The Importance of FCT Testing in PCB Manufacturing & Assembly!

By | Date posted: | Last updated: January 24, 2022
FCT Testing

While it is important to stick to the highest quality standards in the process of PCB manufacturing, what is equally important is that you ensure that your board will operate as envisioned. This requires undertaking a set of tests at various stages namely prototyping, manufacturing as well as assembly.

PCB functional testing (FCT testing) comprises a whole range of tests that check for proper functioning of the board. Oftentimes, the manufacturer may also need to modify the PCB design for FCT in order to facilitate PCB functional testing. As long as the manufacturer understands your device’s functional requirements as well as your testing requirements, there will not be too many requirements for sending the design files back and forth. A cloud-based system for data access of course works best.

Let us look at PCB Functional Testing (FCT Testing) in some detail:

Simply put, PCB functional testing refers to a comprehensive testing regimen that determines that a manufactured board is ready to serve its purpose. The goal of PCB functional testing is to identify any defects that could impact its reliability. The defects could be by way of any missing components or as simple as any opens or shorts. PCB Functional testing, therefore, entails a wide variety of tests including but not limited to:

  • Visual Inspections
  • In-Circuit Tests
  • Flying Probe Tests
  • Bench Tests

Above everything else, PCB functional testing (FCT Testing) offers a comprehensive view of signal behavior. Some of the potent signal issues that can be identified through a PCB functional test include:

  • Power integrity issues: PCB functional testing can bring to light any issues such as jitter, low frequency noise, and more.
  • Signal distortion: Signal distortion, Skews and other such behavior can be identified through comprehensive functional testing.
  • Incorrect voltage: Incorrect Voltage can often be a result of a missing or incorrect component.

Comprehensive PCB functional testing involves building a custom test fixture. While this comes at a cost, with high volume manufacturing runs, the cost tends to quickly amortize itself, especially as it guarantees high quality

The Benefits of PCB Functional Testing (FCT Testing) Methods

  • Manual inspections – They are used to verify various aspects of the printed circuit board assembly process.
  • Automated Optical Inspection – It can be used to check issues such as:
    • Shorts
    • Any violations in spacing
    • Drilled hole breakout
    • Solder Paste Application
    • Location and orientation of components
  • X-Ray Inspection – X-Ray inspection can be used to examine components such as BGAs for solder defects.

Some of the systems that can undertake functional testing include:

  • Flying Probe Test: It can detect improper solder connections as also include some limited functional testing.
  • In-Circuit Test (ICT): This system works fast as also runs sophisticated functional tests. However, it isn’t used for low volume production as it is time-consuming and expensive.
  • CableScan: This relies on connectors as opposed to test points. It can search for assembly issues such as improper solder connections while also running functional test signals

Collaborating with the experienced PCB manufacturer

Collaborating early in the PCB design stage with the manufacturer is a great way to ensure the comprehensive testability of the board. With many PCB designs being put on hold before manufacturing, this is a great way to improve turnaround time. It’s important to check that the board complies with the manufacturer’s DFM recommendations and testing capabilities.

It is also important to evaluate that the PCB manufacturer offers the following services:

  • They have experienced test engineers that can develop hardware and software for functional testing, as also test fixtures and structures.
  • They have sophisticated testing equipment for a wide variety of testing such as flying probe tests, ICT and manual testing procedures.
  • They have existing relationships with component manufacturers.
  • They thoroughly document testing results.

To Sum Up

Clearly then, the abilities of the local electronics contract manufacturer are imperative to the success of the circuit board build. Done correctly, PCB functional testing is the most comprehensive testing regimen for determining whether a manufactured board is reliable for your purpose or not. Functional testing is integral to eliminating any errors that may crop up during the production phase, while also helping to reduce cost.

TechnoTronix is an ISO 9001:2015 certified company who delivers one-stop PCB manufacturing services with specialized support, reliable testing, and multi-functional features. Our consistent quality and quick turnaround time captivate us to our customers, who look on us as a one-stop-shop for all their PCB requirements.

If you have any requirements regarding our PCB manufacturing or need urgent assistance, contact us at or call us on 714/630-9200.

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