Mounting Instructions

Bonding of the tape

All Exafit references are designed with differential adhesion, with the aim of the non-linered side first onto cylinder or sleeve.
Scapa Hardmount filmic double sided tapes are non differential products and can be then mounted either to the print cylinder / sleeve or to the plate depending on the application or the habits.

Mounting on to cylinders

Unwind the tape and apply its leading edge onto the cylinder. Then, with the heel of your hand wipe it from side to side. Care should be taken in avoiding entrapment of air and the creation of the air bubbles as well as any wrinkles. Continue to lay the tape down onto the cylinder and by continuously wiping it. Keep the tape bowed to allow air to escape and avoid any entrapment. If an air bubble is entrapped, burst it with a scalpel, but make sure to not to scratch the cylinder.

If a neat butt joint is needed, please place a ruler or a blunted doctor blade under the lead edge of the tape to avoid cutting into the cylinder. Wrap the tape around the cylinder and overlap the lead edge. If at all possible maintain a position of the blade as 45º to the cylinder. Cut through both layers of the tape and remove excess.

After the tape has been applied, it is recommended to press it down in order to increase the contact area as such increasing the adhesion and make sure this is done as uniform as possible. If the mounting is done manually, one way of doing this is to use a squeegee.

Many mounting systems facilitate the above mentioned operations, especially for larger widths. Those systems usually include a cutting system. Whenever possible, we always recommend the use of a laminator in order to achieve a good laminating / bonding regularity.

In order to minimise plate lifting, it is always recommended to never cut the tape exactly to the plate dimension, but to allow a good margin of at least 10mm of the tape beyond the cliché.

Mounting on to sleeves

The mounting onto sleeves is very similar to the one onto cylinders and many of the recommendations mentioned here above are applicable. However many sleeves are flexible and thin and care should be taken to preserve their structure during the mounting operations.

The following parameters are recommended:

• Always mount the tape while the sleeve is on the mandrel and the mandrel is expanded 
• Use minimal air pressure to inflate the sleeve, as too much pressure can affect the bond either between the sleeve and the tape or even between the tape and the cliché
• Always remember that sleeve substrates vary in material types and roughness compared to steel cylinders, and therefore that extra care should be taken in cleaning and drying the surface. Before any change in sleeve material, it is also recommended to run some trails as the variation of he surface can affect the bonding performances of the tape

Bonding of the cliché

Remove the paper liner of the tape and if possible store it for future use (see the de-mounting section of this document) and mount the plate into the right position by registering it. There are two key points to achieve an effective plate mounting:

• The correct position of the plate onto the tape;
• The achievement of a perfect bond

A good position is achieved by correctly lining up the marks on the plate. There are various types of marks such as register crosses and micro – dots, but whichever type the objective is to always perfectly align the plate. Accurate positioning is essential or the images of the colours will not be superimposed correctly. Out of registration images results in poor image quality. If there is any butt joint in the tape, make sure the edges of the cliché are not at this joint.

Achieving a good bond is essential so there will be no plate moving or lifting during the printing runs. Here it is also recommended to roll the plate down in order to increase the contact area and the adhesion and make sure they are as uniform as possible. If the mounting is done manually, one way of doing this is to use a squeegee or even better a rubber roller.

Many mounting systems facilitate the above mentioned operations, and we recommend the use of the plate mounting machines to ensure perfect positioning and laminating.

Some of the tape references with lower adhesion or tack may not provide the immediate bond required, especially when they are used in combination with rigid plates and / or small diameter cylinders. In such configuration, the plate memory literally works against the bond and the plate, which is flat in its natural state, tends to pull away from the cylinder or sleeves.

In order to allow the adhesion to build up, a thin poly-film (such as polyethylene packaging or wrapping films) can be tightly wrapped around the plate. Holding the tape-plate-cylinder all together will reduce the stress at the interface of the tape-plate bond and allow the bond to build up to its optimum level.

Considering some references give high bond over time on most photopolymers, for easier removal or large clichés, we recommend that one does not keep the plates mounted after use for more than 4 weeks. This also applies for thin clichés due to possible risk of tearing or kniking.