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Failure mode and effects analysis (FMEA)
A structured way to find every way your product could fail, rank the risks, change the design and rank again. We use it to improve a design at the point where changes cost least, rather than to fill in a form.
- You send
- Your requirements, your CAD model, sketches or drawings, how the product is used, and the process and supplier that will make it, if known
- You get back
- A completed FMEA worksheet with every failure mode ranked, the actions with owners and dates, the design or process changes made, and the risk re-ranked to show it coming down
Overview
An improvement tool rather than a form
Many FMEAs are written once to satisfy a customer and filed. Ours is a loop: the ranking tells us where the design is weak, the design changes, and the ranking is run again. Because it happens at concept stage, on sketches and early CAD, each change costs very little. On one recent product fix, the changes that came out of the FMEA cut the design risk numbers by about 90% before anything was made.
Design and process, together
Whether you call it DFMEA or PFMEA, the best analyses do both in one worksheet. A failure mode usually has a design cause and a process cause side by side: a spring that can jump out of place, and a fixing that can be left untorqued. Ours lists both, with the action and the owner against each, whether that is us, your production team or your supplier.
How it is scored
Each failure mode is rated on three scales: the severity of the effect, the occurrence of the cause and how likely it is to be detected before it reaches the customer. The three combine into a risk priority number that ranks the list. We work to our own structured worksheet, or to your company’s FMEA format if you have one.
- Severity: how bad the effect is for the user or the product
- Occurrence: how likely the cause is, given the controls in place
- Detection: how likely it is to be caught by design checks, tests or inspection
- A risk priority number for each line, ranking the worksheet
- Actions with an owner and a target date, then re-evaluated with new ratings
Risk drawn on the part
An FMEA worksheet is a table. Behind it is a part with a few places that matter far more than the rest: a seal, an edge a spring can catch on, a thread, a thin wall. Because the same engineers model and analyse the part, the ranking goes back onto the geometry, and the top items are checked by calculation or FEA where the score alone is not enough.
Part of design to manufacture
In a whole product, the FMEA is how the concepts are evaluated at stage 02, and it is run again as the detail design settles. Booked on its own, it fits beside design review and drawing work, so a high-ranking item turns into a change in the model rather than a recommendation left in a report.
When to run one
- Choosing between concepts, before detail design starts
- A new product before tooling or production is committed
- A safety-related or regulated product that needs a documented risk analysis
- A design moving to a new supplier or process
- A product with field failures, warranty claims or scrap on the line
- A customer or auditor asking for a DFMEA or PFMEA you do not yet have
Process
How a project runs
- 01
Pin down what it must do
The requirements are written down first, confirmed or marked as assumed, so every failure mode is measured against something agreed.
- 02
Find and rank the failure modes
For each function, the ways it could fail, the cause and the effect. Each is scored for severity, occurrence and detection, so the list ranks itself.
- 03
Change the design
The items at the top get an action, an owner and a date. Most are small changes to geometry, material, tolerance or fixing, made in the model by the same engineers.
- 04
Rank again and measure
The changed design is re-scored and the worksheet shows the risk coming down, line by line. What is left is known and accepted rather than discovered later.
Ready to start? Describe the job and an engineer replies within one working day.Start a projector call 0800 246 1012
Questions
Questions we are often asked
Is this a DFMEA or a PFMEA?
Both, in one worksheet. A design FMEA asks how the design could fail to do its job; a process FMEA asks how making and assembling it could go wrong. Keeping them apart hides the fact that most failure modes have a cause on each side, so we rate both and assign the actions to whoever owns them.
Which FMEA standard do you use?
We run FMEA to our own structured worksheet, rating severity, occurrence and detection into a risk priority number for every failure mode, with a re-evaluation after the actions. If your company or your customer has an FMEA format of its own, we work in that.
How does it improve the design rather than just document it?
The worksheet is run before the design is fixed, so the top-ranked items become changes to the model: a chamfer, a fillet, a different material, a captive fixing. Then the ratings are run again. The record shows the risk before and after, and the design that ships is the one that scored lower.
Can you run an FMEA on an existing product?
Yes. A product with field failures, warranty claims or scrap is a common starting point. The analysis explains the failures that have happened, finds the ones that have not yet, and ranks the fixes.
What do you need from us?
Your requirements as you know them, your CAD model or drawings, how the product is used and what it must survive, and the process and supplier that will make it if they are known. One or two of your people in the review sessions makes the analysis much stronger, because nobody knows the product’s history like you do.
How long does it take?
It depends on the size of the product, how much of it is new and how much history there is to draw on. Tell us about the product and we’ll give you a plan and a price.
Is the FMEA ours to keep?
Yes. The worksheet and everything in it is yours, like the designs and drawings we produce.
Whole products
Whole products, by F-CAD®
Risk in a whole product
In design to manufacture, the FMEA is how the concepts are evaluated at stage 02, Concept, and it is run again through stage 03, Detail & Simulation, as the design settles.
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Tell us about the product
Describe the product, where it is in its life and what is worrying you, and an engineer will reply with how we would run the analysis.
- Freephone
- 0800 246 1012
- Office
- 220 St Vincent Street
Glasgow G2 5SG
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