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How to Increase Productivity with Conical Milling

What is a Conical Mill?

Conical milling (or cone milling) is one of the most common methods of milling in pharmaceutical manufacturing and associated industries. In pharmaceutical production, Conical mills are typically used for size reduction and deagglomeration or delumping of powders and granules, with the goal of achieving a desired particle size distribution (PSD).

Generally used for reducing material to particle size as low as 180µm (80 mesh), Quadro Comil® conical mills produce less dust (waste) and heat than other mill types.

Utilizing decades of experience from the team at Quadro Engineering, and with the gentle grinding action and quick discharge of correctly sized particles, a Comil will ensure pharmaceutical customers can quickly—and consistently—achieve the PSDs they desire for OSD and API production.

How does conical milling work?

Quadro invented the original The Quadro® Comil® conical mill in 1976. Though simple in principle, the Comil was a revolutionary concept that has since evolved into a global processing standard adopted by market-leading pharmaceutical manufacturers around the world.

Each Comil model comprises a vertically mounted rotating impeller that moves material across a milling screen causing a low velocity cutting action on the particle.

Operating parameters of screen size and type, impeller style and size, and tip speed are needed to reach a desired particle size distribution (PSD). Quadro’s experienced team of sales engineers can assist customers in creating the ideal parameters for a particular product.

Once the operating parameters are set, pre-milled material is fed by gravity into the top of the mill head. Because a Comil can easily accept flood feeding—operators don’t need to worry about meter feeding their product.

Under operation, if particles are already the desired size they will pass through the screen and will be discharged immediately. If not, particles will be manipulated in the cutting chamber until they reduce down to the predefined size that allows them to pass through the screen.

screens for milling powders

The Comil’s low RPM, low energy, low heat and low-noise design makes the mill the ideal solution for pharmaceutical particle size reduction applications—especially those with temperature sensitivity. The ability to choke (flood) fed results in low dust, low product waste, and high throughput. Once processed with the Comil, tight particle sizing helps improve the flowability and uniformity of powders before they enter the tablet press.

Conical mills - the perfect solution for pharma applications

Quadro manufactures a range of cone mills from lab-scale through to full-capacity production machines, utilizing both Overdriven Comil Conical Mill and Underdriven Comil Conical Mill drive options. Based on the application and material properties that you require during the development of pharmaceutical OSDs and APIs (such as particle size, moisture content, temperature sensitivity, hardness, and more) our sales engineers can help you get to full production quickly.

Milling equipment for manufacturing OSD Pharmaceuticals

Comil conical mills are well known for helping manufacturers achieve PSDs optimized to produce the correct level of compressibility for the tableting process. Comil mills ensure OSD manufacturers the flexibility and speed they need to reliably produce top-quality product consistently, and competitively with no downtime or waste.

Milling equipment for manufacturing API Pharmaceuticals

In new drug development, particle size is crucial in driving the bioavailability and stability of the API. A Comil makes sure that manufacturers can achieve smaller particle sizes and tighter PSDs than other types of mill, with far less waste generated for improved profitability.

The Overdriven Comil Series: high volume capacity milling

The Quadro Comil Overdriven Series offers a range of production capacities from small scale (ideal for testing) to high volume with consistent particle size distributions, less generated waste and a low total cost of ownership due to simple maintenance. The Overdriven series has an unequaled track record for high-efficiency inline processing for pharmaceutical OSDs and APIs.

(The Comil Underdriven Series shares all the benefits of the Overdriven Series, but in a more compact package.)

The Comil Overdriven range is simple and economical to maintain and operate. Machines are ideal for hand feeding and de-lumping applications, and operators are able to make fast screen and impeller changeovers due to the user-friendly design and operation. The sanitary design and easy-to-clean construction methodology lead to faster maintenance and less downtime.

Quadro Engineering offers the largest number of screen and impeller combinations in the market. With assistance from our highly qualified team of sales engineers, the perfect screen, impeller, and tip speed combination can be identified for all types of particle product, enabling customers to get up to full production faster and easier.

All Comils feature the following benefits:

Gentle handling of product during milling

The low RPM, low energy and low heat operation of our Comil units make them a perfect solution for pharmaceutical applications, enabling consistent, safe and productive milling of APIs and heat-sensitive products. Quadro Engineering has built a global reputation for enhancing production methods and processes for pharmaceutical manufacturers with Comil conical mills.


Easy disassembly and a design with no entrapment areas mean that Comil mills are simple to maintain, keeping downtime to a minimum for higher profitability.


Whatever your capacity requirements, we have a Comil that can match or exceed your needs. And when your capacity requirements grow, you can easily scale up, transfer the operating parameters to your larger Comil machine, and produce product with the same results as before.

Safe product handling

The highly efficient operation of the Comil generates less dust than other milling methods leading to a cleaner environment with less risk of contamination.

Unequaled production capacity

Due to Comil’s plug-feeding capability, and the ability to be choke or flood-fed, Comil’s output capacity is unrestricted and there is no need for a metered feeding system.

Pile of powder particles
Quadro Engineering's range - from lab scale to full capacity

Whether users have smaller production needs or full capacity production requirements there are Comils available to match your required output. And as your production increases, it is a simple process and calculation to scale up to a larger capacity unit using the same parameters. You will be able to process the same type of product and get exactly the same results, every time, at a much larger capacity than before.

Overdriven Comil is currently offered in the following sizes:

197 Overdriven Comil for smaller-scale production

197 Overdriven Comil stats

194 Overdriven Comil
for mid-range capacities

194 Overdriven Comil Stats

196 Overdriven Comil
for production scale

196 Overdriven Comil Stats

198 Overdriven Comil for large volume scale

198 Overdriven Comil

Comil conical mills are integrated into Quadro’s new interchangeable head processing platforms

With Comil well established as the industry standard for pharmaceutical conical milling, Quadro constantly develops new products to help pharmaceutical manufacturers get the flexibility they need in their production workflows.

Quadro have two flexible interchangeable head platforms that offer unmatched flexibility to pharmaceutical manufacturers:

The SLS – Scalable Lab System™. Experiment with different powder processing and milling options on smaller batches.

SLS One machine offering five milling and processing solutions

R&D labs and production firms need the latest cutting-edge technologies for milling, while keeping capital equipment expenses as low as possible. The SLS comes at the right time.

The SLS is a highly versatile, advanced benchtop, multi-purpose powder milling and screening platform with interchangeable heads on one common drive.

Operators can quickly experiment with, and switch between different processes and then reach their testing and research goals faster—all with a low investment. When they’re ready to go to full production, their process results can be matched exactly on our range of production capacity equipment.

Learn more about the SLS – Scalable Lab System

The SDx Series™. Empowering production scale milling versatility with strict budget control.

Sdx The world's most advanced production-scale milling & screening platform

Pharmaceutical manufacturers need their powder processing equipment to be flexible, highly efficient, and with a low total cost of ownership. The SDx Series ticks all the boxes.

The SDx Series is the most advanced powder processing platform with three interchangeable heads, allowing operators to quickly switch between several distinct powder processing and milling operations in seconds.

Changing the processing head (rather than having to work across several machines) allows users to switch between conical milling, hammer milling, or sifting, and work faster producing several batches at once. The SDx replaces three separate workstations, all with their own space, operator, and power requirements.

Learn more about the SDx Series Powder Processing Platform.

Customers benefit from Quadro Engineering's wealth of experience

With thousands of equipment installations around the world, the team at Quadro has earned the respect of customers globally. And because we manufacture the industry’s most extensive and flexible line of conical milling equipment, we also have the largest range of screens and impeller/rotor options to suit all powder milling and processing applications.

Quadro’s extensive selection of Screen types and sizes accommodates most particle size requirements. Screens are available with openings as small as 0.150mm (0.006”), and as large as 38mm (1.5”). Screen choices are extended further with options for round or square perforations, wire mesh or for grater or Conidur holes.

Image of milling screens

Dozens of different profiled Impellers can also be used to suit the specific application requirements. Basic options include round arm, square arm, or beveled arm impellers. More aggressive profiles are also available. Impellers can be further enhanced with available special finishes and add-ons.

Our team travels around the world to help customers optimize their processes and get the results they need. Our in-house experts have decades of experience in helping customers select the perfect size reduction mills and powder milling equipment. Experience counts for everything.

If you’d like a demonstration of our products, please contact us and we’ll put you in touch with a local sales engineer.

Achieve the required particle size distribution Speak to the milling and sizing experts.   Contact our team
Posted by Matt Baumber


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Quadro has earned the respect of customers with a wide variety of applications in more than 80 countries. Our recognized leadership in specialized process equipment was launched by a single idea in 1976 that has stood the test of time.