Metal Additive Manufacturing of Plastic Injection Molds with Conformal Cooling Channels

Area of Science:

• Manufacturing Engineering
• Materials Science
• Thermal Engineering

Background:

• Conformal cooling channels (CCCs) enhance plastic injection molding by improving product quality and operational performance.
• Metal additive manufacturing (MAM) facilitates the fabrication of complex tooling with CCCs.
• Traditional cooling channels limit cooling efficiency and uniformity in injection molds.

Purpose of the Study:

• To investigate the metal additive manufacturing (MAM) of a plastic injection mold insert with various CCC designs.
• To evaluate the cooling performance and thermal uniformity of CCCs compared to traditional channels.
• To optimize mold geometry using multiobjective optimization for improved cooling efficiency and reduced pressure drop.

Main Methods:

• Design and computational thermal & mechanical simulations of mold inserts with circular, serpentine, and tapered CCCs, with and without body-centered cubic (BCC) lattices.
• Multiobjective optimization to determine the optimal mold geometry based on cooling time, temperature non-uniformity, and pressure drop.
• Manufacturing of mold inserts using Direct Metal Laser Sintering (DMLS) and quality analysis via X-ray Computed Tomography (X-ray CT).

Main Results:

• CCCs demonstrated up to 62.9% superior cooling performance and enhanced thermal uniformity on the mold surface compared to traditional channels.
• The multiobjective optimization procedure identified an optimal mold geometry balancing cooling efficiency and operational parameters.
• X-ray CT analysis confirmed high accuracy in DMLS manufacturing, with deviations less than 5% for channel parameters and 0.06 mm for BCC strut diameters.

Conclusions:

• MAM is a viable technology for fabricating advanced injection molds with CCCs, significantly improving cooling performance.
• Optimized CCC designs lead to enhanced product quality and operational efficiency in plastic injection molding.
• The study validates the effectiveness of CCCs and MAM in addressing limitations of conventional cooling systems.