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AFGROW | DTD Handbook

Handbook for Damage Tolerant Design

  • DTDHandbook
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    • Sections
      • 1. Introduction
      • 2. Fundamentals of Damage Tolerance
      • 3. Damage Size Characterizations
      • 4. Residual Strength
      • 5. Analysis Of Damage Growth
      • 6. Examples of Damage Tolerant Analyses
      • 7. Damage Tolerance Testing
      • 8. Force Management and Sustainment Engineering
      • 9. Structural Repairs
      • 10. Guidelines for Damage Tolerance Design and Fracture Control Planning
        • 0. Guidelines for Damage Tolerance Design and Fracture Control Planning
        • 1. Design Loads Spectrum
        • 2. Material Selection
        • 3. Structural Configuration Analysis
        • 4. Manufacturing Process
          • 0. Manufacturing Process
          • 1. Review of manufacturing process and inspections
          • 2. Development of Critical Parts Accountability
        • 5. References
      • 11. Summary of Stress Intensity Factor Information
    • Examples

Section 10.4.1. Review of manufacturing process and inspections

Three major items comprise the function of the manufacturing process quality control.  They are:

(1)               Definition of inspection requirements

(2)               Demonstration of inspection methods

(3)               Review of manufacturing process and inspections

The basic document for the manufacture of each fracture critical part is the process specification.  It lists all of the processes that must be performed on the part.  This forms the basis for selection of the inspection methods.  Limits for acceptance are also a part of the process specification.  The scheduling of inspections during the process must be considered.  A trade-off between inspection cost, rework cost, and loss due to scrap must be made.  This process may be more critical in a fracture critical part than in another part since there may not be as many rework options open.  Thus, it may be more efficient to have more inspections than to risk losing a large amount of process time.  Parts that do not pass an early inspection may be reclaimed through rework options still available at this time.

The demonstration of the efficiency of nondestructive process inspections can be made through destructive testing or through a more rigorous nondestructive inspection.  This demonstration is made early in the program and may be subject to periodic checking over the life of the project.  As experience is gained with the process, the inspection frequency may be decreased.

It should be noted that whenever either new process equipment is installed or inspection equipment is changed, the inspection procedure should be tightened until confidence is again attained.  This also should include periodic review of the inspection process to insure that the quality of the inspection is being maintained.