1. What is DFMEA?
Design Failure Mode and Effects Analysis (Design FMEA or DFMEA) is a risk assessment method used to evaluate potential failure mode of product design and drive corrective actions to prevent or reduce the chance of defects occur.
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2. DFMEA Form
A common DFMEA Form has a lot of columns. Depend on the need, organization can add, remove or modify the columns to make the template suitable for their risk assessment. DFMEA is an structure analysis, their columns have relationships.
1 Items: component, part or item of the object analyzed. An Item has one or many functions.
2 Function: the respective functions of the component. A Function has one or many requirements.
3 Requirement: respective requirements of the function. A requirement has one or many potential failure modes.
4 Failure Mode: (or Potential failure mode) The way that item potentially fails to meet the requirement. A failure mode has one or many potential effects.
5 Effects: (or Potential effects) Effects of the potential failure mode on the function and customers.
6 Severity (S): a ranking number reflects the most severe potential effect of a failure mode. Severity ranks on a 1 to 10 scale, 10 is the most severe risk.
7 Class: Special product characteristic or high risk failure mode.
8 Cause: What allows the failure mode to occur. A failure mode has one or many potential causes; the potential causes should be separate from each other but still aligned with its failure mode.
9 Prevention Control (in Control Method): is a design control method for preventing potential cause to occur.
10 Occurrence (C): a ranking number reflects the possibility of occurrence of the Failure. Occurrence ranks on a 1 to 10 scale, 10 means the highest possibility of occurrence.
11 Detection Control (in Control Method) is a design control method for detecting the cause or failure if it happens.
12 Detection (D): a ranking number reflects the best detection control method. Detection ranks on a 1 to 10 scale, 10 means worst detection capability.
13 RPN: (stands for Risk Priority Number) An indication number to evaluate the risk of the process based on Severity, Occurrence, and Detection. Depend on RPN and S, O, D indexes, the responsible team/individual has to decide corrective action needed for each failure mode. RPN formular is: RPN = S x O x D
14 Action: Corrective action to eliminate or reduce the chance of the causes of failure mode.
15 Responsibility: Person/Department who has a responsibility to complete the corrective action.
16 Target Finish Date: The plan completion date.
17 Actual Finish Date: The actual completion date.
18 Severity: re-rating severity of failure mode after corrective action
19 Occurrence: re-rating occurrence possibility after corrective action
20 Detection: re-rating detection capability after corrective action
21 RPN: re-calculate Risk Priority Number after corrective action
3. Why use a DFMEA?
Quality is critical to satisfying your customers and retaining their loyalty and keep them continue buying the product. A lot of recent quality scandals with many companies show the fact that serious design problems can ruin the reputation of any company or put them out of business. Less serious design problems can dissatisfy customers, delay launching of new product and place a substantial financial burden on the company.
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4. Who has to conduct a DFMEA
A good DFMEA performance needs knowledge and experience of many departments in a company. So it should be handled by a cross-functional team and led by the responsible product designer. The involved departments should include but are not limited to Design, Production, Supplier Quality, Product Quality, Service and Logistic.
5. When to conduct a DFMEA
With DFMEA, designers can ensure that all design requirements are completely met before start the production or continously improvement.
5.1 When to start
For a new product, DFMEA should start with product design and before prototype manufacturing.
5.2 When to review
The team should continuously review and update DFMEA document in the events of product changes:
- Change of Product Design: Change product dimension, the material could be the reason to review DFMEA. In this case, the change point and effected points should be focused.
- Quality Problem caused by product design: New internal defects or customer return should be reflected in DFMEA to re-analyze and re-evaluation and consider for corrective action.
DFMEA should reflect the current status of product design, and that is why it is called a living document. However, keep DFMEA “living” is not easy. That’s because of a complicacy of DFMEA and its linkage to other documents, maintaining DFMEA living is much easier if we use proper DFMEA software.