Team Members Problem Statement Product Description
Design Evaluation   Knowledge Gained

Design Evaluation

Evaluation of the Adjustable Joggle Die Set was directed at determining if the die set met the objective of producing repeated joggles within the 0.010 inch tolerance on 99% of the joggles attempted.

There are two dimensions on a joggled stringer that must meet the 0.010 inch tolerance in order for the stringer to be useable.  These dimensions are the joggle transition length and the joggle depth.  The figure shown below depicts the profile of a joggled stringer and the location of geometry of the measured dimensions.






The results of the design evaluation testing showed that the adjustable die set met the 0.010 inch tolerance for both transition length and joggle depth with 99% certainty. 

In addition to the tolerance and certainty evaluation qualitative testing of the joggle stringers was done with die penetrant tests, see Figures 1 and 2 below.

Figures 1:  Control Stringer, intentionally cracked for visualization Figures 2:  Quantitatively and Qualitatively tested stringers.  All of the stringers joggled passed the die penetrant test.



Over the course of the design of the Adjustable Joggle Die Set the DFMEA showed the following to be the major issues of concern:

  1. The dove tails on the die set not sliding properly when heated.
  2. Problems associated with manufacturing of the die set.
  3. Calibration of the die set to the joggles in the 604series stringers.

The completion machining and design evaluation testing eliminated the first two DFMEA major issues of concern and produced the following issues of concern:

  1. Calibration of the die set to the joggles in the 604series stringers.
  2. Consistency of calibration over an extended period of use.