Adaptive Conformal Cooling of Injection Molds Using Additively Manufactured TPMS Structures

Abstract

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).

Automated Design of Honeycomb Conformal Cooling Channels for Improving Injection Molding Quality

“…Other adjustment methods based on cavity offsets involve modularized design, in which the space between the center of a cooling element and the mold cavity is occupied by solid steel, and cooling channels compose the remaining space. Such methods yield conformal cooling cavities and may enable skipping the layout design stage, thereby simplifying the cooling channel design stages (Au and Yu, 2007;Brooks and Brigdam, 2016;Kanbut et al, 2019;Oh et al, 2022). Cooling element addition is the other key task of preliminary design.…”

MaSMaker: An open-source, portable software to create and integrate maze-like surfaces into arbitrary geometries

“…Due to its simplicity, surfacebased structures, particularly, Triply Periodic Minimal Surfaces (TPMS) [8], have been extensively studied and applied, since their geometrical properties can be controlled by varying a few parameters. In this sense, TPMS have raised interest for several applications such as structural mechanics [9][10][11], medical devices [12,13], and heat transfer [14,15], among others.…”

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

“…Designing adaptative channel geometries capable of maintaining a constant distance between the part surface and the cooling channels, even in those difficult areas where material accumulation occurs, can dramatically decrease cooling time and increase the uniformity of temperatures at the surface of the molded part [ 22 ]. In the same way, a uniform distribution of temperatures on the surface of the part helps to not only reduce the cooling time, but also helps to improve the quality of the part in terms of metrology [ 23 ]. An unbalanced temperature map can cause warpage in the plastic part and result in the rejection of manufactured parts, which goes against the industrial sustainability criteria currently required [ 24 ].…”