Cone Mill: The Ultimate FAQ Guide

What is a Pharmaceutical Cone Mill?

Cone mill is a special machine you can use in the pharmaceutical, food processing, or any other industry for size reduction.

It reduces the sizes of large products, which can be hard or medium into small, soft pieces.

Generally, it plays an integral role in material processing industry where it reduces large product particles to smaller particles.

Material processing

What is Cone Mill Used For?

Cone Mill Machine

• Reducing the size of dry material in a product, this increases the surface area of material hence increasing its solubility rate
• Deagglomeration – it is useful in breaking apart powder or crystals without further disintegration.
• Granulation – This process involves the formation of grains from powdery or solid matter which is later packed as granules and used as dosage.

You can divide the process into two, namely; wet granulation that requires liquid in the process and dry granulation that does not require any liquid in its processing.

• Sizing of wet materials – It allows the materials to dry faster due to the large surface area.
• You can use it to retrieve powder from tablets that have failed to meet the required standards so that they are used again in the processing industry.
• Dumping, through shredding of the oversized pharmaceutical products to the required standard size.

Are There Other Size Reduction Equipment Apart from Cone Mill?

Yes, and they include:

• Hammermill uses an impact action principle. It is used in almost all drugs but not on abrasive materials
• Ball mill, also known as tumbling mill, works on the impact between the rapidly moving balls and powder both enclosed in a hollow cylinder principle. It is suitable for brittle drugs and not soft materials.
• Jet mill, fluid energy mill, microfibers or ultra-fine grinder, work on the principle that materials are reduced in size by attrition and impact. It is suitable for moderate hard and friable materials and not soft and sticky materials
• Rotary cutter mill uses the principle of cutting with sharp knives. Suitable for animal and vegetable drugs and not friable materials.
• Roller mill uses the principle that by applying stress, it causes materials to crush. It is ideal for soft materials and not abrasive materials.
• The colloid mill uses the principle of shear, where small particles are broken down by coarse particles.
• When it comes to edge runner milling, it depends on the crushing force due to stone’s weight. It produces a force that breakdown non-sticky material.
• End runner mill, here heavyweight of steel causes the size reduction through crushing. It is suitable for grinding materials

What is Material Size Reduction in the Pharmaceutical Industry?

It is the reduction of either large solid unit masses or coarse particles or even fine particles drugs to achieve a standardized dosage

Size reduction chamber in a conical mill

Why is Material Size Reduction Important in the Pharmaceutical Industry?

It is because it helps achieve a standardized dosage.

It also increases the solubility rate of a drug which in turn increases the absorption rate of a drug by the cell. Of course, this is due to an increase in the surface area.

Moreover, it also facilitates uniform and easy mixing of the dosage. It allows for more drug extraction due to increased surface area and also reduces the heaviness of crude drugs

What Factors Affect Material Size Reduction of Conical mill?

• Hardness – The harder the material, the more difficult is the size reduction
• Toughness and fibrous drugs – You should lover the temperature hen reducing these materials. It is beneficial since it reduces the decomposition of thermolabile materials.

Besides, it also does away with explosion, oxidation, and loss of volatile materials.

• Stickiness – Sticky materials make it difficult for size reduction as they stick on the surface; this can. You can, however, solve this by drying or adding inert materials.
• Slippery materials act as lubricants that also increase the efficiency of a cone mill machine.
• Moisture content influences hardness, stickiness, and roughness of a material.
• Melting point
• Size of starting material
• Quantity of material to be reduced
• The feed size to product size ratio
• Lubrication, this increases the efficiency of a cone mill since it minimizes friction. Remember, heat reduces machine performance. It also prevents rusting that may slow down cone mill speed.
• The sieve pores should be interchangeable to meet the required specification of the end products
• Maintain temperature within a reasonable range so as not to alter product properties.

Also, heat loss to the environment should be minimal or none during the process since it will reduce the machine efficiency.

As a result, more time will be needed to cool off the machine

What are Common Material Reduction Techniques Pharmaceutical Industry?

• Cutting or slicing: Materials are cut into pieces by a sharp knife or root cutter. You can use a cutter mill.
• Compressing: By applying pressure materials are crushed. You can use equipment such as roller mill or motor and a pestle.
• Impact: Stationary materials are hit by a moving object at as higher velocity hence reducing the size by a single rigid force. Equipment such as hammer mill and mortar and pestle play a key role in this process.
• Attrition: It scrapes particles against each other or a rigid surface hence compression pressure is created. Equipment that uses this is a roller mill.
• Impact and attrition: Here, both impact and attrition play a fundamental role. Equipment such as fluid energy mill and ball mill are suitable here.

What is the Smallest Particle Size Conical Mill Produces?

In most cases, it is about 150 microns. However, it can be smaller depending on the design of the cone mill equipment.

How Do You Estimate Energy Requirement for Material Reduction in Cone Mill?

You can use the following laws to estimate the energy you will need for size reduction:

• Rittinger law – The amount of energy you will need for material reduction in cone mill is proportional to the surface subjected to shear forces. This law is more applicable to a fine powder.
• Kick’s law – Here, the useful energy you will require for reducing sizes of material is proportional to the logarithm in the ratio between initial and final diameter.
• Bond’s law – It states that useful work done to reduce particle sizes is directly proportional to the new surface area.

But also, the length of the crack is proportional to the square root of the new surface area produced. It therefore implies, the amount of useful energy will be inversely proportional to the product diameter square root minus the diameter of the feed.

Are there Standard Specification for Designing a Conical Screen Mill?

Yes, for example, the belt-driven impeller that rotates inside a screen should be at 60° including screen angle.

Also, the conical screen mill should be cGMP, CCC, RoHS, and CE compliant. Parts in contact with the material should be stainless steel.

Besides, prevent cross-contamination of material and pollution.

What is meant by Gravity Feeding and Vacuum Transfer in Cone Mill?

In conical mill, vacuum transfer is an automated way of receiving materials directly from the hopper.

In gravity feeding, the come mill depends on the gravitational force to material from the hopper.

Which Industries Uses Cone Mill?

• Food industries
• Cosmetic industries
• Chemical industries
• Pharmaceutical industries

How do Under Driven Cone Mill Compare to Over Driven Cone Mill?

Under driven and overdriven cone mills have similar features. For instance, they are:

• Constructed from stainless steel for parts that are in contact with the product
• cGMP, CE and FDA compliant
• Produce less noise hence better working environmental conditions
• Designed with different screens for a range of material reduction capabilities
• Constructed with changeable screens for versatile production requirements

What are the Advantages of Cone Mill?

• Changing of impellers and sieves can be done quickly
• Reduces the buildup of residual powder due to its cone shape
• Used in different industries due to their versatility
• They are easy to clean hence hygienic
• Their hourly capacity is high
• Do not require much labor
• Granules are protected from any form of damage as they move from different levels due to inline vacuum conveying
• Does not affect quality of product during the size reduction process

How Does Cone Mill Incorporate Material Milling and Sifting Technologies?

Through deagglomeration, materials are broken down into powder or crystals then passed through a screen where only fine particles pass through.

Is Multi Cone Mill Same as a Cone mill? How do they compare?

No.

The multi mill can process both wet and dry materials compared to a cone mill which only processes one at a go.

What are the Main Parts of Cone Mill?

• Cone mill hopper, this is where you will place powder and crystal materials or even tablets that are unprocessed before milling.
• Cone mill screen or conical sieve, this is where finer materials or products pass while those that are ungranulated is left behind for processing or re-use in other processes
• Receptacles, This is where all finished products move to the conical sieve
• Cone blades – The blades shred or cut material, thereby reducing the sizes as it moves in high speed.
• Rotary knife – Also called granulator knife rotates at high speed, thereby creating a whirling motion. It forces materials on the sieve mesh.

How does a Cone Mill Work?

A cone mill works on the principle if rubbing force by the blades which are rotated on a selected screen to get the standardized size reduction.

Materials enter the cone mill hopper either by manual feeding (hands) or gravity.

The machine grinds material before forcing it into the cone mill screen where the rotary knife rotates creating a whirling action on the materials. Consequently, it places them on the sieve mesh surface through centrifugal force.

During the process, it grinds materials forming particles through shearing force. Once the particles attain the right size, they leave the cone mill through the sieve aperture.

Are there Recommended Screen Types for Cone Mill?

Yes, and they may include the round mesh, square mesh, and grater mesh.

Of course, custom screen types for cone mills are also available.