ES0755 rev A 1/11
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be within tolerance, there almost certainly is contamination or damage between the mating flange
surfaces that is creating this error. The unit will have to be completely separated, the surfaces
re-stoned and recleaned thoroughly, and the entire leveling/squaring process will have to be
repeated up to this point.
2. Verify the sweep of the Y/Z-axis by repeating the previous section (“Sweeping the Y-Axis / Z-
Axis”).
f
ine
l
evelinG
the
m
achine
Now that the preliminary leveling is done and the bases are securely mated, the machine can be treated as a
unit with confidence that the geometry will be maintainable as long as adequate control is maintained in the
fine leveling process. The process begins with loading the remainder of the leveling screws very lightly and
working into an equally loaded situation that does not affect the geometry already achieved.
The column base will be the first section effected, and will be fine leveled with respect to the table at the
middle of travel.
CAUTION! Do not rush the leveling process. Any drastic attempt to fine level the column base will be propa
-
gated to the table base assembly and may be nearly incorrectable if not addressed early in the process.
The table base is more complicated to fine level, and small steps will be taken to preserve the level to earth
established at the middle of travel. The first step of the process will be to begin to load the leveling screws
over the length of the base. The second step will be to begin to pull the overall length into earth level. The
third step will be to fully pull the base into level.
1. Begin with the column base assembly. Place the level in the column, parallel with the Y-axis and
run the column through the range of travel. If no deviation in the reading exists, the column base
is flat in the direction of the Y-axis. Move the level to each of the linear guide surfaces in front of
the column. If the readings are zero, the column is flat to earth in the direction of the Y• Power
up the control-axis. Place the level on the spindle head parallel to the X-axis. Run the column
through the range of travel. If no deviation in the reading exists, the column base exhibits no twist.
Place the granite parallels across the linear guide surfaces in front and behind the column. Place
the levels on the granite. If the readings are zero, the column base is flat to earth in the X-direc
-
tion.
2. Move the levels to the table and place them as close to the center as possible. One level should
be parallel to the X-axis and one level should be perpendicular to the X-axis. If the readings are
still zero, then the table at the center of travel is still level to earth.
3. If any deviations exist, they need to be corrected at this time. If the deviations are very small,
the mating flange of the two bases does not need to be unscrewed. If the deviations are very
large, attempting to correct the level may induce a large stress in the assembly that will not allow
earth level to be fully achieved. It is important for the geometry of the machine that earth level be
achieved.
The table at center of travel is now known to be at earth level and the column base is also at earth level. The
process of extending that level over the travel of the X-axis may now begin by starting to load the remainder
of the leveling screws.
4. Lower the remainder of the table base leveling screws to touch off on the leveling pads below.
5. Move the table toward zero so the levels are in line with the next set of leveling screws after the
primary leveling screws. Make a very slight correction to the leveling screws at that location if the
level deviates from zero.
NOTE:
Attempting to compensate for all of the deviation at any single
position may compound an otherwise small error. Do not try to final
level the table base in a single pass over the travel of the X-axis.
6. Continue moving the table toward zero, stopping at each instance where the levels are in line
with the leveling screws. Make small adjustments that
begin
to correct the deviation from earth