Utilizing an FMEA Chart in Electronics Design

October 30, 2019 Cadence PCB Solutions

 

Failure mode and effects analysis overlaid on an image of graphics

 

Regardless of how many books I’ve read about parenting, I’m back to square one when I welcome the birth of my son. That was 7 years ago. It was a journey of sleepless nights, at least in the first couple of years, and attempts at guessing why my poor child is crying. 

After many attempts, I started to differentiate the subtle signs indicating hunger, sleepiness, or the discomfort of wetting his diaper. In electronics, you don’t have to deal with wet diapers, but there are many instances when a design could go wrong, particularly after being deployed.

Whether it’s a blown capacitor or unstable serial communication, it is part of a PCB designer’s responsibility to investigate the cause of failures and to ensure that the appropriate revisions in the design are made. There are various tools that can aid a PCB designer’s effort, including the FMEA chart.

What Is an FMEA Chart

FMEA stands for “failure mode effect analysis”, it is a process of identifying potential or actual failures in a design or system. Besides identifying how a particular system could fail, FMEA is also used to highlight the consequences that affect end-users. 

In practical usage, the process is documented in a table, often referred to as the FMEA chart. The FMEA chart documents possible points of failure in a design, the implications, mitigation measures, and causes of the failure. 

The information is used to recommend improvements to the design, and they are reflected in the FMEA chart. Follow-ups of the improvisations, such as design review, revision, or other measures, are also recorded in the FMEA chart. 

When Should You Use an FMEA Chart

Obviously, the FMEA chart is a helpful tool when you’ve encountered problems in a design that is operational in the field. The chart helps you to zoom in to the problem and trace the possible root causes. Remedial action, whether it’s an impromptu modification or revision, can be taken based on the analysis. 

With that said, the application of the FMEA chart as a tool should be employed way before the design hits the field. The FMEA chart should be utilized in the early stage of electronics design when you’re drafting the specification of a product. Using the FMEA chart helps you to identify potential points of failure that you can address during the design process.

You’ll also find the FMEA chart helpful when you are redeploying the same hardware for different applications. Even if the hardware goes largely unmodified, using the FMEA chart helps to provide a clearer picture of how the design would fare in a different environment. 

The FMEA chart shouldn’t be viewed as a one-time document, but rather a process that continuously supports a design throughout its entire lifecycle. It can be continually updated and referred to when problems pop up during and after the design phase. 

 

Graphic representation of the FMEA process

The overall goal of an FMEA process is to both track risk assessment and track attempts at resolution.

 

How To Apply FMEA Chart In PCB Design

As a PCB designer, you have to be on your toes when anticipating potential issues in your design. Regardless of your technical skill, there are many variables that can cause problems in the functionality of the electronics.

Unmanaged thermal dissipation in design can cause hot spots and affects the functionality of the circuit. Overlooking electromagnetic interference (EMI) susceptibility invites signal integrity issues that disrupt communications between components. Dozens of other issues may cause problems when the design is manufactured and deployed.

It helps to draft an FMEA chart during the design phase and list down potential problems that may arise due to the characteristics of the components, design, manufacturing, and the environment. Note how these problems will affect the functions that are expected from the design. 

It also helps when you prioritize the severity of the problems and indicate how likely the issues are bound to occur. For example, you will want to prioritize the transient problems that damage communication IC over the deterioration of LEDs over time. Doing so helps you to focus on follow up actions and recommendations for the list of possible failures.

Of course, your effort in providing a more accurate analysis can be boosted by the right PCB design and analysis software. When it comes to FMEA, analysis tools help to provide better power and signal integrity analysis, but it really comes down to proper communication within your team and properly using the tools at your disposal within the trusty OrCAD PCB Designer layout.  

If you’re looking to learn more about how Cadence has the solution for you, talk to us and our team of experts

About the Author

Cadence PCB solutions is a complete front to back design tool to enable fast and efficient product creation. Cadence enables users accurately shorten design cycles to hand off to manufacturing through modern, IPC-2581 industry standard.

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