The AFG Fluidised Bed Opposed Jet Mill from Hosokawa revolutionised jet milling when it was introduced in 1981, and this iconic piece of processing equipment for ultrafine milling has been going from strength-to-strength ever since. There are now more than 1,000 examples in circulation globally, across diverse manufacturing industries, which has allowed us to amass unparalleled technical knowledge, gathered from decades of trials collaboration with our customers’ materials, while the larger AFG models are consistently the preferred choice of the talc industry, thanks to their high throughput rates and high fineness values. Benefitting from an integrated deflector classifier wheel for greater fineness control of the processing bulk material, this impact mill effortlessly grinds soft to hard materials – everything from talc to diamonds. Its unique design means it is perfect for contamination-free milling and maximum purity of materials, such as silica gel, special metals, pharmaceutical ingredients and dental ceramics. Hosokawa’s expertise in jet milling means we are continually improving the energy efficient AFG and expanding the range of industries that can benefit from its excellent performance, flexible processing capabilities, reliability and cost-effectiveness.
The Picojet model from Hosokawa’s Picoline range of laboratory equipment is a miniature version of the AFG Fluidised Bed Opposed Jet Mill, capable of processing batches of materials of less than a gram in weight, so is perfect for R&D.
The efficient TFG variant of the AFG jet mill is available for the specific needs of the toner, powder coating and pigment industries.
The AFG Fluidised Bed Opposed Jet Mill range can be manufactured from stainless steel, mild steel or Ni Alloy and conveniently comes in a wide range of sizes and models, accommodating the need for laboratory and pilot scale, right through to large full production versions. The 1500/3 AFG is the world’s largest jet mill, while the Picojet is a miniature version of the AFG, for processing materials of less than a gram.
There’s a huge choice within the technically sophisticated AFG Fluidised Opposed Jet Mill range, developed over many decades to accommodate the ever-evolving needs and requirements of industry sectors from pharmaceuticals and food, to chemicals and minerals.
Hosokawa Micron specialises in bespoke jet milling systems that are unique to each customer and perfect for their current and future requirements. Specialist versions for hazardous materials and sterile processing are available.
In addition, there are several alternative options that are based on the AFG, widening Hosokawa’s fluidised opposed jet milling product range, such as the TFG and the new TDG – see below for further details.
Hosokawa’s AFG Fluidised Bed Opposed Jet Mill is used for the extremely fine grinding of even the most solid, ultra-hard materials, particularly when contamination-free processing is paramount. The impact mill is perfect for the processing of heat-sensitive, abrasive, hard, magnetic, highly pure, composite and electrical materials for a wide variety of industries.
The original, industry-standard, high-performance jet mill
The patented gas jets used in the Hosokawa AFG Fluidised Bed Opposed Jet Mill intersect at the speed of sound. The exit velocity of the processing material is increased to above this level by the integration of Laval nozzles, characterised by their hourglass shape.
The Hosokawa AFG Fluidised Bed Opposed Jet Mill signalled a ground-breaking leap in processing capability and has developed at pace over the past forty years, since the jet milling technology was invented by our sister company, Hosokawa Alpine.
Not only have our customers achieved superior-quality, contamination-free, end products across a wide range of sectors, but the technology has facilitated their elevated market positions by increasing application capabilities and allowing them to expand, develop and refine their product ranges in line with technology and materials advances.
A huge number of materials can be processed extremely effectively by the AFG, including traditionally hard-to-process materials, such as those sensitive to heat, as well as magnetic, hard, abrasive and composite materials.
The AFG’s principle of operation is based on kinetic energy, with multiple gas jets intersecting at the speed of sound right at the heart of the milling chamber. Powder particles that are suspended in a fluidised bed are captured in the, Hosokawa-patented, Megajet® gas jets and impact against each other, efficiently breaking down into ultrafine powders of very high purity.
This is achieved by the contamination-free opposed jet mill processing technology, which includes an air classifying process, using state-of-the-art ceramic wheels, that provides extremely efficient, sub-micron classification grinding, leading to the increased quality control and superior fineness of the end product.
The level of fineness is set by the speed of the classifying wheel. The high product loading capabilities of the AFG allows for a high concentration of particles to enter the grinding chamber, resulting in the high impact of the materials and ultrafine powder that is then produced. The amount of material passing through the chamber can either be controlled by load cells, by monitoring the classifier drive loading, direct into the milling chamber or by injector feed.
The combination of hot compressed air and the four Megajet® nozzles optimises the machine’s performance. Hot gas mode is of particular advantage to the cost-effective processing of large amounts of ultra-fine mineral powders, while circuit gas systems are perfect for pyrophoric materials that require extreme safety procedures.
The jet mill’s very efficient performance is enhanced by the use of hourglass-shaped Laval nozzles, which increase the product’s exit velocity to above the speed of sound. Nozzle length can be adapted to suit the operating pressure.
Milling can be performed at low or high pressure, depending on the product to be processed, with either inert gas (including N2) or hot gas. Compressed air of 20°C and 6 bar over pressure is commonly employed as the gas for grinding, which delivers an exit speed of approximately 500 m/s.
The speed of the gas jets reduces extremely rapidly after exiting the nozzles because of the way the gas and product is drawn from the fluidised bed.
The AFG Fluidised Bed Opposed Jet Mill is extremely flexible and may be tailor-made and adapted to meet customer requirements. Suitable for use as part of complex multi-process systems, it can be easily integrated into a sterile isolator, for example, if the processing requires a containment element, or can be partnered with several classifier mills from Hosokawa’s portfolio, such as the Spiral Jet Mill, UPZ or Turboplex ATP.
Hosokawa Micron has decades of accumulated technical knowledge and expertise manufacturing safe and reliable process systems and containment equipment – including Gloveboxes, Isolators, Downflow Booths and Filling and Weighing Systems – on behalf of customers from industries including pharmaceutcals, chemicals, nuclear and defence, cosmetics and food and beverage.
The AFG can be configured for the processing of APIs and potentially hazardous and explosive materials in accordance with current industry standards, including ATEX. CIP/WIP/SIP for our AFG process systems are an option, as is the integration of an Isolator, for maximum operator protection and aseptic conditions during processing, including when/if the equipment needs to be accessed mid-process.
Safety features can include remote monitoring, aeration of machine zones and no dead zones, to ensure optimum drainage and sterilisation.
Laboratory-scale and pilot-scale jet milling systems are available from Hosokawa, enabling research centres and laboratories to manufacture small amounts of product before up-scaling to industrial levels of production. The AFG 100 was specifically created with this scenario in mind. This multi-process system accurately mimics the processing levels required from larger models.
The Picojet is a miniature version of the AFG, for processing batches of less than a gram, while the AFG 140 bridges the gap between laboratory and full production scale, offering customers an excellent range of options to choose from.
Hosokawa Micron Ltd offers a full range of laboratory services dedicated to helping customers develop their products, including powder testing, product trials, R&D and contract manufacturing. Please contact our expert in-house Technical Services team for further details.
As with all Hosokawa equipment and process systems, our service includes everything from design studies and product testing, to engineering, manufacture, installation and commissioning. A wide range of dedicated lifecycle and digitalisation services augment the diligent and reliable customer service we also offer.
Active Ingredients/Hazardous Materials Option
For large batches of active substances, the AFG is pressure and shockproof and can conform to the latest ATEX directive for materials that are a dust explosion hazard. Hosokawa Micron supplies a test certificate for Zone 20/21 as standard.
Sterile systems featuring CIP/WIP/SIP are available to give maximum protection to the operator and provide aseptic conditions during production.
Hot Gas Mode Option
The AFG Fluidised Bed Opposed Jet Mill generally mills at room temperature. However, if heat-sensitive materials need to be milled (such as minerals, resin, wax, fat, ion exchangers, dyes and pigments) the AFG can operate in hot gas mode, allowing for the cost-effective production of large amounts of ultrafine powders.
TFG Toner Fluidised Bed Opposed Jet Mill
The TFG is a variant of the AFG Fluidised Bed Opposed Jet Mill, created to meet the needs of the highly specialised toner, powder coatings and pigments industries. Virtually identical to the AFG design, the TFG has a vertically driven classifier wheel shaft, specially designed for processing toner, as well as a flat-bottomed grinding chamber that minimises the amount of unground material residue.
One of its great advantages is its practical design. A hydraulic mechanism allows the classifier head to be swung through 180°, which makes it extremely easy to clean and maintain, enabling the fast product changes typical of processing multiple colours through the same equipment. For further information, please visit the TFG Toner Fluidised Bed Opposed Jet Mill page.
NEW – TDG Fluidised Bed Opposed Jet Mill
The TDG is the latest edition to Hosokawa’s Fluidised Bed Opposed Jet Mill collection, created to process ultrafine materials such as talc, industrial mineral powders including mica, natural graphite and barium sulphate down to < 1µm fineness. Available in three models, the equipment includes a high-performance classifier and uses a dry ultrafine grinding process.
The TDG offers benefits such as steep particle size distribution, a compact design and a simple, flexible process that is low in contamination risk, energy-efficient and cost-effective. Hot gas operation up to 200°C is possible. For further information regarding the technical specifications of each model, please contact our sales team.
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