An ACM (Air Classifier Mill) delivers fine and ultra-fine powder with integrated impact grinding and dynamic air classification. The particle size is normally quoted as D97, meaning 97% of particles are smaller than that value.
Typical Fineness Range
- Standard production range: D97 = 10–75 μm (the most common working window for mineral fillers, chemical powders, battery raw materials)
- Optimized configuration for brittle friable materials: down to D97 = 5 μm (special rotor, hammer setup and high classifier speed required)
- Coarser setting: up to D97 = 150–200 μm (low classifier speed for products that do not need high fines)
Feed size limit: raw material usually ≤8–10 mm before entering ACM grinding chamber.
Key Factors That Shift The Particle Size Window
- Classifier wheel speed – primary online adjustment: higher speed = finer top cut; lower speed = coarser product
- Hammer count & rotor tip speed – defines impact intensity and fines generation baseline, as covered in the previous article
- System airflow – controls particle residence time inside grinding zone
- Material friability & hardness: Soft brittle minerals (calcite, talc, kaolin) reach finer sizes easily; tough or elastic materials are harder to grind below D97=10 μm.
Important Comparison Note
ACM is excellent for fine powder with sharp top-cut control and relatively narrow PSD. For consistent submicron powder (below 1 μm), jet mill technology is normally selected instead, as ACM mechanical impact has practical lower limits for ultra-fine grinding.
JACAN ACM series supports flexible tuning across D97 5 μm to 150 μm, with ceramic-lined rotor options for high-purity materials. Operators can adjust classifier frequency online, while hammer count modification is a mechanical offline change to alter fines yield and overall PSD distribution.
