1 / 8

PURPOSE OF DFMEA (DESIGN FAILURE MODE EFFECTS ANALYSIS)

PURPOSE OF DFMEA (DESIGN FAILURE MODE EFFECTS ANALYSIS). Identify , quantify , and reduce design risk (especially for critical systems) Provide a traceable document for making design decisions Prioritize which design activities to pursue next

meris
Télécharger la présentation

PURPOSE OF DFMEA (DESIGN FAILURE MODE EFFECTS ANALYSIS)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. PURPOSE OF DFMEA(DESIGN FAILURE MODE EFFECTS ANALYSIS) • Identify, quantify, and reduce design risk(especially for critical systems) • Provide a traceable document for making design decisions • Prioritize which design activities to pursue next • NOTE: A DFMEA is not a one meeting activity(It needs to evolve with the product)

  2. DFMEA INPUTS • Product Design Requirements • Design requirement document (if available from customer) • Legal and technical regulations • Bill of Materials (BOM) and Specific Hardware • List of components • Components and/or samples as supplied by the customer • Product Definition • Drawings, sketches, animations, and simulations • Description of systems and components • Previous Experience (Lessons Learned from Others) • Experience with similar concepts, designs, and DFMEA • Customer and supplier inputs • Design guides and design standards (for example ASME codes)

  3. DFMEA OUTPUTS • RAN: Risk Assessment Number • RAN = (Severity) x (Occurrence) x (Detection) • Identification of both systems and components with high RAN values represents a summary of high risk items. • Identification of Critical and Significant Characteristics (This is also normally required by a customer)

  4. DFMEA METHODOLOGY • (1.) Complete the top of the form • Project, year, team members, date, and DFMEA iteration • (2.) List items and functions • Start with the system, then subsystems, and finally components • (3.) Document potential failure modes • How could the design potentially fail to meet the design intent • Note: this might be the cause of failure at a higher level (i.e. component to subsystem) or the effect of a failure at a lower level. • Consider all types of failure • (4.) Document the potential effects of failure • How would the design potentially fail to meet the design intent.

  5. DFMEA METHODOLOGY: (CONTINUED) • (5.) Rate the severity of the failure effect (linked to the effect of the failure)1 = device operable with minor loss of functionality 2 = device operable with significant loss of functionality 3 = device damaged and inoperable, but repair is possible 4 = device damaged beyond repair 5 = failure causes moderate to severe operator injury • (6.) Document potential causes and mechanisms of failure • Failure causes and mechanisms are an indication of design weaknesses • Potential failure modes are the consequences of the failure causes • A single failure mode may have multiple failure mechanisms • Don’t be afraid to identify as many potential causes as you can

  6. DFMEA METHODOLOGY: (CONTINUED) • (7.) Rate the occurrence of the failure1 = likely to occur at some point in product testing2 = likely to occur periodically across multiple test sessions3 = likely to occur during almost every test session • (8.) List the design controls • Design controls are intended to: • Prevent the cause of the failure mode (1st choice solution) • Detect the cause of the failure mode (2nd choice solution) • Detect the failure mode directly (3rd choice solution) • Applicable design controls include • Predictive code analysis, simulation, and modeling • Tolerance “stack-up” studies • Prototype test results (acceptance tests, DOE’s, limit tests) • Proven designs, parts, and materials

  7. DFMEA METHODOLOGY: (CONTINUED) • (9.) Rate the detectability of the failure1 = uses sensors and active controls to avoid upset condition2 = uses operator training/procedures to spot imminent failure3 = fails without warning • (10.) Calculate the RAN of each potential failure effect • RAN = (Severity) x (Occurrence) x (Detection) • What are the highest RAN items? • (11.) Define recommended actions • These could be design changes, tests, or revised operation procedures

  8. DFMEA METHODOLOGY: (CONTINUED) • (12.) Assign action items • (13.) Complete “Action Results” Section of DFMEA • Change ratings if action results justify adjustment, but the rules are: • Severity: May only be reduced through elimination of the failure effect • Occurrence: May only be reduced through a design change • Detection: My only be reduced through improvement and additions in design control (i.e. a new detection method, better test methodology, better codes) • (14.) Repeat: undertake the next revision of the DFMEA Revise your DFMEA frequently! Include documentation of your results!

More Related