Archive for Resource Centers

Elements of a PPAP Package

PPAPs are based on product and process data.

  • The PPAP consists of the Documentation Package including the Part Submission Warrant (PSW) and relevant part samples.
  • To build the Documentation Package, use data on both the subject product or part and the corresponding process captured from a significant production run to complete the 18 Elements.
  • There are 5 Levels of Submission for a PPAP Package; the levels have increasing higher levels of requirements for the supplier.  The customer determines the level.

Elements of a PPAP Package

PPAP Package Elements

Element 1: Design Record

  • The Design Record is typically provided by the customer as the part is usually designed by the customer.
  • Including full documentation of the Design Record in the PPAP Package helps ensure that both the suppler and customer are discussing the same part and same revision level.

Element 2: Authorized Engineering Change Documents

  • There are times when the PPAP is due to a request for a change to a product or related specification.
  • When this occurs, the change request and approval must be included in the PPAP package.

Element 3: Customer Engineering Approval

  • Customer Engineering Approval usually refers to (a positive outcome of) a trial at the customer’s facility conducted with production parts from the supplier.

Element 4: Design-FMEA

  • A Design-FMEA is a bottom-up analysis of all of the items or components of the design.
  • One output of the analysis, the Risk Priority Number, helps focus attention on potential risks with the highest exposure.
  • The resulting DFMEA with its corresponding corrective actions become part of the documentation included in the PPAP Submittal Package.

Element 5: Process Flow Diagrams

  • Process Flow Diagrams (or flowcharts) document the details of the process.
  • All activities and tasks are mapped; decision points, wait periods, feedback loops and rework loops are all documented.

Element 6: Process-FMEA

  • A PFMEA is an FMEA on a Process as opposed to a DFMEA, an FMEA on a Design.
  • A PFMEA is a structured technique that helps a team think through “everything” that may go wrong in a process.
  • The severity or impact of each failure is rated, the potential that a specific failure may actually occur is factored in and the probability that the failure can be prevented or at least detected is considered.
  • The intent is to identify risks that are unacceptable and initiate corrective plans that mitigate those risks and help make the process more robust.

Element 7: Control Plan

  • The primary intent of a Control Plan is to create a structured approach for control of process and product elements while focusing the organization on characteristics important to the customer.
  • Control Plans are a compilation of process and product characteristics, test methods to monitor those characteristics, specifications and sampling or testing intervals.
  • A Control Plan does include well thought-out reaction plans to be used in case an out-of-control condition occurs.

Element 8: Measurement System Analysis (MSA)

  • The analysis of a measurement system involves understanding the uncertainties associated with taking a particular measurement and then, where possible, quantifying those uncertainties.
  • The uncertainties that can be quantified (by statistical means) include issues of accuracy, linearity, stability, repeatability and reproducibility.
  • A GR&R (Gage Repeatability & Reproducibility) study is used to determine if the measurement device or system can be relied upon or if the measurement system must be improved before it can be used.

Element 9: Dimensional Results

  • For the report of Dimensional Results, identify part numbers and change or revision levels.
  • For approval, all dimensions must be within the specification tolerances designated by the Design Record.
  • Dimensional Results are to be reported for each manufacturing process the supplier will use.

Element 10: Records of Material / Performance Test Results

  • Material Tests refer to chemical, physical or metallurgical requirements specified by the Design Record or Control Plan.
  • Performance Tests must be performed and results reported for all parts or product materials when performance or functional requirements are specified by the Design Record or Control Plan.
  • It is often helpful to include the Design Verification Plan and Report (DVP&R) with the Record of Material and Performance Test submittals.  The DVP&R summarizes validation tests performed.

Element 11: Initial Process Studies

  • Initial Process Studies are used to evaluate whether a (supplier’s) process can meet Special Characteristics or (Critical Characteristics) defined by the customer.
  • Objectives of Initial Process Studies are to determine if production processes are stable, will yield acceptable outputs for critical or special characteristics and are ready to begin process validation builds.

Element 12: Qualified Laboratory Documentation

  • Inspection and testing is to be performed by a lab qualified (or accredited) to conduct the types of tests and measurements.
  • When submitting test results, include documentation showing that the laboratory is qualified or accredited.

Element 13: Appearance Approval Report (AAR)

  • Complete an Appearance Approval Report (AAR) for each part (or series of parts) that have appearance requirements noted on the Design Record.
  • If the part or product does not have appearance requirements, the AAR is not required

Element 14: Sample Production Parts

  • The supplier must provide the customer with a sample of the subject part (or parts) for approval.
  • The part(s) must come from a significant production run and be the same part(s) referenced in the PPAP package.
  • A complete set of data on the subject part(s) must be included in the PPAP package.  A photo of the parts is typically included in the PPAP package noting the storage location of the samples.

Element 15: Master Samples

  • A Master Sample is to be signed off by both the customer and the supplier when they agree that the sample part meets all the design requirements and any special customer requirements.
  • It is often used as the benchmark for future production runs.

Element 16: Checking Aids

  • Checking Aids are special (and sometime custom) tools used to inspect, test or measure parts during the production process.
  • Even if Checking Aids have been developed informally, they need to be controlled just as any “formal” gage.

Element 17: Records of Compliance with Customer-Specific Requirements

  • All requirements over and above the standard PPAP documentation level specified by the customer are included in this element.
  • If no Customer-Specific Requirements are required, it is prudent to include a waiver that none exist.

Element 18: Part Submission Warrant (PSW)

  • The PSW is a summary of the PPAP submission complete with all applicable data for the 18 Elements.
  • A PSW is required for each of part or part number.
  • If bulk materials are used in the production of customer’s parts, they are eligible for a Warrant.  However, a PPAP Warrant for the Bulk Material is NOT required unless the customer specifies it.  If specified, a completed Bulk Material Checklist and Warrant is needed for bulk material used in production parts

Detection Evaluation Criteria

FMEAs help us focus on and understand the impact of potential process or product risks.

  • A systematic methodology is used to rate the risks relative to each other.
  • An RPN, or Risk Priority Number, is calculated for each failure mode and its resulting effect(s).

The RPN is a function of three factors:

  • The Severity of the effect
  • The frequency of Occurrence of the cause of the failure
  • The ability to Detect the failure or effect

Calculating the RPN

  • The RPN = The Severity ranking X the Occurrence ranking X the Detection ranking.
  • The RPN can range from a low of 1 to a high of 1,000.

Taking action

  • Develop an Action Plan to reduce risks with unacceptably high RPNs.

Linking FMEAs to Control Plans

  • Use FMEAs as the basis for Control Plans.
  • Control Plans are a summary of proactive defect prevention and reactive detection techniques.

Occurrence Evaluation Criteria

FMEAs help us focus on and understand the impact of potential process or product risks.

  • A systematic methodology is used to rate the risks relative to each other.
  • An RPN, or Risk Priority Number, is calculated for each failure mode and its resulting effect(s).

The RPN is a function of three factors:

  • The Severity of the effect
  • The frequency of Occurrence of the cause of the failure
  • The ability to Detect the failure or effect

Calculating the RPN

  • The RPN = The Severity ranking X the Occurrence ranking X the Detection ranking.
  • The RPN can range from a low of 1 to a high of 1,000.

Taking action

  • Develop an Action Plan to reduce risks with unacceptably high RPNs.

Linking FMEAs to Control Plans

  • Use FMEAs as the basis for Control Plans.
  • Control Plans are a summary of proactive defect prevention and reactive detection techniques.

Severity Evaluation Criteria

FMEAs help us focus on and understand the impact of potential process or product risks.

  • A systematic methodology is used to rate the risks relative to each other.
  • An RPN, or Risk Priority Number, is calculated for each failure mode and its resulting effect(s).

The RPN is a function of three factors:

  • The Severity of the effect
  • The frequency of Occurrence of the cause of the failure
  • The ability to Detect the failure or effect

Calculating the RPN

  • The RPN = The Severity ranking X the Occurrence ranking X the Detection ranking.
  • The RPN can range from a low of 1 to a high of 1,000.

Taking action

  • Develop an Action Plan to reduce risks with unacceptably high RPNs.

Linking FMEAs to Control Plans

  • Use FMEAs as the basis for Control Plans.
  • Control Plans are a summary of proactive defect prevention and reactive detection techniques.

Prioritizing Risk and Taking Action to Reduce Risk

FMEAs help us focus on and understand the impact of potential process or product risks.

  • A systematic methodology is used to rate the risks relative to each other.
  • An RPN, or Risk Priority Number, is calculated for each failure mode and its resulting effect(s).

The RPN is a function of three factors:

  • The Severity of the effect
  • The frequency of Occurrence of the cause of the failure
  • The ability to Detect the failure or effect

Calculating the RPN

  • The RPN = The Severity ranking X the Occurrence ranking X the Detection ranking.
  • The RPN can range from a low of 1 to a high of 1,000.

Taking action

  • Develop an Action Plan to reduce risks with unacceptably high RPNs.

Linking FMEAs to Control Plans

  • Use FMEAs as the basis for Control Plans.
  • Control Plans are a summary of proactive defect prevention and reactive detection techniques.

AIAG-VDA FMEA-MSRs

FMEA-MSRs focus on how well monitoring systems can identify faults (or failures).

FMEA-MSRs were added as a new, supplementary form of FMEAs with the 2019 version of AIAG-VDA FMEA Handbook.

  • The “MSR” in FMEA-MSRs means “Monitoring and System Response.”
  • FMEA-MSRs are intended to help maintain a safe state and a state of compliance during customer operations.
  • FMEA-MSRs identify possible errors or failures that can occur under normal operating conditions.

A key focus of the analysis is to determine if the system (or the end-user) detects an error when a failure does occur and then, as important, what happens next.

  • FMEA-MSRs focus on how well monitoring systems can identify faults (or failures) and how useful response systems are in maintaining a safe state and a state of regulatory compliance throughout the useful life of the product.

Use of FMEA-MSRs help ensure that safety objectives and related regulatory compliance requirements have been fully considered and met.

  • While DFMEAs focus on detection (and prevention) of potential failures, FMEA-MSRs focus on the efficacy of the monitoring system.
  • The intent of FMEA-MSRs is to validate that diagnostic monitoring and the corresponding system responses work as they are intended. This new type of FMEA brings the ISO 26262 functional safety standard into play.

While FMEA-MSRs are intended primarily as a supplement to DFMEAs, not every design warrants a corresponding FMEA-MSR.

  • If a design does not contain active or passive monitoring and response components, there is no need to conduct an FMEA-MSR.

FMEA-MSRs are conducted using the same basic seven-step team approach as DFMEAs. However, there are a few important and significant differences in how the Focus Element is defined and how risk is evaluated; the major differences are recapped below:

  • Determination of Failure Analysis (Step 4): If the component can detect (i.e. Monitor) a failure, a System Response can either fully mitigate the Effect or reduce the impact (the Severity) of the Effect.

Linking DFMEAs to FMEA-MSRs

  • The Risk Evaluation Criteria: With FMEA-MSRs the Occurrence and Detection ratings are replaced with the Frequency Potential rating and the Monitoring Criteria respectively.
  • The Action Priority Tables: The Action Priority Tables used to assign Priority Levels for each issue of an FMEA-MSR are different than those used for DFMEAs, however the basic methodology used to assign Priority Levels is the same.
  • The format for Step 5: Risk Analysis & Step 6: Optimization: Since FMEA-MSRs use a S-F-M (Severity-Frequency-Monitoring) evaluation of risk rather than the S-O-D factors used in DFMEAs, FMEA Worksheet form used to document FMEA-MSRs is modified accordingly.

AIAG-VDA Seven-Step PFMEA Process

AIAG-VDA Seven-Step FMEA Process

The AIAG-VDA Harmonization Project defined a seven-step process for conducting FMEAs.

  1. Planning and Preparation
  2. Structure Analysis
  3. Function Analysis
  4. Failure Analysis
  5. Risk Analysis
  6. Optimization
  7. Results Documentation

The seven-steps are summarized into three phases:

  • Steps 1 through 3 represent the “System Analysis” phase of an PFMEA study.
  • Steps 4 through 6 represent the “Failure Analysis and Risk Mitigation” phase of an PFMEA study.
  • The third phase, Communication, is Step 7, Results Documentation

Step 1: Planning and Preparation

  • The PFMEA study starts with a purposeful and careful definition of the scope.
  • The management team is responsible for setting the scope of the study.
  • Step 2: Structure Analysis

  • Structure Analysis is used to identify and breakdown the the process into its sequential steps, interfaces and logistical elements.

AIAG-VDA Seven-Step PFMEA Process

  • The Structure Analysis uses the boundaries set by the definition of scope in Step 1 to identify each step, interface and logistical element of the process under study.
  • Structure Analysis consists of three expanded columns whose purpose is to facilitate a thorough understanding of the process. Start with the Focus Element in the “middle column,” then identify the Process of which the Focus Element is a part and finally identify all Process Work Elements of the Focus Element.
  • Step 3: Function Analysis

  • Think of the Function Analysis step as exploring what the product should be doing and what the overall process (and each of its steps) should be doing and how that functionality is facilitated.
  • Using the Structure Analysis developed in Step 2, each element is analyzed separately in terms of its function(s) and corresponding requirement(s).
  • Step 4: Failure Analysis

  • In Step 4, the concept of a “Failure Chain” is used to visualize failures as part of three links of a chain.
  • The Failure Chain is comprised of the Failure Mode (FM), the corresponding Failure Effect (FE) and the Failure Cause (FC).

AIAG-VDA FMEA Failure Chain

  • A Failure Mode represents any manner in which an item (the Focus Element) could fail to meet its intended function.
  • A Failure Effect is the consequence of a Failure Mode.
  • A Failure Cause is an indication of why a Failure Mode could occur.
  • Analyzing failures involves identifying how the Focus Elements detailed during the Structure Analysis may fail to perform intended functions documented by the Function Analysis.
  • A failure mode leads to a failure effect triggered by a failure cause.
  • Determining potential causes is at the heart of a PFMEA.

Step 5: Risk Analysis

  • In Step 5, the Severity, Occurrence and Detection of each failure chain is evaluated
  • An Action Priority Level of “High, Medium or Low,” based on S-O-D evaluations as indicated by the Action Priority Tables.
  • The Action Priority Tables do not establish a “risk priority” but rather a priority level for action needed to reduce the risk of failure to function as intended.
  • Every potential evaluation combination is assigned a High, Medium or Low priority according to the AP Table.
  • If the AP level is High, action to improve prevention and/or detection controls (or justification on why current controls are adequate) MUST be taken.
  • If Medium, action to improve prevention and/or detection controls (or justification on why current controls are adequate) SHOULD be taken.
  • And if Low, action to improve prevention and/or detection controls COULD be taken.

Step 6: Optimization

  • The primary objective of the Optimization step is to develop actions that reduce risk and increase customer satisfaction by improving the process.
  • Most actions will likely involve lowering the likelihood of the occurrence of failure causes or improving detection controls; either approach leads to a more robust process.

Step 7: Results Documentation

  • The results of each FMEA study should be fully documented.
  • An FMEA study is not finished until Step 7 has been completed.

AIAG-VDA Seven-Step DFMEA Process

AIAG-VDA 7-Step FMEA Process

There are seven-steps for conducting an AIAG-VDA DFMEA:

  1. Planning and Preparation
  2. Structure Analysis
  3. Function Analysis
  4. Failure Analysis
  5. Risk Analysis
  6. Optimization
  7. Results Documentation

The seven-steps are summarized into three phases:

  • Steps 1 through 3 represent the “System Analysis” phase of a DFMEA study.
  • Steps 4 through 6 represent the “Failure Analysis and Risk Mitigation” phase of a DFMEA study.
  • The third phase, Communication, is Step 7, Results Documentation

Step 1: Planning and Preparation

  • The DFMEA study starts with a purposeful and careful definition of the scope.
  • The management team is responsible for setting the scope of the study.

Step 2: Structure Analysis

  • Structure Analysis is used to identify and breakdown the design into the system, subsystems, assemblies and component elements for DFMEAs.Structure Analysis step of an AIAG-VDA DFMEA
  • The Structure Analysis uses the boundaries set by the Scope Definition (Step 1) to identify every component of the product (design).
  • Structure Analysis consists of three expanded columns whose purpose is to facilitate a thorough understanding of the process. Start with the Focus Element in the “middle column,” then identify the System of which the Focus Element is a part and finally identify all Components Elements contained within the Focus Element.

Step 3: Function Analysis

  • Think of the Function Analysis step as exploring what the product should be doing and how that functionality is facilitated.
  • Using the Structure Analysis developed in Step 2, each element is analyzed separately in terms of its function(s) and corresponding requirement(s).

Step 4: Failure Analysis

  • In Step 4, the concept of a “Failure Chain” is used to visualize failures as part of three links of a chain.
  • The Failure Chain is comprised of the Failure Mode (FM), the corresponding Failure Effect (FE) and the Failure Cause (FC).AIAG-VDA DFMEA Failure Chain Concept
  • A Failure Mode represents any manner in which an item (the Focus Element) could fail to meet its intended function.
  • A Failure Effect is the consequence of a Failure Mode.
  • A Failure Cause is an indication of why a Failure Mode could occur.
  • Analyzing failures involves identifying how the Focus Elements detailed during the Structure Analysis may fail to perform intended functions documented by the Function Analysis.
  • A failure mode leads to a failure effect triggered by a failure cause.
  • Determining potential causes is at the heart of a DFMEA.

Step 5: Risk Analysis

  • In Step 5, the Severity, Occurrence and Detection of each failure chain is evaluated
  • An Action Priority Level of “High, Medium or Low,” based on S-O-D evaluations as indicated by the Action Priority Tables.
  • The Action Priority Tables do not establish a “risk priority” but rather a priority level for action needed to reduce the risk of failure to function as intended.
  • Every potential evaluation combination is assigned a High, Medium or Low priority according to the AP Table.
  • If the AP level is High, action to improve prevention and/or detection controls (or justification on why current controls are adequate) MUST be taken.
  • If Medium, action to improve prevention and/or detection controls (or justification on why current controls are adequate) SHOULD be taken.
  • And if Low, action to improve prevention and/or detection controls COULD be taken.

Step 6: Optimization

  • The primary objective of the Optimization step is to develop actions that reduce risk and increase customer satisfaction by improving the product.
  • Most actions will likely involve lowering the likelihood of the occurrence of failure causes or improving detection controls; either approach leads to a more robust design.

Step 7: Results Documentation

  • The results of each FMEA study should be fully documented.
  • An FMEA study is not finished until Step 7 has been completed.

AIAG-VDA FMEAs

FMEAs help us focus on and understand the impact of potential process or product risks.

  • A systematic methodology is used to rate the risks relative to each other.
  • An RPN, or Risk Priority Number, is calculated for each failure mode and its resulting effect(s).

The RPN is a function of three factors:

  • The Severity of the effect
  • The frequency of Occurrence of the cause of the failure
  • The ability to Detect the failure or effect

Calculating the RPN

  • The RPN = The Severity ranking X the Occurrence ranking X the Detection ranking.
  • The RPN can range from a low of 1 to a high of 1,000.

Taking action

  • Develop an Action Plan to reduce risks with unacceptably high RPNs.

Linking FMEAs to Control Plans

  • Use FMEAs as the basis for Control Plans.
  • Control Plans are a summary of proactive defect prevention and reactive detection techniques.

Traditional (RPN) FMEAs

We use the phrase “Traditional (RPN) FMEAs” to refer to the way FMEAs have been conducted for over 70 years. A key distinction of these types of FMEAs is that the failure analysis process results in a Risk Priority Number or RPN that is used to prioritize failure modes for improvement and risk reduction efforts.

In 2019, the automotive industry revamped the FMEA process used in their global supply chain. We call these FMEAs AIAG-VDA FMEAs (AIAG and VDA are the American and German Automotive Industry Associations that spearheaded the task force that developed the new approach to FMEAs). A key change with the updated methodology is the elimination of the RPN. In its place are Action Priority Tables. Initially, this type of FMEA is only used in the automotive industry although we expect other industries will adopt the new process.

This section of the FMEA Resource Center, deals with the Traditional (RPN) FMEAs. If interested in the AIAG-VDA FMEA process,