SMT related technology

Electronic components, integrated circuit design and manufacturing technology

Electronics circuit design techniques

Circuit board manufacturing technology

Automatic SMT equipment design and manufacturing technology

Circuit assembly manufacturing process technology

The development and production of auxiliary materials used in the assembly manufacturing technology

SMT requirement for PCB

First: the appearance of requirements, smooth level off, do not wrap or rugged. No substrate will appear crack, scars, as well as the rusty spot. The second: the relationship between the thermal expansion coefficient. Element is less than 3.2 * 1.6 mm only suffering from stress, element is greater than 3.2 * 1.6 mm, must pay attention to. Third: the relationship between the coefficient of thermal conductivity. 4: the relationship between heat resistance. Resistance welding heat experiment required to reach 260 degrees for 10 seconds, its heat resistance should be consistent with: 150 degrees after 60 minutes, no bubble and substrate surface damage. Fifth: copper platinum the strength of the adhesive is generally to 1.5 kg/cm * 6 cm: bending strength to achieve more than 25 kg/mm 7: electrical requirements: 8 reaction to cleaner, 5 minutes in a liquid impregnation, the surface does not produce any bad, and have a good impact load

Wave soldering and reflow soldering Major difference: 1, wave soldering is through article tin tin slot will be dissolved into a liquid, stirring formation wave using motor, let the PCB and parts are welded together, in the hand of the plugin is commonly used in welding and SMT glue board. Reflow soldering is mainly used in SMT industry, it by air or other thermal conduction, will be printed on the PCB solder paste melting and parts are welded together. 2, the craft is different: spray starch wave soldering flux, again after preheating, welding, cooling zone.

Reflow soldering after preheating zone, backflow zone, cooling zone. In addition, wave soldering is suitable for hand plate and the rubber sheet, and require all components to heat, a wave surface can not have once SMT solder paste components, SMT solder paste board can only lead reflow soldering, wave soldering cannot be used.