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FAA Specification Meeting

Valuable feedback on FiberCote Industries' specification framework for enhancing product quality with recommendations for improvement and certification testing guidelines.

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FAA Specification Meeting

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  1. FAA Specification Meeting Steven Peake FiberCote Industries Waterbury, CT

  2. General Comments • This specification is an excellent framework, but… • It tries to achieve quality by inspection • We should control the product with SPC, “ISO” and a process control document Customer view of FCI contribution FCI View of Contribution Customers Feel the Variance, Not the Mean

  3. General Comments • Some certification tests are redundant and not tied to key attributes • Many changes that require are 3 batch qual are not reasonable and exceed common industry practice • Not every contigency must be in the spec. • Users can add conditions [to a PO]

  4. Specification Purpose • Qualification Material characterization • Allowables • Prepregging processing • Certification  Material consistency • Tests must relate to key attributes in prepreg manufacture and end-use application • Avoid the inspection mentality: • Use certification tests to monitor product consistency

  5. Qualification Testing • Chemical Tests to “fingerprint” resin • IR, HPLC, rheology • Physical tests to define prepreg system • Resin content. FAW, volatile • Mechanical tests to provide allowables data • Processing prepreg and laminates at extremes • Process Control Document for prepreg • Statistical basis for certification tests

  6. Certification Issues • Choose tests that relate to product variability • Choose tests that measure fundamental properties and relate to material key parameters: • Resin composition (HPLC, IR) • Fiber properties (tension) • Flow and gel (Rheology) • Fiber-resin interface (flex) • Service temperature (Tg or elevated temp. compressive) • Need procedures for • retest with assignable cause • Shelf-life recertification • Lot/batch testing based on resin film set or fiber creel set change

  7. Tests to avoid • Repeat testing on the same variable • HPLC, IR & DSC (cure) • Fiber tensile, fabric tensile, laminate tensile • Tests that are dependent on 2 or more process parameters • Flow: resin content, rheology, composition, advancement • Gel: rheology, resin composition, advancement, technique

  8. Certification Tests for Uncured Prepreg Fundamental Prop. Reproducibility Comments Key attribute Fast & easy Good Fair Poor

  9. Certification Tests for Laminates Fundamental Prop. Reproducibility Key parameter Comments Fast & easy Good Fair Poor

  10. Specific Comments • P 10 - What are the criteria for an acceptable PCD? Must insure uniform standards among ACO’s • P11 - How is the composition of the industry committee determined? • P12 - What is the procedure for PCD revision if it not a major change? Will they be audited? • P 18 - Supplier must have raw material specifications for all raw materials. • P19 - Why restrict this spec to epoxy resins and carbon fiber • P20 - Resin properties: • HPLC and IR are redundant tests (for certification). Test on the prepreg, not resin. • Why test moisture diffusion? Moisture absorption OK, but test on laminate. • Microcracking on neat resin? Stress cracking with solvent maybe. • P21 – Spreadability should not be in a spec. It is a supplier issue.

  11. Specific Comments (cont.) • P 21 - Uncured Prepreg properties: • HPLC, IR and DSC are redundant for certification. Use HPLC & don’t run on uncured resin. • Use Fiberite system for tack • What is meant by spool length? Sides of spools? • Roll edge alignment is only critical for ATL • P22 – Procedure needed to re-certify if out of storage life. • P24 Cured laminate properties: • Hot/wet Tg not practical for certification; method dependent test • Uni compression more sensitive than [0,90] to use for certification • What are we learning from RT short beam shear? • P31 – need to define prepreg batch and resin batch • P31 – cure cycles: • not practical to have material with longest shelf life: what if it has a 2 year shelf life? • Need to define slow/fast cure cysle, long/short thermal history. OEM cure cycles are typically much longer than spec. certification cure cycles.

  12. Specific Comments • P34 - Level 2 Changes • What is change in feedstock? Why different than “Alternate vendor for chemically identical raw materials”. • Is T300/Toray to T300 AMOCO a level 1 or 2 and who decides? • Level 2 “Modifications to process equipment… that do not change key characteristics…. If a new pump is added, is that a level 2 change? Suggest equipment for this description be Level 1 and process changes be level 2. • P35 – Level 3 Changes • What test are required beyond certification tests? 3 Batches is onerous for these changes • Changes in tack should not be Level 3 • I doubt that the current industry practice for OEM’s for cure cycle changes is level 3 • P36 – Level 4 Changes • These should not be level 4 FAW, resin viscosity, tow count changes • P 40 – Future needs • Measure only to remove and monitor sources of variability • HPLC and IR can already quantitatively determine resin components • Equipment already exists for in-line FAW and resin content determination

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