Manufacturing of single sided printed circuit board, Physics

 

In single sided PCB the conductor tracks run only on one side of copper clad board. Thus crossing of conductors is not permitted. Base material is chosen as per the application. It is mechanically and chemically cleaned. Then the photo resist solution is evenly applied. Photo resist is a organic solution, which when exposed to light of proper wavelengths, change their solubility in the developers. There are two types of photo resist (1) Negative acting photo resist. (2) Positive acting photo resist. Negative acting photo resist is a mixture of which is initially soluble in its developer but after exposure to light, it is not soluble. So the unexposed soluble is selectively dissolved and washed away, leaving the desired resist pattern on the copper clad laminate. Coating of photo resist is done by

(1)         Spray coating

(2)         Dip coating

(3)         Roller coating

The coated copper-clad laminate and film negative are kept in glass frame in intimate contact with each other. The assembly is exposed to ultra violet light for 3 minutes. The exposed board is rinsed in the developer tank. Proper developer has to be taken and used for a particular photo resist. Then the PCB is coloured in a tray. The dye revels the faults due to contrast. The faults are then separated by retouching. Etching eliminates the unwanted copper. Spray etching gives best results. Ferric chloride or cupric chloride is used as etching materials. Cupric chloride is regenerative and is thus preferred to ferric chloride. The etching solution is kept agitating by circulating low pressure air nozzles. Than the board is washed with water and dried. The board is then drilled with high speed drilling machine. The drill sizes range from 0.5mm to 1.8mm. Centring of hole on the land pad is done automatically.

 

Posted Date: 7/9/2012 3:48:23 AM | Location : United States







Related Discussions:- Manufacturing of single sided printed circuit board, Assignment Help, Ask Question on Manufacturing of single sided printed circuit board, Get Answer, Expert's Help, Manufacturing of single sided printed circuit board Discussions

Write discussion on Manufacturing of single sided printed circuit board
Your posts are moderated
Related Questions
When is the combination of cells advantageous and why? (Mar 2009) What do you mean by internal resistance of a cell? Write down the value of internal resistance of an ideal cell

What are bare fibers? It used mostly with PMMA fibers and refers to the optics which have no external protection sheath.


formula to get vi if the givens are distance and acceleration

A block of mass m is tied to a cord of length L that is pivoted at the center of a frictionless table. A second block of mass m is tied to the ?rst block also on a cord of length L

Binding energy of a system is described as the energy released when its constituents are brought from infinity to form the system. It can also be explained as the energy required s


luxon: A particle which solely travels at c (the speed of light in vacuum). All of the luxons have a rest mass of zero exactly. Though they are massless, luxons carry momentum

What happens if a person travels faster than light in a space shuttle?  Ans) Interstellar space travel is manned or unmanned travel among stars. The concept of interstellar trav