Operating Manual
5
1300-87075-1A
1.0 Introduction
The Spex 8200 Planetary Mill grinds samples with a mechanical motion rotating the jar in one direction while
the platform, planetary wheel (often referred to as the sun wheel) is rotated in the opposite direction. The
mechanical milling is performed at a 2:1 ratio causing the jar to rotate twice for every single rotation of the sun
wheel. As the jar is moved, the relative centrifugal force is transferred to the grinding balls causing them to move
in a circular motion, into each other and against the jar wall, grinding the sample. Generally, the grinding jar and
grinding balls are made from the same material.
The 8200 Planetary Mill is used for pulverizing rocks, minerals, sand, cement, slag, ceramics, glass, and other
brittle to hard samples.
Functionally described as a high-shearing or a high-energy ball mill, the 8200 Planetary Mill is capable of rapidly
rotating a jar in a circular motion several hundred times a minute. This multipurpose mill is capable of rapidly
reducing hard and brittle samples to analytical fineness, blending powders or making emulsions.
The 8200 Planetary Mill also features a touch screen display, sleek modern design, forced-air cooling, a safety
interlock, and a choice of hardened steel or stainless steel grinding jars and media, which are purchased
separately.
The jar, containing the sample and grinding media, is secured in the clamp and moved energetically in a circular
motion. The circular motion is combined with the rotating movement of the sun wheel, so that the jar appears
to be resembling a planetary movement as it moves. During each rotation of the jar, the balls impact the sample
and the walls of the jar, both milling and mixing the sample. Because of the amplitude and velocity of the clamp’s
movement, each ball develops high centrifugal forces, enough to pulverize the toughest rocks, minerals and
ceramics.
1.1 Disclaimer
While many materials can be safely ground and/or mixed in the 8200 Planetary Mill, some materials pose
hazards and are not appropriate for use with the Planetary Mill. Reactive materials can generate heat and
pressure and are not suitable for use in a closed vessel such as the Planetary Mill jar. Spex is available to offer
guidance to our customers. However, users are responsible for knowledge and understanding of the potential
hazards of the material with which they are working.
Grinding jars do not provide an airtight seal. Purging a jar with an inert gas prior to grinding will not ensure
exclusion of oxygen.
