Table1.Suggested Process Failure’s Severity Evaluation Criteria
| Effect | Criteria: Severity of Effect This ranking results when a potential failure results in a final customer and/or a manufacturing/assembly plant defect. The final customer should always be considered first. If both occur,use the higher of the two severities. (Customer Effect) | Criteria: Severity of Effect This ranking results when a potential failure results in a final customer and/or a manufacturing/assembly plant defect. The final customer should always be considered first. If both occur,use the higher of the two severities. (Manufacturing / Assembly Effect ) | Ranking |
| Hazardous without warning | Very high severity ranking when a potential failure affects safe product operation and/or involves noncompliance with government regulation without warning | Or may endanger operator (machine or assembly ) without warning | 10 |
| Hazardous with warnings | Very high severity ranking when a potential failure affects safe product operation and/or involves noncompliance with government regulation with warning | Or may endanger operator (machine or assembly) with warning | 9 |
| Very High | Product or item inoperable (loss of primary function) | Or 100% of product may have to be scrapped, or product / item repaired in repair department with a repair time greater than one hour. | 8 |
| High | Product or item operable but at a reduced level of performance. Customer very dissatisfied | Or product may have to be sorted and a portion (less than 100%) scrapped, or product/item repaired in repair department with a repair time between a half-hour and an hour | 7 |
| Moderate | Product or item operable but Comfort/Convenience item(s) inoperable. Customer dissatisfied. | Or a portion(less than100%) of the product may have to scrapped with no sorting,or product/item repaired in repair department with a repair time less than a half-hour. | 6 |
| Low | Product or item operable but Comfort/Convenience item(s) operable at a reduced level of performance. | Or 100% of product may have to be reworked, or product/item repaired off-line but does not go to repair department. | 5 |
| Very Low | Fit and Finish/Squeak and Rattle item does not conform. Defect noticed by most customers (greater than 75%) | Or the product may have to be sorted, with no scrap, and a portion(less than 100%) reworked. | 4 |
| Minor | Fit and Finish/Squeak and Rattle item does not conform. Defect noticed by 50% of customers. | Or a portion (less than 100%) of the product may have to be reworked, with no scrap, on-line but out-of-station | 3 |
| Very Minor | Fit and Finish/Squeak and Rattle item does not conform. Defect noticed by discriminating customers (less than 25%). | Or a portion (less than 100%) of the product may have to be reworked, with no scrap, on-line but in-station. | 2 |
| None | No discernible effect | Or slight inconvenience to operation or operator, or no effect. | 1 |
Note : It is not recommended to modify criteria for ranking values of 9 and 10.Failure with a rank of severity 1 should not be analyzed further.
Severity (S) : Severity is the rank associated with the most serious effect for a given failure. A reduction in severity ranking index can be effected through a design change to system,subsystem or component,or a redesign of the process.
Articles from FMEA Third Edition DaimlerChrysler Corporation, Ford Motor Company, General Motors Corporation.
