TITLE: On-Line NDE for Process Control of Continuous Resin Transfer Molding^TM

Abstract:
An on-line nondestructive evaluation (NDE) method has been developed for polymer matrix composites fabricated by the continuous resin transfer molding (CRTM) - process.* This work was performed under the "Affordable Polymeric Composite Materials Synthesis and Processing Program" (MDA972-93-2-0004), sponsored by the Advanced Research Projects Agency (ARPA). CRTM(tm), developed by Ciba, is an extension of the current RTM process which allows the affordable, high rate manufacturing of long standard structural shapes. The process provides access to the part surface at the die exit, making it possible to perform NDE continuously and in near real time. As a result, the NDE data can be used to trigger an expert process control system when defective conditions are sensed, so that the necessary corrections to process parameters can be made.

The Mobile Automated Scanner (MAUS) III, a portable ultrasonic NDE instrument developed by McDonnell Douglas Aerospace (MDA), is the basis for on-line NDE of the CRTM(tm) process. The MAUS III was used in the through transmission mode for this program in order to inspect a wide range of laminate thicknesses and conditions. The MAUS III normally displays and stores a continuous C-scan as a record of the inspection; the system software will be modified to relate attenuation levels to approximate porosity content. Carbon/ epoxy, glass/vinylester, and hybrid glass/carbon/vinylester materials are included in the study of attenuation vs. porosity. Ultimately, void content estimates from the modified MAUS III will be analyzed in near real time by the CRTM(tm) process expert control system.

Source: Proceedings of the 'NDE applied to Process Control of Composite Fabrication' - Conference, 4-5 Oct 1994 St. Louis, Missouri. Publisher and Organizer: Nondestructive Testing Information Analysis Center (NTIAC) Texas Research Institute Austin, Inc. Austin, Texas [http://www.ntiac.com] [Buying the Proceedings]