Acer Supra 818PD Operation Manual page 42

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triangle.
The corresponding height of opposite side (The composite height of block) between 0º and 90º can be
calculated by triangular principle. Below contents give calculation of composite block height:
Sine of desired angle = Opposite side / hypotemus = Composite block height / Sine bar length. For
example: if a 125mm long of sine bar is employed, then the sine angle = Composite block height / 125.
Composite block height = 125 * Sine height.
EXAMPLE: Suppose a 125mm long sine bar is used with 150º angle adjustment, find the composite
block height. Composite block height = 125 * Sin 15º = 12.5 * 0.25882 = 32.3525mm. Sine value
corresponding to any angle can be found in the triangular logarithm table.
Setting instruction for grinding angle over 60º: When the workpiece surface angle is bigger than 60º, at
first, you need to calculate the complement angle value, which can be obtained by 90º deducting the
degree to be ground. Use the composite block height of the complement angle for adjusting the sine
bar. Once workpiece is mounted on the angle plate, turn the angle plate to another side, and then the
correct angle can be obtained.
B.
SINE MAGNETIC CHUCK: This type of chuck is a wide sine bar with self magnetic field. It is used for
mounting workpiece for angular grinding. A correct angle can be obtained by using block at one end of
sine bar.
C.
COMPOSITE SINE PLATE AND CHUCK: They are suitable for holding workpiece for composite angle
grinding. The composite sine chuck consists of two sets of blocks for creating a composite angle.
D.
ADJUSTABLE ANGLE PLATE: The workpiece can be clamped on the graduated angle plate end, and
allows for setting angle to be ground. If high accuracy grinding is required, such device is not
suggested.
E.
ADJUSTABLE ANGULAR VISE: It is used for clamping workpiece for angular grinding. The vise base
is equipped with a chain, allowing for tilting 0º~90º.
F.
UNIVERSAL ANGULAR VISE: It permits swiveling and tilting to create a complex angle. When
performing a simple angle grinding, it is requested to swivel the vise base to the 0º position before
clamping the workpiece.
5.6.3 DRESSING GRINDING WHEEL ANGLE
There are two methods usually applied for dressing the grinding wheel angle: The first
method is applying a sine dresser raised by block to dress the grinding wheel to your desired
angle. The second method is applying an angle dresser graduated with 0º~90º, which is
capable of dressing the grinding wheel to any angle as desired. If the sine dresser or angle
dresser is not available, you can adjust the parallel block on the sine bar to a desired angle,
and then clamp it on an angle plate. It may guide the diamond dresser to dress the grinding
wheel surface according to this angle. Dressing the desired angle on the grinding wheel
surface according to following procedures:
a. Set the dresser at your desired angle.
b. Clean the magnetic chuck, and then install the dresser.
c. Adjust the base of dresser and the magnetic chuck position until they are properly square.
d. Move table until the diamond tip is just located at the grinding wheel center position. Make sure the angle on
the grinding wheel to be dressed is correct.
e. Tighten the workpiece securely to avoid longitudinal displacement.
f. Turn the cross feed hand wheel to move the diamond tip approaches the grinding wheel.
g. Start the wheel spindle running, and then lower the wheel head until the grinding wheel just touches the
diamond.
h. Feed diamond across the grinding wheel from the near side.
i. Every time when the diamond moves across the grinding wheel, the grinding wheel lowers
0.005~0.0075mm.
j. Continue dressing the grinding wheel face angle until your desired width is obtained.
5-14
818~2040 PD