Polyurethane materials are widely used in electronic packaging, automotive parts, medical devices and other fields due to their excellent mechanical properties, chemical resistance and customizability. However, residual bubbles generated during polyurethane mixing and curing will cause internal structural defects and impair product performance and appearance. As an efficient defoaming device, the planetary mixing and defoaming machine serves as a key technical solution to this problem through unique mechanical design and process control.

Working Principle of Planetary Mixing and Defoaming Machine

The planetary mixing and defoaming machine integrates dual functions of planetary stirring and vacuum defoaming. While rotating on its own axis, the mixing pot revolves around the container center to form a complex 3D motion track. It enables homogeneous mixing of high-viscosity polyurethane slurry inside the container and destabilizes bubbles. Afterwards, the vacuum system reduces internal pressure to -99.9KPa. Bubbles expand and burst under negative pressure, and gas is exhausted by the vacuum pump. The coordination of stirring speed, vacuum level and temperature control is critical in this process. For example, low-speed stirring (generally 500-1000rpm) can reduce new bubble generation, and gradient vacuum (stepwise pressure reduction) prevents material boiling.

Key Parameters for Polyurethane Defoaming Process

For polyurethane materials of different hardness (such as flexible foam or rigid potting adhesive), the following parameters need optimization:

Viscosity adaptability: The equipment supports viscosity ranging from 500 to 50,000 cP. The five-blade design does not alter the chemical properties of materials.

Temperature control: Maintain material temperature within an appropriate range (depends on formulations) to lower viscosity for better defoaming while avoiding pre-curing.

Process sequence: The typical workflow is pre-mixing (atmospheric pressure) → degassing (vacuum holding for 3–10 minutes) → low-speed defoaming stage.

Technical Advantages and Industrial Applications

Compared with conventional centrifugal defoaming or chemical defoamers, planetary mixing and defoaming machines deliver prominent advantages:

Residual bubble rate can be controlled below 0.01%.

Eliminate adverse impacts of chemical additives on material properties.

Applicable to special systems including two-component AB materials and moisture-curing systems.

In the field of LED packaging, this technology raises lens light transmittance above 92%; in automotive seal production, the tear resistance of products increases by approximately 30%.