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FMECA Lab Last revised 08/25/2005

FMECA Lab Last revised 08/25/2005. Introduction. This lab will walk the user through the steps involved in performing a FMECA using ASENT. In this lab the user will perform the FMECA that was shown in the Introduction to FMECA presentation.

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FMECA Lab Last revised 08/25/2005

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  1. FMECA Lab Last revised 08/25/2005

  2. Introduction This lab will walk the user through the steps involved in performing a FMECA using ASENT. In this lab the user will perform the FMECA that was shown in the Introduction to FMECA presentation. First, a new project will be created in ASENT and then the product tree structure and failure rates will be entered. Next, the reliability tree will be imported into the FMECA. The end effects and severities, failure modes, next higher effects and other FMECA data will then be entered, and reports will be generated.

  3. Step 1: Creating A New Project The first thing we will do is create a new project in ASENT. This is accomplished in the ASENT Session Manager. The slides that follow will guide you through these steps.

  4. Create the New Flashlight Project Create a new flashlight project. From ASENT’s Session Manager select the Project menu option and select the ‘New’ option.

  5. Create New Flashlight Project For the project name enter your <last name>_flashlight. For example, if your last name is Smith, then enter smith_flashlight for your project name. Fill in the other information as shown in this example, then click on the Save button.

  6. Step 2: Creating A Product Tree Structure The next thing we will do is create a product tree structure in ASENT. This is accomplished in the ASENT Reliability Manager. Here, we will build the product tree structure and assign failure rates. Later, we will use this information as we perform the FMECA. The slides that follow will guide you through these steps.

  7. Invoke the Reliability Manager Now that the project has been created, our next step is to build the product tree structure for our flashlight. We do this in the Reliability Manager. To invoke the Reliability Manager, right-click on your flashlight project and select the ‘Reliability Manager’ from the drop-down menu.

  8. Building the Flashlight Product Tree Initially, only a project node will appear in the product tree structure when the Reliability Manager appears. Right-click on the project node and select the ‘Add SubAssy / Board’ option from the drop-down menu.

  9. Adding the Bulb To add the bulb to the product tree, enter the information as shown, and click on the Save button. To user set the failure rate to 50, be sure and check the checkbox, and then you can enter a failure rate.

  10. Adding the Switch To add the switch to the product tree, right-click on the project node and select the ‘Add Subassy / Board’ option, then enter the information as shown, and click on the Save button. To user set the failure rate to 10, be sure and check the checkbox, and then you can enter a failure rate.

  11. Adding the Contact To add the contact to the product tree, right-click on the project node and select the ‘Add Subassy / Board’ option, then enter the information as shown, and click on the Save button. To user set the failure rate to 10, be sure and check the checkbox, and then you can enter a failure rate.

  12. Adding the Battery To add the battery to the product tree, right-click on the project node and select the ‘Add Subassy / Board’ option, then enter the information as shown, and click on the Save button. To user set the failure rate to 40, be sure and check the checkbox, and then you can enter a failure rate.

  13. Calculate Failure Rates The product tree has now been constructed, and it is time to calculate the failure rates. In this example, we are merely summing them up since we supplied user set values. Right-click on the project node and select the ‘Calculate Failure Rates’ option from the drop-down menu. When the Failure Rate Calculator window appears, click on the Calculate button.

  14. Step 3: Performing a FMECA In the Reliability Manager click on theicon to exit the tool. Finally, we will perform a FMECA for the flashlight example that was discussed in the Introduction to FMECA presentation. This is accomplished in the ASENT FMECA Manager. The slides that follow will guide you through these steps.

  15. Invoking the FMECA Manager So far we have created a new project, built a product tree structure and calculated failure rates. Now, we are ready to start performing the FMECA. The tool in ASENT that performs FMECAs is the FMECA Manager. From the Session Manager, right-click on your flashlight project and select ‘FMECA Manager’ from the drop-down menu.

  16. Select Start-up Project Libraries The first time that you enter the FMECA Manager for a project it will have you select the default project to be used to initialize the FMECA. Select the ‘COMMON_FMD91’ project,and click the OK button. Leave all of the checkboxes checked and click the OK button.

  17. Defining a Function / Phase Data in the FMECA is organized by Function and Phase. Fill in your Function/Phase data as shown, and click on the Save button.

  18. Importing the Reliability Prediction Tree A normal starting point for the FMECA is to begin with the product tree structure that was used for the reliability prediction. To start our FMECA we will import the Reliability tree. To do this, right-click on the project node and select the ‘Import’ option. When the Import screen appears make sure that ‘Reliability Manager Trees’ is selected and click on the OK button.

  19. Select the Project to Import Find your flashlight project in the list of projects. Select your project and click on the OK button.

  20. Importing the Product Tree The product tree for your project appears. Initially, it appears fully collapsed so that only the project node is displayed. Since we want to import the entire product tree, merely select the project node and click on the OK button.

  21. Importing the Product Tree Click on the ‘Yes’ button to overwrite the FMECA tree, and click on the ‘No’ button when asked about importing parts.

  22. The FMECA Tree This screen shows the result after we have imported the product tree from the Reliability Manager. Here, in the FMECA Manager, we see the product tree structure for our flashlight example.

  23. Defining End Effects – Step 1 There will be a FMs container for each item in the FMECA product tree. This is a holder for failure modes/effects. The FMs container directly below the project node is used to hold system level effects or end effects. To add end effects, click on the ‘+’ symbol next to your project node to expand the tree, then right-click on the FMs container, and select the ‘Add’ option from the drop-down menu.

  24. Defining End Effects – Step 2 This slide shows the FMECA Manager screen for adding a new end effect. You can either click on the pull-down list in the Failure Mode field to select one from the library or you can click on the icon to enter one on the fly. Click on the icon to add one on the fly.

  25. Defining End Effects – Step 3 Enter ‘constant flashlight output’ for the name and click on the OK button.

  26. Defining End Effects – Step 4 The ‘constant flashlight output’ value that you entered now appears in the Failure Mode field. Move down to the Severity field and select ‘1’ for the severity level, from the pick list. Click on the Save button to record your inputs. After the Save button is clicked you will see the new end effect appear under the FMs container of the project node.

  27. Repeat Prior Steps to Add Another End Effect To add a second End Effect, merely repeat the prior steps, and enter the information as shown here. Here, we define a second end effect of ‘flashlight output dim’ with a severity level of ‘3’.

  28. All End Effects Are Now Defined Create two additional end effects. Create one called ‘flashlight sometimes will not turn on’ with a severity of ‘3’, and create one called ‘no flashlight output’ with a severity of ‘2’. When you have entered all of the end effects and click on the FMs container directly below the project node, then your screen should look like this.

  29. Adding FMs for the Bulb – Step 1 To add failure modes for the bulb, click on the ‘+’ symbol next to the bulb. Right-click on the FMs container and select the ‘Add’ option from the drop-down menu.

  30. Adding FMs for the Bulb – Step 2 This slide shows the FMECA Manager screen for adding a new failure mode. You can either click on the pull-down list in the Failure Mode field to select one from the library or you can click on the icon to enter one on the fly. Click on the icon to add one on the fly.

  31. Adding FMs for the Bulb – Step 3 Enter ‘dim light’ for the name and click on the OK button.

  32. Adding FMs for the Bulb – Step 4 The ‘dim light’ value that you entered now appears in the Failure Mode field. Move down to the Failure Mode Ratio field and enter ‘0.1’. Click on the Save button to record your inputs. After the Save button is clicked you will see the new failure mode appear under the FMs container of the bulb. Note: failure mode ratios are only entered at the lowest level in the product tree structure. The failure mode ratios for all intermediate level nodes can be left blank and ASENT will calculate these for you.

  33. Adding FMs for the Bulb – Step 5 Repeat steps 1-4 and add a second failure mode for the Bulb. Add on called ‘no light’ and give it a failure mode ratio of ‘0.9’. After you have added this second failure mode and clicked on the FM’s container, your screen should appear as shown here.

  34. Adding FMs for the Switch – Repeat Previous Steps Repeat the same procedure that was used to add failure modes to the bulb, to add failure modes for the switch. Here we will enter three failure modes for the switch. These failure modes along with their failure mode ratios are shown here. Note: both the ‘Stuck closed’ and ‘Stuck open’ failure modes exist in the failure mode library. For these two failure modes, enter these by selecting them from the failure mode library pick list instead of clicking on the icon to add them on the fly.

  35. Adding FMs for the Contact – Repeat Previous Steps Repeat the same procedure that was used to add failure modes to the bulb and switch, to add failure modes for the contact. Here we will enter three failure modes for the contact. These failure modes along with their failure mode ratios are shown here. Note: the ‘intermittent’ failure mode was added to the failure mode library when we added it for the switch. For this failure mode, enter it by selecting it from the failure mode library pick list instead of clicking on the icon to add it on the fly.

  36. Adding FMs for the Battery – Repeat Previous Steps Repeat the same procedures that were used earlier, to add failure modes for the battery. Here we will enter two failure modes for the battery. These failure modes along with their failure mode ratios are shown here.

  37. Defining NHEs for the Bulb – Step 1 To define the Next Higher Effects for the bulb failure modes we will do the following. Click on the ‘dim light’ failure mode, as shown, and click on the ‘Next Effects’ tab.

  38. Defining NHEs for the Bulb – Step 2 The Next Effect screen consists of two parts. The left side displays a list of all of the modes at the Next Higher Assembly that have not been selected as a Next Effects for this failure mode. The right side of the screen will display the next effects and their corresponding beta values. The sum of the beta values should add up to 1.0. Select ‘flashlight output dim’ from the Parent Failure Modes list and click on the button.

  39. Defining NHEs for the Bulb – Step 3 After the button was selected, the ‘flashlight output dim’ appeared in the next effects list with a beta value of 1.0. Often, there is only one next effect, so the beta is automatically defaulted to 1.0. If you assigned more than one next effect for a failure mode, then you would have to adjust the beta values, accordingly, so that they sum up to 1.0.

  40. Defining NHEs for the Bulb – Step 4 Next, we select the bulb’s ‘no light’ failure mode. Click on the ‘no flashlight output’ mode from the Parent Failure Modes list, and click on the button to assign it as a next effect for this failure mode.

  41. Defining NHEs for the Bulb – Step 5 This screen shows the end result. ‘no flashlight output’ is assigned as a next effect for the ‘no light’ failure mode for the bulb.

  42. Defining NHEs for the Switch – Repeat Previous Steps Follow the same steps that were used when defining next higher effects for the bulb, to assign next higher effects for the failure modes of the switch. The failure modes along with their corresponding next effects are listed below. Navigate down to the switch and enter the next effects shown below: Failure ModeNext EffectBeta Intermittent flashlight sometimes will not turn on 1.0 Stuck closed constant flashlight output 1.0 Stuck open no flashlight output 1.0

  43. Defining NHEs for the Contact – Repeat Previous Steps Follow the same steps that were used when defining earlier next higher effects, to assign next higher effects for the failure modes of the contact. The failure modes along with their corresponding next effects are listed below. Navigate down to the contact and enter the next effects shown below: Failure ModeNext EffectBeta Intermittent flashlight sometimes will not turn on 1.0 No contact no flashlight output 1.0 Poor contact flashlight output dim 1.0

  44. Defining NHEs for the Battery – Repeat Previous Steps Follow the same steps that were used when defining earlier next higher effects, to assign next higher effects for the failure modes of the battery. The failure modes along with their corresponding next effects are listed below. Navigate down to the battery and enter the next effects shown below: Failure ModeNext EffectBeta Low power flashlight output dim 1.0 No power no flashlight output 1.0

  45. Roll-up Failure Mode Ratios We have now finished defining the failure modes and effects. Now, we are going to calculate the failure mode ratios for any intermediate nodes in our structure. Right-click on the project node and select the ‘Roll-up Failure Mode Ratios’ option from the drop-down menu. Click on the ‘OK’ button when the window below appears.

  46. Calculate Criticality Numbers Next, we will calculate the criticality numbers. Right-click on the project node and select the ‘Calculate Criticality’ option from the drop-down menu Click on the ‘OK’ button when the window below appears.

  47. Assign Failure Mode Indicators Failure Mode Indicators are identifiers that are commonly used in the Logistics LSAR database, but they can also be helpful in sorting and identifying failure modes in reports. ASENT will automatically generate these for you. Right-click on the project node and select the ‘Create FMIs’ option from the drop-down menu. Click on the ‘Yes’ button when the window below appears.

  48. Generating a FMECA Report To generate a FMECA report, right-click on the project node and select the ‘Reports | FMECA’ option from the drop-down menu. Click on the ‘OK’ button when the window below appears.

  49. FMECA Report Output

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