Page 46 - Training 2019

Higher quality felts will offer longer life and higher vibration absorption.
Lower quality felt seals will usually have more thickness variations. It is
important the felt seals are properly lubricated. The right amount of a
food grade lubrication can extend the life of the seal by reducing the
friction as well as, the possibility of ink build-up. Food-grade petrolatum is
more effective than oils, as oil flows away (down) from the top of the seal
as it is heated. Conversely, petrolatum stays cooler at the base of the seal
and “wicks” toward the top of the seal as friction heat is generated.

Foam end seals are still a very popular and cost effective solution.

Some new foams, especially those with coatings, can prove to last as long
as many felt seals and be more cost effective.

Flexo end seal materials are available with different durometers
or compression ratios.

This is important as the doctor blade needs to have some upward
pressure from the end seal to ensure an adequate seal is made between
the shoulder of the end seal and the underside of the blade. It is
important that the seal is sized properly and does not apply too much
upward pressure that it causes the blade to “flare” (the end is lifted
upwards beyond a degree or two from anilox parallel). Too much flare on
the blade will require excessive pressure to ensure even blade pressure to
the anilox and will cause uneven wear.

Good seal design for a proper fit is critical to minimize chamber
leaking from gaps.

This is especially true on older presses where alterations may have been
made or vendors for end seals have changed and you are working with
“copies of copies”. This is the most critical in the radius of the seal. If you
are considering looking at new end seal options, it is important to also
supply the diameter of the anilox roll to make sure that the end seal
radius is correct.

Make sure when installing your seals that they are not too tight
that it distorts when it is put in to the chamber.

Check to make sure the face of the seal fits squarely against the chamber
with no gaps or distortion.

The condition of the anilox roll can also play a role in chamber
leaks.

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CHAMBER BLADE END SEALS TRAINING MANUAL
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Updated - 24 June 2019