Ulvac EGL-206M Instruction Manual page 36

5.2 Care to be taken in disassembling the EB Gun
(1) Before removing the hearth and hearth deck, be sure to drain the water
remaining in the hearth with air. If this is not done, water will overflow
and may cause a serious trouble.
(2) Remove the filament lead, magnet coil wiring, etc. from the hearth deck.
Color code the wires for identification so that you do not mistake in
connection later.
(3) Remove the four bolts that fix the main magnet pole and pull the hearth
deck straight upward. At this time, the joint and cap nuts of the piping
must be removed.
(4) The hearth can be removed by removing the Allen screw in the center of
the hearth.
1. Be sure to pull it straight upward. If it is subjected to slant force, the seal
may be scarred. So be cautious in the work.
2. There is a clearance of 1 mm between the hearth deck and hearth. Powder
or fragments of evaporant may fall in between them. In that event,
disassemble the electron beam gun and remove the evaporant on the rear of
the hearth deck and top of the hearth.
3. Remove the evaporant on the rear of the hearth deck and top of the hearth
with knife edge, sandpaper, wire brush (one with long bristles) or the
like. Use care not to scar them.
(5) Remove the O-ring using care not to scar the O-ring groove of the hearth
shaft. Check the O-ring for scar and plastic deformation. Change old
O-rings with new ones, if possible. Also check the O-ring groove of the
hearth shaft and the seat surface of the hearth for scar.
If there is scratch in the O-ring groove of the hearth shaft or in the seat surface
of the hearth, replace parts or request repair with returning the parts.
(6) Replace the bearing if it has gathered much rust or does not rotate
smoothly.
SECTION 5
CAUTION
CAUTION
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