hair

After 30 minutes of dry grinding, sample starts sticking stronger to bowl and balls.

This uses to happen after the majority of particles reached a fineness of < 20-30 µm. Interacting forces between fine ground particles will become bigger as their own g-force. Therefore, particles will stick to each other and become compressed by the used grinding balls. These clusters of particles also contain bigger particles which will not be ground any further.

A longer dry grinding is not possible. Still pieces of hear with a length up to 500 µm can be found.

Hair uses to be flexible and ductile; for this, a longer grinding time is expected to be needed.

It took about 20 minutes until a sticking occurred with the Planetary Micro Mill PULVERISETTE 7 premium line. Afterwards, the fineness of ground sample has been checked by optical microscopy. We are still able to find particles up to ~ 100 µm.

Longer dry grinding time is not possible. To eliminate sticking effects, we recommend proceed grinding in suspension.