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Objectives    We will be designing Magma's second Thunderbolt Expansion Chassis that will be able to hold twice as many PCIe cards as their current Thunderbolt PCIe expansion system. When in use, heat builds up inside the system rapidly as each PCIe card emits around 75W so an efficient cooling system is essential to keep the system from overheating. Since this is a consumer product, the system must also be as quiet as possible, satisfy EMF emission standards, and stay at reasonable temperatures. The new design is also required to maintain the same aesthetic and ease-of-use as the current Thunderbolt expansion system as Magma's target demographic is Apple computer users and they want their products to fit in with Apple's aesthetics. Another design consideration is that Magma intends to modify the newly designed chassis to house a hard drive bay as well as a separate product.Design Features• Consistent aesthetic design

• Ability to hot-swap PCI-E cards and fans

• Quiet and efficient cooling

• Small footprint

Design Solution

    Much of the noise and thermal inefficiency was coming from the fan choice in the ExpressBox 3T design so we decided to start there. Since the product is meant to be mass manufactured, the fans we could choose from were limited to commercially available fans. We performed extensive testing of sound levels and mass flow rate on various fans from different brands to find the optimal one for our considerations.

The fans are also set at a 15° angle, which we found through fluid analysis to provide more flow into the crevices between PCIe cards.

We decided to use some of the chassis from the ExpressBox 3T model to save on costs. Aside from doubling the width to account for more PCIe cards, the new ExpressBox 6T would have similar dimensions as the ExpressBox 3T.