How To Avoid PCB Defects

- Mar 06, 2017-

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.

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