PCB Assembly and Cleanliness Issue

Component manufacturing these days require production of smaller and neater packages that are fractions of a millimeter. Place and pick machines contain brand-new accessories. Using these it is possible to place even the seemingly invisible parts where the components remain as close together as possible. Cleaning under such minute parts is quite difficult. Everything comes together with a synchronization of the supporting parts at manufacturing floor itself.

One of the major reasons of failure of the electronic product surprisingly is inadequate cleanliness or presence of contaminants during PCB assembly. Printed circuit board uses CAD advanced design system. Use of features like copper ultra-close fill or pour can increase the chances of shorts having catastrophic consequences. Decisions made during design implementations influence the other steps of the process.

It is important to understand that not all lab bare boards are necessarily clean. Similarly, delivered components may have contamination issues and may be unclean. Flux may pose problems and pouring it upon the board may lead to heating and hindered operations. PCBs sometime contain residual hidden flux as contamination. These may pass the quality control with proper operations. Problems occur in the operating environment. When these come in contact to high temperature and humidity swings, they generate condensation.

Such circuit boards from approved prototype PCB now start showing issues with residual flux. Ultimately, it leads to the formation of leakage paths leading to failures. Stray sources of voltage easily destroy the circuits of high impedance related to modern-day micro power electronics. Ideally, one should wash the PCBs after soldering. This produces a sparkling board ready for subsequent steps. Washing does not involve mere wash cycles but special combinations that contain chemicals, temperature, timing, and wash cycle.

This signifies complete cleaning that is not possible any other way. Quality and performance both depend upon this factor. Presence of residues leads to electrical impediment or field failures. There should be acceptance criteria related to various testing levels with directions regarding sample numbers to be tested. Modern companies are more aware of the problems. They have begun researching the issues and finding solutions. Through the years, minor transformations in packaging design, CAM/CAD software, chemistry, material, and board fabrication changed manufacturing process robustness.

This has unwittingly created scope for defects not possible before. To discover the root of the problem thorough evaluation of steps and materials related to manufacturing process is important. A foolproof cleanliness process involves:

• installation of new equipment with supporting subsystems
• development and implementation of evaluation, test procedures
• routine checking of the boards both before and after assembly process
• ensure soldering process did not have contaminants from fabrication process
• ensure complete cleanliness of boards after soldering
• use of 100% green cleaning processes
• test evaluation and validation of test processes as 100% stable

Optimum cleanliness eliminates failure and susceptibility of the products to corrosion also decreases, minimizing repair and maintenance needs. For worry free prototype PCB assembly solutions that bring your projects to life, do not forget to visit the website https://www.bestproto.net/.

About The Author

David Fischer is an Engineer and has a special interest in the world of circuit board. He is also a part of the lab testing teams in various companies. He loves to write and share his extensive knowledge & experience in this field. He highly recommends BestProto.net for building electromechanical and PCB prototypes.