Tuesday, July 21, 2009

PC Board Fabrication

PC board fabrication involves two aspects, namely:

* designing of circuit diagram
* inlaying it over the surface of the board

With the availability of high-tech machines, PC board fabrication has become simpler and economical.

Steps in PC Board Fabrication

Typically, PC board fabrication comprises the following steps:

Preparing artwork: This involves:

* preparing a basic circuit diagram on white paper.
* A conventional style is to use thin felt-tip pen, specially designed stencils or auto transferable stickers to prepare circuit diagram.
* Today’s contemporary style involves using CAD technology through specifically made software.
* CAD has simplified the designing process along with reduction in time.

Transporting design: At this stage, the artwork design is transferred onto the circuit board. A variety of techniques are used, such as:

* manual designing over the metal surface using a felt-tip pen.
* using self-adhesive films that are placed on the board’s surface.
* the use of photo-sensitive spray.
* employing special photo-sensitive circuit boards as such PC boards are expensive but have uniform photo sensitivity that facilitate high quality design transport.

Exposure to UV rays: The circuit board is then placed in a specially-designed box to get exposed to UV rays. A thin UV stream of 125W is used for this purpose. Following stages are:

* UV exposure transfers the circuit diagram onto the photo-sensitive plate.
* This stage requires specialist supervision to define the time of exposure.
* Later, the board is chemically treated with a mixture of caustic soda and water.
* It helps to remove the photographic film from the board and you get a printed circuit board with the circuit design inlaid.

Etching: The technique of plating copper on the surface of the circuit boards to form charge flow route is called as etching. Unwanted deposition of copper is chemically removed. The circuit board is then coated with a solder paste which brings forth a green color.

Drilling: This involves:

* making holes, called as vias, onto the circuit board.
* Vias allows for soldering of the electrical components.

World over, most of the large scale PC board fabrication is done through automated processes. US-based PNC Inc. excels in the manufacturing and repairing of PC boards. By producing double-sided and multiple circuit boards, PNC Inc has pursued excellence as its endeavor to meet client requirements.

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