Sharp SH-920 Instruction Manual page 35

3.4 The wheel dressing can be done either by diamond dresser mounted on the
magnetic chuck (Fig.18b) or on the parallel dressing attachment (Fig.18a)
which mounted beside spindle cartridge.
3.4.1 The diamond tool should be located at an angle to the center line of
the wheel as shown on Fig.18a, so that when the diamond loses its
keenness (Fig.18c) it can be turned an angle, and another sharp
edge can be utilized (Fig.18d).
3.4.2 The wheel dressing should begin from the middle of the width, as
shown on (Fig.18e), due to two edges are usually worn out. If
dressing begins at the edges, there may result in a danger of the
higher pressure in the middle, so as overstress the diamond tool and
chattering it. As far as the life of the grinding wheel and diamond is
concerned the light dressing with more time is better than a heavy
dressing.
3.4.3 Various degrees of roughness can be produced by varying the feeds
and speeds of the diamond dressing. For a 0.2mm or 0.3mm stock
removal, it is advisable to roughen the wheel, this is done by feeding
the diamond in about 0.03mm and let the diamond moves quickly
over the wheel, this will makes the wheel bite well and the stock
removal good. If the workpiece is to be finish-ground to size with the
same wheel, the wheel must be redressed in different ways. In this
time, the dressing operation should be proceed slowly in two or three
passes, with the diamond dressing feed limited to 0.01mm.
3.4.4 Experience has shown that, with highly accurate grinding or better
surface finish is required, the dressing operation with the diamond
dresser mounted on the magnetic chuck is better than which
mounted on the spindle housing. The former is more stable than the
latter and the latter condition will causes light undulation in the
surface of the wheel.
3.4.5 Sufficient coolant supply spray to contact point of wheel and
diamond is necessary.
3.4.6 A 250mm/min to 1000mm/min wheel travel to pass through diamond
is recommended. For rough grinding higher travel speed is better.
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