How to avoid PCB defects
Today we will share some knowledge about the PCB challenges. On top of rapid innovation, shrinking components and sophisticated circuit geometries, the fabrication of a printed circuit board consists of many steps and moving parts. The nature of the manufacturing process provides numerous opportunities to introduce a defect in the mix, unintentionally.
Consequently, failure analysts face a variety of challenges when finding manufacturing defects:
High-speed Printed Circuit Boards (HSCBs)- HSCBs, which have grown more complex and use a variety of integrated components, continue to grow in popularity. However, the components require boards that are composed of two or three materials that increase the possibility of failure in extreme high-speed applications. Failures also occur from pins and chip placed in an incorrect manner on the board.
Lead-free Assembly Process- The lead-free assembly process requires a higher temperature and traditional tin-lead solder, which leads to higher temperatures for the reflow and wave soldering. This results in an adverse effect on the solder joint and electronic components. Check out NTS Tin Whisker Testing services.
Plated Through Hole Barrel Cracking- Barrel fatigue, which is the circumferential cracking of the copper plating that forms the plated through hole (PTH wall), is the most prevalent failure mode. It occurs as a result of differential expansion between the copper plating and the out-of-plane coefficient of thermal expansion (CTE) of the printed board.
Correct Surface Finish Selection- The most important decision for the electronic assembly may be the surface furnish, which affects the process yield, the amount of rework necessary, field failure rate, the ability to test, the scrap rate and the cost.
Conductive Anodic Filament- Conductive Anodic Filaments (CAF) or metallic electro-migration describes an electro-chemical process that involves the transport of a metal across a nonmetallic medium under the influence of an applied electric field. The condition causes current leakage, intermittent electrical shorts and dielectric breakdown between conductors in PCBs.
Nonetheless, MOKO take the proper care to adhere to exact tolerances and specifications to avoid failures. This requires an effective root cause analysis to investigate and probe into components and systems, and make the necessary quality improvements.