Viscoelastic Application Of Silicone Rubber Rolls
🕙 2023-11-01 👆
In the actual printing production, the viscoelastic effect of rubber has a direct impact on the dynamic hardness of the roller, the printing pressure and the heat accumulation in the roller.
Heat accumulation in lithography offset printing is relatively easy to occur, so the rubber roller material used in lithography printing should be selected with a relative viscoelastic lag, which is very important for controlling the dimensional stability of the roller and rubber aging, and preventing excessive printing pressure.
The same is 25℃ rubber, the internal friction is relatively large rubber material in the printing process of dynamic pressure and dynamic hardness are relatively large, and it is easier to accumulate heat under the same printing conditions.
Higher temperature and wider indentation will lead to a nonlinear increase in the actual pressure during the printing process, resulting in a sharp increase in the heat accumulation in the roller body, which directly leads to the damage of the roller. In addition, in different printing methods, the heat accumulation of the roller is also different, such as offset printing, and the heat accumulation of sheet offset is higher than that of web offset.
Therefore, even if the rubber type that can be used normally at a certain temperature has been selected, in the actual printing, the correct indentation width should be used (the manufacturer generally provides the appropriate indentation requirements for its original rubber roller in the manual), and measures should be taken to prevent temperature rise. Especially when the machine is idling. The use of special empty car protection paste, can get the effect of reducing the temperature.
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