Lesson 5 of 14 Ways to Acquire
Reliability Engineering Knowledge
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In the meantime, practice keeping an open mind. Note when your defense come up, and what triggered the reaction. Learn to notice when you’re shutting down a chance to learn.
Ask yourself if there is another way to view this subject or problem. It takes practice. Set reminders for yourself as you work to master this behavior.
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Mangan tells us to keep an open mind, consider both sides from all angles, and examine each new object or situation with an open mind and be willing to learn from the many points of view. For reliability we often observe a rush to solution during failure analysis work.
Stop, walk around the problem, and examine the problem including all the information. Fully understand the problem before selecting a solution. You will no doubt learn something and likely find a better solution.
Same advice applies when interacting with your colleagues. Although physically walking around them with a steady gaze may be inappropriate, you can learn by exploring how they see the world. What is important to them about reliability? How do they fit into the reliability program?
A Motor Failure
An example may illustrate this method of learning. Consider the situation where a motor has failed within a printer. The immediate solution may be the replacement of the motor or finding a stronger motor to use as a replacement. Before replacing the failed motor, take the time to walk around it to explore why the motor failed and the cause leading to the failure. Examine the operation of the motor including:
- the mechanical attachment and location,
- the electrical elements and supply, and
- the general environment, including temperature, dust, etc.
In this case we found a faulty drive circuit causing high torque and excessive heating, which leads to the failure within the motor. Replacing the motor would not address the issue and we learned by exploring around the subject and looking for the many possible stresses and interactions involved with the motor operation.
A Marble Quarry Problem
Henry Petroski in Design Paradigms: Case Histories of Error and Judgment in Engineering
describes a common design team mistake for which the concept of walking around it would help solve. Petroski describes a marble quarry in ancient days commissioned to deliver a 6-m-long column in a single piece of marble. Up till this request, marble blanks were no longer than 3 m and could be safely supported off the ground with a timber placed under each end of the marble. A quarryman commented that the unsupported mid-section may be sufficient to crack the beam as it bowed under its own weight between the two supports.
The team considered the issue and, to solve the bowing problem, decided to add a third timber under the center of the column blank. In the morning the blank had a crack which ruined the piece. The crack was on the top of the beam over the center support. The team did not consider other failure mechanisms, such as uneven settling of the supporting timbers that could created a diving-board structure. Solving the bowing issue created another failure possibility.
Considering the impact on the overall system with a local change is a form of walking around it. It is a way to learn.
A Simple Tool
The cause-and-effect diagram (Ishikawa or fishbone diagram) is a tool useful when attempting to consider many elements that surround an issue or topic. To create the diagram, start with the issue (failure mode or symptom), then create a branching structure with major elements of the device, process, or category of potential causes.
Finally, off the category lines, add smaller branches for variables or detailed potential causes. The cause-and-effect diagram aids a group in considering the many potential causes for a failure. Once it is populated the next step is to consider the most likely causes and either conduct confirming experiments or explore possible controls or solutions. The diagram helps one explore and learn about possible failure causes.
Walk around it is a way to learn by being open to new information. Changing your point of view, considering alternatives, assessing the impact are all ways to prepare yourself to learn.
Next Week: Experiment
Bring out the mad scientist in you as you form hypothesis to test. Try alternatives, see what happens with a small change. For product testing, what are the limits? Have fun.
In the meantime, practice keeping an open mind. Note when your defense come up, and what triggered the reaction. Learn to notice when you’re shutting down a chance to learn.
Ask yourself if there is another way to view this subject or problem. It takes practice. Set reminders for yourself as you work to master this behavior.
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