Air Classified Milling

There are many reasons for milling materials: to increase solubility speed, to combine materials into a fine milled product, to give good 'mouth feel' & taste impact.

Air classifier mills can achieve particle size reduction down to 4 to 15 microns. This depends on the mill selection and the characteristics of the material to be milled. Spray dried powders mill finer than crystalline powders.
There are principally two types of mill process: mechanical impact milling & air jet milling. In mechanical impact mills, milling is achieved by impact between a high speed rotor fitted with hammers or pins and a stationary grinding track. Contact components are stainless steel. Materials harder than Mohs 3.5 are unsuitable for processing on these mills.
Air jet milling uses compressed gas to impact the particles against each other. The advantages are higher energy input thus potentially finer milling and milling of abrasive materials. The disadvantage is often very high energy input for the compressed gas.
In both types of mill particle size is controlled using an internal rotating classifier.
Cryogenic freezing of raw material can permit milling of tough materials which become brittle when frozen. Depending on the requirements of the process and product temperature, controlled milling is also possible with either cooling of the mill or with introduction of heat into the mill air stream.
Some products are sensitive to air oxidation during milling. At Custom Powders Ltd it is possible to run air classifier mills under an inert nitrogen atmosphere.
Throughput on these mills is highly dependent on the raw material properties and the final particle size required. With 35 years experience in air classifier milling we can usually make a reasonable estimate for a new product based on historical data.
Custom Powders Ltd offer air classified milling in 4 production suites ranging from FSSC22000 food grade, industrial and even to medical grade plastics.