Design Review Based on Failure Mode
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Design Review Based on Failure Mode (DRBFM) is a tool originally developed by the Toyota Motor Corporation. This tool was developed based on the philosophy that design problems occur when changes are made to existing engineering designs that have already been proven successful.
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[edit] Methodology
DRBFM Methodology was developed by Tatsuhiko Yoshimura, a Quality Expert, and a professor at Japan's Kyushu University. Yoshimura knew that design problems occur when changes are made without the proper level of supporting documentation. Using the philosophy of Preventative Measures (Mizenboushi), he created his own philosophy of DRBFM.
The Philosophy of DRBFM centers on three concepts:
- Good Design
- Good Discussion
- Good Design Review
[edit] Good Design
The basis for reliability is not to change a design; therefore, Mr. Yoshimura believes that if a design changes, the change should occur in small increments. Disturbance to a design is caused by the discontinuity of implementing changes affecting the interfaces between parts. The design should not be changed in two different places simultaneously, because making too many changes too fast has the potential to result in failures faster than our capacity to detect them. One key to successful change is to make changes visible.
[edit] Good Discussion
In discussions we should concentrate on the proposed changes to a design. If a proven good design is applied to future products, then the risk of failure is low; however, if changes are made to the existing design, then the probability of failure is increased.
Mr. Yoshimura advises individuals to work to understand the changes as opposed to trivializing them. He also advises that validation testing can help to identify design weaknesses; but, he also states that good discussions held at preliminary design reviews can achieve the same result. The good discussion that Mr. Yoshimura refers to here is also known as DRBFM.
The analysis for DRBFM is modeled after the standard column work sheet for Failure Mode Effect Analysis (FMEA). Although the initial intent of DRBFM was to distance itself from FMEA (due to its bad reputation), Yoshimura recommends using the DFMEA format if a good FMEA process is already in place. A comprehensive, well-done FMEA can be considered a prerequisite for a DRBFM; the DRBFM need only be implemented when design changes occur. The intent of the DRBFM is to make these changes visible by discussing them at length, as well as every possible concern for failure that may potentially occur.
[edit] Good Design Review
The objective of a good design review is to examine the results of validation testing, making all mistakes visible. This examination involves applying DRBFM to another concept, Design Review Based on Test Results (DRBTR). When applying DRBTR, we must, wherever possible, observe the test failure. DRBFM encourages the designer to discuss potential design problems or weaknesses from a cross functional multi-perspective approach, and to share this information. DRBTR has the designer observing actual test pieces and discussing test results in open discussions during design reviews. Furthermore, when dissecting test results, one must use the results to determine if it is the most effective means to find problems.
