What is FMEA? Definition & Manufacturing Examples

What is FMEA?

FMEA (Failure Mode and Effects Analysis) is a systematic, structured methodology for identifying potential failure modes in a product design or manufacturing process, evaluating the risk associated with each failure mode, and prioritizing actions to reduce or eliminate the most critical risks. It is a proactive tool — used before failures occur — making it a cornerstone of preventive action in manufacturing.

Originally developed by the U.S. military in the 1940s (MIL-P-1629), FMEA was adopted by the aerospace industry and later became a requirement in the automotive industry through AIAG (Automotive Industry Action Group) and the APQP (Advanced Product Quality Planning) process. Today, FMEA is used across virtually all manufacturing sectors and is referenced in ISO 9001, AS9100 (aerospace), and IATF 16949 (automotive) quality standards.

There are two primary types of FMEA. Design FMEA (DFMEA) analyzes potential failures in the product design — what could go wrong with how the product is designed. Process FMEA (PFMEA) analyzes potential failures in the manufacturing process — what could go wrong during production. Both types follow the same structured methodology but focus on different aspects of the product lifecycle.

How FMEA Works in Manufacturing

The FMEA process is conducted by a cross-functional team and follows these steps:

1. Define the scope. Identify the product, process, or system to be analyzed. Break it down into components, operations, or steps.

2. Identify failure modes. For each component or step, list all the ways it could fail. A failure mode is any way the item could fail to perform its intended function. Examples include fracture, corrosion, misalignment, short circuit, wrong dimension, and missing operation.

3. Determine effects. For each failure mode, describe the consequences if the failure occurs. Effects are assessed from the customer's perspective — both internal (next operation) and external (end user).

4. Assess severity (S). Rate the seriousness of each failure effect on a scale of 1 to 10, where 1 is negligible and 10 is hazardous (safety issue with no warning).

5. Identify causes. For each failure mode, identify the potential root causes. One failure mode can have multiple causes.

6. Assess occurrence (O). Rate the likelihood of each cause occurring on a scale of 1 to 10, where 1 is extremely unlikely and 10 is almost certain.

7. Identify controls. List the current design or process controls that either prevent the cause or detect the failure mode before it reaches the customer.

8. Assess detection (D). Rate the ability of current controls to detect the failure on a scale of 1 to 10, where 1 is almost certain detection and 10 is no detection possible.

9. Calculate RPN. Risk Priority Number = Severity × Occurrence × Detection. RPNs range from 1 to 1,000.

10. Prioritize and act. Focus corrective actions on the highest RPNs and on any failure mode with a high severity rating regardless of RPN. After implementing actions, re-score and recalculate RPNs to verify risk reduction.

FMEA Example

A manufacturer of hydraulic cylinders conducts a Process FMEA on the chrome rod grinding operation:

The burn marks failure mode has the highest RPN of 216 and the highest severity of 9. The team's corrective actions include installing an in-process surface temperature monitor (reducing Detection from 6 to 2), updating the feed rate parameters in the CNC program (reducing Occurrence from 4 to 2), and adding a surface inspection specification to the work instruction.

After implementation, the burn marks RPN drops from 216 to 36 (9 × 2 × 2), representing an 83% risk reduction.

Why FMEA Matters for Production Scheduling

FMEA directly supports production scheduling by identifying potential process failures before they disrupt the schedule. By proactively addressing high-risk failure modes, manufacturers reduce the frequency of unplanned downtime, rework, and scrap that consume scheduled capacity.

FMEA also identifies which operations need additional inspection time built into the schedule. If a Process FMEA reveals that a particular operation has high-severity failure modes with limited detection capability, the scheduler should allocate time for enhanced inspection at that point in the process.

Scheduling software like Resource Manager DB allows planners to incorporate the insights from FMEA into operation planning — adding inspection steps, adjusting cycle times, and scheduling preventive maintenance for equipment identified as high-risk in the FMEA.

Related Terms

• Root Cause Analysis — investigative tool used to identify failure causes within FMEA
• Corrective Action — the systematic process for implementing fixes to FMEA-identified risks
• Six Sigma — quality methodology that uses FMEA as a key analysis tool

FAQ

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This term is part of our Manufacturing & Production Scheduling Glossary. Learn more about quality control, scheduling, and manufacturing terminology.