Heat Exchangers

With VELO3D‘s SupportFree processes and thin wall capabilities, engineers can manufacture higher quality internal channels, flow paths, and high aspect ratio walls for new designs that optimize heat transfer.

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33% Less Back Pressure

320um Leak-Tight Walls

Pressure Tested to 6 Bar

220um Turbulators

Application Benefit

Anywhere you find oil, fuel, or electronics in a high-performance vehicle, you are going to find a heat exchanger. For example, a typical commercial jet needs four to six heat exchangers per engine and the average commercial craft can contain 20+ heat-exchanger units overall. Drone design is about balancing tradeoffs between engine size and cooling-system weight to achieve optimum power and range. Satellites are crammed full of heat-generating electronics. Heat exchangers are everywhere.

The Challenge of Brazing

Until now, brazing has been the standard for heat-exchanger manufacturing. Complex, multi-part assemblies (such as an array of cooling fins) can be brazed into a connected whole, with very little distortion, to exponentially increase the surface area available for heat dissipation and/or transfer.

However, brazing is not efficient. Most heat-exchangers used in aviation are still assembled largely by hand. This requires hours of skilled labor and multiple production steps. Part count can range from hundreds to thousands per unit. Plus, brazing and welding commonly create byproducts of highly toxic substances. These substances are increasingly being controlled, if not banned, in the same countries that aircraft-related manufacturing facilities call home. The industry as a whole is looking to reduce or eliminate such chemicals without impacting quality and performance.

The VELO3D Sapphire printer demonstrated the ability to produce class-leading thin-wall capabilities and high-quality surfaces with zero porosity.
- Matthew Bryson, General Manager, Engineering, PWR

Heat Exchanger Design Challenges

To fully optimize heat exchanger design, engineers need to maximize the surface area that exists between the hot side and the cooler fluid or gas. In addition, they need to decrease the thickness of the walls to allow faster heat transfer while keeping the walls leak tight. This means that, often for high performance designs, engineers are looking to produce complex internal channels with very thin, high aspect ratio walls.

Conventional Additive Manufacturing

Most AM printers today have limitations. Due to the layer-by-layer process, the repetitive melting and solidification of metal causes stress accumulation. For example, if you were to print a flat strip of metal in a typical printer, the stress would eventually pull the metal up into a loop or ring shape. This has led to design rules for AM engineers. Low overhangs, or flat parts require supports – printed metal beams that work like metal staples to hold the part down to a build plate. This prevents designers from using unsupported angles of less than 45-degrees to the build plate. This is known as the “45-degree rule” and impacts enclosures and inner diameters similarly.

The second limitation has to do with the hardware. When typical printers move through the z-orientation of a part, they deposit and planarize new layers of powder. This is called recoating. To create a flat plane of powder, the printer scrapes away the excess with a recoater blade. Unfortunately, due to the thin nature of the powdered layers, if the part deforms (due to accumulated stresses), it can protrude above the desired powder height and contact the recoater. This can cause damage to the part, the recoater blade, or even fault the build completely. This results in limitations around aspect ratios for metal parts. The limit for most printers today is around an 8:1 aspect ratio.

VELO3D SupportFree Processing

SupportFree metal powder-bed fusion from VELO3D provides the ability to print horizontal (down to zero degrees between the part and the build plate) surfaces without supports and with a high quality surface finish, eliminating the need to post process internal support structures. This achieves much higher quality internal channels and flow paths for gas or fluids.

Thin Walls? No Problem

Furthermore, VELO3D’s non-contact recoater floats over the powder bed, reducing the risk of a part collision. The VELO3D solution also features sensors that continually monitor the height of the part and powder bed to assure a uniform layer of powder and prevent recoater collisions. This means that designers can print up to 3000:1 aspect ratio (virtually limitless) on the VELO3D solution. Thin walls down to 300 micron in thickness, combined with high aspect ratio capability unlock many new designs that optimize heat transfer.

Contact the Metal AM Experts at VELO3D

VELO3D unlocks the power of SupportFree Metal AM Printing for mission critical applications. With the Sapphire Metal AM Printer, Flow print preparation software, and Assure quality assurance and control system, engineers have the means to  print the impossible for higher performing solutions.

Contact our engineers to get started