Will Six Sigma Be Relevant For The Future
  • Failure modes and effects analysis (FMEA) is an approach for identifying all possible failures in a design, process, product, or service.
  • It focuses:
    - Processes on “prevention” rather than “fire fighting.”
    - Uncover process problems that may result in customer dissatisfaction.
    - Defects in product or service production process.
    - Reduced process efficiency.
    - To generate a prioritized list of risks & corrective actions
  • One should perform FMEA:
    - Before design a new system or a product or a process
    - Improving a current design of a system or a product or a process.
    - Changing a current design of a system or a product or a process.

FMEA Types

System FMEA
  • System FMEA a high-level system failure modes and effects analysis are done considering the whole system.
  • Consider an Automobile as a system FMEA which is done to understand the potential failures that could occur as an integral system and how each component or parts interact with each other during both functional and when undergoing certain analysis.
  • System FMEA is done along with Design and Manufacturing process teams of various component led by the actual Design & Assembly team owner
Design FMEA
  • Design Failure Mode and Effect Analysis is done to assess the potential failure due to design & analyzing the effect of the failure.
  • DFMEA received input from System FMEA, and DFMEA act as an input for Process FMEA.
Process FMEA
  • A Process FMEA focuses on each step of the process and identify the potential failure opportunities & identify the causes and control.
  • PFMEA receives input from DFMEA.

FMEA Terminologies

Failure Mode
  • The way in which a specific process output or input fails –and if not detected and either corrected or removed, will cause the “Effect” to occur. It can be associated with an error or a process input variable that does not meet a customer requirement. Anything that a person can see that’s wrong could be considereda Failure Mode.
  • Example: Airbag system: Airbag does not open on impact
  • Impact on customer requirements. Generally, external customer focus, but can also include downstream processes or effect on internal customer.
  • Example: Airbag system: Injure passengers
  • It refers to the cause (or potential causes) of the failure mode. Sources of process variation that causes the failure mode to occur. Identification of causes should start with Failure Modes associated with the highest severity ratings.
  • Example: Airbag system: Airbag sensor not functioning properly
Current Controls
  • Systematized methods/checks to prevent or detect the failure modes or causes (before causing the effects) Prevention consists of mistake proofing, automated control and set-up verifications. Controls consist of audits, checklists, inspection, training, procedures, etc.
  • Example: Airbag system: Indicator to notify if system is malfunctioning
Severity (of Effect)
  • Consequences if a failure does occur. The importance of customer requirements could also be concerned with litigation/compliance and other risks if a failure occurs. (1=Not Severe, 10=Very Severe)
Occurrence (of Cause)
  • Likelihood failure will occur over time, given a certain number of opportunities. This can often be determined with data or estimated from other processes. (1=Not likely, 10=Very likely).
Detection (capabilityof Current Controls)
  • Likelihood failure could be detected if it occurs (or before it occurs). 1=Likely to Detect, 10=Not likely at all to detect
Risk Priority Number
  • Risk Priority Number is a prioritized list of existing or potential risks. The way we prioritize is the Risk Priority Number.
  • It is calculated as the product of three quantitative ratings, each one related to the effects, causes, and controls:
  • RPN = Severity(Effects) X Occurrence(Causes) X Detection(Controls)
  • Severity should never be reduced because of the process improvements.
  • Efforts must be made to constantly reduce Occurrence & Detection Scores

FMEA Steps

FMEA usually produces the best outcomes when teams work within the specified project scope. FMEA is used in a series of stages by the team.

Will Six Sigma Be Relevant For The Future
  • List down all the process step
  • Write down all the potential failures that can happen with each step
  • List down the potential effects on the output for each step
  • Write down the severity number between 1 to 10
  • List down all the potential causes for each step
  • Write down the occurrence number between 1 to 10
  • List the current controls been placed for each process
  • Write down the detection between 1 to 10
  • Calculate the RPN; RPN = Severity X Occurrence X Detection
  • Recommended actions are provided for the highest RPN number.

Expert's Comment

  • FMEA, a powerful tool built by NASA used well can benefit by following
    - To identify what can go wrong in System/ Design / Process
    - To understandthe severity of the problem
    - To understandif we have any control mechanism either by prevention or detection
    - To prioritizethe failure modes which need to be addressed
    - To find actions to reducethe occurrence of the failure
  • A must for every industry,especially the one impact on life, environment