SURFACE MOUNT TECHNOLOGY LAB
INTRODUCTION
Surface Mount Technology was first developed in the 1960’s.
It is the latest technology used for constructing electronic circuits.
In this method, components are mounted directly onto the surface of printed circuit boards.
Surface-mount components are much smaller than lead components and they are designed to be handled by machines.
Advantages of SMT over older techniques:
• The components are much lighter and smaller, and thus easier to handle.
• The components can be fitted to both sides of the circuit board, thus allowing higher circuit density.
• Surface Mount boards have lower lead resistance and inductance. As a result, they give a better performance for high frequency parts.
EQUIPMENT
• SMT Board
• Solder Paste (Tin 58%, Lead 40%, Silver 2%)
• Surface Mount Components
• Flux (Rosins and an alcohol)
• Fine mesh polyester screen
• UV Sensitive Emulsion
• Vacuum Pen
• Infra-Red Heating Source
COMPONENTS LIST
• Integrated Circuits(IC’s)
• Transistors
• Capacitors
• Light Emitting Diodes(LED’s)
• Resistors
PROCEDURE
• Manufacture of the solder paste screen:
The fine mesh polyester screen is put over an ultra-violet sensitive emulsion. Then the screen is exposed to UV light. Through parts of the screen which are not opaque, UV light enters and reaches the emulsion. The emulsion hardens and sticks to the screen.
• Silk-Screen Printing:
It is a technique through which a solder paste is filled up into the slots where the components are going to be placed in a circuit board.
During the silk-screening process, a gap of at least 1mm-2mm was maintained between the polyester screen and the circuit board.
• Placing Components on the Board:
All the components were initially kept in a carousel. They were manually picked up with...