Fiber-breakage evaluation of plasticated resin based on a newly developed heating cylinder with multiple ports for in-process sampling

Ma, Sai; Shibata, Kazuyuki; Yokoi, Hiroyoshi

doi:10.1016/j.polymertesting.2017.09.020

Cited by 2 publications

(2 citation statements)

References 14 publications

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“…As the mechanical strength of the resin depends on the fiber length, long glass‐fiber pellets are often preferred to shorter ones. However, previous studies have found that long glass fibers (GFs) tend to break at the following points of the injection process: (1) when the resin is plasticized inside the heating cylinder , (2) when the resin bypasses the check ring , and (3) when the resin flows into the mold . These findings suggest that the original fiber length cannot be maintained throughout the manufacturing process of the molded product.…”

Section: Introductionmentioning

confidence: 97%

Visualization analysis of reciprocating‐screw plastication process of glass fiber‐reinforced resins in a glass‐inserted heating cylinder

Shibata

Yokoi

2018

Polymer Engineering & Sci

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One challenge in injection molding of long fiber‐reinforced resins is minimizing the fiber breakage during resin plastication and resin flow into a mold. Such fiber breakage reduces the strength of the molded product. Reciprocating plastication is subjected to periodic positional fluctuations of the screw and cylinder in the molding cycle. In this study, visualization experiments were conducted on the reciprocating plastication of long glass fiber (GF)‐reinforced polypropylene with 50 wt% GF. It was found that: (1) temporary voids form in the resin during the metering process, and the pellets rotate from an orthogonal to parallel orientation in the flight direction; (2) length of the weight‐averaged fiber temporarily decreased in the middle stage of the injection process; (3) length of the weight‐averaged fiber was most strongly influenced by the waiting time; and (4) for constant waiting time, the fiber breakage could be minimized by lowering the rotation speed, lowering the back pressure, and shortening the charge stroke. POLYM. ENG. SCI., 59:846–853, 2019. © 2018 Society of Plastics Engineers

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Section: Introductionmentioning

confidence: 97%

Visualization analysis of reciprocating‐screw plastication process of glass fiber‐reinforced resins in a glass‐inserted heating cylinder

Shibata

Yokoi

2018

Polymer Engineering & Sci

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“…However, fiber breakage and fiber pilling due to incomplete fiber defibration are problems encountered when long-fiber-reinforced resin is injected in an injection molding context. These problems occur during resin material plastication in the heating cylinder [1][2][3][4][5][6][7] and when the resin passes through the narrow flow path of the nozzle through the reciprocating screw's check-ring [8][9][10][11][12]. When evaluating the strength of injection-molded thermoplastic fiber-reinforced resin, high average fiber length does not always lend the molded product high mechanical strength.…”

Section: Introductionmentioning

confidence: 99%

Visualization Analysis of Defibration and Distributive Uniformity of Fibers in Long-fiber-reinforced, Injection-Molded Resins

Owada

et al. 2020

Polymers

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The pursuit of mechanical strength in the injection molding of long-fiber-reinforced resins continues to pose major challenges, namely (1) improvement of fiber defibration and fiber distribution and (2) suppression of fiber breakage during the molding machine’s plastication process. In the present study, a new defibration and distribution evaluation mold is developed to quantitatively evaluate the defibration and distribution of long fibers in nozzle-injected resin. A quantitative analysis method using this evaluation mold is proposed for visualizing and observing long-glass-fiber-reinforced resin up to 30 wt % and long carbon fiber-reinforced resin up to 10 wt %. The method, based on the intensity of light transmitted from a backlight source, is also used to evaluate areas of undefibrated fiber pilling and for evaluating the influence of molding conditions on fiber defibration and uniform distribution. The results clarify that fiber distribution non-uniformity can be reduced by improving the concentration adjustment procedure for the dry blending of high-concentration pellets. Additional results show that fiber defibration and distributive uniformity can be improved by applying high back pressure.

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Fiber-breakage evaluation of plasticated resin based on a newly developed heating cylinder with multiple ports for in-process sampling

Cited by 2 publications

References 14 publications

Visualization analysis of reciprocating‐screw plastication process of glass fiber‐reinforced resins in a glass‐inserted heating cylinder

Visualization analysis of reciprocating‐screw plastication process of glass fiber‐reinforced resins in a glass‐inserted heating cylinder

Visualization Analysis of Defibration and Distributive Uniformity of Fibers in Long-fiber-reinforced, Injection-Molded Resins

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