Original Date: 05/08/1995
Revision Date: 01/18/2007
Information : Design for Manufacturing and Assembly
McDonnell Douglas Aerospace (MDA)-St. Louis has developed a process called Design for Manufacturing and Assembly (DFMA) to reduce inventory and work-in-progress, which together represent 51% of MDA’s total assets. DFMA is an integrated process encompassing Integrated Product Development, Manufacturing Support, and Production Operations teams. The process concentrates on Integrated Product Development data sheets which represent assembly, tooling, and tolerance information and are associated with the product’s Unigraphics master model.
DFMA includes a production flow analysis (Figure 3-2) in which assembly sequences are captured in precedence diagrams. Personnel and production resources are then allocated, and a resource-constrained critical path for assembly is generated with the help of MDA-developed Compass software. Potential assembly problems due to part tolerance variation can be analyzed (Figure 3-3) using Variation Simulation Analysis (VSA), a commercially available manufacturing statistical simulation and analysis package. This analysis can then be used to identify causes of variation and to indicate potential areas where tolerances might be adjusted to minimize defects without compromising quality.
DFMA has been used on the C-17 landing gear pod program to reduce the number of different fastener types, reduce the overall part count, and simplify the assembly process. This effort has resulted in a shorter assembly cycle time and reduced cost.
Figure 3-2. Production Flow Analysis
Figure 3-3. Variation Simulation Analysis
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