Jet Milling

The Air Jet Milling Services offered by Custom Processing Services, Inc., are based on the use of micronizing mills.

Fluid Bed Jet Mill
The fluid bed jet mill is ideal for, but not limited to, air jet milling abrasive  materials using compressed air. In the fluidized bed jet mill, the high speed incidental wall collisions are reduced to near zero. In the mill, the air nozzles convert the pressure to velocity in a bed of material at the bottom of the mill, entraining and accelerating the particles within the bed. This grinding action utilizes the extreme edges of the bed as a wear liner, preventing contact at high velocities to parts of the machine. It prevents pick up of contamination to the material being ground.
The milling machine has an internal mechanical classifier to perform the particle size reduction, and it is easy to change the particle cut required. The oversized material is rejected from the classifier wheel within the mill and returned to the grinding section of the mill for further size reduction.

This particular machine can also be run with hot compressed gasses, making the mill more efficient by using heat to raise the escape velocity of the gas without requiring additional pressure, and thereby making the cost of compressing the gasses less. It still maintains the same velocity. It can also perform some drying of the material.

Steam Fluidized Bed Jet Mill
A version of the fluidized bed jet mill that can grind even finer than noted above utilizes superheated high-pressure steam to perform dry grinding of material. Some dense materials have been successfully ground using this dry processing method to 100% less than 1 micron. Traditionally, wet processing systems were the only method to process materials to less than 1 micron.

This system does not wet the product, and it can even initialize chemical reactions on some products or it can even dry other materials from some levels of moisture.

Below is more information about the air jet milling system used by CPS.

CGS Fluidized Bed Jet Mill

The grinding energy is created by gas streams from horizontal grinding air nozzles. Particles in the fluidized bed created by the gas streams are accelerated towards the center of the mill colliding with slower moving particles.

The particle laden air transports the particles up to the classifier wheel. Coarse particles are rejected by the classifier wheel which allows only those fine particles that meet the requirements (rotational speed, air volume) to pass through.

Here are some of the CGS mill’s special features and benefits:

  • Tight particle size control
  • Large and small batch quantities
  • Hinged classifier head opens to 180°
  • Easy cleaning and maintenance
  • Turnkey system
  • For products of every degree of hardness
  • Contamination free
  • Milling with cooled gas (20°C)
  • Reproducible results
  • Quiet operation

CGS 150 Fluidized

Bed Jet Mill


Air flow
8640 m³/hour
Classifier wheel power
90 kW (125 hp)
Max. classifier speed
1700 RPM
Number of grinding nozzle
Nozzle diameter
22.4 mm
5-90 µm (d97)

Micronizing Mill Schematic




Applications for CGS Fluidized Bed Jet Mill



  • Toner
  • Pigments, organic
  • Powder Coatings
  • Pharmaceutical Substances
  • Crop Protection
  • Graphite
  • Tungsten Carbide
  • Ceramic Pigments