Control of mixing process in mixer
Mixing the compound with the mixer is the mainstream trend of the rubber mixing process. How to control the mixing cycle of the mixer is the focus of attention. Because it is properly controlled, it can not only improve the rubber mixing capacity of the factory, but also reduce the energy. Consumption, in order to achieve this goal, usually through three ways, but not very ideal.
(1) Control by time
According to common sense, as the processing time of a batch of rubber compound is extended by the internal mixer, the dispersion of each component is gradually uniform, as long as the best time point is found. But in fact it is not the case, because as time goes on, the temperature gradually rises, causing the temperature of the rubber to rise, the viscosity of the rubber to decrease, and the shearing effect to be weakened. The result is often counterproductive.
(2) Controlled by temperature
According to the fact that the rubber material is in contact with the rotor, the wall of the internal mixer, and the friction, the temperature is inevitably caused. Therefore, the temperature increase can be used to control the rubber mixing cycle. However, the factors affecting temperature are very complicated. The temperature of the different components is not equal, and the composition of the same raw material is ever-changing. Even if it is necessary to set a uniform temperature standard for a specific formulation, it is difficult.
(3) Controlled by the energy consumed in the rubber
Since the entire rubber mixing process is also a process of energy consumption, the rubber material consumes energy in the mixing process to cause the machine to shear/knead. Therefore, it is well-founded to use energy consumption to control the cycle. However, the problem is that this correlation is also affected by external factors. Especially when the plasticity of the plastic compound fluctuates, obvious interference occurs, and the accuracy of the control is lost.
In summary, the above three control methods will be affected by external factors and lose reliability. Therefore, it is proposed that the mixing process is directly linked to the viscosity of the rubber compound, and the “visual power change” is used to reflect the viscosity change of the rubber compound, thereby controlling the mixing process. At the same time, the concept of “best viscosity” (ie, the viscosity of the rubber mixture at the optimum dispersion) was proposed as the basis for controlling the mixing cycle. That is to say, for each compound of the specific formula, the specific mixer instantaneous power value is selected as the basis for controlling the mixing cycle.
