Course Length: 5 days
Pre Requisites:
None required but students should have some familiarity with composite structures, materials, and processes.
Summary:
Designed for onsite delivery only at select composite repair stations requiring devoted training in hot bond repair, this "combined" repair course is for repair technicians, mechanics, supervisors, and quality assurance personnel directly involved in providing high performance repairs to advanced composite structures.
Introduction:
This class includes an introduction to composite materials & processes and is devoted to developing hands-on repair skills. Students will be introduced to typical repair instructions and given damaged parts or structures to perform repairs throughout the week. Much emphasis is made on proper thermocouple and heat blanket placement with different bag schedules (i.e. peel ply, release films, bleeders & breathers) to facilitate quality repairs using hot-bond repair equipment.
Topics:
Key Lecture Topics:
- Introduction to advanced composite materials/structures.
- Resin/adhesive systems: thermosets vs. thermoplastics, mix ratios, viscosity, service temperature limits, cold storage requirements/shelf life limits, pot life, etc.
- Material Forms: dry cloth and wet resins vs. prepregs, weave/styles, etc.
- Fundamentals of Fabrication: prepreg cloth handling, ply orientation, etc.
- Cure cycles and rheology of thermoset resin systems during cure.
- Repair design considerations and determination of proper approach.
- Bagging techniques for actual parts with limited vacuum integrity.
- Proper thermocouple placement and heat blanket selection criteria.
- Programming and use of portable process controllers (hot bonders).
- Identifying and responding to heat blanket and thermocouple problems.
Workshop Exercises:
- Panel layup using prepreg carbon uni-tape materials; symmetric and asymmetric laminates.
- Vacuum bagging using non-autoclave bleeder/breather schedules.
- Use of repair instructions and determination of repair approach.
- Damage identification and assessment.
- Damage removal and taper-scarf preparation.
- Core removal and replacement in sandwich structures.
- Repair scarfing: including on actual or mock aircraft part surfaces.
- Cure programming and monitoring using portable process controllers (hot bonders).