Sharp SH-920 Instruction Manual page 38

(D) GRINDING OPERATION
The grinding results obtained depend to a very large extent on the choice
1.
of the correct grinding wheel and suitable operation.
1.1 For stock removal efficiency
For intensive stock removal a coarse grain (about 30-60) wheel should be
used. The wheel is dressed by passing over the diamond quickly, so that
the surface of the wheel is roughened and bites well.
1.2 Surface finish is required
If fine finish is to be produced, a finer grain wheel is required (40-80). In this
case the diamond is passed slowly over the wheel, so as to break up the
grain.
1.3 Distortion of the workpiece
If the workpiece shows too much distortion as it is being ground, it
announces that the stock removal is too great and the longitudinal and
cross movements of the table are too slow, or the grinding wheel is blunt or
"clogged".
1.4 If the workpiece appears undesirable burns and grinding cracks, it
announces that the wheel is too hard, or the wheel is blunt or "clogged".
Selection of suitable grinding wheel:
2.
Grinding wheel are usually characterized by the kind of abrasives, the grain size,
the grade of bond, the structure and the type of bond which they selected. The
different symbols of each item format the expression of a grinding wheel. We are
in need to familiar with them.
For instance, the expression WA 46K8V of a wheel which denotes:
WA: Kind of abrasive
46: Grain size
K: Grade
8: Structure
V: Bond type
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