Assurance of product quality during production and processing of SMC-Materials
The complexity of the parameters which influence the fabrication, and the specific problems associated with manufacturing and processing SMC prepregs, are described in a generalized form. To evaluate actual variations in the quality of SMC-prepregs, produced under practical conditions, the material was investigated in regards to its mutual dependencies on manufacturing, processing and testing.
Extensive comparative investigations of various standard R-SMC systems were performed to determine the reproducibility of the material composition and effects of the fabrication conditions. Large variations in mechanical properties, which proved to be independent of the processing conditions, were observed through static, dynamic and impact loading tests. An obvious orientation of the chopped glass fiber bundles exists, induced by the prepreg production process. The extent of this orientation is mainly influenced by the production speed of the SMC-line. The fiber content also varies greatly, primarily due to the varying diameters of the glass fibers. Microscopic investigations have shown that the thermoplastic shrinkage compensator used in the LS-SMC acts as a structural weakness, which is the location for the principal initiaton of multiple cracking processes during fatigue loading. Current concerns of this manufacturing technology deal with insufficent material homogeneity, which occurs both during the course of producing a batch and in the reproducibility at the resumption of a batch production run. These problems, especially the insufficient material homogeneity over the production width of the prepreg, are fairly independent from the SMC production line and the SMC system.Lesen Sie die deutsche Zusammenfassung auf Kunststoffe.de
SMC, Sheet Moulding Compound, Quality Assurance
Institute / chair: Technische Fakultät der Universität Erlangen-Nürnberg
Technical consultant for expert services: Prof. Dr.-Ing. Dr. h.c. Gottfried W. Ehrenstein (Betreuer), Prof. Dr.-Ing. Volker Altstädt
Publication year: 1996
Provider: Wissenschaftlicher Arbeitskreis Kunststofftechnik (WAK) / Kunststoffe.de
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