A (Birth)Day In The
Chances are, these days, one of the first
things you do when you arrive at work is use
a computer. Ever wondered just how that
computer came into being?
By ROSS PHILLIPS
To the general public, even in
1989, computers are rather formidable devices. To those with a
technical "bent", they're rather
less frightening but most of us still
think of a computer as a "black
box".
SILICON CHIP has a large proportion of readers whose interest goes
more than skin deep. So we thought
you'd like to go behind the scenes
and visit a computer manufacturer.
As well as the several locally
manufactured computers, there are
literally hundreds of brands being
made around the world. Most come
from Asia: Taiwan and Korea,
Hong Kong, Japan, even China. And
most have similar methods of production, with various degrees of
automation.
Singapore, also, has a thriving
computer industry - and when the
opportunity arose for someone from
SILICON CHIP to visit Singapore's
leading computer manufacturer,
we naturally said yes.
The company, Essex Electric,
makes a range of IBM compatible
computers under the "IPC" brand
(the letters standing for Intelligent
Personal Computer).
A small proportion of their production is for the Singapore market
but the vast majority - over 1000
per week are destined for
distributors throughout Europe,
Asia, Australia and New Zealand.
The first thing that struck us
about the Essex Electric manufacturing facility, located approximately half way between the
business centre of Singapore and
Changi (of War Prison and later in-
ternational airport fame), is the
lack of salubrious surroundings.
However, we soon learned that
this was typical of Singapore; apart
from the fact that every square centimetre of land is precious (meaning
factories are high rise for the most
part), the tropical climate makes
painting the buildings a waste of
time and money.
No robots
Another surprise was the lack of
automation. No robot assembly
lines here: IPC computers are made
almost entirely by hand apart from
flow soldering of the PCBs.
However, labour in Singapore is
relatively cheap compared to, say,
Australia: the average worker in a
factory earns around S$1000 to
S$1200 per month (A$700 to
A$800). Hence labour intensive industries can succeed where they
would not elsewhere.
But we're jumping ahead of the
story. Let's go back to the start.
Essex was formed in 1980 by two
brothers who graduated in electronic engineering from the University of Essex (UK). Initially set up as
a specialist printed circuit board
manufacturer, it now concentrates
entirely on the making of computers
and related products.
In fact, the original PCB manufacturing facility was sold off in
1984 - and Essex has remained its
largest customer.
The philosophy has always been
"quality first" . The company made
a decision very early in its life not
to cut corners to save money.
Research and development
READY FOR ASSEMBLY: a blank PC board is placed on a conveyor belt so that
the sockets and passive components can be fitted. The boards are pre-baked
in an oven to force out every last smidgin of water.
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This attention to quality becomes
obvious in the research and development department. No pressure is
applied to the team of engineers to
produce faster - even if it takes a
little longer, management knows
that the designs coming from R&D
will be optimum.
While we were there, a team of
engineers was working on the next
Life Of A Computer
in microns, not millimetres!
When completed, a copy of the
CAD software is sent off to the PCB
manufacturer, who has the ultraprecision plotters necessary to convert it to film.
Completed boards are delivered
back to the factory hermetically
sealed and each one is visually inspected for flaws.
PCB assembly
AFTER THE PASSIVE components have been fitted, all the ICs (with the
exception of the RAM chips) are installed. The earth strap fitted to the
worker's wrist protects the ICs from static electricity.
Essex product, a point-of-sale (POS)
terminal suitable for everything
from the smallest motel or service
station through to the largest retail
chain.
The enthusiasm of the design
team was infectious: before we left
the laboratory, we were firmly convinced that the Essex POS terminal
will be the greatest thing since sliced bread!
Many prototypes are made of
each design. Every one is subjected
to " worst case" analysis to allow
for component tolerances well in
excess of what could be expected.
Many are tested to destruction.
PCBs are designed, tested and retested. Layout is done with the aid
of a $300,000 CAD system, and in
some cases extends to a 6-layer
board. Track widths are measured
Immediately before assembly,
each board is baked in an oven to
force out every last smidgen of
water - particularly from the component holes. This simple step virtually eliminates dry joints when
the boards are later soldered.
The boards are assembled in two
stages on one production line. First
of all, the sockets and many of the
passive components are inserted,
then the active components,
crystals, etc are inserted, all by
hand.
Components purchased for use in
the Essex plant are top quality,
prime spec devices. Even then, all
batches are randomly sampled by
quality control. If any devices are
not to spec, the whole batch is
rejected.
It is perhaps fortunate that the
modern computer board uses so
ABOVE: WHEN DRY, the boards enter an
automatic testing station before passing to the
next stage of assembly.
LEFT: AFTER FLOW flow soldering, the still hot
board is dunked in a bath of pure water!
JULY 1989
7
FOLLOWING THE AUTOMATIC testing station, each board is powered up and
run for a full 24 hours in an enclosed cupboard. The heat build-up inside the
cupboard further stresses the components and shows up any faulty boards.
few components: a completed board
emerges from the assembly line
every few minutes.
Once the board has reached the
stage where static damage-prone
devices are involved, all workers on
the line are earthed to both the
board and a common earth via
wrist straps.
Immediately before the flowsoldering machine is a quality control officer, who visually inspects
all boards and pushes down all ICs,
sockets, etc to ensure they are fully
"home".
We weren't quite ready for the
next stage of production: as each
board leaves the flow-soldering
machine, while it is still hot, it
drops into a bath of pure water.
That's right, each board is immersed in water - for a period of
about five minutes!
The quality control manager explained that this is one of their most
important tests. Because the board
is still hot, the cold water causes a
mild shock to every component and
solder joint.
As any serviceman will tell you,
it's those dry joints which get you:
often years later. The shock of the
cold water bath shows any suspect
joints immediately - no waiting!
But that's not all: each board is
then thoroughly washed in a hot
water spray. This removes any flux
or solder residue and again places
the board and its components under
high stress.
The pre-baking and the water
bath between them have virtually
eliminated dry joints in this factory.
Assuming the board has passed
this stage, it is then dried off with
compressed air, then thoroughly
baked for several hours to completely dry it out.
After drying, the boards are
placed on another chain conveyor
where component _pigtails etc are
removed by a high speed rotary
saw.
Finally, each board is given close
visual inspection by another quality
control officer before being passed
through to dynamic checking.
More quality control
Each board then enters a 100%
component and operation check in
a fully automatic testing station.
The PCB is placed in a jig, and is
brought into contact with many
hundreds of "fingers".
Under computer control, every
facet of operation is checked in just
a few moments. The readout on the
computer screen is simple: "good"
- everything passes, or "bad" - a
ABOVE: AFTER FINAL assembly, the computer,
together with its monitor and keyboard, is checked
for a full 48 hours in the "burn-in" room.
LEFT: A TECHNICIAN examines a reject board
from the automatic testing station. If a faulty
component is the cause, it is replaced on the spot
and the board re-enters the test procedure.
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single failed test procedure means
rejection.
In fact, the computer testing procedure will print out a report indicating to the technicians which
component or area of operation is
faulty, making the subsequent
repair simple.
If a PCB is repaired, it re-enters
the testing procedure as if it had
just come from assembly.
24-hour burn-in
Each PCB is then powered up and
run for a full 24 hours in a specially
designed cupboard containing
perhaps 20 or 30 other boards and
power supplies.
Because the cupboards are fully
enclosed and insulated, the heat
build-up is high - subjecting the
components to further stress; far
more than they would be expected
to undergo in normal life.
Final assembly
If the PCB gets the nod from
quality control, it is then stored in a
controlled atmosphere ready for
final computer assembly. As the
computer is assembled, the memory, disk drives, display cards, etc,
as specified by the customer, are
fitted.
The "customer" is not the
distributor: he or she is actually the
end-user customer. For example, a
customer in Australia might order a
"NEAT (286) type with 4Mb
memory, 40MB 28ms hard disk,
1.2MB 5¼in and 1.44MB 3½in
floppy drives, and VGA graphics, in
a desktop tower case".
The local distributors, CompuHelp Australia, would fax this
order direct to Essex in Singapore,
and a work sheet would be
prepared immediately listing that
configuration.
Each component necessary to
build the computer to those
specifications would be taken from
the store, and routed through to the
final assembly area.
Around 20 technicians are involved in assembly and each one
can complete a computer in around
half an hour. So, depending on the
hours worked, the factory has a
production capacity of between 250
and 300 hand-built computers per
day.
THE FINISHED PRODUCT: this particular machine uses the new enhanced AT
chipset and runs at 20.5MHz in turbo mode. It is equipped with a 5¼-inch
1.2MB floppy disc drive and a 40MB hard disc.
When completed, the technician
will power up the machine and test
basic operation. He will then format the hard disk, load DOS [the
disk operating system) and ensure
the computer is fully operational.
When the technician is satisfied
with his handicraft, he despatches
it to the final stage of production,
the 48 hour burn-in room. Here,
every computer is "married" to its
appropriate video monitor and
keyboard, and all are checked for a
full 48 hours with a series of
diagnostics and routines that cycle
through every component.
Only if the computer system
passes through every check with
100% success is it considered now
finished. Each of the quality control
check-lists stays with its computer
until delivery to ensure nothing is
left to chance.
Despatch
While the computer might be
electronically finished, it still has to
be prepared for the rigours of
transport. Specially designed foam
[not styrene) packaging holds the
computer firmly and securely
within its transportation box,
which also contains the keyboard
and manuals. The monitor is packed separately.
Normally, computers are despatched by air, meaning the customer
doesn't have to wait any longer
than necessary for his or her
machine.
~
JULY 1989
9
