Design review based on failure mode
Design review based on failure mode 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.
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, he created his own philosophy of DRBFM. Dr. Tatsuhiko Yoshimura supported the development and usage of DRBFM at many companies. He believes companies that implement the usage of DRBFM will be a better company. He believes the implementation of DRBFM requires discipline and engagement of everyone to the one goal of adding value to the customer by meeting engineering functional requirements and customer expectations.The philosophy of DRBFM centers on three concepts:
- Good design
- Good discussion
- Good dissection
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 and interactions between systems. 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.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 a linkage between a good design review and FMEA. A comprehensive, well-done FMEA can be considered one of the inputs to decide the scope of a DRBFM but an FMEA is not required since the focus is based on the changes and interfaces. DRBFM is implemented based on novelty of change at any level of the product. 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 - anything that impacts quality, cost, or delivery.