The steps of the FMEA process

PCB Assembly Essentials Part 3: Supply Chain FMEA

Unfortunately, there is always a risk of failure—even when perfection is the objective. The risk of failure plagues the building of electronics systems, which begins with the PCBA development process. It is not surprising that the complex process of building electronic circuit boards involves a risk of failure modes. Most significant are threats that affect the component procurement process, which includes shortages with various root causes. One of the best tools to mitigate the potential unavailability of needed components is to employ supply chain failure mode effects analysis (FMEA).

What Is FMEA?

Prior to discussing supply chain FMEA, it is important to have a more general understanding of the FMEA process, which can be defined as follows:

The FMEA process consists of a set of specific actions or steps that are taken to identify, quantify and develop an effective means of response to risks that may occur during the stages of system development or operation.   

Although specific implementations of FMEA may vary a bit, the general steps include:

  1. List failure modes
  2. Assign risks to failure modes
  3. Rank risks in terms of severity
  4. Quantify each risk
  5. Determine the probability of a risk occurrence
  6. Create a mitigation control for each risk
  7. Identify a failure mode occurrence
  8. Apply control(s) and monitor results
  9. Update the process, if necessary

FMEA is a risk management technique for implementing a risk management plan. This often used tool is typically applied to system development, performance analysis, software development, service implementation, product design and manufacturing processes. For PCBA development, the latter two listed applications are common as well as supply chain FMEA.

How to Best Utilize Supply Chain FMEA

There are many aspects of PCBA development where FMEA can be a valuable tool to avoid mistakes, errors and failure modes. However, one of its best utilizations is to improve and ensure efficient and reliable component procurement, which is especially important as shortages from the effects of the Covid-19 virus continue. For example, following the steps above for supply chain FMEA could proceed as follows:

Supply Chain FMEA Example

  • Failure Mode: component package footprint mismatch
  • Risk: Stop assembly process
  • Severity: high as boards could not be assembled
  • Quantify Risk: risk assigned a value of 100
  • Risk probability: probability is medium
  • Mitigation control: check BOM MPNs against board layout package footprint
  • Occurrence: placed component to small for pad on board (44-pin quad package procured could not be placed for 60-pin quad package footprint)
  • Control Applied: step added to check BOM against layout footprint prior to fabrication
  • Process Updated to include control step

For this example, a simple added step virtually eliminates the possibility of a high risk failure mode occurring. Risk cannot always be completely eliminated; however, by following good guidelines as listed below, the probability of a failure mode occurring can be significantly reduced.

Understanding PCBA Complexity: Designing for Trouble Free Manufacturing

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Achieving the Best Supply Chain FMEA

🔗    Know what risks can impact the supply chain.
Risks to a component supply chain begin with design and include the supplier(s)
and CM. Common risks include selecting obsolete components, lack of distributor
inventory and long lead times for receipt by the CM.

🔗    Know the severity of each risk.
It is important to also know how each supply chain disruption will impact a project.
For example, if a development schedule permits, it may be possible for the CM to
substitute a comparable component—with the same footprint—from a different supplier
and save the designer some redesign time.

🔗    Have a means to observe the supply chain process.
Transparency is also an asset that allows designers to see if the supply chain is meeting its schedule or if a mitigation control needs to be enacted before it can cause severe
issues.

🔗    Develop and use a risk management matrix.
As there are many risks that may befall a supply chain, it is a good idea to take
advantage of risk management matrix templates to simplify the design and
implementation of a supply chain FMEA strategy.

🔗    Know and utilize real-time component availability data.
Data is the key to FMEA, and for supply chains, one of the most important pieces of data
is component availability.

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Tempo Automation, the industry’s leader for fast, high-quality PCBA prototyping and low-volume production, works with designers to optimize supply chain efficiency by sourcing from the most reliable electronic component suppliers and providing real-time availability data.

And, to help designers get started on the best path, Tempo Automation furnishes information for DFM checks and enables designers to easily view and download DRC files. Altium Designers or Cadence Allegro users can simply add these files to their PCB design software. For Mentor Pads or other design packages, Tempo Automation furnishes DRC information in other CAD formats and Excel.

If you are ready to have your design manufactured, try our quote tool to upload your CAD and BOM files. If you want more information on supply chain FMEA, CAD files or how to incorporate your design into a CAD format, contact us

Articles in this PCB Assembly Essentials series:

Part 1:  PCB Yield Calculations

Part 2: PCB Inspection Methods

Part 3: Supply Chain FMEA

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