Dental 3D Printing for Automotive Conformal Cooling Channels Injection Molds

Industrial Current State: Conformal Cooling in Automotive Molds

In traditional injection molding, cooling accounts for up to 70% to 80% of the entire molding cycle time. Standard cooling channels are manufactured using straight-line gun drilling, which severely limits the channels' proximity to the mold cavity. As a result, complex, curved automotive parts—such as headlights, dashboard trims, and structural brackets—suffer from uneven cooling. This thermal imbalance leads to warping, sink marks, internal stresses, and prolonged cycle times.

By integrating dental 3D printing precision with advanced mold engineering, manufacturers can design conformal cooling channels that follow the exact contours of the part. This ensures uniform heat dissipation across the entire molding surface. The industrial current state shows that switching to 3D-printed conformal cooling mold inserts can reduce cycle times by 20% to 50%, while dramatically improving the dimensional stability of the molded plastic parts.

Furthermore, the automotive sector is shifting toward lightweighting and electrification. This transition demands high-strength plastics and composites that require higher molding temperatures. Standard tool steels often fail under thermal fatigue or suffer from corrosion due to specialized plastic additives. Implementing dental-grade alloys, particularly spherical Cobalt-Chromium (CoCr) powders, has emerged as a premium solution for high-wear mold inserts.

Deep Application Analysis: Materials Science at the Core

The success of printing conformal cooling channels relies entirely on the quality of the metal powder. In Selective Laser Melting (SLM), laser beams melt thin layers of metal powder to build the mold insert layer by layer. If the powder particles are irregular or contain high oxygen levels, the printed mold will have internal voids, micro-cracks, or rough internal channel surfaces. Under cyclic thermal and mechanical loading, these defects propagate, leading to catastrophic mold failure.

This is where AVIMETAL’s expertise in spherical powder preparation becomes vital. By utilizing advanced Electrode Induction Melting Gas Atomization (EIGA) and Vacuum Induction Melting Gas Atomization (VIGA) technologies, we produce highly spherical powders with low oxygen content, excellent flowability, and high tap density.

Specifically, Cobalt-Chromium (CoCr) alloy powders, traditionally used in dental prosthetics, exhibit remarkable properties when applied to automotive conformal cooling mold inserts:

• Thermal Fatigue Resistance: CoCr alloys maintain high yield strength and tensile strength even at temperatures exceeding 600°C, preventing crack initiation from rapid heating and cooling cycles.
• Polishing and Surface Finish: Due to the fine grain structure of printed CoCr, the mold cavity can be polished to a mirror finish, ensuring high-quality surface aesthetics for automotive exterior parts.
• Reduced Flow Resistance: The smooth internal surfaces of the printed channels minimize pressure drops and prevent the accumulation of scale or mineral deposits from the cooling water.

Engineering Challenges in Conformal Cooling Channel Design

While the benefits of conformal cooling are clear, designing and manufacturing these molds presents unique engineering challenges. The first challenge is powder removal. Because conformal channels are curved and internal, removing unmelted powder from the channels post-printing is difficult. If powder remains inside, it will block water flow and cause localized overheating. AVIMETAL solves this through optimized channel geometries (such as self-supporting tear-drop or elliptical shapes) and specialized post-processing cleaning techniques.

The second challenge is residual stress. The rapid heating and cooling during the SLM process build up significant residual stresses within the mold insert. If not properly managed through heat treatment, the mold will warp or crack during post-machining or during operation. AVIMETAL provides comprehensive technical services, including precise vacuum stress-relief annealing and heat treatment protocols customized for each alloy type, ensuring dimensional stability and long mold life.

Lastly, surface roughness inside the cooling channels can lead to turbulent flow and erosion over time. Utilizing advanced chemical polishing or abrasive flow machining (AFM) ensures that the internal surfaces of the channels are smooth, optimizing fluid dynamics and maximizing heat transfer efficiency.

Development History

2014

• Avimetal was founded in Zhongguancun, Beijing, launching the venture of advanced metal powder materials;

• Put the first set of EIGA furnace MT-E50 into production;

2016

• Established Hebei subsidiary;

• Put the first set of VIGA furnace MT-V100 into production;

• Participated in the revision of China's first aerospace standard for metal additive manufacturing.