Surface Mount Technology

- May 02, 2017-

Today I will briefly introduce about surface mounting technology in the assembly process.

Surface Mount Technology (SMT) uses an assembly process in which the components ares oldered to lands on the surface of the board, rather than inserted into holes running through the board.
 By eliminating the need for leads inserted into through holes in the board, several advantages accrue:
(1) smaller components can be made with leads closer together
(2) packing densities can be increased
(3) components can be mounted on both sides of the board
(4) smaller PCBs can be used for the same electronic systems
(5) drilling of the many through holes during board fabrication is eliminated, but via holes to interconnect layers are still required 
(6) undesirable electrical effects are reduced such as spurious capacitances and inductances. 

Typical areas on the board surface taken by SMT components range between 20% and 60% compared to through-hole components.

pcb assembly

Despite these advantages, the electronics industry has not fully adopted SMT to the exclusion of

Pin-in-Hole (PIH) technology. There are several reasons:
(1) owing to their smaller size, surface mount components are more difficult to handle and assemble by humans;
(2) SMT components are generally more expensive than leaded components,although this disadvantage may change soon as SMT component production techniques are improved;
(3) inspection, testing and rework of the circuit assemblies are more difficult in SMT because of the smaller scale involved;
(4) certain types of components are not available in surface mount form.  This final limitation results in some electronic assemblies that contain both surface mount and leaded components.

That’s all the infomation about surface mounting technology.thanks for you patient read.

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