The working principle of the mill

Think about a few questions


Why can open-lapping machine to the high elasticity of raw rubber into a plastic state of plastic? With the open mill for mastication, mainly through the two relatively rotating roller on the rubber produced by the shear, squeeze the role of the original large polymer chain was interrupted, so that the original material Elasticity is reduced, and the plasticity is improved, which is advantageous for the following processing steps. The current use of plastic molding method is mainly package roll plastic melting method and thin plastic method. 

2. How to mix the compound with a variety of mix together? In the process of refining the refining machine mainly rely on two relatively rotating roller on the rubber material extrusion, shearing, after repeated kneading, and the process of refining the chemical associated with the process, the rubber inside the large Molecular chain interruption, so that the composition of the various ingredients mixed evenly, and finally reached the purpose of refining. The film discharged from the roll gap is coated on a roll due to the difference in the speed and temperature of the two rollers and returns to the two rolls, which is repeated several times to complete the refining action. In the plastic refining to promote the molecular chain of rubber from the long short, the elasticity from small to small; in the mixing to promote the composition of the various components of the material constantly updated, evenly mixed. In the intermittent operation of the mill, after feeding the material repeatedly through the roller several times, and finally cut the next piece.

In the continuous operation of the mill, the compound is continuously fed from one end of the roll and repeatedly through the roll several times according to the refining process. The desired strip is continuously cut from the other end of the roll

3: rubber in the open-processing machine on the processing, what conditions should be in order to get a good effect of refining it? We will discuss from two aspects, that is, from the perspective of mechanics and rheology to be discussed. 

From the mechanical point of view to study the conditions of the rubber into the roller gap in the rubber operation we can see that when the rubber coated with a roller between the two rollers there is a certain amount of accumulation of plastic, these accumulation of plastic The rotating roller is brought into the nip, and the new stack is continuously formed. The effect of these stacked plastic on the refining effect is great. If the accumulation of too much, too much accumulation of plastic can not enter the nip in time, only gently shake the ground, then refining effect significantly decreased. If the accumulation of plastic is too small, you can not form a stable and continuous operation. It can be seen that it is necessary to determine the amount of deposited glue, and for this it is necessary to introduce a concept called contact angle.

Whether the compound can enter the nip depends on the friction coefficient of the compound and the roll and the size of the contact angle.

In the process of refining the rubber, the rubber on the roller radial force (resultant) - that is, lateral pressure, in turn, according to the relationship between the force and the reaction force, the roller to produce a similar size, the opposite direction Force - the reaction force of lateral pressure,The force is broken down into a horizontal force and tangential force, the squeeze on the rubber material, and to produce deformation, and then roll out the material roll distance.

In addition, the rubber and roller between the movement in the process of friction, that is, the presence of friction, rubber friction on the roller with the direction of departure from the roller distance. In turn, the friction of the roller to the compound, the direction of the roll into the roll, its role is to pull the rubber into the roll distance.

From the analysis we can see that only when the friction angle is greater than the contact angle, the rubber can enter the roll distance.