Design Review Based on Failure Mode

Failure detection aided design change or Design Review Based on Failure Mode ( DRBFM ) is a development method that accompanies the development process of a process / product. It is used in the context of quality management for preventive error prevention.

Origin

Design Review Based on Failure Mode was developed by Toyota and is applied there successfully. It arose from the realization that changes contain the highest potential for error, and was derived in large part from the FMEA ( Failure Mode and Effects Analysis ).

Explanation of terms

The acronym stands for DRBFM " Design Review Based on Failure Mode" and shows the essential elements in action at:

  • DR = Design Review: Review of the development of internal and external experts ( customers, suppliers) that are not involved in the project.
  • FOM = Based on Failure Mode: Does the one hand, that at the time of a DRBFM meetings a FMEA was created. Furthermore, means Based on Failure Mode and that the origin of the DRBFM is to look in the FMEA. The inventor of the method, Prof. Dr. Tatsuhiko Yoshimura, first tried to convince the engineers to a creative design review by an FMEA sheet form, but realized that the creativity in the design review through the formal structure of the FMEA form sheet was not given.

Procedure

In DRBFM is in contrast to FMEA usually not worked with moderators. However, there are technical professionals who have the appropriate mindset required. The method DRBFM represents no other management tool, but is a tool to generate a robust designs already in development. This means that DRBFM is a method that is used by the developers and engineers to achieve a robust design in the early phases of product development.

The reaction takes place on a preferably printed in DIN A0 format worksheet to create in active discussion a collaboration with high information content.

Methodology

The DRBFM focused on changes in the derivation (seen here in a broader sense: a new platform or application is a change). It provides the detailed changes to the functions of the component elements. The changes are fully quantified (eg " wall thickness of the pressure chamber before 1.2 mm, wall thickness after 0.75mm reason. Reaching a lower 29% component weight " instead of " lesser wall thickness " or "before. 20 mantissa bits, After 56 mantissa bits reason. reducing signal noise at the output by 14 dB "instead of" higher calculation accuracy ").

In this matrix, the so-called " concerns" are being sought. A " Concern " is a verbal or written objection formulated which outlines a change conditional potential problem in the considered design. These ( and only these) changes will be applied and processed in the "Worksheet " (or " Worksheet "). A " Concern" is described technically accurate and understandable, so that means " 5 × Why" analysis, the basic reason for the feared problem can be determined or that it can be shown quantitatively that the " Concern" is not, or has no relevant influence ( the design meets after the change still the specification).

Fictitious example: " By reducing the wall thickness of the pressure chamber to 0.75 mm, there is the danger that during production step " " arise casting due to the manufacturing variations illegal wall thinning or holes, so that the component no longer airtight as specified at 1.2 bar internal pressure ( absolute) ". Based on the " 5 × Why" analysis, the fundamental cause ( the "root cause" ) is determined. Example: . " 1 Why this may happen because in order to maintain the internal pressure of a minimum wall thickness of 0.5 mm is necessary, but maximum production fluctuations of 0.3 mm are measured in 2% of previously manufactured parts This leads to the change to a deficit of 0.05 mm. 2 Why do manufacturing variations of 0.3 mm? Because ... ". As a result could indicate that the "Root Cause", which will lead to " Concern", a 15% to a low working pressure of the molding device in this fictitious example. The working pressure without demonstrably relevant consequences of 25 % could be higher. This higher pressure would be based on a plausible interpretation rule lead to a reduction in the maximum fluctuation of 0.1 mm.

In our review, the focus is on additional measures in the design, testing or production. For example, therefore the dummy would be conceivable as a measure for eliminating the problem of increasing the operating pressure of the molding apparatus by 25%, and to define a process that detects the effectiveness of the performed measure quantitatively.

Publications

  • Beginners Guide to DRBFM, Toyota, Nov. 2005
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