How Are Printed Circuit Boards Manufactured? - Miracle Aerospace

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How Are Printed Circuit Boards Manufactured?
Printed Circuit Boards or PCBs form the backbone
of all major electronics like computers,
televisions, smartphones, digital cameras,
calculators, digital electronics, etc. A PCB is
responsible to direct electrical signals through
electronics, which satisfies the devices
electrical and mechanical circuit requirements.
In short, PCBs are the components that tell the
electricity where to go, thus bringing your
electronics to life. PCBs direct the current
around their surface through a network of copper
pathways, the complex system of which determines
the unique role of each piece of the PCB. To
design a PCB, circuit designers and fabricators
communicate with each other over the
manufacturing demands, which reduces the risk of
errors in the designing stage. There are various
stages involved in the production of PCBs, which
are mentioned in this blog. A leading
manufacturer like Miracle Aerospace takes care
that all these processes are precisely followed
to provide clients with the best quality PCB
assembly from India.
1) A PCB design software is used to create a PCB
layout. The most commonly used PCB design
software include OrCAD, KiCad, Pads, Eagle, and
Altium Designer. The designers are required to
inform the contract manufacturer about the
software version used, so that any issues caused
by discrepancies are avoided. Once the design is
approved, designers export the design into the
format that the manufacturers support. The most
frequently used program is extended Gerber.
Different PCB design software calls for different
Gerber file generation steps, encoding
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• comprehensive vital information like copper
  tracking layers, apertures, drill drawing,
  component notations, etc. All the aspects are
  checked to ensure that no errors go undetected.
  After a thorough examination, the PCB files are
  forwarded to PC Board Houses for production,
  where design-for-manufacture checks are
  performed.
• A special printer known as the plotter is used to
  make photo films of the PCBs to print circuit
  boards. These films are used to image the PCBs
  using incredibly precise printing technology to
  provide a highly detailed film of the PCB design.
  The final product is a plastic sheet with a photo
  negative of the PCB in black ink. For the inner
  layers, the black ink represents the conductive
  copper parts of the PCB, and the clear portion
  denotes the areas of non-conductive material. On
  the other hand, for the outer layers, the black
  area refers to that of non-conductive material,
  and the clear areas denote the copper parts. The
  film is developed by the plotter, which is
  securely stored to prevent any unwanted contact.
  Each layer of PCB and solder mark receives such
  clear and black film sheet, thus mapping out the
  PCB alignment. To achieve perfect alignment,
  registration holes are punched through all films.
• Here, the actual PCB is constructed. It is a
  laminate board of epoxy resin and glass fiber.
  Copper is pre-bonded on both sides, which is
  whittled away to reveal the design from the
  films. The copper-sided laminate is cleaned, and
  passed into a decontaminated environment such
  that no dist particles settle on the surface, or
  else the circuit could be short or remained open.
  The clean panel then receives a layer of
  photo-sensitive film, which comprises of a layer
  of photo reactive chemicals that harden after
  exposure to UV light. This ensures an exact
  match, which are fit onto pins that hold them in
  place over the laminate panel. The UV light
  passes through the clear parts of the film,
  hardening the photo-sensitive film on the copper
  the other areas slated for removal. The board is
  then washed with alkaline solution that removes
  any unhardened areas, and then dried.
• Next, a powerful chemical preparation is used on
  the board to remove any excess copper. In this
  way, the desired copper remains completely
  protected.
• With clean layers, alignment punches are required
  to line up all the layers. The registration holes
  align the inner layers to the outer layers,
  which are placed into a machine called optical
  punch for accurate punching.
• Now, the layers are fused together, where the
  outer layers are joined with the substrate
  through layering-up and bonding. The top and
  bottom of the original substrate are covered by a
  thin copper foil. All of this is then sandwiched
  together, such that any shifting is prevented
  during alignment. A bonding press computer is
  used to heat up the stack by applying pressure at
  the

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• right places, and having it cooled at a
  controlled rate. The multi-layered PCB product
  are then unpacked.
• Then precision drill holes are bored into the
  stack board, with an X-ray locator identifying
  the proper drill target spots. The additional
  copper that lines the edges of the production
  panel then undergoes removal by a profiling
  tool.
• The next step is plating, where the different
  layers are fused together using chemical
  deposition. The panel then undergoes a series of
  chemical baths, which deposits a thin layer of
  copper over the surface of the panel.
• The photo-sensitive film is now reapplied to the
  panel, with the exception of the outer layers
  being imaged with the PCB design.

The panel is then electroplated with a thin layer
of copper, and then tin plated where the tin
guards the section of the panel meant to remain
covered with copper during the next etching
stage to remove unwanted copper foil from the
panel.
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The unwanted exposed copper again undergoes
removal through application of chemical solution.
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The next stage is applying the solder mask to
both sides of the board, before which the panels
are cleaned and covered with an epoxy solder mask
ink. The board is then passed into an oven to
cure the solder mask.
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Next, the board is plated with gold and silver,
and provided with hot air-leveled pads to result
in uniform pads. The board is then provided with
ink-jet writing that is used to indicate all
vital information pertaining to the PCB. Finally,
the PCB passes onto the last coating and curing
stage.
13)
Finally, all possible electrical tests are
performed on the PCB to check for errors after
which the boards are cut from the original panel.
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