A Rheological Model for the die Entry Flow of Reinforced Polymers

Gibson, A.G.; Corscadden, S.P.; McClelland, Alexander

doi:10.1177/089270578800100202

Cited by 2 publications

(4 citation statements)

References 4 publications

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“…3. The deviations seem to be a little larger in lower injection speed (region A), though maximum deviation is less than 7.5 µm, indicating that the increase of injection speed results in more consistent process [7]. As a result, optimum injection speed can be selected in the region where variation of viscosity does not occur in in-mold rheology curve due to high injection speed.…”

Section: Resultsmentioning

confidence: 97%

“…In particular, dimensional deviation in micro components depend largely on homogeneous and complete filling of feedstock into micro mold. For shot-to-shot mold filling consistency, the viscosity of feedstocks in mold, which is changed by shear rate (or injection speed), have to be kept constantly [6,7]. It is, therfore, very important to determine injection speed in range where the feedstock shows Newtonian flow behavior.…”

Section: Introductionmentioning

confidence: 99%

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In-Mold Rheology Curves with Feedstock and Mold Dimension

Jang

Cha

Lee

et al. 2011

AMR

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In this work, in-mold rheology curves were generated by injection molding machine and the effects of feedstock and mold dimension on in-mold rheology curve were studied. The rheology within mold in µMIM process depends on the shape and/or size of cavity and process conditions rather than intrinsic viscosity of feedstock. The optimum injection speed was determined in region of Newtonian flow of in-mold rheology curve. The dimensional deviation was below about 5 µm in the micro part injected with the optimum speed.

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Section: Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

In-Mold Rheology Curves with Feedstock and Mold Dimension

Jang

Cha

Lee

et al. 2011

AMR

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“…To determine the elongational viscosity of the polymers studied, the experimental data obtained using truncated capillaries, (comprising a converging section only) were analyzed following Gibson's analysis (4,12,13). Only 45", 60".…”

Section: Elongational Viscositiesmentioning

confidence: 99%

“…Thus, the total entrance pressure drop is the sum of that due to shear flow, P,, and that due to extensional flow, P,. The shear and extensional components can be treated separately, by a method originally proposed by Cogswell (1 l), and subsequently modified by Gibson (4,12,13). Cogswell assumed a "power law" model for the shear viscosity, q. and a constant elongational viscosity A, where X= 37,; 7 is the zero shear viscosity.…”

Section: Introductionmentioning

confidence: 99%

Shear and elongational viscosities of a thermotropic liquid crystalline polymer and its blend with polycarbonate

Beery

Kenig

Siegmann

et al. 1992

Polymer Engineering & Sci

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The shear and elongational viscosities of a thermotropic liquid crystalline polymer (LCP), polycarbonate (PC), and their 20%LCP/80%PC blend, were studied using a capillary rheometer. The investigation focused on experimental studies using two sets of capillaries. The first set comprised capillaries having a converging entrance followed by a cylindrical section. The second set, “zero length” set, included capillaries having only the converging section. In the two sets various entrance angles were used. Experimental results have shown that shear viscosities and entrance pressures are practically independent of the entrance angles. The entrance pressure drop was small in the case of PC and reached 50% of the total pressure drop for LCP. The elongational viscosities of the LCP were found to be higher than those of the PC in the elongational‐rate range studies, while shear viscosities of the LCP were higher in the lower shear rate region and lower in the higher shear rate region compared to those of PC. This was attributed to the orientability of LCP in elongational and shear flows.

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A Rheological Model for the die Entry Flow of Reinforced Polymers

Cited by 2 publications

References 4 publications

In-Mold Rheology Curves with Feedstock and Mold Dimension

In-Mold Rheology Curves with Feedstock and Mold Dimension

Shear and elongational viscosities of a thermotropic liquid crystalline polymer and its blend with polycarbonate

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