you need to rationally spend printed material, I can not run a print run, and at least 100 sheets will be printed on the print run.In addition, according to the rules of our printing house, I must give one of the first impressions to the corrector for approval, in order to exclude the error and the marriage of the circulation.

 

[Andrei83]

I'll try to combine the image in 10-12 sheets. I will write the results. Previously, it was enough 4-5 sheets. Wash the rubber to make 5 more impressions and start printing. The tags were in place did not go anywhere.

 

[Andrei83]

I do not have auto registers on a printing press. Previously, I worked on a simpler two color printing machine, used the recipe as in the first message and was 100% successful.similarly Speedmaster CD 102 6+l.

 

[turbotom1052]

Andrea,
you came here looking for solutions to a problem. You were offered input from 2 different sources that you chose to reject. I suppose you will not be happy until you hear just what you want to hear. Perhaps if you keep asking you will eventually get the answer you want.

 

[Andrei83]

Yes, I probably agree with you. It is necessary to drive more sheets 15-25.

 

[maas]

make ready number is too low imo (inline with other responses) when was the last time you cleaned your grippers?

 

[Andrei83]

Yes, I cleaned the grips and supports.