Komori LS29 - Thrust Bearings

We have been experiencing a lot of doubling and slurring on our 2007 LS29. Press has 70MM impressions. Recently replaced all cam followers and adjusted all grippers. Problem is better but different and we are told the thrust bearing need changed. This seems premature to me so I am asking if anyone has any experience with the life expectancy of these bearing. Thanks

 

Which thrust bearings and what reason did they give?
Which units are doubling and where on the sheet, what direction is the doubling in?
I would be suprised if it is a thrust bearing, Komori use high quality bearings everywhere.
If the problem changed/got better after the work on cam followers and grippers I'd guess that is where the problem is.

YG

 

They are telling us they can not adjust the thrust bearings, they are bottomed out. What they are telling us is lateral and circumferential register is sloppy. New thrust bearings will eliminate the movement and the print issues. It just seems premature to me. Has anybody out there changed these and if so at how many impressions? Thanks,

 

Is this on all units or just one? Who is it who's telling you this, are they Komori specialists? How have they determined there is play in these bearings? I have modified faulty register thrust bearings back in the 80's due to a manufacturing fault but have never heard of them failing on a Lithrone. Unless they suffer oil feed failure they should last forever. Or if the machine has had a problem in the past, been stripped and not assembled correctly, has it been stripped?
A loose thrust bearing on the register would cause the cylinder to climb in the helical gear and move the position of that units print significantly Once it had reached the limit of the play in the thrust it would satabilise and not cause doubling at a constant speed. If you slowed the press down the position of the print would change.

YG

 

Komori specialists are telling us this - they want to change all 6 units!!

 

Well good luck, maybe they know something about that particular machine. Let us know if it cures it.

YG

 

I sure hope so. We have been putting out some pretty sub standard work for the last 6 months. We need to put this to bed. Thanks for your help.

 

Very premature (If the press hasn't ran out of oil or had some other drastic change to it...). May I ask, are you getting this problem in all units or just one?

 

We are being told that some of the thrust bearings are bottomed out and can not be adjusted. Also telling us we should change them all if we are changing some. I truly do not think this is the print issue. Thanks for the post.

 

Hi,
So if I understand your post right, this is not a problem in all of the print units, just one in particular? But they are saying since you are changing one, you should change them all?

Also, just as a sanity check.... : If you are only getting the problem on one unit, have you checked :
1 - The bearer pressure
2 - Packing on that unit

Is there a pattern to the bad register? Every 3rd sheet? Every 2nd sheet? etc...

-K

 

Do you have a colour bar with star targets on? If so do the star targets show a figure of 8 shape either vertical or horizontal?

 

On Heidelberg presses a visual indicator of worn thrust bearings is dark oil leaking from the seals near the cylinder axel on the operator side of the press. I don't know if this can be seen on a Komori. Gear configuration and cylinder rotation create a natural pull force on the cylinders and the purpose of the thrust bearing is maintain a constant alignment of the cylinder. A worn bearing will allow a slight cylinder shift towards the gear while running, causing a diagonal double in your image. Each colour printed before the unit(s) with worn bearings will double. You need to do some simple testing to determine which unit(s) have worn bearings. Select your first two units for printing, if the first colour doubles the problem could be unit 1 or 2, if no sign of doubling put your next unit on impression. If the first two colours double then your problem is in the third unit, and so on. NOTE: If you find the problem unit and don't print with it but print with units before and after the problem unit you will still experience doubling as the cylinder continues to pull back and forth.

It does seem a bit premature to be advised to change all of the thrust bearings now. Doing the tests will locate the suspect bearings and save you time and money. Regardless of how reliable and well built previous bearings have been on other presses, these are pieces of metal and some will wear out, and when they do they definitely need replacing.

The press I work on is a 12 col. perfector and we currently have a thrust bearing problem in 2 units after the perfector and I get doubling on two sides of the sheet. I'm fighting the same quality issues you are experiencing.

 

Grant B, I will have to look into the oil leaking if I can see it, i do have a mechanic coming out Wed. to see what he thinks is going on.

 

Tonyc, I do have star targets at the tail of the sheet, I do get the figure 8 pattern but not consistent job per job. mosty horizonal, IE sometimes the black is worst, then could be Megenta or cyan, then again maybe all.

 

We got an independent repairman into give a second opinion on the thrust bearings and he did not think that was our problem after looking at several jobs and how our targets printed. Did some adjusting of the grippers on the yellow unit and things really cleaned up. Not sure why Komori missed this but I think we can rule out the thrust bearing for now. We are going to concentrate on gripper springs and the adjustment screws. Thanks for your help on this issue.

 

Thanks for posting back the results!

 

Maybe give the original 'specialists' a wide berth, glad you seem to be getting it sorted now.

YG

 

Yes... we have had thrust bearings replaced on the L628. I would have to check it out, but it doesn't have near as many impressions as your LS29. Now, we have issues on the K unit (3rd) with them again. It will not move circumferentially, and very sluggish
laterally. Also, the M unit (5th) will not move laterally. So, we have to get those fixed soon, so maybe it is not so unusual after all. I have to wonder if this happens prematurely by adjusting them on the fly. I know that a couple of our operators start up jobs and get them rolling... and then adjusting the plate to plate positions on the fly. It can't be a good thing for the press.. in my humble opinion.