The reliability for PCB board assembly-2
From the components of the rational use of the design, substrate selection of design , layout and orientation of the design elements , SMT solder paste printing and reflow soldering quality control these 5 ways on how to improve the reliability of PCB board level assembly are described . Two components of the rational use of the design components of rational use of PCB board assembly design is the key part .
According to technology , equipment and design requirements of the identified components of the electrical performance and features to choose SMC / SMD package form and structure , this density circuit design , producibility , testability and reliability play a decisive role . SMT components are numerous and structure of different specifications , to achieve the same function may exist in a variety of integrated circuit package ; in the circuit board PCB design copy should be provided by the supplier according to market specifications and component capabilities of existing production equipment And precision, a reasonable choice.
Rectangular chip component for sheet resistors, capacitors and chip inductors sheet , frequently asked questions are designed pads and components do not match the shape size .
Pad size is much larger than components Dimensions , copy plate welding by the accumulation of solder to connect , easy to create components in the vibration of the crack , and copy board pad size of less than components Dimensions can not be welded .
SOP and SOJ Small Outline Package
IC DIP package that is scaled , pin main European wing , J -shaped and I -shaped . Frequently Asked Questions are designed PCB copy board feet of screen printing without a tag , resulting in welding can not confirm the direction; because the oxidation of pins , easily lead after the reflow soldering Weld .