GTO 52 ZP-S transfer gripper set

[paulox]

Dear friends,

We are having registration problems with a noticeable doubling phenomenom from unit 1 to unit 2.

What is the most suitable way to perform a syncronized setting on the two transfer grippers bars? Some special tricks to do this easily?

I know this problem can be from a more serious source, but I would like to know how to check this setting first.

Regards,

Paulo

 

[junker1984]

Especially since this is a perfector, it will require specialty tooling. Have you determined that the problem is grippe settings, or do you have a bad cam follower on one of gripper bars? What direction is the doubling? Is the sheet not being held stable through transfers or is it being distorted.any nicking of the sheet lead edge?

 

[paulox]

Especially since this is a perfector, it will require specialty tooling. Have you determined that the problem is grippe settings, or do you have a bad cam follower on one of gripper bars? What direction is the doubling? Is the sheet not being held stable through transfers or is it being distorted.any nicking of the sheet lead edge?

Our technician replaced all bad cam followers, the rods and all grippers in the double drum one year ago. All ok initially but now the problem is back. This doubling is circunferential and is very noticeable when printing speed is over 6000 sheets/hr. Most of time the doubling come in a perfect cycle but sometimes we have worse ones breaking up this cycle.

What tool we need to check all grippers?

 

[junker1984]

Paulox, it's unlikely you'll be able to acquire the tooling for this job. It's all specialty (proprietary) stuff only Heidelberg has...with some exceptions.

 

[glamoura]

Junker1984..i also have a similar problem with my GTO 4 color...but it happens with my 3rd unit...its not doubling..but its misregister...most of the time it occurs in a perfect cycle and on the gear side...what do u think is the problem...and the easiest way to set grippers...hope to hear from u..thx

 

[junker1984]

Hi Glamoura, wish there was an easy fix for you, but there really are so many possibilities. Have you checked all cam followers, have you looked at and tested all gripper bar pillow blocks as overflows water pans can destroy the needle bearings. You mention mainly in perfect, is it an every other sheet pattern? Are both sucker bars on the storage drum operating as they should? Try inching a sheet through the transfer from storage drum to reversing cylinder (in straight print) and pull lightly on the sheet tail. If it readily comes out, any of the previously mentioned items may be culprit. There is no means to adjust grippers without the proper tooling, all you can do, if you fully undèstand what is supposed to happen at cylinder "hand off" is to wing it by adjusting grippers by guess. You could put yourself in a worse place by doing so. Good luck.

 

[paulox]

Thanks for your reply, but I hope there is another way to check these grippers without calling a Heidelberg guy.

Maybe someone here know how to do it with some calibrated stripes and another basics tools?

 

[junker1984]

If the problem is mainly in perfect, have you checked the tail suckers?

 

[paulox]

We are doing multicolor jobs all the time. Perfect is not being used.

junker, do you know what is the angle position of gripper closing and opening time on this machine? I want to move the machine in the correct sheet transfer position looking the angle numbers on the CpTronic panel. I think this is a nice start to check all machine grippers, specially in the double drum, you agree?

Maybe there is a angle chart or something like this.

 

[junker1984]

In my previous posts, I thought you were speaking of GTO. What model?

 

[paulox]

Yeah we are talking about a GTO ZP-S 1994 with CpTronic and stream feeder.

This changes your mind about the tools and requirements to set the grippers in this machine? Maybe a easy way to do this with the CpTronic panel.

 

[exheidmech]

There is no easy fix for a doubling issue between 1 and 2. CpTronic will be of no help. You stated earlier in this thread that you had already the cam followers and rods replaced in the storage drum. This will likely need to be done also in the reversing drum. Yes, special tools and special skill is involved in this. You will need to replace both cam followers, reset grippers, reset fixed grippers and check all the internal bearings in each segment. This is about an 8 hr job if you have done it before and have the required tools.

 

[paulox]

Thank you exheidmech.
What about the toothed segments and his gears in the reversing drum? We do not realize significant looseness on moving them by hand, but some guys told us to replace them too.

 

[exheidmech]

Its pretty rare to have to replace the gear segments. To properly check gear lash, by hand move the fixed gripper up and down. You should barely be able to feel movement, do the same with the spring loaded side. If measuring with an indicator it should be less than .10mm. The only time I replace the gear segments is when the internal needle bearings in the segments have eaten their way into the shaft. To check this, the segments need to be removed from the machine and pulled out of their housing. Without looking at your machine and knowing the condition of it there is no way to know for sure if your segments need to be replaced. If your machine is well taken care of and no major water pan overflows onto the perfector, than it is unlikely that you will need to replace the segments which can be quite costly. Usually you can get away with replacing the cam followers and internal bearings, reset the pincer bar and your good. Like I said above, about 8-10 hour labor.