To select the proper work speed, take a cut with the
work speed set at 50 fpm. If the wheel acts too soft,
decrease the work speed. If the wheel acts too hard,
increase the work speed.
Wheel speed and work speed are closely related.
Usually, you can adjust one or both to get the most
suitable combination.
DEPTH OF CUT
The depth of cut depends on such factors as the
material from which the work is made, heat treatment,
wheel and work speed, and condition of the machine.
Roughing cuts should be as heavy as the machine can
take; finishing cuts are usually 0.0005 inch or less. For
Figure 10-4.--Overlapping disk balancing ways (roller type).
as a trial. Then, adjust the machine until you get the best
cutting action.
Not cause rust or corrosion
Have a low viscosity to permit gravity separation
The cutting fluids used in grinding operations are
of impurities and chips as it is circulated in the cooling
the same as hose used in other machine tool operations.
system
Synthetic coolants are the best, but you also may use a
Not oxidize or form gummy deposits that will
mixture of soluble oil and water. As in most machining
clog the circulating system
operations, the coolant helps to maintain a uniform
temperature between the tool and the work to prevent
Be transparent, allowing a clear view of the work
extreme localized heating. Excessive heat will damage
Be safe, particularly in regard to fire and accident
the edges of cutters, cause warpage, and may cause
hazards
inaccurate measurements.
Not cause skin irritation
In other machine tool operations, the chips will fall
aside and present no great problem; this is not true in
The principles discussed above are basic to
grinding work. If you have no way to remove chips, they
precision grinding machines. Keep them in mind as you
can become embedded in the face of the wheel. This
study about the machines in the remainder of this
embedding, or loading, will cause unsatisfactory
chapter.
grinding and you will need to dress the wheel
frequently. A sufficient volume of cutting fluid will
help prevent loading. The fluid also helps to reduce
friction between the wheel and the work and to produce
WHEEL BALANCING
a good finish. When you select a cutting fluid for a
You may need to balance wheels larger than 14
grinding operation, it should have the following
inches, but usually not smaller ones. A wheel that is
characteristics:
slightly out of balance may cause chatter marks in the
Have a high cooling capacity to reduce cutting
workpiece finish. One that is drastically out of balance
temperature
may damage the grinder or fly apart and injure the
operator.
Prevent chips from sticking to the work
You should balance grinding wheels on either the
Be suitable for a variety of machine operations
overlapping disk balancing ways (roller type) (fig.
on different materials, reducing the number of cutting
fluids needed in the shop
these stands as level as possible, mount the wheel on a
Have long life and not emit obnoxious odors or
balancing arbor, and place it on the rollers or ways. The
vapors harmful to personnel
heavy side will rotate to the lowest position. Adjust
10-4