8000D Mixer/Mill
Page 8 of 21 SPEX CertiPrep 8.21.03
SN and Higher
5. OPERATION
Plug the power cord into the mill’s electrical inlet, and then into an approved grounded outlet.
Ensure that the On/Off switch (next to the power inlet) is in the off position, before plugging the
unit in. After the unit is plugged in, switch the power on by means of the rocker switch.
After loading each vial with the sample to be mixed or ground, place it in a clamp. Tighten each
clamp with the knob, and lock each clamp with the locking tab. Close the lid and fasten down the
lid with the manual latch.
NOTE: Two vials of the same material must be loaded onto the clamps, in order to assure
proper balance of the grinding mechanism.
Adjust the timer setting as described above under
Electronic Timer.
Start the mill sample run by pushing the Start button. To stop the mill during a run (e.g., an
emergency stop), push the Stop/Pause button twice, or cut off power by pressing the power
switch on the back of the mill to 0. If you want to interrupt a run but keep the current position in
the timer sequence, push the Stop/Pause button once only, and the mill will stop. After a pause,
the milling cycle can be resumed by pushing the Start button. It is important to note that the lid
latch will not release when the mill is in the Pause Condition.
NOTE: When the 8000D timer cycle has ended and the motor stops, wait until the lid latch
releases before opening the lid.
Loosen the locking tabs, then open the clamps and remove the vials.
5.1
MIXING AND GRINDING
Mixing is usually done in a plastic vial with plastic balls. Depending on the nature and amount of
material to be mixed, one or several balls may be used. With a small amount of material and
more than one or two balls, the impact may break the bottom of the plastic vial, so keep the
number of balls to a minimum. Plastic vials and balls can also be used to grind soft metals (e.g.
antimony), carbon, and other easily friable materials.
For samples that cake during mixing, a slurry with water or alcohol may be helpful. Water may
be dried out afterwards by heating plastic vials in a very low oven. If caking is due to static
charges, a small amount of graphite can added to the vial.
Grinding is done in the metallic and ceramic containers: steel, tungsten carbide, alumina,
zirconia, agate, and silicon nitride. Dry grinding is the simplest approach and is most often used.
The criteria for container selection are usually those of grinding efficiency vs: contamination;
steel and tungsten carbide grind more rapidly than ceramics or agate, but contaminate more.
Most 8000-series vials accept 3 to 10 ml of sample for grinding.
