The Mikro® V-UMP Mill is a vertical, high-speed cutting mill designed for the fine size reduction of plastics, polymers and fibrous materials that do not respond well to other forms of impact milling. This unique mill design allows for interchangeable rotor configurations depending on the fineness required and was developed to grind heat sensitive and soft materials without liquid nitrogen or conditioned air.

The V-UMP is the next step in the evolution of the Mikro® UMP Attrition Mill by providing the same grind as a rigid rotor setup while adding the flexibility of converting to a pin mill for fine size reduction.

Raw material enters the grinding zone from a feeding device through the centrally located feed inlet. Size reduction takes place between the adjustable stator plate and high-speed rotating grinding plate. The particle size is reduced as the raw feed passes through the tapered plates, which have a wider gap at the center of the plates where the material is introduced, and the tightest gap is at the periphery of the plate where material exits. The finely ground product exits the grinding zone and discharges into the evacuation and collection system. Essentially the fineness of the product is dictated by the number of teeth on the plates, rotational speed of the rotor, as well as the gap between the plates.

Multiple system options are available to further enhance the performance and flexibility of the Mikro® V-UMP Mill.


  • Pin or Attrition rotor options
  • Can process heat sensitive materials
  • Compact design, low profile design with Vertical Drive
  • Sizes available from 2 HP to 75 HP
  • Process 5 lb/hr up to 3,000 lb/hr
  • Capable of ultra-fine milling down to d97 < 75 μm
  • More energy efficient than other polymer milling systems
  • Variable speed rotor drive with tip speeds up to 150 m/s
  • Adjustable rotor plate gap
  • Three (3) access ports to facilitate rotor gap adjustment
  • Fabricated stainless-steel construction
  • Dust free operation
  • Cryogenic option for more difficult to grind materials
  • Variety of system configurations



The standard mill is constructed in 304 stainless steel with a highly cleanable finish. Higher quality finishes are available for specialty applications. The top cover is easily removed and allows for quick access and inspection to the mill interior. The high-speed bearing housing includes maintenance free, sealed for life bearings. 


Hosokawa’s attrition plates are uniquely engineered to finely grind heat sensitive materials, and in many cases, without cooling gas or liquid nitrogen. The serrated teeth of the rotating and stator plates create shear forces that cut materials into fine powders with a narrow particle size distribution. The plates are highly durable and can be easily re sharpened to maintain high performance.


The pin disc assembly includes a stationary pin disc mounted to the inside door cover. As an option, the door and stationary pin disc can be provided as one single piece if required for a specific application. A rotating pin disc rotor is mounted to the main drive shaft of the mill. During rotation the interlacing pins create a labyrinth the product has to pass through — providing ultra fine size reduction through a high number of impacts of the feed with the pins. At high speed, the Mikro® V-UMP Pin Mill can process materials to a top size of 35 microns or even finer in certain applications.


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