Delivery Grippers on PM52 releasing sheets too late........sometimes.

2006 PM52 4 color has an problems with delivery grippers releasing too late, regardless of the position of the sheet release cam adjuster. It seems more prone to happen on a text/book stock than on cover stock. When it starts doing this, it can sometimes be corrected by stopping the press and starting it back up, and it will be fine. Other times I must manually open the grippers by the cam follower. Machine is very well maintained and only run by me since it was new. It just is so inconsistent as to why is starts or stops happening. Any ideas or suggestions are appreciated!

 

To me it doesnt sounds as much to me as a delivery gripper problem as a slow down wheel problem. Make sure you slow down wheels are good. Max the blower out so it is a max suction, move all 3 levers to max suction and put a sheet on the slowdowns, there should be a good amout of resistance. These slow down pumps are also prone to failure so it may simply be a bad pump.

 

You were right on the money exheidmech! With the vacuum from the decurler and the air blow down, I didn't even notice that the slowdown vacuum wasn't working. I just turned off decurler and air blow downs and the slowdown pump could not even be heard. But then I started the press back up and it was fine the rest of the day.

Why is it not working some of the time? Will this become more of a problem soon or will it gradually die on me ? Is a more reliable pump available from heidelberg? Any other manufacturers?

Thanks for your knowledge exheidmech. Your solutions with many obstacles we face in the business are invaluable.

 

I think it is just a sign that your pump is going out. One thing you might try, if you dont use your decurler much, you could swap the decurler pump with the slowdown pump, they are the same pump. Other than that you are best off ordering the correct pump from Heidelberg, newer versions of the pump are better and should work just fine.