How to solve the uneven operation of industrial multi-shaft mixer

In modern industrial production, multi-axis mixers are key equipment and are widely used in chemical, food, pharmaceutical and other fields. In order to ensure its efficient and stable operation, it is essential to conduct a comprehensive inspection of the power system of the mixing shaft regularly. Multi-axis mixers are usually driven by multiple motors or one-to-many linkage drive. In this process, if the coupling is not accurately aligned, the chain is loose, the gear meshing is poor, the reducer is worn internally, and other mechanical parts have defects, it will directly lead to uneven load distribution between the shafts. This imbalance may cause problems such as abnormal speed, idling or high load of one or more shafts.

In on-site diagnosis, it is recommended to use a laser alignment instrument to detect the installation accuracy of the shaft system. At the same time, a vibration analyzer can also be used to monitor the operating status of bearings or couplings to ensure that they are within the normal working range. In addition, the normal oil supply of the lubrication system is also key, and it is necessary to check whether there are fatigue cracks or lubrication failures to avoid affecting the overall performance of the equipment.

The stability and synergy of the electronic control system should also not be ignored. Multi-axis mixers are usually equipped with a frequency converter drive system that supports multi-axis independent speed control or collaborative linkage control mode. If the inverter parameters are improperly set, the voltage is unstable, the encoder signal is disturbed, and the servo response is not timely, the output torque of each motor will be inconsistent, which will cause the speed difference and synchronization mismatch between the stirring shafts. To this end, the inverter needs to be calibrated, the acceleration and deceleration time, PID parameters and speed upper limit value need to be adjusted, and the PLC logic program in the control system needs to be checked to ensure that the speed settings of each shaft are reasonable and do not conflict with each other. In addition, the integrity of the signal transmission line also needs to be checked to eliminate problems such as data drift and control delay caused by interference.

Under the premise that both the mechanical and electronic control systems are checked and there are no abnormalities, it is very important to further analyze the matching of material process parameters and stirring structure. Multi-axis stirring equipment is usually equipped with different types of stirring blades such as anchor type, spiral ribbon type, butterfly type or high-speed dispersion paddle. If there are unreasonable aspects in the design of the stirring paddle, such as the paddle diameter does not match the size of the kettle body, the paddle arrangement is asymmetric, and the paddle angle is not optimized, it will lead to uneven material flow path or unbalanced shear rate distribution in the stirring zone. This imbalance will cause the workload of some axes to be low, while other axes may be overloaded.

In order to optimize the design of the stirring paddle, the flow field and shear field distribution during the mixing process should be analyzed by computational fluid dynamics (CFD) simulation based on the rheological parameters such as viscosity, density, and thixotropy of the material, so as to adjust the shape, installation angle and operation order of the paddle to achieve coordination between the shafts and uniform distribution of shear energy.

The temperature control system also has a potential impact on the operating state of the stirring shaft. Some high-viscosity materials are highly sensitive to temperature. If there is a temperature control deviation or uneven temperature distribution in the jacket heating system, the local viscosity of the material inside the kettle will change dramatically. This change will cause a sharp increase in the stirring resistance in some areas, thereby affecting the speed and load of the corresponding stirring shaft, resulting in uneven operation. To this end, it is necessary to adjust the heat medium flow, optimize the jacket structure design, and use multi-point temperature sensor layout and dynamic feedback control logic to achieve accurate management of the temperature field and ensure the thermal stability of the stirring environment.