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Author Popp, Andrew. Klosterman, Don. Chartoff, Richard. Institution Univ of Dayton, Dayton, OH, USA
Source International SAMPE Symposium & Exhibition. v 45 (I) 2000. p 90-102.
Abstract This is the first study to correlate prepreg tack with process performance in Laminated Object Manufacturing (LOM). A commercially available fiber glass/epoxy prepreg was used as a model system. Prepreg tack was varied by aging prepreg sheets at 50 degree C, 75 degree C, and 100 degree C for one hour. The room temperature compressive tack index (CTI*) of the aged prepregs, in addition to unaged prepreg, was measured with a technique previously developed by Seferis and Meissonier. The tack test results indicated significant differences between the tack of the non-aged prepregs (CTI* equals 2.3), the 50 degree C and 75 degree C aged prepregs (CTI* equals 1.5) , and the 100 degree C aged prepregs (CTI* equals 0.1). There was no significant difference in the tack of the 50 degree C and 75 degree C aged prepregs. The performance of these four prepregs during LOM was observed. Four critical processing events which are strongly influenced by tack were identified. An empirical scale of performance was assi gned for each event. Difference in CTI* led to noticeable and predictable differences in prepreg behavior during LOM processing. A CTI* of 1.5 corresponded to an ideal level of tack required for optimum process operation. Next, the resulting panels were cured in a vacuum bag/oven. It was demonstrated that, within a certain aging window, one can adjust the prepreg tack for optimum LOM process performance without affecting the fiber volume fraction of the final cured panels. The results of the study can be used to formulate new prepregs or alter existing prepregs (e.g. through B-staging) such that optimum process performance in LOM is achieved without sacrificing final panel qualities. (Auth abstract) [References: 12] XX