Mold-Face Heating Mechanism, Overflow-Well Design, and Their Effect on Surface Weldline and Tensile Strength of Long-Glass-Fiber-Reinforced Polypropylene Injection Molding

Huang, Po Chin; Peng, Hsin‐Shu; Choong, Wei-Huang

doi:10.3390/polym12112474

Cited by 7 publications

(7 citation statements)

References 33 publications

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“…In 2020, Ren et al [27], introducing optical injection, found that, under proper optical injection parameters, two sub-combs originating from two orthogonal polarization components of the VCSEL(vertical-cavity surface-emitting laser) can splice into a broadband total-OFC(optical frequency comb). In 2020, Huang et al [28] obtained results regarding optical-microscopy images and moldcavity pressure distributions which indicated that the weldline tensile strength and the interface compatibility between fibers and melts at the weldline region during the molding stage were higher in their use.…”

Section: Literature Reviewmentioning

confidence: 99%

Using Recognizable Fuzzy Analysis for Non-Destructive Detection of Residual Stress in White Light Elements

Chang

Mao

et al. 2021

Applied Sciences

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The phenomenon of residual stress in optical lens injection molding affects the quality of optical devices, with the refractive errors that are caused by geometric errors being the most serious, followed by the reduced accuracy and function of optical components; it is very important to ensure that the lens geometry remains intact and that the refractive index is reduced. This paper uses a photoelastic stress compensation method for measurement verification along with fuzzy theory to reorganize a set of processes that can be used to evaluate the residual stress of a product, whereby the use of corresponding theoretical formulas can effectively quantify and measure the residual stress of the product. A mold flow simulation is used to analyze the molded optical components and determine the feasibility of evaluating the quality of the lens. Through the measurement of the refractive stress value of the optical components, the molding quality of the lens can be improved, and its force distribution effects can be investigated. Geometric analysis and shear stress affect the performance of optical components, and these errors may also cause irreparable problems during secondary processing. Therefore, it is crucial to reduce the residual stress of optical components. When the stress distribution is uniform and the internal melting pressure is reasonably configured, the product’s shrinkage rate can be controlled; the method for determining the residual stress is the core theme of this research.

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Section: Literature Reviewmentioning

confidence: 99%

Using Recognizable Fuzzy Analysis for Non-Destructive Detection of Residual Stress in White Light Elements

Chang

Mao

et al. 2021

Applied Sciences

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“…The authors proved that the technology can be used to improve the melt flow length in injection molding, which increased from 38.6 to 170 mm, while the balance of the melt filling was also clearly improved. The influence of infrared heating on the improvement of quality of the parts with long-fiber polymers was also studied [ 25 ]. The studies showed that the infrared heating method improved the quality of flowing polymer melts’ weld-line.…”

Section: Introductionmentioning

confidence: 99%

Application of Selective Induction Heating for Improvement of Mechanical Properties of Elastic Hinges

et al. 2021

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Injection molding is a polymer processing technology used for manufacturing parts with elastic hinges. Elastic hinges are widely used in FMCG (Fast Moving Consumer Goods) packaging (e.g., bottle closures of shampoos, sauces) and in the electrical engineering industry. Elastic hinge is a thin film that connect two regions of the injection molded part, where significant shear rates are present, which can lead to the degradation of polymers and the decrease in mechanical properties. Selective induction heating is the method that improves the flow of the polymer melt through thin regions by the local increase in mold temperature. In this study, selective induction heating was used to improve mechanical properties of elastic hinges by the reduction of material degradation due to high shear rates. To verify the change of shear rates, selective induction heating simulation and injection molding simulations were performed. The linear relation between mold temperature and maximum shear rate in the cross-section was identified and the mechanical tests showed significant differences in hinge stiffness, tensile strength and elongation at break.

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“…Therefore, to address this issue, instead of heating the entire volume of the mold plate, recent research has suggested new heating methods in which only the cavity surface is heated. To achieve this, many methods for mold heating have been suggested, such as hot gas heating [ 30 , 31 , 32 , 33 ], induction heating [ 34 , 35 ], and infrared heating [ 36 , 37 , 38 ]. These methods could support high mold temperatures for improving the melt flow length by reducing the amount of frozen layer formed during melt flow.…”

Section: Introductionmentioning

confidence: 99%

“…However, despite achieving the target of reducing both the heating time and thermal energy wastage, the heating time was not adequately minimized. In general, when raising the cavity surface temperature to that of the glass temperature of the plastic material, the required heating time is around 10 s or longer [ 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ]. This means that the molding cycle time is longer than the traditional cycle of around 10 s, i.e., it significantly exceeds 10 s.…”

Section: Introductionmentioning

confidence: 99%

Improving the Melt Flow Length of Acrylonitrile Butadiene Styrene in Thin-Wall Injection Molding by External Induction Heating with the Assistance of a Rotation Device

Minh

2021

Polymers

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In injection molding, the temperature control of the dynamic mold is an excellent method for improving the melt flow length, especially of thin-wall products. In this study, the heating efficiency of a novel heating strategy based on induction heating was estimated. With the use of this heating strategy, a molding cycle time similar to the traditional injection molding process could be maintained. In addition, this strategy makes it easier to carry out the heating step due to the separation of the heating position and the mold structure as well as allowing the ease of magnetic control. The results show that, with an initial mold temperature of 30 °C and a gap (G) between the heating surface and the inductor coil of 5 mm, the magnetic heating process can heat the plate to 290 °C within 5 s. However, with a gap of 15 mm, it took up to 8 s to reach 270 °C. According to the measurement results, when the mold heating time during the molding process increased from 0 to 5 s, the flow length increased significantly from 71.5 to 168.1 mm, and the filling percentage of the thin-wall product also increased from 10.2% to 100%. In general, the application of external induction heating (Ex-IH) during the molding cycle resulted in improved melt flow length with minimal increase in the total cycle time, which remained similar to that of the traditional case.

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Mold-Face Heating Mechanism, Overflow-Well Design, and Their Effect on Surface Weldline and Tensile Strength of Long-Glass-Fiber-Reinforced Polypropylene Injection Molding

Cited by 7 publications

References 33 publications

Using Recognizable Fuzzy Analysis for Non-Destructive Detection of Residual Stress in White Light Elements

Using Recognizable Fuzzy Analysis for Non-Destructive Detection of Residual Stress in White Light Elements

Application of Selective Induction Heating for Improvement of Mechanical Properties of Elastic Hinges

Improving the Melt Flow Length of Acrylonitrile Butadiene Styrene in Thin-Wall Injection Molding by External Induction Heating with the Assistance of a Rotation Device

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