The vapor chamber manufacturing process varies depending on whether a stamped (2-piece) or tube (1-piece) design is utilized. Each approach offers distinct advantages and potential drawbacks that engineers should consider.
Shared Vapor Chamber Manufacturing Process Steps
- A fine metal powder is applied to the inner walls of a metal enclosure to create the wick structure.
- The enclosure is then baked in a hydrogen oven at over 900°C, sintering the metal powder to form a porous matrix that enables capillary action for fluid movement.
- A structural support mechanism is incorporated, either in the form of internal posts or a spacer, ensuring mechanical strength and preventing collapse under clamping pressure.
- A fill tube is inserted, and the enclosure is hermetically sealed to prevent leakage and maintain structural integrity.
- The chamber is evacuated to a near vacuum and sealed after a precise amount of working fluid (typically water) is injected through the fill tube to enable efficient phase-change cooling.
2-Piece Stamped Vapor Chamber
Vapor Chamber Manufacturing Process
The traditional method for producing vapor chambers involves two stamped metal plates that closely mirror each other in shape, allowing for a range of designs from a basic square to more complex configurations. Metal posts are usually used as the separating method for the top and bottom halves.
2-Piece Stamped Vapor Chamber
Advantages
- Design Flexibility: Offers a high degree of flexibility in shape, only tempered by the inherent limitations of the metal stamping process. Additionally, design features such as through-holes and embossed pedestals.
- Wick Design Variability: Allows for a high degree of flexibility of wick design within a single device, including varying wick thickness, porosity, and shape.
- Market Availability: Easily accessible in the market.
Disadvantages
- Post-Production Limitations: Generally not bent post-stamping; any small ‘steps’ or bends are done as part of the stamping process.
- Lead Times and Costs: Longer lead times and higher production costs due to the complexity of the manufacturing process.
1-Piece Tube Vapor Chamber
Manufacturing Process
An alternative manufacturing process begins with a large copper tune (25-70 mm diameter). Next, a metal mandrel (column) is inserted into the tube after one end is sealed. Metal powder is poured in and the device is baked.
1-Piece Tube Vapor Chambers
Next, a specially designed spacer which allows for vapor flow while proving structural support is added after the device has been flattened to the required thickness (~3-5mm).
Advantages
- Cost-Effectiveness: Lower cost relative to 2-piece vapor chamber designs as tooling cost is lower and manufacturing process is faster while still achieving higher performance than multi-heat pipe solutions for near cost parity.
- Faster Turnaround Time: Quicker time to prototype and mass production due to a simpler manufacturing process.
- Post-Production Bending: The ability to bend the device post-production into L and U-shapes in the Z-direction increases design flexibility compared to traditional 2-piece designs.
- Dimensional Advantages: These vapor chambers can be as wide as 110mm and offer a width-to-height ratio of 30:1, far exceeding the 4:1 ratio of flattened heat pipes.
Disadvantages
- Shape Limitations: Limited to rectangular shapes due to the nature of the tube-based manufacturing process. However, small cutouts along the edge or corner are achievable. Embossments up to a couple of millimeters are also possible.
- Wick Design Constraints: Offer less wick variation within a single device compared to 2-piece designs; wick thickness, porosity, and permeability need to remain uniform.
- More Susceptible to Deformation: Under Qmax / temperature loading conditions above the specification (roughly 120 oC), this vapor chamber design may begin to bulge.
Contact us to learn more about which vapor chamber manufacturing process is best for your application.
