In the most general terms: FMEA analysis is used for quality management. It’s an efficient and cost-effective method that helps consider what failures may occur in the analyzed facility and what the causes and effects may be.

Currently, the most popular standard for FMEA, not only for the automotive market, is the manual published in 2019 by AIAG & VDA (AIAG – Automotive Industry Action Group and VDA – Verband der Automobilindustrie are the American and German organizations of major automotive manufacturers). 

One of the main requirements of this standard is to conduct FMEA analysis according to the 7 steps.

Take a look at the article below, to see what each of these steps consists of.

Table of contents

Step 1 – Planning and preparation

Step 2 – Structure analysis

Step 3 – Function analysis

Step 4 – Failure analysis

Step 5 – Risk analysis

Step 6 – Optimization

Step 7 – Results documentation

 

STEP 1 – Planning and preparation

Planning is an important, but often overlooked stage of analysis. Planning out the work in advance has an impact on better organization and optimization of the resources, which helps avoid some mistakes and the need to correct them in the future. Performing this stage doesn’t guarantee a correct analysis, but it undoubtedly brings us closer to that goal.

This step is based on drawing up a project plan using the 5T method, in which you need to define 5 topics:

  1. inTent – you need to determine whether it’s a new project, a post-complaint activity, or perhaps a data update.
  2. Timing – the analysis shouldn’t be done at the last minute, it should be started early enough, so that it doesn’t lose its preventive form.
  3. Team – in order to do the analysis, you need to appoint people to do it. Importantly, they must be competent. The AIAG & VDA manual clearly defines the composition of teams, dividing them into basic and extended teams. A novelty compared to previous standards is the demonstration of the role of the facilitator, who should be responsible for the course of the analysis in terms of content as well as practically is to manage the team.
  4. Tasks – at this stage expectations for the various phases of analysis should be discussed.
  5. Tools – it’s necessary to determine how we will carry out the analysis, whether we will use any specific software, for example.

Basic information about the project should be documented in the header of the form (company name, project name, responsible person, team, dates etc).

STEP 2 – Structure analysis

Describing the structure is fundamental in any FMEA. The correct structure of the analysis is to facilitate the identification of all potential failures, their effects and causes. Depending on the type of analysis we perform it will vary.

In the case of DFMEA the structure should show the system, subsystems and components and how they are connected.

It’s worth remembering, that the AIAG & VDA manual introduced (or actually developed) the concept of so-called levels. We are talking about:

  • The focus (middle) element, which is the main component of the analysis – it’s for it that we will dissect the failures.
  • The next lower level (the level to the right of the focus element), it’s a component of the focus element or when there is no focus element, it’s a specific characteristic of the product.
  • The next higher level (the level to the left of the focus element), which is the basis for defining the effects of failures.

For PFMEA the process flow diagram (PF) is the basis of the process analysis. The structure for a process FMEA is to define three levels, which are:

  • Process item – usually this is the name of the product with the option to indicate the process or the name of the system, subsystem, part element. The effects of failures will be referred to it.
  • Process step – are the successive operations that need to be performed in the process, in order to produce the previously described process item.
  • Process work element – these are the elements (“participants”) of the process involved in a particular phase of the process. They are defined on the basis of the 4Ms (man, machine, material, environMent). In further stages of the analysis, the listed working elements will become potential causes of failures.

STEP 3 – Analysis of function

This stage is one of the most essential parts of the analysis and involves defining the requirements to be met.

Similar to the structure analysis (to which it alludes with the rest) it has three elements to define:

IN THE DFMEA

  • Next higher level function and requirement – determines how the system works.
  • Focus element function and requirements – these are the requirements for a system component to ensure that the function is achieved for the entire product.
  • Next lower level function and requirement or characteristic – analogous to the above, from these requirements the above functions are derived.

IN THE PFMEA

  • Function of the process item – this is information on what the product characteristics provide to the customer (broken down into: internal, external, end user and others – if needed);
  • Function of the process step and product characteristic – these are properties that characterize (distinguish) the product and relate to the previously described process phases, such as length, diameter etc;
  • Function of the process work element and process characteristics – this is a description of the requirements that a specific work element should meet. Functions assigned to one element can be more than one.

STEP 4 – Failure analysis

The essence of this step is to consider all possible undesirable situations, in which defects will arise.

For DFMEA, a failure can be defined as a failure to achieve the intended function.

For PFMEA, a failure is considered as not achieving the intended function.

The AIAG & VDA ed. 1 manual introduced several designations for so-called failures, which should be identified at this stage of the analysis:

  • FM (failure mode) – a type of failure.
    It refers to the previously mentioned specific function and is the way in which a process can cause a product/process to fail to meet or achieve a given function. The effects and causes of nonconformity are assigned to this element. When defining failures we should ensure that the description is complete and take into account the analysis of complaints, rejection and disposal reports and the experience of the team.
  • FE – failure effect.
    Failure effects refer to the function of a process item/higher level function (i.e., usually the product being analyzed) and are described in relation to established groups of customers (e.g., internal, external, user, service, environment), who are selected depending on what type of FMEA analysis we are conducting.
  • FC – failure cause.
    It indicates why a particular type of failure could have occurred. Any real potential cause in production, assembly or construction for each type of failure should be described. It’s recommended, that the cause be described concisely and clearly, so that planned improvement actions can later be properly targeted.

*When PFMEA:

You should assume, that the materials (raw materials) at the input are correct (although if you have an ongoing problem with the supplier and such problems occur, you would need to change this assumption).

Typical failure causes should include the classic 4M approach: Man, Machine/EquipMent, Material, Environment, but we don’t have to limit ourselves to this scope.

Reasons will inform us of a “task” or function not performed or performed correctly.

Identical FM, FE, FC designations are used in both DFMEA and PFMEA.

STEP 5 – Risk analysis

This step consists of a risk assessment, to form the basis for prioritizing needed actions. However, in order to assess risks, we still need to define current ones:

  • prevention controls (PC), i.e. activities to prevent or minimize the occurrence of the cause of nonconformity;
  • detection controls (DC), i.e., activities, that are intended to detect the presence of the cause of the defect or it’s type before the item leaves the process or is shipped to the customer – both failures cause controls (FC) and failure modes controls (FM) should be written out and remember to distinguish between them, which is important because failure mode controls are assigned to all causes within a defect.

Once the current activities have been identified, you can proceed with a proper risk assessment according to the three criteria outlined in the standard:

  • severity (S),
  • occurrence (O),
  • detectability (D).

Each criterion has a 10-point scale, with 10 indicating the biggest “problem”.

Based on the ratings assigned an AP (action priority) indicator is assigned. It’s determined differently than the RPN indicator we are familiar with. It takes into account possible combinations of S, O, D grades and on this basis defines the priority of action: low, medium and high.

In AP the most important thing is the severity, only later the occurrence and finally on detection (that is, control has the least impact on the priority of action).

STEP 6 – Optimalization

The goal of this step is to plan and implement measures, to reduce the level of risk, thus optimizing the process.

Initially, identify and plan the actions necessary to reduce the level of risk. It’s important, that each sentence be assigned a responsible person and a completion date. The planned activities should be implemented with evidence of their effectiveness and a reassessment of the risk should be conducted.

STEP 7 – Identification of results

This is a summary of the results of the work with analysis and documentation of all activities.

In the last phase of the analysis, an FMEA form and report should be prepared (it doesn’t have a detailed form it should keep). An important element of such a report can be: revision history, summary statistics, e.g. the number of failures with a high AP level, a summary of improvement activities including their status and many other summaries available in software designed for FMEA analysis.

Summary

The 7-step approach introduced by the AIAG & VDA standard can be helpful in performing the analysis correctly. Going through all the steps described above one by one will help the organization work with the risk analysis, impose some things to think about, and may reduce the possibility of mistakes.