Fabrication of tube-embedded cooling channel through press-fit and directed energy deposition

Thermoplastic polymeric products are widely used in everyday life; the quality of their molded parts is substantially affected by the cooling characteristics of the mold. This study proposes fabricating a cooling channel through tube embedding inside the mold using directed energy deposition (DED). The heat-transfer characteristics of three fabrication methods (round, flat-sink, and flat-half) are compared in terms of deposition characteristics, channel geometry, cross-sectional area, and width. During tube embedding, the groove dimensions affect the pressure between the mold and tube. Excessive pressure causes tube buckling during DED, whereas insufficient pressure causes thermal deformation. The flat-sink method, in which the center of the tube is located below the mold surface, inhibits thermal deformation of the tube during deposition. Alternatively, sufficient fusion between the tube and deposited powder is expected to enhance bonding in the round method, but it increases the complexity of deposition-path setting. Among the three configurations, the flat-sink tube-embedded mold minimized the gap at the tube–mold interface and provided a larger coolant cross-sectional area, leading to a 15.1 % higher initial cooling rate than that in the round configuration. The groove dimensions and tube geometry jointly controlled tube deformation, dilution behavior, and cooling performance. The findings offer practical guidelines for designing tube-embedded cooling channels in additively manufactured molds.