Q&A

Can I use a mechanical mill instead of a jet mill?

Yes in some cases you can. It’s going to depend on the process and the product. But first let’s start with some definitions.

mechanical mill grinds the product by crushing the particles between 2 mechanical parts: a static part called the stator and a moving part that rotates around it (called the rotor). Both are in the milling chamber.

Now a spiral jet mill works very differently: it doesn’t use any mechanical part. Instead it uses a high-pressure gas and forces the particles to collide against each other until they break to a very small size. Once they are small enough, they can exit the milling chamber.

Another difference is that a mechanical mill can discharge the product directly into a bag or a keg, right underneath the milling chamber.

Whereas a spiral jet mill requires a separation cyclone or a filtering sleeve to separate the process gas from the powder. Only afterwards can the powder be collected into a drum or a bag.

Because of the different grinding techniques, the final particle size and the particle size distribution are quite different between jet mills and mechanical mills. Jet Mills can reach a final particle size of just a few microns. Mechanical mills can’t go that low.

So your choice is driven mostly by the particle size you want to achieve. Down to a few microns? You’ll need a jet mill. Higher than a few dozen microns? a mechanical mill should be enough.

And if you are not sure what you need, you can always rely on FPS Excellence Center to run some tests for you in their ISO7 cleanrooms. They have all the milling equipment needed to determine the best technology and the best systems to reach your final particle size.