SMT components should meet the following basic requirements

1. Assembly adaptability - It is necessary to adapt to various assembly equipment operations and process

 flows. (1) SMT components should be placed on the circuit board using a SMT machine before welding, so the upper surface of the components should be suitable for picking up the vacuum nozzle of the SMT machine.

(2) The lower surface of SMT components (excluding solder joints) should retain space for the use of adhesives.

(3) The size and shape should be standardized and have good dimensional accuracy and interchangeability.

(4) The packaging form is suitable for automatic mounting of the SMT machine and can protect the device from external forces during transportation, maintaining the flatness of the pins.

(5) It has a certain mechanical strength and can withstand the installation stress and bending stress of the circuit substrate.

2. Welding adaptability - to adapt to various welding equipment and related process flows

(1) The welding ends or pins of components have good coplanarity, meeting the requirements of mounting and welding.

(2) The materials and packaging of components have good high-temperature resistance and are suitable for welding conditions:

Reflow soldering: (235 ± 5) ℃, welding time: (5 ± 0.2) s.

Wave soldering at (250 ± 5) ℃, with a soldering time of (4 ± 0.5) seconds.

(3) It can withstand cleaning with organic solvents after welding, and the packaging materials and surface markings must not be melted.