Water form gear removal

[Deleted member 16349]

Thanks Erik,

What browser are you using?

Al

I have tried both Safari and Firefox. No luck with either.

 

[Lukew]

I have never had a lot of luck with this particular dampener design. Many versions use a bracket design that increases the pressure from the chrome (or ceramic) roller to the form roller significantly when the dampener engages. Too much pressure at this point causes great difficulties for running without alcohol and my attempts to reduce this pressure to a moderate one when the press was running led to a gap between these two rollers when the press stopped, allowing water from the first unit to drip onto the register board. Other than the dampener design, a nice little press.

Dan the water form is meant to have a gap between the chrome when it isn't engaged to the plate & chrome. If it didn't, when ever you washed up the roller wash would transfer straight into your fountain solution. Also if you ran a dry deck with off duty lube it would transfer straight to the chrome.

The way the water form is set is when there has been no fount run up into the trays and the chrome is dry and at room temperature. Then ink the roller train up including water form, without the machine running press the engage water form button. This will leave the stripe on the chrome & the plate showing you what pressure the water form to chrome is during running.

Earlier shinohara's used to run a 3mm stripe. The latest shino 52's are recommended to run a 4mm - 5mm stripe. I have found running a 3mm stripe helps a little.

Your country has done IPA free for 20+ years & I'm sure there are many Sakuri / shinohara's over there. My guess is though your roller companies have their heads around what compound and shore A hardness is needed for the water form & metering roller for this 3 roller setup.
I believe the issue we have is an incorrect compound for the water form, as this issue happens no matter what level alcohol is run. you can put 15% IPA in the mix and the beading still happens.

 

[Dan Roll]

I will check and see what some of my contacts in the roller business think about this and if they have a special elastomer product for Sakuri/Shinohara dampeners.

 

[john beniston]

So did anyone offer a solution to this guys problem ?

 

[Lukew]

Thanks for that Dan.

I'm guessing though that all the various machines over there running alcohol free have had both the metering roller & water form roller changed out.

Seems absurd to me to run a metering roller with alcohol free compound, but then run a water form roller in a standard compound and not a water form roller designed for alcohol free printing. But I'm just the printer and not the roller manufacturer.
The fount is trying to make its way through the nip of the chrome-water form, exactly the same as it does between the chrome - metering roller nip.
My thoughts are, you have a good free flow of fount from the metering roller nip, then it hits a road block when it hits as standard compound water form roller. Hence the reason why the issue still exists no matter the level of alcohol.

 

[john beniston]

Yes you are right we have had various compounds over the years
We have even run the metering roller at 20deg shore 'A' hardness.
You might want to look into a recent roller we received from Japan.
They are called Techno Roll. I think they are mostly for UV operations, but I think they also have some conventional compounds.
They are extremely good rollers.
But it does not seem like a very good solution as I am sure the macbine worked just fine after the installation technicians had set it up, and handed it over to you. I bet it worked just fine at that time. So since the set up crew left your press to you guys, you have to look into what has changed since that time. Changing stuff out just because everyone thinks that it is the latest and greatest is not Kosher.Putting the machine back to specs is the best way and provides a reasonable base line to work from.
We run the temperature of the dampening fluid at around 10.5C in the tank. This gives us about 12C in the water trough which we find cold enough.
I cannot think of a good reason for these cool temperatures but somehow they seem to work.
If the fluid is not passing adequately through the nip something has to be causing this to happen. Is the nip too tight, is the fluids surface tension too high? Do you have any one who could help make a root cause analysis?
Good luck

 

[Lukew]

Yes you are right we have had various compounds over the years
We have even run the metering roller at 20deg shore 'A' hardness.
You might want to look into a recent roller we received from Japan.
They are called Techno Roll. I think they are mostly for UV operations, but I think they also have some conventional compounds.
They are extremely good rollers.
But it does not seem like a very good solution as I am sure the macbine worked just fine after the installation technicians had set it up, and handed it over to you. I bet it worked just fine at that time. So since the set up crew left your press to you guys, you have to look into what has changed since that time. Changing stuff out just because everyone thinks that it is the latest and greatest is not Kosher.Putting the machine back to specs is the best way and provides a reasonable base line to work from.
We run the temperature of the dampening fluid at around 10.5C in the tank. This gives us about 12C in the water trough which we find cold enough.
I cannot think of a good reason for these cool temperatures but somehow they seem to work.
If the fluid is not passing adequately through the nip something has to be causing this to happen. Is the nip too tight, is the fluids surface tension too high? Do you have any one who could help make a root cause analysis?
Good luck

In my first post I listed the Standard specification for the water form & metering roller shore A hardness.
Water form 23 shore A
Metering roller 30 shore A

The water rollers supplied are
Water form 27 - 28 shore A
Metering roller 25 shore A

I have trialled a water form roller of 22 shore A and the issue mostly goes away , but the roller company told management the roller will not last. And recommended we utilise the standard compound they sell.

Running your fount temp cooler increases the viscosity of the fountain solution slightly, we are running at the same temp you are although we have run as high as 16 deg to see the difference.

Next order of rollers we will run Bottcher.

 

[Dan Roll]

After waiting out the long weekend spent observing Memorial Day, I checked with several of my acquaintances in the roller business asking what percentage of their U.S. sales are made up of specialty rollers designed for enhanced dampening performance. The answers were always 'we have a great roller for that purpose' followed by 'we don't sell very many'. One representative of a major international roller company told me he couldn't remember the last time he had sold a specialty roller for dampening.
There used to be a strong belief that soft rollers were superior for dampening, but we did an experiment (many years ago) based on the suggestion that soft rollers were considered to be superior being based on comparisons to older, harder, rollers. When new rollers of different durometer were switched from one press to another during our comparison, the operators involved reported no differences. I think as long as the dampener rollers are in excellent condition, other elastomer or surface properties are less (not to say not) important.

 

[Lukew]

Dan, Thank you for taking the time to speak to a roller manufacturer over there for me.
That is interesting to hear him say that, and his conclusion of roller shore A hardness is similar to what I've been told here and what Europe use. It seems weird to hear that the actual compound of the roller doesn't really make a difference.

I've checked the westland & Katsura website to check what dampening rollers they offer & both offer several compounds (Not meaning the shore A hardness) of both water form rollers & metering rollers.
They have a compound for IPA printing in several shore A hardness. They also have rollers with a specific compound for IPA free / reduced printing in several shore A hardness.
They claim the IPA free compounds for use in water pan / metering / water form positions are more hydrophilic then the standard compounds all except the Lototec metering /water pan roller from westland.

I've been thinking about our issue a little more now, and I'm wondering if the actual dimensions of the water form / chrome / metering roller and the gear ratio on this particular press could give rise to this issue.

 

[Alois Senefelder]

Please read !

Please read !

Hello Lukew,

I suggest you read my post - Page 1 - The Mechanics of Fluid Transportation


Regards, Alois

 

[Dan Roll]

"I've been thinking about our issue a little more now, and I'm wondering if the actual dimensions of the water form / chrome / metering roller and the gear ratio on this particular press could give rise to this issue."

I think there is something here, the two metering rollers (chrome and pan) are turned by their shafts, not by surface contact, so their surface speeds are the result of both the shaft speed and the roller diameter. Several manufacturers have experimented here in order to avoid paying royalties for using someone else's dampener patent. Friction is an enemy of alcohol free printing, so too much of a speed difference between these two rollers would be expected (by me anyway) to cause problems.

 

[CKL]

Dampner gears and roller size

Dampner gears and roller size

I have experimented with +/- 1.5 mm on the Komori dampner form from their spec.

Be mindful of the gears bottoming out and causing damage.
Most Komori's need the speed differential for the cleaning of hickies.