I had been thinking other failure modes in FMEA after posting the previous article. Then I found a good information in ASQ (American Society for Quality) regarding the FMEA. Based on the information and my experiences, I added some other failure modes and created a list of them..
1. FMEA neither help process improvement nor quality improvement
The purpose of FMEA is to make an action to prevent, mitigate, or avoid the identified risks. Creating the FMEA table itself is not the purpose. If people satisfy by creating the FMEA table and make no action, the FMEA has no point.
The action items for risk reduction must be related to the process improvement and/or the product quality improvement. Sometime a countermeasure for a risk and a test item for a risk are confused as an action item in the FMEA. The test item is a detection and not an action item for risk reduction. The countermeasure for the risk should be the action item for risk reduction.
2. No re-evaluate the ratings
The Severity, the occurrence, and the detectability ratings have been changed as the project goes. As well as the ratings, the countermeasure (i.e., action items) have been changed as the process or the design changes. But people don’t re-evaluate the FMEA once after created. The FMEA should be re-evaluated and updated frequently as the project goes.
If the FMEA keeps an old action items with a wrong priority, it could lead a bad decision in the project.
3. No action to high severity
The FMEA in general determines the priority using the RPN (Risk Priority Number). The RPN is calculated by Severity x Occurrence x Detectability, and the bigger RPN has the higher priority. But when the severity is very high, we have to make a countermeasure to reduce the risk even the RPN is low.
The occurrence is the same. If the occurrence is very high, we have to make a countermeasure to reduce the occurrence even the RPN is low.
Prioritization only with the RPN could be dangerous. We need to prioritize the risks along with high severity and high occurrence items too.
4. FMEA has no influence on Project Plan and Test Plan
The action items identified in the FMEA could take time to mitigate/reduce/avoid risks, and incur substantial cost. According to the impacts on schedule and cost, the project management plan should be updated. The FMEA can be a good tool for communication with the project management for the update.
If the root-causes (or the noise factors) identified in the FMEA have not been tested, the test plan should add the new test items for the potential root-causes.
5. Missing cross-functional interface
Many errors (over a half of all errors?) occur at cross-functional/external interfaces in the process or the product. When creating the FMEA, the cross-functional/external interfaces must be considered. The FMEA tends to focus on the target system (i.e., the process or the product), and less considers the cross-functional/external interfaces.
When creating the FMEA, a block diagram and a boundary diagram should be used as a preparation of the FMEA.
6. No feedback from customer
A failure mode occurring at a customer side (internal/external) should have a higher severity rating. Even the FMEA has such failure mode, the FMEA tends to be created without any feedback from the customer (internal/external). Without the customer feedback, the FMEA cannot be created with correct information.
Involving the customer to the FMEA creation could be necessary.
7. Mixing up different levels
Many layers of FMEA can be created hierarchically from the top level to the detailed level of the system. To avoid confusion and difficulty of creation, the level of details in the FMEA must be consistent. Otherwise, managing FMEA becomes pretty hard, and execution of action items becomes impossible.
If the high level FMEA contains both the high level failure modes and the low level failure mode, it is impossible to evaluate the severity and the occurrence of the failure modes in the different levels. Also the number of FMEA items increases. Assigning a responsible person or group to an action item is pretty hard to if the FMEA mixes up the different level of items.
When creating the FMEA, the level of details must be consistent.
8. Too late to act
Sometimes creating the FMEA has a lower priority, and be treated as an extra task or a burden. Then the FMEA is created at later phase of the project, and executing the action items are too late.
The sooner is creating the FMEA, the better is the risk management. But creating the FMEA too early in the project is not good because we have yet fully understood the process or the product. If we create the FMEA before fully understanding the process or the product, we could need to re-work on the FMEA in later phase. It is inefficient.
9. Have inadequate team members
Creating the FMEA needs wide variety of SMEs (Subject Matter Experts) in different areas. If the team members are inadequate with a missing SME, the evaluation of FMEA could be skewed. To create a balanced FMEA, selecting the team members is critical.
10. Inexperienced in FMEA
If the team members are inexperienced in the FMEA, not only creating the FMEA could be inefficient, but the FMEA itself could be incorrect. The team members must be trained in the FMEA, and an experienced facilitator should be attend the FMEA creation.
Using a Parameter Diagram, Block Diagram and Boundary Diagram is a good preparation for creating the FMEA, and help the team members to create a good FMEA.
11. Not enough time
Creating the FMEA needs substantial time with many team members. So having the FMEA meeting is pretty hard. Even the team members start creating the FMEA, they could not complete it because they don’t have enough time for it. To avoid “Time Out”, they must allocate enough time in the project schedule.
To proceed the FMEA meeting, an experienced facilitator should be attend the FMEA meeting.
12. Lack of sense of business
When identifying the failure modes, the sense of business is needed such as the customer satisfaction, warranty cost, market price, production cost, etc. If the team members don’t come from wide variety of areas including the business side, the team members must have the sense of business. Otherwise, the FMEA could not help to reduce the risks in the business.
There could be more failure modes in the FMEA.