Monday, August 19, 2013

Steps To Follow In Manufacturing Of PCB

By Cara Torres


Technology has simplified manufacturing of PCB. The procedure is more innovative and utilizes advanced technological aids to achieve the best results. Assembly begins with acquiring the right photo resist board. It is made of glass and plastic used as reinforcement. One end has a copper coating that is photo sensitive. The photo sensitive surface will be revealed when the plastic film is peeled off.

You will then place the now transparent printed circuit board beneath the photo resist board. They should be of exact same size. The surface is sensitive after the removal of the plastic film. Placing the mask in the right way-up ensures that the tracks do not end up facing the wrong direction. The board is then ready for transfer into the UV light box.

An appropriate cover should be placed on the box to ensure that it is completely shut. The UV light box is then switched on and left to run for approximately two and a half minutes. Plastic tongs will be used to get the board out of the box after which it is placed on a tank ready for development. The approximate time the board should be left in the box is ten seconds. It should not exceed this limit or go below it by considerable margin.

Plastic tongs are used to hold the board during all these operations. It is transferred into an etching tank after carefully washing in clean water. Heating allows the bubble etch tank to complete a very important process. The process involves etching away all unwanted copper materials. You will only be left with carefully drawn tracks. Success during this stage demands constant checks.

Etching takes between fifteen and forty five minutes. Letting the board remain in the tank for too long is likely to damage the tracks. There is a possibility that those tracks may get removed or damaged. This calls for caution by ensuring that the entire process is carefully monitored, minute by minute. Experience will make the process faster and more accurate.

The layout for PCB is best produced using an auto CAD or Computer Aided Design system. This is a system that allows you to input your own data and later transfer it to your manufacturer. The system allows you to earmark and define the copper layers you need for each job. The component notations and soldier marks will also be clear.

Photo tools are prepared using laser photoplotters. A controlled dark room is the best environment for such work. It makes it easier to manage temperatures and humidity. Data for the board is turned into a pixel image making it easier to work with. The film is written using a laser writer. The film develops automatically and is unloaded by the operator.

Manufacturing of PCB is not complete until profiling or V-cut scoring is done. This is done from the production panel. A scoring machine is used in this process. Cutters are either above or below the panel. The cut is made at a third of the entire thickness in order to leave a film that connects the board together. The board is then checked thoroughly by an experienced person to ensure that everything is in order.




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