1、 Working principle
1. Preprocessing and feeding: Dry powder materials (with a moisture content of ≤ 5%) are quantitatively added through a vibrating hopper or a screw feeder, and after degassing and preloading, powder gaps are eliminated to ensure uniform delivery to the rolling mill area.
2. Compression molding: Two rolling rolls rotate synchronously in reverse through gear meshing, and the surface is designed with special patterns (such as strip-shaped grooves or diamond shaped grooves) to increase friction. The material is instantly compressed into a dense sheet or block structure by the high extrusion pressure (up to 6kN/cm ²) applied by the hydraulic system in the arc-shaped groove of the rolling mill.
3. Crushing and sizing: After the formed material leaves the rolling mill due to elasticity, it is crushed into irregular blocks by a crusher, and then cut and screened by a sizing machine to obtain the target particle size (usually 16-80 mesh). The screened fine powder is recycled and granulated through the return system to improve the utilization rate of raw materials.
2、 Core application areas
1. Pharmaceutical industry:
Handle heat sensitive drugs (such as cephalosporin antibiotics, probiotics) and moisture sensitive traditional Chinese medicine extract powder to avoid degradation of active ingredients caused by high temperature or moisture.
Directly pressing tablets or filling capsules eliminates the drying process of wet granulation, shortens the process, and reduces the risk of contamination.
2. Food and Chemical Industry:
Suitable for granulation of dry powders such as instant food additives, fertilizers, ceramic powders, etc., to enhance solubility and flowability.
Flammable and explosive materials (non friction sensitive) can be safely treated by temperature control using water-cooled rollers.
3、 Technical advantages
1. Energy saving and environmental protection: No need to add adhesives or solvents, no drying energy consumption, energy saving of over 40%, in line with green production requirements.
2. Intelligent control: The hydraulic system accurately adjusts the extrusion force, and the PLC automatically controls the particle size uniformity (particle qualification rate ≥ 70%), supporting fault self diagnosis.
3. Flexible adaptation: It can handle materials with large differences in fluidity, optimize compression effect by changing the roller pattern (embossing/smoothness), and adapt to laboratory to industrial production capacity (10g/h-80kg/h).
4、 Key process parameters
1. Roll design: Rough patterns (rolling patterns) enhance powder gripping force, while smooth rolls require higher screw speed to compensate for fluidity.
2. Degassing degree: Fully degas to avoid compression bubbles, prevent subsequent blockage, and prevent excessive fine powder rate.
3. Pressure and gap: Pressure affects the density of the material and needs to be adjusted according to the plasticity of the material; The width of the roller gap is usually 2-3mm.
Note: This technology is sensitive to material characteristics and requires targeted optimization of parameters to avoid issues such as crystal transformation or insufficient tablet hardness.