Process
Equipment
Batch House
The company has a modern, well-equipped batch plant
with updated computerized controls for the accurate
weighing and mixing of batches for color television
panels and funnels to the exacting standards desired.
Furnace
The company has 3 furnaces for melting panel and funnel
glass separately on totally independent lines. The
furnaces capable of melting approximately 100 MT per
day are fired with natural gas and are cross-port
regenerative furnaces. The glass flows from the melter
through a throat in to refiners and there on to forehearth
for delivery to the forming press.
The furnace activity involves maintaining of the furnace
temperature profiles as per set values to assure proper
melting and fining of molten glass. The furnace department
is also responsible for maintaining the refiner and
glass consistency till it reaches the forming presses.
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Panel
Forming
The panel forming section as the name indicates is
where the forming of the panel takes place. The molten
glass, as a gob at around 1010°C, is delivered
from the forehearth to the mold of Forming press in
which the panel is pressed under very high pressure
into the desired shape and contour.
The Company has ELP presses capable of pressing the
panels into shape utilizing a fully automatic handling
system integrated with computerized measuring and
controlling system for critical parameters such as
weight, temperature of the glass gob and also of the
mold settings.
An automatic transfer system conveys the hot panel
to the Stud Insertion Machine (SIM) where the studs
of appropriate size are inserted into the sidewall
or band of the panel. Thereafter another automatic
loader loads the hot, studded panels into the Annealing
lehr (tunnel) for conditioned cooling.
After exiting from the lehr the panels are sufficiently
cool to permit inspection. 100% dimensional check
is done by automatic contour and periphery gages after
visual inspection.
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Funnel
Forming
The funnel forming section as the name indicates is
where the forming of the funnel takes place. The molten
glass as gob at around 1020°C is delivered from
the forehearth to the mold of the Forming Press in
which funnel is pressed under very high pressure into
the desired shape and contour.
The Company has ELP press capable of pressing the
funnels into the shape utilizing the fully automatic
handling system integrated with the computerized measuring
and controlling system for critical parameters such
as pressing pressure, mold temperature, timing variables
and forehearth temperature.
After the funnel is formed, it is automatically transferred
via a "takeout and turnover" mechanism onto
a conveyor belt that takes the funnel to a gas button
machine (GBM) where the anode buttons are inserted
into the body of the funnel.
From the GBM, the buttoned funnels are transferred
to annealing lehr for controlled cooling to bring
it to room temperature for inspection. 100% dimensional
check is done for periphery of funnels after visual
inspection.
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Panel
Finishing
The raw panels after visual and dimensional inspection
go through the next stage of operations that is Finishing.
This essentially consists of the following steps:
- Single Head Grinding
The panel face is rough ground on a single-head
rotating machine so that a thin layer of surface
glass is ground off taking away the surface defects.
The panel then becomes ready for the final grinding
and polishing actions that give the panel face a
polished appearance. 80 grit Pumice is used as grinding
medium.
- Pumicer
After the single head grinding the panel is rinsed
and then loaded into a 14 head Pumicer machine that
mainly takes off the roughness of the single head
grinding process. On a rough estimate, the layer
removal of the Pumicer would be 1/10 of the single
grinding machine. 100 grit Pumice is the grinding
medium.
- Polisher
From the Pumicer, the panel is loaded into a nine
head Polisher. The glass removal is negligible at
this stage. The main function is to give a high
polish to the panel face with Cerium Oxide as polishing
Medium using a felt sleeve to deliver the high gloss.
- Abrasive Rinse -
Washer -- Dryer
The panel is then thoroughly washed and rinsed (with
DM water and corn-cob that delivers a scrubbing
action without scratching the glass) and dried to
bone dry condition by "air knife drier"
before exiting the machine for inspection and packing
subsequent to release for dispatch to the customer.
At this stage, 100% gauging is done for monitoring
the Center Face Thickness (CFT).
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Funnel Finishing
The raw funnels after visual and dimensional inspection
go through the next stage of operation that is Finishing.
This essentially consists of the following steps.
- Funnel Edge Grinding
The funnels are gripped with the help of vacuum
suction pads from the nubbin (the short glass rod
at the yoke end of the funnel caused during forming
operations) end and pressed firmly with rotation
against rotating diamond wheels in presence of water.
The purpose is to grind off the funnel edge to make
it perfectly flat to facilitate matching with the
flat seal edge of the panel at the customers’
end. There are 2 diamond-grinding mills in operation.
The high capacity Diamond Grinding Machines from
The Netherlands were installed to replace conventional
machines which use garnet as grinding medium. Apart
from the higher quality and increased output the
diamond machines use only water, which results in
substantial savings on garnet.
- Mechanical Seal Edge
Polisher
After the seal edge is ground, there is an optional
facility to polish off the ground edges depending
on customer preference. The funnels pressed -
seal edge down - against polishing pads in the presence
of water. A smooth finish is given to the seal edges.
- Washer - Drier
The funnels after MSEP pass through a washer where
they are thoroughly rinsed with hot water and cold
water to remove garnet stains and then dried by
air.
- Crack off
The ground, polished, washed and dried funnels then
move on to the Nubbin Crack off machines where the
nubbin is "cut off" by point heating by
oxy-gas flame at a precise height on the nubbin
of a rotating funnel followed by the cold touch
of a cut off wheel. There are six crack off machines
used for this purpose.
- Automatic Vertical Neck
Sealing (AVNS) machine
After the nubbin has been cut off the funnel moves
to the last stage of operations that is sealing
of a neck on to the yoke end. The funnel is placed
seal edge down on to the machine and the neck gets
perfectly sealed to the yoke at the crack-off point.
Pot annealing to relieve stresses followed by normal
cooling over an open conveyor completes the operations.
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The funnels are inspected for visual defects and dimensional
tolerance by NTRO (neck tilt - run out) gage
before packing and release for dispatch.
Laboratory
A modern fully equipped state-of-the-art laboratory,
with Atomic Absorption Spectrophotometer, UV-VIS,
Coulter Multisizer, TV interfaced Petrographic microscope
etc has been set up for glass and raw material analysis.
Mold
Shop
The company has a fully equipped mold shop capable
of producing and repairing mold equipment such as
plungers, shell rings and mold bottoms for the panel
and funnel forming sections. Considering the accuracy
desired the shop is equipped with:
- CNC lathes for computerized cutting and contouring.
- CMM for automatic dimension measuring at programmed
points.
- State of the art benches for hand benching requirements.
- Robot aided computerized plasma spray equipment.
- In addition, there exist the normal facilities
such as general-purpose machines, annealers, welding,
electroplating, stripping and cleaning facilities.
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