Saturday 21 September 2013

What Manufacturing Of PCB Entails

By Helene Norris


Almost all electronic gadgets and devices have printed circuit boards as part of the components that constitute them. Manufacturing of PCB is not a difficult process and even amateur electricians can just provide the manufacturer with their own designs in order to get it done. The boards are divided into three categories; multi layer, single and double side boards. Conduction of these boards is usually done using copper, nickel or aluminum based material. The material is chosen depending on how complex or dense the circuits are. Described here is the process followed when going about creating them and the stages involved.

A conductive material is used to plate the backing. Conduction between the layers is enhanced by drilling holes into the backing. To remove any small conductor particles that may be present, the board is scrubbed. Filtration process is applied to recycle the recovered particles. This is because, if not recycled, the copper may form a mixture with the other wastes and then become quite hazardous to the environment.

Cleaning of the board is then done. In the next stage, there should be adequate adhesion and therefore to enhance this, etching is also done. One more layer of conductor is added next. The holes that had been drilled earlier should be conducted; hence the application of electrolysis copper plating is vital. Acidic based solutions and alkaline ones are used so that the pH is properly balanced.

The final circuit design I achieved by the use of photo imaging. Copper is electroplated to the printed circuit in order to get the final thickness. The final circuits should be well protected in the next etching and it is therefore important to apply a thin layer of lead or tin solder. The copper will be exposed by getting rid of the tin or lead solder, because it will not be a component of the final circuit. The unwanted copper is etched away using either sulfuric acid solution or an ammonia based solution.

Obtaining alternative resist can be achieved by use of other compounds that are photosensitive or organic. They can be used in their dry or wet forms. When exposed to ultraviolet light, they become hard.

In order to spread the liquid resist, one can use a silk screen, squeegee, roller or spray. One or both sides can have the liquid on. However, application can also be done to a specific area on the surface. Finer circuits can be produced by use of light.

The formation of multi layer panels is the final stage of this process. The inner cores of the layer are put together. The panels that are assembled together look like a copper foiled book with alternating epoxy sheets.

The book is then placed in a lamination press and high heat and pressure applied to it. The epoxy layers will melt and form a bond. An oven is used to cure the panel. It also undergoes trimming and buffing and then the required holes are finally drilled into it. Summarily, manufacturing of PCB requires a careful and properly calculated procedure in order to achieve the desired results.




About the Author:



No comments:

Post a Comment