1.2 Grinding with a Cyclone Mill (Udy, Cyclotec or equivalent)

Safety Precautions:

Wear hearing protectors and monitor the noise (decibel) level produced by the grinder.
Wear a dust mask and avoid inhaling dust.
Observe all safety and operating instructions supplied by the manufacturer.

Inspect the mill for cleanliness before using. Insert appropriate screen (1 mm required for NIR).
Clamp on the appropriate lid or head. Use the forage head for any sample that was oven dried.
Insert a clean sample bottle beneath the clear plastic cyclone and turn on the mill.
Slowly feed the sample into the mill. Do not overload the mill. A 15 cm powder funnel aids in feeding forages into the mill.
If the sample bottle becomes full before all the sample has been ground, shut off mill and empty the bottle into a clean aluminum pan. Then continue grinding the sample.
After the last of the sample has passed through, press the palm of your hand against the opening of the forage head. Keep the opening closed for about 5 sec, then release. This forms a vacuum inside the grinding chamber which helps clean out residual sample.
Shut off mill.
Thoroughly mix the sample and transfer to sample container.
Remove the head and screen and clean the mill using a brush and air. The impeller can be cleaned by wiping with a towel.

Comments:

Equipment should be maintained on a regular schedule. The condition of the sieves, rotors, blades or other grinding surfaces should be monitored and regularly recorded in a designated log book.
When a belt breaks, replace all belts at the same time. Proper tension of the belts is critical.
Replace impeller when blades become worn or broken.
Replace the grinding ring when the surface starts to become smooth.
Replace the screen when it becomes dented, corroded, or begins to clog.
Some samples may need to be drier than 85% dry matter to grind properly to pass a 1 mm screen in a cyclone mill.
Samples to be scanned by NIR must be dried by the same method used to develop the calibration equation.
Keep all equipment clean to avoid contaminating one sample with another.
Care should be taken with the cyclone grinder not to heat the sample during the grinding process. Heating will change the chemical analysis.
Transfer samples quantitatively. Do not leave sample portions in grinder.
Ground samples must be stored in airtight, properly labeled containers away from heat and light.