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Test Yourself

Beginning with this issue, ACMA’s Technical Services Manager Larry Cox will pose several questions related to manufacturing in the composites industry. The questions will be garnered from personal experience, ACMA manuals and documents, magazines, and other sources. Some may be relatively easy, others more difficult, and maybe even one or two that are downright impossible. I hope that they will be educational, and entertaining.

  1. Can polyester resins be both thermoset and thermoplastic?
  2. What are four principles to consider in using FRP?
  3. Fiber reinforcement to resin ratios is important in open molding for several reasons. Name three methods of determining this ratio.
  4. Based upon a 2004 ACMA report, the total impact of composite manufacturers and suppliers on the U.S economy in jobs and dollars in 1998?
  5. True or false: The U.S. glass reinforced thermoset transportation market represented the largest market segment in 2005.

Answers:

  1. Yes. The very basic chemistry of polyester, reacting a glycol with a diacid produces polyester. The reaction, referred to as condensation polymerization results in either a saturated or an unsaturated polyester resin. Saturated polyester is a thermoplastic, while unsaturated polyester is a thermoset.
  2. First Principle: Mechanical strengths of the finished part. These properties will dictate the selection of reinforcement type, amount and configuration.
    Second Principle: Chemical, electrical, thermal performance. These considerations will determine the matrix needed.
    Third Principle: Design and production requirements (part shape, size, volumes). These are necessary in determining the process required for production.
    Fourth Principle: Cost and performance evaluation. Is the program feasible?
  3. A. Visual inspection, looking for extremely glossy, wet surface (too much resin).
    B. Weigh the resin used and the glass used accurately to produce the part.
    C. Use an ignition burn out test
  4. The composites industry contributed 287,120 jobs and $ 45.31 billion.
  5. False. The construction market was the leader with over 1.8 billion pounds of shipments, the marine market was second with .9 billion pounds, and transportation third with .5 billion pounds.