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I
NSTRUCTION
M
ANUAL
3601 E. 34th St. Tucson, AZ 85713 USA Tel. +1 520-882-6598 Fax +1 520-882-6599 email: [email protected] Web: http://www.metallographic.com
Please read this instruction manual carefully and follow all installation, operating and safety guidelines.
NANO 2000T Polisher
Rough or planar grinding, is required to produce flat specimens and to reduce the damage created
by sectioning. The planar grinding step is accomplished by decreasing the abrasive grit particle size
sequentially to obtain surface finishes that are ready for polishing. Care must be taken to avoid being
too abrasive in this step, and actually creating greater specimen damage than produced during
cutting. This is especially true for very brittle materials such as ceramics and silicon.
The machine parameters which affect the preparation of metallographic specimens include: grinding /
polishing pressure, grinding direction, and the relative velocity distribution between the specimen and
the polishing wheel.
Grinding Pressure
Grinding / polishing pressure is dependent upon the applied force (pounds or Newton's) and the area
of the specimen and mounting material. Pressure is defined as the Force/Area (psi, N/m
2
or Pa). For
specimens significantly harder than the mounting compound, pressure is better defined as the force
divided by the specimen surface area. Thus, for larger hard specimens, higher grinding / polishing
pressures increase stock removal rates. However, higher pressure also increases the amount of
surface and subsurface damage produced in the specimen.
Note regarding SiC grinding papers: as the abrasive grains dull and cut rates decrease, increasing
grinding pressures can extend the life of the SiC paper.
Higher grinding / polishing pressures can also generate additional frictional heat which may be
beneficial for the chemical mechanical polishing (CMP) of ceramics, minerals and composites.
Likewise for extremely friable specimens (such as nodular cast iron), higher pressures and lower
relative velocity distributions can aid in retaining inclusions and secondary phases.
Grinding Direction
The orientation of the specimen can have a significant impact on the preparation results, especially
for specimens with coatings. In general, when grinding and polishing materials with coatings, the
brittle component should be kept in compression. In other words, for brittle coatings, the direction of
the abrasive should be through the coating and into the substrate. Conversely, for brittle substrates
with ductile coatings, the direction of the abrasive should be through the brittle substrate and into the
ductile coating.
Manual Preparation
In order to ensure that the previous rough grinding damage is removed when grinding by hand, the
specimen should be rotated 90 degrees and continually ground until all of the scratches from the
previous grinding direction are removed. When necessary, the abrasive paper should be replaced
with a newer paper to maintain cutting rates.
4.4.1 Rough / Planar Grinding
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