Sheet molding compound characterization using spiral flow

Abstract

Sheet molding compound (SMC) is a fiberreinforced polymeric composite. It is often used in automotive, marine, and industrial applications over other materials because of its high strength to density ratio, resistance to corrosion, and low cost. There is a demand in the SMC industry to be able to characterize SMC processability. This is particularly true for heavy truck body panels, one of the fastest growing applications of SMC. Because of their large size and high strength requirement, the molding forces have a major influence in the molding cycle. Also because of the long flow paths involved, the ability of the paste to carry glass needs to be properly characterized when developing new SMC materials. In this article, we demonstrate the benefits of using spiral flow as a processability tester.

Design of experiment study of compression moulding of SMC

“…It have also been observed that a higher ram velocity increases the flow of inner layers into deep ribs. 15 The complexity of the flow is further increased by curing, which, for example, have been shown by Rabinovich et al, 16 where a spiral flow tool, allowing long flows, were used to characterise SMC. The test showed that higher mould temperatures decreased the flow length for SMC.…”

Towards the simulation of mould filling with polymer composites reinforced with mineral fillers and short fibres

“…It must be pointed out that such testing conditions, despite their simplicity, are not so far from the industrially encountered ones. Indeed, during the short duration of the compression mouldings, it is fair to assume [5] that the temperature of the compounds (i) is sufficiently low to avoid curing of the polymer and (ii) is approximately constant except near the lower and upper parts of the mould, where the heated polymer matrix acts as a lubricant [6,11,31,40,44].…”

Influence of fillers content on the viscosity of unsaturated polyester resin/calcium carbonate blends

“…Rabinovich and co-authors have studied the rheological behavior of SMC using a spiral flow tool. 12 They evaluated the SMC flow, at high temperature, under pressure, for two CaCO 3 contents (56% and 65%). Their results show that the filler level within the ranges studied has little influence on the molding forces, contrary to glass level which has a greater effect.…”