V roller ?

2004 LS640
When V roller is changed out we get a streak/scum line on the drive side about 50-80mm from the grip edge. Komori mechanic said it was because the W roller needed changed. Changed that out it is still there. Triple checked roller settings. Turning the skew up around 10 seems to make it bigger. Anyone familar with this. Will try and get pictures up. Bridging the rider to the A fixes it.

 

picture as promised

 

Seems like an interior form roller is either not touching the vibrator, or way too fat. Double check those rollers and see what you find. We had that exact same streak earlier this week; the B form was not touching at all, and the D form had a stripe of 8mm.

 

What was the final conclusion with this streak? We are getting it on start up on both of our LS640s.

 

I reset all rollers nothing was to bad, but also in the morning before start up the turned up the air pressure to the ram. Between the both it fixed it.

 

iS THIS THE MAIN REGULATOR FOR THE PRESS OR IS THERE SOMETHING DEDICATED TO THE AIR CYLINDERS AT THE DAMPENERS? ALSO DO YOU JUST TURN IT UP MOMENTARILY?

 

just for the ram and we left it turned up it is behind the side frame cover on the drive side

 

Thanks, We'll give it a try.

 

Update well I started running our LS more and more it this problem was still happening on the second unit. It was bugging me that I had to run it with the ridge roller intergrated so after 3 days of messing with it setting the forms to the plate small was the answer.

damp form 4mm
A form 3mm
B form 3mm
C form 3mm
D form 2mm

My guess is that the rollers old they are shrunken in the middle and fat on the ends and some how are bouncing or bumping the plate to hard.

 

Those stripes are small compared to factory recommended settings, those are the settings we set on our 28's.

Have you double checked the v roller journals for correct installation? Having the bridge roller on to fix the problem reeks of an improperly installed, or worn out dampner form, i.e, the diameter of the roller is too small for the adjustments to work and retain a setting, letting the roller bounce around giving you that streak.

 

Yes i know they are small that is just what made it go away. all the damp roller are new(er). The rest are old and very shrunken I was just sharing what fixed the problem for all the shops that dont get new rubber until it falls off the the cores. what do you mean by journals ours has more of just a cap that bolts over the bearing?

 

Oh I understand about the rollers with rubber falling out, we have an older 1998 Lithrone 640 that has ancient rollers in it, starting that press up takes some getting used to.

The journals have a bearing cap that has a notch cut out, that receives into the journal itself, to make instillation dummy proof. I know it seems crazy, but I have seen where the caps were on wrong, not tightened down all the way, the bridge gap bearing cap loose, all giving that kind of streak.
But as like you said, old worn out form rollers will give you fits too.

The only thing I could recommend without actually seeing the press run, is for you to watch the V form to chrome adjustment as the press is running sheets. If the adjustment is not worn out, and the roller is newer you should not see it move, bounce or be able see any movement at all. If the adjustment is worn out, you will be able to see some movement, shock from the form hitting the plate and bouncing around.

The Bridge gap roller when turned on will apply more pressure to the form to chrome, creating a larger stripe albeit nominal. It also provides stability when running, preventing any bouncing around, hence my installed properly guess. I had an 072 solid on my last unit a couple weeks ago that was doing the same thing. We have been turning the bridge gap on to get us by with varnishes and such, but that was not an option with the 072. I could get a nice 5mm stripe to the plate and chrome, but when the press was running, you could see where the roller diameter was so small, the adjustment was bouncing around. I ended up changing out the roller and that was that.

 

That pic looks a lot like what happens when the chrome->water form nip is weak.