thermosetting resin

After one minute of grinding, the complete sample has been ground to a fine powder. Because of a light sticking of sample to grinding bowl and balls, a longer dry grinding is not possible.

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.

To achieve a better fineness, only a grinding in suspension is plausible with a planetary mill.

To check the present fineness, we used our Vibratory Sieve Shaker ANALYSETTE 3 Pro for sieving an aliquot with a test sieve of 125 µm mesh. 67% of sample is passing the 125 µm test sieve.

The complete amount of sample has been fed within two and a half minutes. The majority of ground particles can be found in the collecting glass of the cyclone separator (220 gr).

To determine the fineness of ground particles, we used the Laser Particle Sizer ANALYSETTE 22 MicroTec plus and dry dispersion unit (see meas. nr. 67381 on separate page).

The rest of sample is sticking lightly by electrostatic charge to the collecting pan of PULVERISETTE 14; or is sticking in the separation part of the cyclone.

Because only minimal amounts used to stick to the impact rotor and sieve ring, a grinding of higher amounts is still possible. Cleaning can be performed by vacuuming with a soft brush.

Even with a low speed of feeding the particles used to stay attached to the sieve ring by electrostatic charge. Therefore, particles started melting by friction between sieve ring and impact rotor.

The output into the collecting pan is only minimal. Because of this grinding of higher amounts is not possible.

Cleaning of the sieve ring with the melted sample uses to be complicated.

Only sieve rings with 0,2 mm trapezoidal perforation (see result 2) or bigger should be used for comminution.