Gear Streaks

[Jeremy]

I'm getting horizontal streaks across my blanket on my 3302M. They're about 1/16" wide and about ever 1/8" down the blanket for the entire blanket. The lines seem to coincide with the gear teeth. What causes this and how do I fix it?

 

[Leo Caproni]

Re: Gear Streaks

Is the press new or recently purchased used? Has this problem just surfaced after an accident (bad paper jam or rag in cylinders) or change in types of blankets, plates or packing material? First check your plate and blanket thicknesses and packing height of both with a caliper and pack to factory specifications. If that does not solve the problem call in a technician and look for a problem with the impression setting system or cylinder gearing. I have also seen this type of problem which looks like gear streaking from the continuous dampener on another brand of press due to emulsification in the inker, strange as it sounds which was resolved by washing up the press and keeping a proper ink and water balance.

 

[Lukew]

Re: Gear Streaks

We have had that problem on the same machine, but from memory it was due to incorect packing..
We have also had this issue on the shinohara.. now if you are running a shinohara and have a tech tell you to run the tightest nip you can get between water form and pan roller before the pan roller inks up.. think twice and don't do it.. what can happen is during the run the speed of the pan roller can be altered by the water form roller effectivly speed up , now even if there isnn't over emuslification of the ink the gear marks will still ocure.

 

[Jeremy]

Re: Gear Streaks

There has not been a large jam up. The press is a 2000 so it has some age to it but my cat is older. I use the Ryobi blankets that are made by Ryobi with their matching under blanket. That is all I pack. I actually checked the pressure nips when I replaced this set of blankets, suspecting it was off. It was a bit so I put them to what the operation manual suggests and it's still happening. Does this press have cylinder bearings that could be adjusted or worn? I don't know much about that kind of stuff.

 

[inky]

Re: Gear Streaks

What dampeners are you running?

 

[Jeremy]

Re: Gear Streaks

Crestline Altra, the five roller system.

 

[inky]

Re: Gear Streaks

I developed the same problem over night, literally over night, but with Kompacs, I never got to the bottom of it even after having the press re-geared and new bearings. After a year I sold the machine, I'm embarrassed to say I believed it was the Kompacs but the engineer who bought the press off me said the new owner never had any problems.

I still can't believe it was chemistry, I guess I'll never know.

 

[Damodara Pai]

Re: Gear Streaks

Have u checked the size of the plate and blanket, even if it's little more than, that specified by the machine supplier, there are chances of the same problem.

 

[Jeremy]

Re: Gear Streaks

Yeah, I checked those. The blanket is manufactured by Ryobi for this press and the plate pressure is adjustable to the thickness of the plate. It also only appears to do it on the second unit. The first unit is fine, which obviously uses the same plates and blankets.

 

[Jeremy]

Re: Gear Streaks

I take it back...both units are doing it.

 

[Damodara Pai]

Re: Gear Streaks

But make sure u don't have the problems in other units too. For colors like yellow u cann't see the streakes properly even if its present. I suggest u print with Cyan or Magenta in all the units with 50 % or 60 % screen and then decide. When i said about plate size, check the dimension in the direction of the sheet / web.

 

[inky]

Re: Gear Streaks

Where's Offset Guy when you need him? I would have thought he'd have some idea. Perhaps you could PM him?

 

[keldrewett]

Re: Gear Streaks

Its a slapping in the drive gears and caused by wear or past jam etc..
The only way to "band-aid" it is to run every pressure setting as light as possible. EVERYWHERE.
Plate-blanket-imp cylinder pressure is most critcal to ease the slapping.
Hope this helps mate!!

 

[Jeremy]

Re: Gear Streaks

is it possibly caused by worn or loose gears in the water system doing that same slapping, possibly making the form roller skid on the plate and wearing it out?

 

[keldrewett]

Re: Gear Streaks

No its the gears on the cylinders. Take the side cover off and have a look and what is going on in there.
Ease everything off to help the load on the gears!!

 

[DANNY]

Re: Gear Streaks

Have you tried looking at the form rollers. Make sure they are not moving side to side.
We had this problem before on the same press and it was form rollers.

 

[Jeremy]

Re: Gear Streaks

Yeah, I checked all the forms for bounce and end play and they all looked good. I just had the gears replaced in the water unit as they were very sloppy. It looks better but the jury is still out. I'll let you know if it fixed it or not.

 

[Jeremy]

Re: Gear Streaks

Well, my technician replaced the gears in the water unit and I still have the streaks (no surprise). They refuse to believe it could possibly be bearings or an incorrect pressure setting. They're starting to blame the plates, which I've also ruled out. How could I check and prove that the blanket is driving the plate?