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[Case Study] Cooling Channel Design with 3D Printed Pure Copper for High-Power Modules

Cooling design is becoming a packaging problem

In many power modules, the thermal issue is no longer separate from the mechanical package. Higher power density means the cooling path has to fit close to the heat source, work within limited space, and keep pressure drop within a practical range.

That is difficult when the cold plate is limited to straight channels, simple serpentine paths, or features that must be machined, cast, brazed, or welded. These methods are mature and useful, but they often make the cooling layout follow the process rather than the heat map.

3D printed pure copper changes the starting point. Instead of asking which channel can be machined, the design team can first ask where heat must be removed, how coolant should move, and which internal structure can be inspected, cleaned, and manufactured reliably.

Why pure copper is useful, and why it is hard to print

Pure copper is a natural candidate for cooling parts because it combines high thermal conductivity with high electrical conductivity. The difficulty is processing. Copper reflects much of the energy from conventional infrared laser systems and conducts heat away quickly, which can make stable melting difficult.

Green-laser powder bed fusion helps address this processing window. In the source data behind this article, a 532 nm green laser shows about 40% absorptivity on copper, roughly 8 times higher than near-infrared laser absorption under comparable reference conditions.

This does not make every copper geometry easy to manufacture. Process parameters, part orientation, powder removal, cleaning, sealing surfaces, and post-processing still need engineering review. The point is more practical: better laser absorption gives pure copper additive manufacturing a stronger basis for producing dense parts with internal cooling features.

The design shift: from manufacturable channels to targeted cooling

A conventional cold plate design often starts with the manufacturing route. Once the route is chosen, the channel shape, minimum feature size, draft angle, joining method, and inspection method start to define the thermal solution.

A printed copper cold plate can be approached differently. The thermal target can come first, followed by CFD-driven channel design and then manufacturability review. This does not remove constraints; it changes where the constraints are handled.

· Hot zones can receive denser or more direct coolant paths.

· Flow distribution can be separated from local cooling in a multi-layer layout.

· Feature shape can be tuned for heat transfer and pressure drop instead of tool access alone.

· Internal structures such as TPMS or lattice-like surfaces can be built as part of the component.

· The number of joints and secondary assemblies can often be reduced.

Four cooling structures worth evaluating

1. Staggered internal channels

Staggered channels increase heat transfer area and disturb the flow field. They are useful when the design goal is not only to move coolant through the part, but to keep coolant interacting with heated surfaces along the path.

In one reference comparison under an 8,000 W heat source, a staggered-channel design reduced peak temperature by 9 deg C while reducing flow resistance by 20%. A second optimized version reduced peak temperature by 11 deg C. These values are design-specific, but they show why three-dimensional channel placement can matter.

2. Teardrop-profile heat transfer features

A fin or rib is not only extra area. Its shape affects separation, turbulence, pressure loss, and how evenly fluid reaches the heated surface. Teardrop-style features can guide flow more smoothly than simple cylindrical ribs while still creating useful mixing.

In a 5,000 W reference case, one teardrop-based design reduced peak temperature by 10 deg C compared with the baseline. Another design reduced peak temperature by 7 deg C and reduced flow resistance by 2 kPa. The second result is useful because it shows that a lower thermal result is not the only possible design target; pressure drop can also be part of the optimization.

3. Multi-layer flow paths

A multi-layer cold plate can separate distribution and local cooling functions. One layer can spread coolant across the part, while another layer can place high-intensity cooling closer to the heat source. This can help reduce local temperature differences across a module.

This type of design is difficult to manufacture with conventional joining methods because each layer has to be sealed and aligned. Additive manufacturing can integrate the structure into one printed component, but the design still needs checks for powder removal, leak testing, and access to critical surfaces.

4. TPMS and high-surface-area structures

TPMS structures are continuous internal surfaces with interconnected flow paths. In liquid cooling, they can increase surface area and repeatedly redirect coolant. This helps refresh near-wall fluid and can disturb the thermal boundary layer.

The trade-off is that TPMS designs must be evaluated carefully for pressure drop, cleanability, powder removal, and inspection. They are not a default answer for every cold plate, but they can be valuable when a compact component needs more active heat transfer within the same volume.

How to decide whether a printed copper cold plate is worth reviewing

A printed copper cooling structure is most relevant when the heat source is localized, packaging space is limited, or conventional channels cannot reach the required thermal target without high pressure drop or additional assembly complexity.

It may be less suitable when the part is simple, the channel geometry is easy to machine, or cost is more important than thermal density. Material choice should also be reviewed. Pure copper is useful when thermal conductivity is the main driver. CuCrZr may be considered when higher strength or better high-temperature stability is needed. Aluminum may be suitable when weight and cost are more important than maximum conductivity.

Information needed before a design review

For a useful review, the engineering team should look beyond the CAD file. The thermal and operating context is just as important.

· STEP or STP model, plus a 2D drawing if tolerances are important

· Heat source power, heat flux distribution, and target temperature

· Coolant type, inlet temperature, flow rate, and pressure limit

· Packaging limits, mounting surfaces, and sealing requirements

· Quantity, lead time, and inspection requirements

· Expected post-processing, including machining, cleaning, polishing, or leak testing

Practical takeaway

The strongest reason to use 3D printed pure copper in thermal management is not complexity by itself. It is the ability to place cooling features where they are needed and to shape the flow field around the heat source.

The source cases show peak temperature reductions of 7 to 11 deg C in specific optimized designs, with one case reducing flow resistance by 20% and another reducing pressure drop by 2 kPa. Those numbers are not automatic outcomes, but they are useful evidence that channel architecture, feature profile, and material choice can work together.

For high-power modules, the design question is therefore simple: if the thermal limit is being set by the manufacturing process rather than the heat source, 3D printed pure copper cooling channels may be worth an engineering review.

If you are evaluating pure copper 3D printing for a cooling component, the next step is usually not a quote alone.

· Review the thermal management white paper for more data, design considerations, and application examples for 3D printed cooling components. Please visit

https://www.addireennow.com/en/green-laser-copper-thermal-management/ad64d

· See how Addireen applies metal 3D printing to liquid cold plates, heat exchangers, heat sinks, and high-conductivity thermal modules. Please visit

https://www.addireennow.com/en/industries/advanced-thermal-management/c44da

· Submit your cooling component design for manufacturability review, material feasibility, post-processing planning, and quotation. Please visit https://www.addireennow.com/en/quote