blanket torque

[neversatisfied]

What should I torque blankets to on a Komori 28. I have asked Komori and they said to ask blanket manufacture, I did and they said ask Komori.

 

[GazKL440]

Im not sure what the blanket torque specs are, but we run a 26 and 40 inch Komori, and simply tighten hard, run a few sheets on impression, then re torque the tail edge...

 

[J. de Drukker]

blanket torque

Normaly we use the next formula

lenght of the blanket in cm x 0.6 = strenght in N/m
ex.ample: heidelberg speedmaster 102 (lenght of the blanket is 105 cm)
the formula is 105(cm) x 0.6 = 63 N/m
so in this examlple you should tighten our blanket with 63 newton/meter

 

[jlind]

When I was testing blankets, the blanket rep gave the press operator a torque wrench that clicked at the right value for the Komori L628. On the SM52, for a blanket test of multiple blanket manufacturers, the most common response was 45 ft pounds (sorry, no metric conversion...)

John Lind
Cranberry Township, PA
724-776-4718

 

[tmason]

We torque to 23 lbs. at the tail and gripper on new blankets to avoid smashing the lead edge. We will re tighten to 25 lbs. if we notice slurring.

If you over tighten it destroys the integrity of the carcass. I think 45 lbs. is way too tight and you will not get the rebound out of your blanket when it takes a hit and if you print full coverage to the gripper, it will smash the lead edge quickly.

 

[GazKL440]

If you over tighten it destroys the integrity of the carcass. I think 45 lbs. is way too tight and you will not get the rebound out of your blanket when it takes a hit and if you print full coverage to the gripper, it will smash the lead edge quickly.[/QUOTE]

Thats interesting to note, as i mentioned above we just wind them tight and re torque after a few impressions, and im fairly sure that we tighten at least as hard as 45 lbs... however we dont get much of a rebound at all, running hard packing (3xpacking sheets) and we lose a few blankets to bingles here and there, but also end up with a few impression marks after running a few hundred thousand sheets of mail out that show up in better quality jobs as shadows in screens etc...could this be a result of high blanket tension or hard packing?? i have tried to get under blankets as the cost is similar to the packing sheets (and we have none of the above issues on our 26 running under blankets) but management know better and feel that we should not change...

 

[LSW]

Information I have from Bottcher lists Komori Lithrone/Sprint 28 as 51Nm - 37 ft pounds.
see file attached

 

[nhprinter]

also end up with a few impression marks after running a few hundred thousand sheets of mail out that show up in better quality jobs as shadows in screens etc...could this be a result of high blanket tension or hard packing??

We call this "blanket ghosting". I don't think the torque has anything to do with it. One of the reasons we use the blankets we use is because we don't get this. Some of the blankets we tested did.

 

[KomoriCommunity]

blanket torque

This is a fairly common question and an even more common answer. The dilemma lies in the gap between manufacturing: the press manufacturer looks at the situation and says, "We don't make the blanket so please ask the blanket manufacturer where the torque should be set for the best blanket performance." The blanket manufacturer looks at the same situation and says, "We don't make the press; please ask the press manufacturer what the torque setting should be to get the best print performance."

This I know from personal experience because we went through the same scenario. Therefore, per our tests with Day International 3000 blankets the torque settings that optimized blanket life and dot reproduction was 43 ft/lbs.

The most important thing is to be consistent - same torque on every blanket on every unit every time. Good advice is to use a torque wrench that cannot be adjusted other than the target torque.

Doug Schardt
Komori America

 

[jlind]

Doug: Just because I know you might have an answer...
1. What happened when the torque was 35 ft lbs?
2. What happened when the torque was 50 ft lbs?

Regards,
John Lind
Cranberry Township, PA
724-776-4718

 

[tmason]

To all blanket manufacturers.

Do different blankets need different torque?

Some blankets have a carcass that is as stiff as a board while others are very soft. Gripper edge integrity is a concern for image area and even tension is a concern for a huge host of reasons. We also do not want to over torque the carcass so it is no longer a compressible blanket.

Remember, it is only a guideline, not gospel.

 

[KomoriCommunity]

blanket torque

John:

To be honest, I don't recall exactly what happened at those specific torques - we did the test a number of years ago. But in general if the blanket is slightly loose the dot quality "shimmered" slightly. I suspect this is because the rubber surface didn't have enough stiffness. This shimmering is very minor and most people wouldn't even notice it, but it was there. If the blanket is way too loose you get doubling and waves.

When we "overtorqued" the blanket - and by that I mean our definition of overtorqued - we had an uneven break in print at the lead and tail. Our test showed a tendency for the blanket to start getting thinner at the lead and tail after a certain point was reached. My guess is once the blanket starts actually stretching it initially gives up mass closest to the clamps. When that happens if you run breakaways you can see the slightly uneven break in pressure.

Our number of 43 lbs fell just below that point of unevenness.

Bear in mind, this was a test to determine the ideal blanket torque to optimize dots. We didn't test for ink release, solid lay, etc. After determining our number we later went on to check durability and the ability to take a hit without smashing (ultimately this was inconclusive), I am sure different blankets may have different ideal torques, etc. but our test gave us a good number that has proven successful over the years.


Doug Schardt
Komori America

 

[GazKL440]

When the blankets are a touch loose on the 40 inch komori i run they tend to advertise this fact with a slight clunky noise during impression cycles, and the general corner yo corner fit of the job will go away on whatever blanket is loose.. at this point we will have already determined which blanket is loose and take up the slack...as i have noted previously in this thread we dont use a torque wrench, just crank it up tight...

KomoriCommunity: just a quick note on the Lithrone 40.... lovely piece of iron reliable, fast, damn productive and in general a bloody god press to run

 

[jlind]

Good answer Doug. I appreciate it. All the best.
John Lind
Cranberry Township, PA
724-776-4718

 

[KomoriCommunity]

GazKL440,

It is good to hear that you are so pleased with your Lithrone 40. We appreciate the feedback!


Komori Community

 

[Johnston Collins]

Maximun print length in cm, less 10%= setting for n/M
eg, XL75, print length = 59cm less 10% = 53 newton meters.

 

[rapid3]

On our SM74/CD74 we torque to 30ft/lb. We used a packing guage to
check the blanket height at the gripper, the center, & the tail of the blanket.
Using a torque of 30ft/lb gave us the same blanket height around the
cylinder. Going higher would make the center height change by approx
.001"-.002". Go any lower and the blanket is too loose.

 

[Servicetech]

Blanket torque

Blanket torque

I always recommend 1 foot pound of torque for every inch of blanket width.

it has worked well for me on machines from 20 to 50 inches with various brands of blankets

 

[dyctechnodude]

Komori 28

Komori 28

What should I torque blankets to on a Komori 28. I have asked Komori and they said to ask blanket manufacture, I did and they said ask Komori.

Hello my name is John Crisp and I am the Technical service Manager for DYC printing Blanket CO here in Virginia Beach Virginia

Answer to your Question:444 inch pounds / 37 FT.Pounds / 51 newton Meters
I broke it down in 3 forms for you.If you have any question further I can be reached at
1-800-446-8240

 

[saso777]

Different blanket,different torque ,you may find about blankets more information from producers.