Standard Test Method for Prepreg Resin Impregnation Level

ABSTRACT: Carbon fiber reinforcements pre-impregnated with resin (prepregs) are growing as a base material for many aerospace products. As such, prepreg quality is ever important and a key quality metric is its level of impregnation (LOI). However, high tolerance of prepreg LOI is difficult for manufacturers to maintain and is further complicated as industry-wide standards do not exist for accurate measurement of prepreg LOI. The Ultran Group, Inc. (Ultran) has developed ground-breaking non-contact ultrasound (NCU) technology used for numerous non-destructive testing applications. One such application is the measurement of prepreg LOI using NCU transmittance data. While use of NCU for prepreg LOI measurement is not known industry-wide, Ultran supplies NCU systems products to leading aerospace-grade prepreg manufacturers for online (inline) and off-line inspection. Much of the existing knowledge of the correlation between NCU transmittance and prepreg LOI is proprietary to the companies who use NCU systems from Ultran. However, considering the demonstrated success of NCU for prepreg LOI measurement, The Ultran Group, in partnership with Aurora Flight Sciences Corporation, will prove feasibility of prepreg LOI measurement using NCU and determine the correlation between NCU transmittance and prepreg LOI to provide the basis of an ASTM standard for LOI certification. BENEFIT: Sale of online (in-line) non-contact ultrasonic systems for prepreg material inspection during manufacturing. Sale of off-line X-Y or static systems for inspection of prepreg material. Commercialization of services through certification of customer-provided prepreg material for level of impregnation determination. Possible integration of ultrasonic components with automated fiber/tape placement systems.