Conformal Mold Heating and Cooling Using a Carbon Nanotube Film Heater and Additively Manufactured Cellular Metamaterial

You, Jeong-Hee; Lee, Jun–Won; Oh, Seo-Hyeon; Park, Keun

doi:10.1007/s40684-021-00407-7

Cited by 23 publications

(7 citation statements)

References 38 publications

(38 reference statements)

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“…To satisfy the dimensional allowance of the wall thickness, the TPMS conformal cooling requires 10 s cooling time, while the conventional cooling requires 25 s cooling time. The appropriate cooling time that satisfies the four dimensional requirements is 15 s when the conformal cooling is used, which corresponds to a 40% reduction compared to that of the conventional cooling, 25 s. Therefore, the cooling performance of the developed mold could be improved, not only to maintain uniform mold temperature, but also to reduce part deformation, by circulating coolant through the entire microcellular region of TPMS [ 39 ].…”

Section: Resultsmentioning

confidence: 99%

Adaptive Conformal Cooling of Injection Molds Using Additively Manufactured TPMS Structures

Park

2022

Polymers

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In injection molding, cooling channels are usually manufactured with a straight shape, and thus have low cooling efficiency for a curved mold. Recently, additive manufacturing (AM) was used to fabricate conformal cooling channels that could maintain a consistent distance from the curved surface of the mold. Because this conformal cooling channel was designed to obtain a uniform temperature on the mold surface, it could not efficiently cool locally heated regions (hot spots). This study developed an adaptive conformal cooling method that supports localized-yet-uniform cooling for the heated region by employing micro-cellular cooling structures instead of the typical cooling channels. An injection molding simulation was conducted to predict the locally heated region, and a mold core was designed to include a triply periodic minimal surface (TPMS) structure near the heated region. Two biomimetic TPMS structures, Schwarz-diamond and gyroid structures, were designed and fabricated using a digital light processing (DLP)-type polymer AM process. Various design parameters of the TPMS structures, the TPMS shapes and base coordinates, were investigated in terms of the conformal cooling performance. The mold core with the best TPMS design was fabricated using a powder-bed fusion (PBF)-type metal AM process, and injection molding experiments were conducted using the additively manufactured mold core. The developed mold with TPMS cooling achieved a 15 s cooling time to satisfy the dimensional tolerance, which corresponds to a 40% reduction in comparison with that of the conventional cooling (25 s).

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Section: Resultsmentioning

confidence: 99%

Adaptive Conformal Cooling of Injection Molds Using Additively Manufactured TPMS Structures

Park

2022

Polymers

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“…To avoid these problems, other authors use layouts whose axes follow a zigzag [ 35 , 36 ] design. For highly complex geometries, it is possible to use cross-linked channel designs [ 37 ], porous [ 38 ], lattice [ 39 , 40 ], or vascularized [ 41 ] topologies. However, all these geometries [ 35 , 36 , 37 , 38 , 39 , 40 , 41 ] have the problem of requiring a connection between channels, so in the event of an obstruction caused by foreign elements, it could not be easily removed from the layout.…”

Section: Introductionmentioning

confidence: 99%

“…For highly complex geometries, it is possible to use cross-linked channel designs [ 37 ], porous [ 38 ], lattice [ 39 , 40 ], or vascularized [ 41 ] topologies. However, all these geometries [ 35 , 36 , 37 , 38 , 39 , 40 , 41 ] have the problem of requiring a connection between channels, so in the event of an obstruction caused by foreign elements, it could not be easily removed from the layout. Another way to cool complex cores is the use of inserts made of high thermal conductive materials, such as high conductive steel alloys.…”

Section: Introductionmentioning

confidence: 99%

Application of New Conformal Cooling Layouts to the Green Injection Molding of Complex Slender Polymeric Parts with High Dimensional Specifications

et al. 2023

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Eliminating warpage in injection molded polymeric parts is one of the most important problems in the injection molding industry today. This situation is critical in geometries that are particularly susceptible to warping due to their geometric features, and this occurs with topologies of great length and slenderness with high changes in thickness. These features are, in these special geometries, impossible to manufacture with traditional technologies to meet the dimensional and sustainable requirements of the industry. This paper presents an innovative green conformal cooling system that is specifically designed for parts with slender geometric shapes that are highly susceptible to warping. Additionally, the work presented by the authors investigates the importance of using highly conductive inserts made of steel alloys in combination with the use of additively manufactured conformal channels for reducing influential parameters, such as warpage, cooling time, and residual stresses in the complex manufacturing of long and slender parts. The results of this real industrial case study indicated that the use of conformal cooling layouts decreased the cycle time by 175.1 s—66% below the current cooling time; the temperature gradient by 78.5%—specifically, 18.16 ºC; the residual stress by 39.78 MPa—or 81.88 %; and the warpage by 6.9 mm—or 90.5%. In this way, it was possible to achieve a final warping in the complex geometry studied of 0.72 mm, which was under the maximum value required at the industrial level of 1 mm. The resulting values obtained by the researchers present a turning point from which the manufacturing and sustainability in the injection molding of said plastic geometries is possible, and they take into account that the geometric manufacturing features analyzed will present a great demand in the coming years in the auto parts manufacturing industry.

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“…Zhang and co-authors [16] developed a kind of curing technology of direct pressure shaping with inner mould and a controlled telescopic metal mould with high heat conductivity and electromagnetic induction heating. In other fields of the polymer industry, even more advanced techniques for conformal heating of moulds are being experimented [17], and they might very well be transferred to the tire curing sector. However, before any improvement can be done, it is essential to develop a deep knowledge, i.e., to model, how the energy flows inside the vulcanization process and to be able to estimate the efficiency of all steps and tools of the process.…”

Section: Introductionmentioning

confidence: 99%

Energy Efficiency of the Vulcanization Process of a Bicycle Tyre

Pentakota¹,

Albertelli

Strano

2023

Int. J. of Precis. Eng. and Manuf.-Green Tech.

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The production of tyres is one of the most energy consuming manufacturing activities in the rubber sector. In the production cycle of a tyre, the curing operation has the maximum energy loss. This is mostly due to the extensive use of steam as a source of heat and pressure in the vulcanization process. To the author’s knowledge, no scientific work is available in the literature where the energy efficiency of a tyre vulcanization press is estimated by means of a comprehensive model of all main components, including the moulds, the press with its heated plates, the bladder and, of course, the tyre. The present work aims at filling this gap. First, the press used for developing the model is described, along with its components and its typical product, a bicycle tyre. The instruments used for measuring flow rates, temperatures and pressures are also listed. Then, a numerical model is presented, that predicts the energy transfers occurring in the vulcanization press during a full process cycle. The numerical model, developed with the software Simcenter Amesim 2021.1, has been validated by means of measurements taken at the press. The results indicate that the amount of energy which is actually consumed by the tyre for its reticulation process amounts to less than 1% of the total energy expenditure. The paper demonstrates that the tyre industry is in urgent need of an electrification conversion of the traditional steam-based processes.

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Conformal Mold Heating and Cooling Using a Carbon Nanotube Film Heater and Additively Manufactured Cellular Metamaterial

Cited by 23 publications

References 38 publications

Adaptive Conformal Cooling of Injection Molds Using Additively Manufactured TPMS Structures

Adaptive Conformal Cooling of Injection Molds Using Additively Manufactured TPMS Structures

Application of New Conformal Cooling Layouts to the Green Injection Molding of Complex Slender Polymeric Parts with High Dimensional Specifications

Energy Efficiency of the Vulcanization Process of a Bicycle Tyre

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