Repair

WHEN IS REPAIR NECESSARY? Quality Assurance applies acceptance criteria during in-process inspection, final inspection, and/or field inspection → part may be discrepant (defective) and rejected Discrepancy report (DR) written

QUALITY ASSURANCE/ENGINEERING HAS TO CLASSIFY REPAIR REQUIRED apply judgment may be explicitly stated in repair criteria guideline (General Repair Specification) repair classifications rework standard repair Material Review Board (MRB) - members include Quality Assurance and Engineering

EXAMPLE OF GENERAL REPAIR SPECIFICATION Class IV - cosmetic, negligible repair - rework - non-structural repairs to bring part up to required drawing finish Class III - minor structural repair - standard repair procedure applicable Class II - major structural repair - standard repair procedure applicable Class I - major structural repair - requires MRB review

TYPES OF COMPOSITE REPAIRS bolt on repair filling resin/adhesive/syntactic foam/composite removing/filling scarf repair (50:1 if possible)

REPAIR MATERIALS resins/adhesives syntactic foam/foaming adhesives viscosity cure time and temperature syntactic foam/foaming adhesives reinforcing fabric, milled fibers preimpregnated fabric and tape

WET SYSTEM ADVANTAGES room temperature cure can use minimal process materials and equipment

PREPREG SYSTEM (HOT BONDERS) ADVANTAGES resin content control cleaner system to work with may provide better match with existing material Wichitech Composite Repair Systems

REPAIR PROCEDURES in general, these four steps are followed surface preparation application of material cure: time, temperature, and pressure finishing