ideal durometer for metering roller?

[Albert Noel]

for years we've used 25 shore "a" and let them get as high as 32-35 before changing them out, however i came across the july/aug '99 issue of gatf world at work lastnight, that has an article about alcohol free printing where they insist 18-20 shore "a" is what it should start at for better results. roland says 25 shore "a" for alc sub. so i'm a little confused.

will i see better results with a softer metering roller? i'm getting close to replacing 1 or 2 of them and want to know if i should change them or keep them at 25.

 

[keldrewett]

for years we've used 25 shore "a" and let them get as high as 32-35 before changing them out, however i came across the july/aug '99 issue of gatf world at work lastnight, that has an article about alcohol free printing where they insist 18-20 shore "a" is what it should start at for better results. roland says 25 shore "a" for alc sub. so i'm a little confused.

will i see better results with a softer metering roller? i'm getting close to replacing 1 or 2 of them and want to know if i should change them or keep them at 25.

I have found 20 to be the sweet spot. Under that it is a bit too hard to control.
Over 25 you also loose the control.
You will see better results with the softer shore hardness, but more importantly make sure you get the rubber compound for IPA free. There are different compounds available.
Also if you are running a Heidelberg make sure the crown has been eliminated on the roller profile!!

 

[Albert Noel]

i'll get 20 this time aropund then and make sure it's made for ipa free.
i'm on a man roland 300 so i dont have much control other than nip.
i'll see what happens.

I have found 20 to be the sweet spot. Under that it is a bit too hard to control.
Over 25 you also loose the control.
You will see better results with the softer shore hardness, but more importantly make sure you get the rubber compound for IPA free. There are different compounds available.
Also if you are running a Heidelberg make sure the crown has been eliminated on the roller profile!!

 

[ronson]

I´m also considering going IPA free in the future, what is this "crown" in roller profile and why is eliminating it so important?

 

[GazKL440]

is "crowned" also known as "domed"?? we have metering rollers that are domed in that they are fractionally larger in circumfrence in centre of roller (only a few thou) than they are at the outer edges... promotes water coverage at edge of sheet when running a full size sheet...

 

[Mike Herndon]

is "crowned" also known as "domed"?? we have metering rollers that are domed in that they are fractionally larger in circumfrence in centre of roller (only a few thou) than they are at the outer edges... promotes water coverage at edge of sheet when running a full size sheet...

You can test both and see which ones work well with your set up. Some shops run 0 crown and I've seen some go up to 25%. We tested 0 and 5% and ended up using the 5% crown on our sm102 water pan rollers both alcolor and vario. Our shore starts around 20 when new and usually close to 26-28 when we change them. Zero crown just did not work for us but I know shops that use them successfully.

edit- we run alcohol free, does make a difference when it comes to rollers, hardness, crown etc.

Mike

 

[keldrewett]

Yep Mike is correct. The crown will have an adverse effect when running IPA free as it pushes too much water to the ends of the plate. Mainly seen on Heidelberg not Komori.

BTW Are you running IPA free GazKL440?? Its very easy on Komori's mate!

 

[GazKL440]

Kel; no we run IPA, around 7-10 percent varying with the season(more in summer to help battle temp) as its an un airconditioned factory floor... and we use bloody heaps too around a 44gal every week or 10 days on our 40" and 26" presses... i dont know what the hardness of our rollers is but they are essentially run till they crap out then swapped

we run a FERAG fount(solar fount) and hostmann steinberg inks, and aside for a bit of build up outside the print are they give us no major probs, unfortunately i dont get a say in chemical usage/choices as our production manager is pretty tight with the rep(state of origin tix dont hurt lol)!!!

On the Roland we used to have you could skew the metering roller if required when running a full size sheet..the slight angle would promote higher water film towards edges, but then you had to try and get that bucket of shite to fit across a 1020 sheet, but that was tired grippers not the dampeners..and damn near impossible..

 

[keldrewett]

Kel; no we run IPA, around 7-10 percent varying with the season(more in summer to help battle temp) as its an un airconditioned factory floor... and we use bloody heaps too around a 44gal every week or 10 days on our 40" and 26" presses... i dont know what the hardness of our rollers is but they are essentially run till they crap out then swapped

we run a FERAG fount(solar fount) and hostmann steinberg inks, and aside for a bit of build up outside the print are they give us no major probs, unfortunately i dont get a say in chemical usage/choices as our production manager is pretty tight with the rep(state of origin tix dont hurt lol)!!!

On the Roland we used to have you could skew the metering roller if required when running a full size sheet..the slight angle would promote higher water film towards edges, but then you had to try and get that bucket of shite to fit across a 1020 sheet, but that was tired grippers not the dampeners..and damn near impossible..

I can give him a fount that will save him having to buy any IPA at all.
He can then buy everyone SOO tickets and XXXX!!

 

[GazKL440]

"wash up for gold" (XXXX gold) heheh always good

i think a drum of ipa is what $500, $600 odd?

would be a useful saving... probably 3 drums a month...

 

[Albert Noel]

so, if i had to guess, my rollers should have 0% crown since my metering roller is pre-skewed and already promotes water to the ends right?

i haven't talked to the roller rep yet and my labels don't say anything about crown.
they come from rotadyne)

 

[keldrewett]

"wash up for gold" (XXXX gold) heheh always good

i think a drum of ipa is what $500, $600 odd?

would be a useful saving... probably 3 drums a month...

Yep!!
PM me and i'll send you some info.

 

[keldrewett]

so, if i had to guess, my rollers should have 0% crown since my metering roller is pre-skewed and already promotes water to the ends right?

i haven't talked to the roller rep yet and my labels don't say anything about crown.
they come from rotadyne)

Yep the crown is there to compensate for presses that can't skew (Heidelberg)
Try Westland or Katsura rubber if you can get it.

 

[sivabalan]

For Alcohol free printing the right durometer (Shore A) will be 18 -22 & for normal printing it is suggested to use durometer (Shore A) 25- 30. Softer roller tend to be more water-receptive. Their softness increase the width of the nip between the metering roller and the chrome tranfser roller without increasing the pressure, giving press operator more adjusting latitude.

 

[Albert Noel]

hate to bring back an old thread.. but still having some issues with scum in the center of the plate and flooding on the ends.

im wondering, is there such a thing as negative crown on a metering roller?
say if i wanted the center of the roller to be slightly smaller in diameter than the ends?
our 300 has pre-skewed meters and they cant be paralleled. i think if the rollers were a bit smaller in the center that would eliminate my problem.

would that work or am i crazy?

 

[Alois Senefelder]

Metering Roller

Metering Roller

Hello fellow Lithographers,

I suggest you read the PDF I posted on the 31/10/09 -- re - flooding at the ends of Metering Roller.



Regards, Alois

 

[Albert Noel]

Hello fellow Lithographers,

I suggest you read the PDF I posted on the 31/10/09 -- re - flooding at the ends of Metering Roller.



Regards, Alois

i looked at it. i use the same length of metering roller as was originally installed in the press, which is roughly .75in longer than the inkers. also, my pan roller osculates so a collar on the end of the roller would not work.

 

[loopyg66]

albert

albert

have you made sure your meter rollers are paralled by following the instructions in the manual? also, stick with the 25 durometer......softer is not going to help your issue.