With the increasing demand for rapidly growing industries like data centers driven by increased adoption of artificial intelligence (AI) applications, companies are investing in new products like heat sinks and heat exchangers to ensure efficient and reliable operations in this growing infrastructure. Manufacturers like Fotofab are at the forefront of responding to this demand, leveraging their expertise in diffusion bonding and photochemical etching to create the parts essential for the next generation of data centers.

Fotofab, part of The Partner Companies, is a leading provider of diffusion bonding combined with photochemical etching solutions. Fotofab specializes in creating small cavity and microchannel structures within metal parts – a design hard to achieve in traditional manufacturing methods. Fotofab’s use of etching in diffusion bonding processes elevates its capabilities, with diffusion bonding’s robust, solid-state joining, and application versatility allowing it to create different designs concurrently. It is one of the few companies that combines etching & bonding based in the U.S., accredited in ISO 9001: 2015 and AS9100D certifications, and has an International Traffic in Arms Regulations (ITAR) registration.

Given challenges to scale and manufacturability concerns that come with 3D printing and traditional manufacturing methods, Fotofab’s diffusion bonding solutions help develop precise products with tight tolerances, while scaling for cross-industry application, including aerospace and defense, medical, automotive, energy, industrial and electronics.

Understanding Diffusion Bonding

Diffusion bonding is used to create strong, precise structures without the need for filler materials. Manufacturers often turn to diffusion bonding to achieve seamless, high-strength joints in hermetic seals. The process creates embedded structures with complex venting or flow channels, which cannot be created using traditional machining methods. This is an especially important attribute in thermal management applications where diffusion bonding helps maximize heat transfer efficiency through increased surface area while maintaining structural strength.

The solid-state joining process combines etched layers and laminated parts together to form a completely bonded part. Once the layers are etched and aligned in the final stack, Fotofab places them in a vacuum furnace, an inert gas with hydrogen, to ensure there’s no oxidation. The vacuum furnace heats up the metal to approximately 80% of melting point, then applies pressure.

The process of heating and applying pressure causes metallic bond electrons from each layer of metal to be shared with its neighboring layer until the stack is internally joined together. Strong materials and joints are created with 90-95% of the mechanical properties of the parent metal.

On average, it takes two to three layers to create a bonded part, though it can take over a hundred layers to create a larger part, depending on need and application use. This becomes a stronger joining process than many other types of bonds, as the majority of the original material’s strength is maintained.

Diffusion bonding comes with several benefits for parts that require tight intricacies within a larger component, including:

• Stronger, Seamless Joints: While brazing or welding needs a filler material to reach the seam, Fotofab follows a simple metal-to-metal process, which reduces the risk of malfunction in service.
• Design Flexibility Across Manufacturing Methods: Diffusion bonding can be combined with various metallization techniques, be it etching or stamping and machining, to achieve fine and precise features.
• Superior Performance: While diffusion bonding shares similarities to other additive manufacturing methods like 3D printing, its metal-to-metal process produces stronger, more durable parts. Unlike 3D printing, which melts material layer by layer to build a component, diffusion bonding stacks etched metal layers and fuses them together resulting in greater strength for demanding applications. Customers often opt for diffusion bonding over 3D printing as plastics lack thermal and electrical conductivity, and melting and solidification of 3D printed metal often introduces porosity, residual stress and anisotropy. Diffusion bonding’s durability and adaptability makes it ideal for parts that require tight intricacies within a larger part.

 

When selecting between diffusion bonding and other additive or traditional manufacturing methods, customers should weigh factors like the time needed, the part geometry and material properties needed to produce the most reliable product. While different methods have their own strengths and weaknesses, diffusion bonding’s versatility enables Fotofab to serve customers’ unique needs and precise requirements.

Diffusion-Bonded Solutions That Cross Industries and Push Boundaries

Fotofab is one of the few etching companies in the U.S. that supports diffusion bonding designs and offers a pure solid state joining process, serving a variety of industries, from aerospace and defense to the growing presence of electric vehicles (EVs) and data centers. One of Fotofab’s most common use cases for diffusion bonding is microfluidics – small channels for fluids to flow through – used in labs for chip testing and blood testing.

There’s a high demand for diffusion bonding for thermal management parts, including heat sinks and heat exchangers. In heat exchangers, being able to produce small, narrow channels allows the design to increase surface area between areas of heat transfer, increasing efficiency per volume. Thermal management parts are found in fuel cells for EV batteries and bipolar plates in hydrogen generation applications, as well as in data centers to support processing equipment. In data centers, coolant distribution units (CDUs) are being designed to be smaller so heat can be transferred away in localized areas, such as chips. This also allows the CDU to be modular, reducing replacement costs overall. Across all of these use cases, these parts play a crucial role in improving energy efficiency and extending the lifespan of equipment.

On a more specialized scale, Fotofab creates custom components used for analytical instruments such as mass spectrometry, fracking and natural gas and even snow blowing machines used at ski resorts.

Selecting the Best Metals for End Applications

Fotofab works with its customers to select preferred metals, dependent on the material’s mechanical, chemical, thermal and electrical properties. Diffusion bonding can be used in joining a variety of metals, with low-carbon stainless steel as a preferred option across various applications.

Stainless steel is often used for applications in electrical and electronic industries that are exposed to moisture or other corrosive elements. Some benefits of using stainless steel for diffusion bonding include:

• Low cost and accessibility
• Corrosion resistance, which prevents easy rusting
• High structural integrity, making the application hard to shift and bend

 

Given its affordable price, stainless steel is often the first metal used in Fotofab’s research and development process to confirm the design is achievable through etching, stamping and bonding. Once the design is confirmed, Fotofab can shift to exotic metals like titanium, tungsten and molybdenum for full production.

These exotic metals are high in demand, as geopolitical tensions are raising the costs of supplying rare earth elements and leading manufacturers to stock up on materials rapidly. Fotofab is committed to supporting this supply chain, as titanium is a critical reliable source for customers across applications. By leveraging TPC’s globally integrated manufacturing model, Fotofab can source materials at low costs and qualify materials for quality and traceability.

Access to exotic materials is essential for pushing the boundaries of design, and Fotofab is one of the few companies with the expertise to use these materials for their fullest potential – delivering thicker, heavier and more advanced solutions that meet customer requirements and drive innovation.

Fotofab as a Preferred Partner

With the persistent AI adoption driving a need for more data processing centers, Fotofab helps customers adapt to evolving manufacturing issues and trends through its diffusion bonding and photochemical etching services. With diffusion bonding, customers overcome obstacles found in traditional machining methods to contribute to large scale and innovative designs that are more serviceable over time.

For more information and to get in touch with Fotofab, visit fotofab.com.