As shown in Fig. 1, first article inspection or FAI takes a back seat at best in a number of today’s PCB assembly and manufacturing operations. At times, it falls victim to large engineering egos with a strong belief that a particular PCB is “a simple, easy board” that doesn’t require extra time and expense doing FAI. Other times, conflicting shipping deadlines take precedence and FAI is simply bypassed to get the project out the door to the customer.
Taking shortcuts like that in PCB manufacturing ultimately has its tradeoffs and most often, they are costly in time and dollars.
However, an issue is identified in the first article, and time is devoted to correcting it. As a result, rework time is saved, as well as considerable cost savings. This is especially true if the PCB requires package-on-package (PoP). Let’s say a first article of five boards out of a batch of 100 is performed, and it’s determined the thermal profile is not correct, for example, and the PoP wasn’t properly stacked together.
Those five boards can be reworked. The thermal profile is corrected and the PoP is properly stacked. Once the other 95 boards are run, good yields result.
Take a look at our article on the importance of FAI to get more details. Click on this link.
http://www.magazines007.com/pdf/SMT-Mar2013.pdf
In the meantime, here are some hints and tips that’ll help you understand the value of FAI in your next project.
- Primarily, check with your contract manufacturer (CM) or EMS provider to see if FAI is exercised on their assembly floor.
- If not and one particular component was misplaced or not placed at all and your order is for 500 boards, all those 500 locations have to be re-worked and those boards also undergo an unnecessary thermal cycle.
- But if FAI is indeed exercised, it conveys critical details at post-placement. Here, the auditor checks to determine that SMT components have been correctly placed; SMT programming is properly performed; and components are picked and placed in the right manner.
- FAI also checks out the thermal profile to find out if any component got skewed, tilted, or burned during reflow.
- The beauty of FAI is it allows sufficient time to make corrections and make them right.
- FAI demands a positive and disciplined mindset. If your CM or EMS provider pays little attention to FAI, it’s time to scout around for another who puts considerable emphasis on FAI.
By its very nature, FAI is cumbersome and demands a correct, positive, and disciplined mindset. The EMS Provider must invest and devote time and resources for the process to be validated. Generally speaking, EMS Providers that aren’t at the top of their game tend to take shortcuts by bypassing FAI due to multiple reasons.