Carbide-bonded graphene coating of mold insert for rapid thermal cycling in injection molding

Xie, Pengcheng; Yang, Huaguang; Zhao, Yungui; Wen-xia, YU; Cheng, Lisheng; Yang, Weimin; Yan, Hua; Tan, Jing

doi:10.1016/j.applthermaleng.2017.04.159

Cited by 18 publications

(12 citation statements)

References 20 publications

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“…Xie et al [ 13 ] implemented replications of microchannel and microlens arrays onto poly(methyl methacrylate) (PMMA) substrates using a CBG-coated silicon mold. Furthermore, the application of the CBG-coated silicon mold realized rapid thermal cycling in injection molding, where the average heating rate was as high as 11.6 °C/s and polypropylene (PP) plate samples with uniform sizes in thickness were produced [ 14 ].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Warpage and Residual Stress of Precision Glass Micro-Optics Heated by Carbide-Bonded Graphene Coating in Hot Embossing Process

Zhou

2021

Nanomaterials

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A newly developed hot embossing technique which uses the localized rapid heating of a thin carbide-bonded graphene (CBG) coating, greatly reduces the energy consumption and promotes the fabrication efficiency. However, because of the non-isothermal heat transfer process, significant geometric deviation and residual stress could be introduced. In this paper, we successfully facilitate the CBG-heating-based hot embossing into the fabrication of microlens array on inorganic glass N-BK7 substrate, where the forming temperature is as high as 800 °C. The embossed microlens array has high replication fidelity, but an obvious geometric warpage along the glass substrate also arises. Thermo-mechanical coupled finite element modelling of the embossing process is conducted and verified by the experimental results. Based on trial and error simulations, an appropriate compensation curvature is determined and adopted to modify the geometrical design of the silicon wafer mold. The warpage of the re-embossed microlens array is significantly decreased using the compensated mold, which demonstrates the feasibility of the simulation-oriented compensation scheme. Our work would contribute to improving the quality of optics embossed by this innovative CBG-heating-based hot embossing technique.

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Section: Introductionmentioning

confidence: 99%

Evaluation of Warpage and Residual Stress of Precision Glass Micro-Optics Heated by Carbide-Bonded Graphene Coating in Hot Embossing Process

Zhou

2021

Nanomaterials

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“…The increase of the surface temperature above the transition temperature of the polymer melt allows the manufacturing of long thin-walled parts. For this purpose, Rapid Temperature Cycling (RTC) technology was developed, where the surface of the mold is periodically heated [ 8 , 9 , 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

“…The higher surface temperature can significantly increase the time of part cooling, especially when technologies such as steam heating or cartridge heating are used [ 10 , 11 , 12 , 13 ]. This is due to the fact that not only the surface but the whole mold is heated to increase the surface temperature.…”

Section: Introductionmentioning

confidence: 99%

“…Magnetic concentrators increase the effectiveness of the heating process by concentrating magnetic flux lines on the most important heating areas (magnetic field control), thereby significantly reducing the duration of the heating. Besides, more heating power is transferred to the selected area of the heated element from the coil with the concentrator reducing energy consumption [ 10 ]. Concentrators are made of magnetic powders and dielectric binders pressed under high pressure and heat treated.…”

Section: Introductionmentioning

confidence: 99%

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Application of Magnetic Concentrator for Improvement in Rapid Temperature Cycling Technology

2020

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The main method to improve the filling of the cavity by the polymer melt is to increase the mold temperature. Rapid temperature cycling (RTC) technologies have been used around the world for several years, improving the quality of injection molded parts with a slight extension of production time. The present work focuses on the application of induction heating technology in the injection molding process since it is the most effective and most intensively developing method of heating in modern RTC technologies. In this research, the application of the induction heating process for selected surfaces was investigated with particular emphasis on the dynamics of the process. The numerical simulations were used to study the influence of the number of coils, the distance between coils and cavity surface and the mold material was examined with and without the presence of a magnetic concentrator. According to the obtained results, several crucial conclusions were made: the efficiency of heating is directly correlated with the distance between the inductor and the mold surface, the presence of magnetic flux concentrator significantly improves the homogeneity of temperature distribution and heating efficiency, application of aluminum mold lowers the obtained surface temperature.

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“…In this way, the ejection can take place sooner thanks to more efficient cooling in the cooling stage, despite a warmer mold surface temperature during mold filling and packing stages. If special molding heating and cooling techniques, such as rapid mold temperature control, rapid heat cycle molding (RHCM), or highly engineered cooling channels, can be employed , the overall cycle time can be improved even more.…”

Section: Introductionmentioning

confidence: 99%

Injection molding of delamination‐free ultra‐high‐molecular‐weight polyethylene

Yilmaz

Yang

Turng

2019

Polymer Engineering & Sci

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When ultra‐high‐molecular‐weight polyethylene (UHMWPE) in powder form is injection molded, the so‐called delamination layering occurs near the skin of the parts. This layering defect hampers UHMWPE's superior wear resistance property and part surface quality. The delamination layer was caused by a combination of excessive shear stress near the part surface and high degree of molecular entanglement of UHMWPE. A mold insulation method that delays the rapid cooling of UHMWPE to reduce the shear stress and improve the polymer chain “interdiffusion” across the entangled chain bundles was used to eliminate the delamination layer. When the insulation layer thickness and mold temperature were optimized, the delamination layer was eliminated completely while still maintaining a reasonable cooling/cycle time. The delamination‐free parts were found to regain UHMWPE's superior impact resistance and tensile properties. POLYM. ENG. SCI., 59:2313–2322, 2019. © 2019 Society of Plastics Engineers

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Carbide-bonded graphene coating of mold insert for rapid thermal cycling in injection molding

Cited by 18 publications

References 20 publications

Evaluation of Warpage and Residual Stress of Precision Glass Micro-Optics Heated by Carbide-Bonded Graphene Coating in Hot Embossing Process

Evaluation of Warpage and Residual Stress of Precision Glass Micro-Optics Heated by Carbide-Bonded Graphene Coating in Hot Embossing Process

Application of Magnetic Concentrator for Improvement in Rapid Temperature Cycling Technology

Injection molding of delamination‐free ultra‐high‐molecular‐weight polyethylene

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