Experimental characterisation and modelling of rheokinetic properties of different silicone elastomers

Ou, Huibin; Sahli, Mohamed; Barrière, Thierry; Gelin, Jean‐Claude

doi:10.1007/s00170-017-0481-0

Cited by 13 publications

(8 citation statements)

References 21 publications

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“…The curing process is based on chemical reaction kinetics. The vulcanization time of an LSR has a significant impact on molding product of a convex lens because the vulcanization is a crucial step in LSR injection molding [ 21 , 22 , 23 ]. Generally, both CHCs and CCCs are a complex heat transfer problem with transient conditions.…”

Section: Resultsmentioning

confidence: 99%

Development of an Epoxy-Based Rapid Tool with Low Vulcanization Energy Consumption Channels for Liquid Silicone Rubber Injection Molding

Kuo

Tasi

Hunag³

2022

Polymers

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Liquid silicone rubber (LSR) parts have some distinct characteristics such as superior heat stability, low-temperature flexibility, aging resistance, and chemical resistance. From an industrial standpoint, the uniform vulcanization temperature of LSR is an important research point. However, the uniformity of the vulcanization temperature of LSR has been limited since the layout of the cartridge heater incorporated in the conventional steel mold does not follow the profile of the mold cavity. Metal additive manufacturing can be used to make LSR injection molds with conformal heating channels and conformal cooling channels simultaneously. However, this method is not suitable for a mold required to develop a new LSR product. In this study, a cost-effective approach was proposed to manufacture an LSR injection mold for the pilot run of a new optical lens. A rapid tool with low vulcanization energy consumption channels was proposed, which was incorporated with both a conformal heating channel (CHC) and conformal cooling channel (CCC) simultaneously. The function of the CHC was to vulcanize the LSR in the cavity uniformly, resulting in a shorter cycle time. The function of the CCC was to keep the LSR in a liquid state for reducing runner waste. It was found that the equation of y = −0.006x3 + 1.2114x2 − 83.221x + 1998.2 with the correlation coefficient of 0.9883 seemed to be an optimum trend equation for predicting the solidification time of a convex lens (y) using the vulcanizing hot water temperature (x). Additionally, the equation of y = −0.002x3 + 0.1329x2 − 1.0857x + 25.4 with the correlation coefficient of 0.9997 seemed to be an optimum prediction equation for the solidification time of a convex lens (y) using the LSR weight (x) since it had the highest correlation coefficient. The solidification time of a convex lens could be reduced by about 28% when a vulcanizing hot water temperature of 70 °C was used in the LSR injection mold with CHC.

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Section: Resultsmentioning

confidence: 99%

Development of an Epoxy-Based Rapid Tool with Low Vulcanization Energy Consumption Channels for Liquid Silicone Rubber Injection Molding

Kuo

Tasi

Hunag³

2022

Polymers

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“…Alternatively, a rheometer may be used by assuming the degree of cure is proportional to the change in viscosity. [ 108 ] These data may then be fit to the various models. [ 39,80,97,78,104,100,109,64 ]…”

Section: Modeling and Simulationmentioning

confidence: 99%

A review of liquid silicone rubber injection molding: Process variables and process modeling

Bont

Barry

Johnston

2021

Polymer Engineering & Sci

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Liquid silicone rubber (LSR) is an elastomer molded into critical performance components for applications in medical, power, consumer, automotive, and aerospace applications. This article reviews process behavior, material modeling, and simulation of the (LSR) injection molding process. Each phase of the LSR injection molding process is discussed, including resin handling, plastication, injection, pack and hold, and curing; and factors affecting the molding process are reviewed. Processing behavior of LSR is marked by transient interactions between curing, shear rate, temperature, pressure, and tooling. Therefore, current LSR models for curing, viscosity, pressure, and temperature are discussed. Process dynamics and material modeling are combined in LSR injection molding simulations with applications in mold design, troubleshooting process‐induced defects, and management of shear stress and non‐uniform temperatures between LSR and substrates during overmolding. Finally, case studies using commercial simulation software are presented, which have shown cavity pressure and flow front advancement within 3% of experimental values. Optimization of LSR materials, data collection, model fitting, venting, and bonding remain areas of continued interest.

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“…It was found that the simulation results fit the shear viscosity behaviors of silicone LSR4350 well and the proposed Isayev-Deng model fits the curing kinetic reaction of elastomer materials well. Ou et al [ 18 ] developed mathematical models for the thermo-kinetic parameters of silicone elastomers.…”

Section: Introductionmentioning

confidence: 99%

Improving Cooling Performance of Injection Molding Tool with Conformal Cooling Channel by Adding Hybrid Fillers

Kuo

2021

Polymers

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Silicone rubber mold (SRM) is capable of reducing the cost and time in a new product development phase and has many applications for the pilot runs. Unfortunately, the SRM after injection molding has a poor cooling efficiency due to its low thermal conductivity. To improve the cooling efficiency, the thermal conductivity of the SRM was improved by adding fillers into the SRM. An optimal recipe for fabricating a high cooling efficiency low-pressure injection mold with conformal cooling channel fabricated by fused deposition modeling technology was proposed and implemented. This study proposes a recipe combining 52.6 wt.% aluminum powder, 5.3 wt.% graphite powder, and 42.1 wt.% liquid silicon rubber can be used to make SRM with excellent cooling efficiency. The price–performance ratio of this SRM made by the proposed recipe is around 55. The thermal conductivity of the SRM made by the proposed recipe can be increased by up to 77.6% compared with convention SRM. In addition, the actual cooling time of the injection molded product can be shortened up to 69.1% compared with the conventional SRM. The actual cooling time obtained by the experiment is in good agreement with the simulation results with the relative error rate about 20%.

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Experimental characterisation and modelling of rheokinetic properties of different silicone elastomers

Cited by 13 publications

References 21 publications

Development of an Epoxy-Based Rapid Tool with Low Vulcanization Energy Consumption Channels for Liquid Silicone Rubber Injection Molding

Development of an Epoxy-Based Rapid Tool with Low Vulcanization Energy Consumption Channels for Liquid Silicone Rubber Injection Molding

A review of liquid silicone rubber injection molding: Process variables and process modeling

Improving Cooling Performance of Injection Molding Tool with Conformal Cooling Channel by Adding Hybrid Fillers

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