Visualization of wall slip during thermoset phenolic resin injection molding
The behavior of glass-fiber reinforced phenolic resin in the presence of the wall surface during injection molding under various processing parameters has been studied with a rather simple but effective and useful method, namely, the spotwise painting of the mold wall surface. The experimental results show clearly a strong slip of the phenolic melt on the cavity surface. The occurrence of slip begins immediately when the phenolic melt contacts the wall surface. This technique was applied to study the slip of thermoplastic melts inside a rectangular mold. However, completely opposite results found between the flow behavior of thermosets and thermoplastics on the cavity surface raise the questions concerning the applicability of thermoplastics injection molding concepts and rheological property testing methods, respectively, simulation packages for thermosets.
KeywordsThermoplastics Thermosets Phenolic molding compounds Injection molding Wall slip
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The first author acknowledges the meaningful discussions with Prof. Dr. G. Mennig and Dr. Tham Nguyen-Chung on injection molding theory.
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