|
 CAM
This is the first step in the manufacture
of a printed circuit, where the files provided by the customer are
analysed and we determine how the circuit must be
manufactured.
The board is prepared (depending on
the size of the printed circuit)
along with all of the necessary tools:
photolithographs with images and different programs for
drilling, machine cutting,
scoring and testing.
Three workstations with specific software are connected by the network to the production plant
to carry out these tasks.
FILMING AND REGISTERING OF PHOTOLITHOGRAPHS
here we film the photolithographs.
This is a critical operation as the final result depends on the quality of these photolithographs.
They must be created and stored in controlled temperature and humidity conditions
to avoid dilation (21C
+/- 1C and 50 %H +/- 5%) and some test
drilling is performed to centre them on
the panels to be manufactured.
Resources:
1 GERBER Crescent Photoplotter
1 MIVATEC 25 Crescent Photoplotter
1 BOHAN puncher
1 BCB diazo light screen
PREPARATION
OF MATERIAL
In this phase we cut the laminated material
used in the panels
for processing.
Resources:
2 Mechanical shears
1 BOHAN pivot
1 POSALUX pivot
INTERNAL LAYERS
IMAGE (Multi-layer process)
The internal layers are laminated with
dry, UV sensitive film for later screening
to transfer the image from the photolithographs
to the panels;
they are devloped in order to show the areas to be etched.
Resources:
1 laminator with DYNACHEM preheating gear for longitudinal and horizontal cutting
1 DUPONT light screen with glass/glass register
BOHAN
1 DYNACHEM developer
INTERNAL LAYERS
ETCHING (Multi-layer process)
In this process the copper which is not protected by the dry film is eliminated
using an ammoniacal process
and the internal layers
are left with their image in copper.
Resources:
1 Etcher with LUMIPLAS stripper with the
McDermid process
CHECKING OF INTERNAL LAYERS AND PRESSING'
(Multi-layer process)
Depending on the number of internal layers
these must be checked and
superimposed one on top of the other, and seperated
one from the other using a glass fibre material
with unpolimerised epoxy resin called
"prepreg". The layers are then pressed
and the group is subjected to a cycle of pressure and temperature
which polymerises the "prepreg". A
base material is thus created which is similar to the dual faced material
except with more internal copper layers - insulated one
from the other.
Medios:
1 PRINTPROCESS recorder
1 Posafor Optic POSALUX drill
1 WABASH hot/cold press
DRILLING
In this phase we package the panels together depending on the
minimum diameter of the
drills and the thickness of the base material.
We then drill the circuits using the
CNC programs created during the CAM stage.
This is performed using precision machinery
controlled by optical rules
and with high frequency motors.
The automatic replacement of the tool
is program controlled. The machine bench is
made from granite to ensure dimensional
stability.
Resources:
2 CNC PLURITEC drills
1 CNC EXCELLON drill
All conected to the plant network.
PLANING
Needed in order to polish the
surface of the laminated copper on the panel and to eliminate
burrs and oxidisation on the drilled edges.
This task is performed using wetted abrasive rollers (so as to avoid
the overheating
of the base material).
Resources:
1 NUBAL planer tool
DESMEAR
(multi-layer process)
This is a chemical process using
permanganate to dissolve the epoxy resin
from the interior of the drill holes
to ensure a reliable connection between the
internal layers for the later
metallization of the hole.
Resources:
1 DESMEAR LUMIPLAS line
McDermid process
DIRECT METALLIZATION
Although this process is called
direct metallization, it is not in fact metallization as such;
rather it is a process used to make the inside of the drilled holes
conductive using carbon which is then metallized
by means of
electrolysis. It involves various phases, such as
removal of grease deposits using ultra-sounds, application
of the carbon, the treating of the carbon in order to
harden it, micro-attack, anti-tarnish, etc.
These procedures are all performed by an automatic line
as the panels pass through
the various modules which make up the line.
Resources:
1 LUMIPLAS black-hole process line
from McDermid
EXTERNAL LAYER
IMAGE
The external layers are laminated with
UV sensitive dry film which is then used
to transfer the image of the photolithographs on to
the panels (which are developed showing the
areas to be metallized).
Resources:
1 laminator with
DYNACHEM preheating gear for longitudinal and horizontal cutting
1 DUPONT Light screen with
BOHAN glass/glass register
1 DYNACHEM developer
METALIZADO
This process is where we metallize
with copper the drill holes and the slots of the printed circuits
adding 25 to 30 micrometers of copper
to all of the conductive areas of the
panel by electrolysis.
A specific current is passed from
the copper anode to the cathode
(which is, in fact, the board itself)
which depends on the metallic surface of
the panel, determined when
the documentation is generated by the
CAM department (I.e. the areas which are not protected by the
dry film.) In the case of the
multi-layers we connect the internal layers together by the
metallization of the drill holes using the
copper which was uncovered
during the desmear process. We then
proceed to protect the copper areas by using
an intermediate tin electrolyte
which will be eliminated at a later stage.
Resources:
1 McDermid process STS electrolytic line
ETCHING
This is a double process
where we first eliminate the copper which is not protected by the tin using a chemical
process and
we configure the external layers
with their image in copper
and then remove the tin,
which has performed its task of
protecting the slots and the inside of the
drill holes
Resources:
1LUMIPLAS etcher with the McDermid process
SERIGRAPHY
This is where we cover the plaque with
with an anti-soldering mask. First
the surface is prepared using a
chemical treatment to ensure
the adherence of the resist solder.
The anti-solder mask is a photopolymer
which is applied by serigraphy
on the panel’s surface. It is heated and
exposed to UV light using the
photolithographs which were filmed by the
photoplotter for polymerisation.
The area where the UV light does not reach
may be developed and the pads shown
Afterwards, using traditional serigraphy procedures
serigraphy for the components is
applied (including graphite for
keys and peelable ink for the protection of those points
where we do not wish to solder components in the
wave solder machine).
The peelable ink must be applied after the
electrical test as it is an insulator.
Resources:
1 LUMIPLAS process micro-attack line
MEC Europe
1 ARGON Hydra printer.
1 MARCAFIX printer. Novafix
1 Vibrosystem AARHUS oven.
1 DUPONT PC-130 exposure unit.
1 HOLMÜLLER developer
METALLIC
FINISH
The metallic finish is
selective 63&37 tin/lead which is applied
onto the exposed copper
so that the components may then
be soldered. This process is performed by applying a
stripper to the copper and a flux to
ensure uniform temperature. The panel
is then submerged in the
sn/pb alloy and when removed
hot air is blown over it to clear the drill holes and
to ensure that the surface is
as flat as possible.
The surface may also be finished
in gold, as is the case of the
side connectors. .
Resources:
1 LUMIPLAS flux line
1 HASL PENTA machine. Model 500
1 LUMIPLAS flux removal line
TOOLING
The final tooling consists in carrying out any
non-metallized drill holes,
any internal machine cutting in the circuit and the final
cutting of the circuit by
CNC cutting and/or any scoring required
as per the programs generated by the
CAM department.
Resources:
1 Scoring TELMEC
2 CNC PLURITEC drills
1 CNC EXCELLON drill
All connected to the plant network.
ELECTRICAL
TEST
In Kelan we electrically test all
of the printed circuits that we manufacture,
and continuity and insulation is verified for all of the
nodes. The programs used to do this
are generated by the CAM department
along with the templates which
are drilled to perfect the
test-in circuit.
Resources:
1 test-in circuit machine for
conventional components (by comparison
of nets
1 automatic load machine
2 face MANIA NExus
2 face MANIA Speedy
FINAL
CHECKS
In this phase visual verification of
all of the printed circuits takes place before they
are packaged.
|
