Correlation between thermal contact resistance and filling behavior of a polymer melt into multiscale cavities in injection molding

Hong, Seok-Kwan; Kang, Jeong-Jin; Yoon, Kyung Hoon

doi:10.1016/j.ijheatmasstransfer.2015.03.061

Cited by 19 publications

(10 citation statements)

References 32 publications

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“…It is because that premature solidification of polymer melt near the mold walls in real micro‐cavities was not properly simulated. Prediction of the mold wall temperature and analysis on the local heat loss of polymer melt near the mold wall, based on the design of cooling line and mold cavity, need to be included . The uniformity of the simulation results was better than the experimental results.…”

Section: Resultsmentioning

confidence: 99%

“…The domain decomposition method can be used to numerically analyze micro‐injection molding. Using this method, one separately simulates a macroscale base plate (BP) and microstructures using a 2.5D mesh . Lee et al carried out a 2.5D analysis with coarse meshes to simulate a BP, followed by a 3D simulation with finer meshes to simulate microribs.…”

Section: Introductionmentioning

confidence: 99%

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Numerical and experimental investigation of plastic injection molding of micro‐engineered surfaces

Lee

Park

2017

Polymer Engineering & Sci

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We carried out experimental and numerical investigations into the effects of injection‐molding parameters on the transcription quality and uniformity of micro‐pillar arrays. For the experiment, we used a precise metallic mold insert, which was shaped like an inverted micro‐pillar array. This was fabricated using UV‐photolithography and a nickel electroforming process. With the mold insert, the effects of the distance from gate and uniformity on the transcription quality could be investigated experimentally by varying the main processing parameters, such as flow rate, polymer melt temperature, and mold wall temperature. The results of the injection molding experiment indicated that increasing the three processing parameters improved the transcription quality of micro‐pillar arrays. In numerical investigation, we used the interpolated domain decomposition method. This was based on 2.5D and 3D simulations, and was used to effectively solve the filling behavior of the polymer melt inside the mold which contains multi‐scale cavities. Numerical results revealed that the transcription quality was significantly affected by the mold wall temperature. Based on the experimental and numerical investigations, the local mold heating (LMH) technique for the high mold wall temperature was employed to enhance the replicability of the micro‐pillar array. The result of injection molding with LMH showed that the transcription quality and uniformity were considerably improved. These numerical and experimental results provide insights into the foundations of the field of injection molding of plastic micro‐engineered surfaces. POLYM. ENG. SCI., 58:E73–E81, 2018. © 2017 Society of Plastics Engineers

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical and experimental investigation of plastic injection molding of micro‐engineered surfaces

Lee

Park

2017

Polymer Engineering & Sci

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“…Second, the interface TCR is mainly obtained through experiments and theoretical derivation. Hong et al [ 4 ] calculated the TCR through recursive methods based on indirectly measuring the filling height of patterns as a function of time, and estimated the changes in the TCR with time and position. Dawson et al [ 5 ] experimentally determined that the maximum heat transfer coefficient between the melt of PMMA material and the surface of the cavity is 7000 W/m 2 K and introduced the concept of an air layer; that is, after the melt is filled, cooled and allowed to contract, there is an air layer between the wall and the plastic part in the cavity.…”

Section: Introductionmentioning

confidence: 99%

Wall Slip Behaviour of Polymers Based on Molecular Dynamics at the Micro/Nanoscale and Its Effect on Interface Thermal Resistance

Lou

Feng

2020

Polymers

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Taking the Poiseuille flow of a molten polymer in parallel plates as the research object and polymethyl methacrylate (PMMA) as the research material, an all-atom analysis model of the molecular dynamic flow of polymer macromolecules is established according to the Navier slip law. The effects of wall wettability and external pressure on the wall slip behaviour of polymer macromolecules, as well as the spatial evolution process of the entanglement–unentanglement process of polymer chains near the wall under different shearing effects, were studied. The interface thermal resistance rule was explored, and an interface thermal resistance model considering the wall slip behaviour was established. Finally, a micro-injection experiment was used to verify the validity and accuracy of the model. The results show that when the wall is hydrophobic, the polymer melt exhibits significant wall slip. As the external pressure increases, the wall slip speed and the slip length increase. However, after a certain pressure is exceeded, the growth rate of the slip length is basically zero. As the external pressure increases, the PMMA molecular chains gradually start to separate, the single molecular chain becomes untangled from the entangled grid, and the chain detaches from the wall after exceeding a certain threshold. Wall slip reduces the interface thermal resistance between the solid–liquid interface and enhances the interface heat transfer performance. The interface thermal resistance value calculated by molecular dynamics can more accurately reflect the heat conduction rule of the solid–liquid interface at the micro/nanoscale than that measured by the thermal resistance experiment, indicating that the micro/nano interface thermal resistance obtained by molecular dynamics simulation is reliable.

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“…Hong et al [4] studied mold filling behavior as function of time and then thermal contact resistance as function of position and time using short shot injection molding. Control of mold roughness and thermal resistance could contribute to superior filling.…”

Section: Introductionmentioning

confidence: 99%

“…The present study is an attempt to investigate mold-filling behavior as a function of injection parameters. Some authors [4,5] studied filling behavior of polymer feedstock in modified metal molds, however the converse, meaning that filling behavior of metal based feedstock in polymer molds still remains a grey area. The present study focuses on filling behaviour of copper-based feedstock in FDM made polymer mold as function of injection pressure and temperature.…”

Section: Introductionmentioning

confidence: 99%

Metal Injection Molding Process Parameters as A Function of Filling Performance of 3D Printed Polymer Mold

et al. 2018

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Metal injection molding (MIM) is a swift manufacturing process, which can produce complex and intricate parts with good repeatability and accuracy. However, to quickly address low-volume demands of customized MIM parts, manufacturing of mold could be a potential challenge. Typically, machined metal molds are used for MIM, but they are expensive and need more lead time. The machined metal mold becomes useless once the design is changed or requirement of MIM parts is met. Therefore, for MIM production of a low volume of highly customized parts, machined metal mold could be substituted by 3D printed polymer molds. However, knowledge of filling behavior of MIM feedstock in polymer mold is a grey area, which demands study to investigate the effects of injection parameters on mold filling. The present study investigates the effects of machine injection parameters on feedstock filling behavior in 3D printed polymer molds. An attempt has been made to determine the trend of feedstock filling in the polymer mold as a function of injection parameters. Further, the design of experiment (DOE) has been used to estimate the weight of injection parameters.

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Correlation between thermal contact resistance and filling behavior of a polymer melt into multiscale cavities in injection molding

Cited by 19 publications

References 32 publications

Numerical and experimental investigation of plastic injection molding of micro‐engineered surfaces

Numerical and experimental investigation of plastic injection molding of micro‐engineered surfaces

Wall Slip Behaviour of Polymers Based on Molecular Dynamics at the Micro/Nanoscale and Its Effect on Interface Thermal Resistance

Metal Injection Molding Process Parameters as A Function of Filling Performance of 3D Printed Polymer Mold

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