< Back to products

ACM Air Classifier Mill

Globally renowned as a pioneer in powder processing innovation, Hosokawa Micron invented the classifier mill concept more than sixty years ago and has continuously developed the technology and product since then to accommodate the evolving requirements of manufacturing industries. Launched by Hosokawa in 1962, the original ACM Air Classifier Mill was the first mill of its type available and it continues to be a very popular choice with customers from many sectors.

The compact design, intuitive arrangement of its components and flexibility of the entire range still set it apart from other classifier mills. Robust, well-engineered and offering an array of useful features and benefits, the equipment enables the efficient comminution of difficult-to-process, heat-sensitive and sediment-prone materials and combines impact milling with dynamic classification to accurately control particle size, distribution and cut point.

The ACM Air Classifier Mill range comprises six unique models – including two user-friendly, laboratory-scale models for research and producing small batches – and can now be fitted with newly developed E3 Beaters, which increase throughput by up to 20%, lower energy consumption and improve product quality.

Product Information

With the impressive pedigree of being the first classifier mill on the market in the 1960s the Mikro ACM can be found in thousands of installations across the world in the minerals, cosmetics, plastics, powder coatings, food, and confectionery industries.

Air Classifier Mill Specifications

  • Available in a range of six models – ACM CX, ACM CL, ACM EC, ACM EC-CL, ACM 2 and ACM 5 – the ACM Air Classifier Mill by Hosokawa can be used as a standalone piece of equipment. It may also be integrated into a complex, bespoke process system with additional optimisation features, such as Hosokawa Gen4, Hosokawa Micron’s unique software, which has been specifically created for data-driven process manufacturing and includes remote monitoring capabilities.The ACM Air Classifier Mill is extremely versatile and comes in a very wide range of sizes and powers, with a raft of configurations and performance options available. Optional add-ons, such as energy efficient E3 Beaters, are available. For manufacturers processing materials requiring very specific results or safe handling levels, ATEX-certification and WIP are possible.Tech spec table required to go here (see ACM brochure, but probably not up to date as from 2014).
    • ACM CX This arrangement of classifier and grinding disc shafts’ coaxial bearings means that vertical product discharge is possible, preventing product deposits.


    • ACM CLWhen a horizontal product discharge configuration is preferred, the direct classifier drive and horizontal duct of the ACM CL provide a short connection to additional system components downstream.


    • ACM ECThis ‘Easy Clean’ model is quicker and easier to maintain than some ACM models. The ACM EC is the perfect option for industries where frequent changing of the raw materials is required or for batch production processing.


    • ACM EC-CLThis model offers all the advantages of the ACM CL model, such as a compact, more direct horizontal duct configuration, with the Easy Clean features found on the ACM EC, so is ideal for horizontal product discharge when quicker cleaning and turnaround times are important.


    • ACM 2 and 5These two models have been created for laboratory and small-batch production. Offering the new ‘Easy Clean’ configuration, the ACM 2 and ACM 5 are a user-friendly, space-saving option, with minimal effort required for. Needing just 15 m² of space for installation, a mains power socket and a compressed air connection, these two models offer maximum convenience when space and time are at a premium.


    The core industries that trust the Hosokawa ACM Air Classifier Mill to provide them with excellent high-quality powders use it to process materials such as sugar, cacao, xanthan, starch, talc, pectin, dried fruit, kaolin, limestone, epoxy, polyester, E-PVC, fungicides and herbicides, tartaric acid, polyamide, lactose, ascorbic acid, aluminium hydroxide, formaldehyde, silica, ammonium phosphate, gypsum and calcium sulphate, amongst many, many other materials.

    NEW – E3 Beaters

    Existing and new ACM Air Classifier Mills from Hosokawa can be equipped (or easily retrofitted) with our newly developed E3 Beater, which is an excellent option for powder processing industries. This game-changing addition was developed with gentler, more effective material handling in mind, as well as the requirement for processing equipment to be more economical and energy-efficient – hence the E3 brand name.

    Vigorous R&D, testing (including comparisons with competitor classifier mills) and real-life customer case studies have proved that the ACM Air Classifier Mill, fitted with our uniquely designed E3 Beater, can substantially enhance throughput by up to 20% while simultaneously reducing the mill’s energy usage and improving the quality of the processed powder by providing lower fines content, lower temperatures during processing and lower levels of product contamination through abrasion. Further advantages of the E3 Beater include the reducing of production costs and the equipment becoming even more durable and easier to clean.

    For customers with an existing Hosokawa ACM, the process of retrofitting an E3 Beater is easy, involving minimal downtime and a simple replacement of the current grinding disc, with no other modifications required. Customers choosing to invest in upgrading to the enhanced grinding disc will see a return on investment in less than a year.

The versatile ACM Air Classifier Mill is used for the fine and ultrafine impact milling, drying and classification of soft to medium-hard materials, including heat-sensitive products and those prone to sedimentation. The ground-breaking mill is consistently a very popular choice for the pharmaceuticals, chemicals, powder coatings, pigments, food and minerals industries.

Compact, robust and hardwearing design

  • Pressure and shock resistant to PSR 11 bar
  • Grinding, classification and drying in a single machine
  • Pneumatic feeding
  • Integrated dynamic classifier
  • Gentle grinding at a low temperature
  • Steep particle distribution
  • Effortless, safe cleaning and maintenance
  • Quiet, energy-efficient operation
  • Easily adjustable, very sharp and precise cut point
  • Suitable for combined grinding and drying
  • ATEX-certified versions are available
  • Laboratory-scale versions available for small batches and trials
  • WIP option available
  • NEW – E3 Beater option


A Hosokawa Gen4-enabled ACM Air Classifier Mill is regularly used by our in-house Technical Services team for product testing and contract manufacturing batches of powder on behalf of our customers. Our pioneering Hosokawa Gen4 digitalisation solutions and software – uniquely created for powder processing industries – was partly developed using an ACM Air Classifier Mill and successfully optimises our milling processes, productivity and profitability, while reducing downtime.


The space-saving ACM Air Classifier Mill is an extremely efficient all-rounder for size reduction and classification of a variety of materials. The product is also suitable for a combined grinding and drying process. The ACM boasts a number of operational advantages, too, such as gentle grinding at low temperatures, energy-efficiency, wear protection, an easily adjustable and very precise cutting action, low noise emissions and steep particle distribution capability.

Material pneumatically feeds into the ACM Air Classifier Mill from the top, allowing for optimised throughput rates. Size reduction of the raw material happens effortlessly as the materials impact against the grinding rotor and fixed liner at high speed and become smaller particles. As an example, a striking velocity of 140 m/s accomplishes a fineness value of d97=10µm.

The product becomes trapped in the downstream fan’s cooling, conveying and classifying airflow, with the product being drawn through the mill and routed along the guide vanes of the vane ring.

Unique to the ACM Air Classifier Mill is its integrated dynamic classifier. The guide vane ring distributes the processing material and air mixture homogeneously to the rotating classifier wheel and, due to the different forces and the masses of the particles, the product is separated into coarse and fine material in the classifying zone. The classifying wheel rejects the course material and returns it to the grinding zone for further size reduction. The finely milled material exits the mill only after successfully passing through the classifying wheel. The adjustable cut point feature is a useful function of the classifying wheel speed, allowing for the manipulation of the precision of cut, even when the ACM is mid-operation.


Hosokawa’s ACM Air Classifier Mill can be used individually or as part of a bespoke process system that may include additional Hosokawa-brand and ancillary equipment, as well as a tailored Hosokawa Gen4 digital strategy solution for connected smart manufacturing, such as remote monitoring.

Complete milling systems – featuring the ACM and elements such as hoppers, cyclones, air filters, sieves, control units and bag fillers – can be designed, engineered, manufactured and commissioned in-house by Hosokawa Micron Ltd to specific customer requirements and our expert sales and engineering team would be pleased to collaborate on the perfect configuration for your application.

For further information about the digitalisation options and solutions available through Hosokawa Gen4, including remote monitoring, please refer to the Digital Services section.

Similar Products

Browse though the Hosokawa Micron product catalogue to view all of our innovative processing equipment or contact us directly on

Zirkoplex ZPS Classifier Mill
The Alpine Zirkoplex ZPS Classifier Mill is used to grind soft products up to a Mohs hardness of 3.5.
ATP Turboplex Ultrafine Classifier
There is hardly another type of classifier that is so well adapted to the demands of practical operation as the Alpine Turboplex Ultrafine Classifier.
Ultraplex UPZ Fine Impact Mill
The Ultraplex UPZ Fine Impact Mill is a versatile but simple to operate size reduction system with exchangeable grinding elements.
Contraplex Pin Mills, C & CW
Alpine Contraplex Pin Mills typically deliver high grinding fineness in the range 10 – 500µm, especially with brittle and crystalline materials.
AFG Fluidised Bed Opposed Jet Mill
As ALPINE launched the AFG fluidised bed opposed jet mill onto the market in 1981, it succeeded in revolutionising jet milling. Since then, over 1,000 machines have been sold for a wide diversity of applications.
Spiral Jet Mill – AS Aeroplex
Alpine Spiral Jet Mills are frequently used in the pharmaceuticals industry and also for the manufacture of fine-grade chemicals for ultrafine size reduction of dry materials with a crystalline structure up to a Mohs hardness of 3.
Services we provide
Training Packages
Protect your investment by up-skilling your operators
Maintenance Packages
Our bespoke Maintenance Packages will ensure the optimal performance of your equipment
Optimisation Upgrades
Future-proofing your equipment, intelligent manufacturing and digital strategy solutions
Refurbishments & Repairs
Economical refurbishments and repairs to extend the life of your equipment
Your form has been submitted successfully
A member from the Hosokawa team will be in touch