Definition
Vacuum planetary mixer is a kind of mechanical equipment that mixes, disperses and defoams materials through planetary motion trajectories in a vacuum environment. Its core feature is that the mixing mechanism rotates around the central axis of the container while rotating, and with the vacuum system, it is widely used in processes that require efficient homogenization and bubble removal.
Principle
When the equipment is working, the main drive shaft drives the revolutionary frame to rotate, and the stirring paddle installed on the frame (usually including frame agitator and dispersion disc) rotates through the gear system while orbiting, forming a complex planetary motion trajectory. This movement causes the material to generate multi-dimensional convection, shear and diffusion within the container. The vacuum system starts synchronously to reduce the pressure in the stirring chamber to the set value, and the bubbles dissolved or wrapped inside the material expand and rupture under negative pressure, and are pumped out by the vacuum pump with the air flow, so as to achieve defoaming and densification mixing. The whole process can be programmed and controlled by the control system for speed, vacuum, temperature and time.
Main measurement and evaluation methods
The evaluation of mixing effectiveness is usually based on mixing uniformity and defoaming efficiency. Mixing uniformity can be quantified by sampling and analyzing the concentration variance of each component, and the formula can be expressed as:S2 = Σ(Ci - C0)2 / (n-1), among themCifor the concentration of each sampling point,C0is the theoretical concentration. The defoaming rate can be calculated by measuring the change in material density or volume before and after treatment, using the formula:η = (ρ1 - ρ0) / ρ1 × 100%, among themρ0Withρ1They are the material density before and after processing. In addition, in-line viscosity monitoring and particle size analysis are also commonly used for process control.
Performance Factors
Device performance is affected by multi-parameter interactions. Mechanical parameters include the ratio of revolution to rotation speed, the shape and number of layers of the stirring paddle, and the gap between the paddle and the vessel wall. The process parameters include vacuum maintenance level, pumping rate, processing temperature and time. Material properties such as initial viscosity, solids content, thixotropy, and volatility can also significantly affect hybrid dynamics and defoaming effectiveness. These factors need to be optimized and matched according to the material system through experiments.
Applications
The equipment has application value in many industrial and scientific research fields. In the field of electronic materials, it is used for homogeneous defoaming of lithium battery paste, conductive adhesive, and packaging materials. In the chemical field, it is suitable for the preparation of adhesives, sealants, and resin composites. In the field of new energy, it is used for the mixing of photovoltaic paste and fuel cell catalytic layer. In addition, it is also used in laboratory research and development and low-volume production of high-end ceramic pastes, food sauces (non-pharmaceutical-related) and cosmetic pastes.
Key points to consider in selection
Systematic analysis is required during selection. First, the characteristics of the material are defined, including viscosity range, shear sensitivity, solids content, and volatile components. Determine the effective volume of the container according to the batch, and consider material compatibility and heat transfer needs. Investigate the technical indicators of the equipment, such as vacuum limit and leakage rate, speed control range and accuracy, and temperature control ability. Focus on safety features such as overload protection, vacuum safety valves, and explosion-proof configurations. For R&D purposes, focus on parameter adjustment width and data recording functions; For production use, it is necessary to pay attention to repeatability, cleaning convenience and capacity matching. It is recommended to verify the suitability of the equipment through material process testing.