A Brief History of Unibody Construction

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In light of the news about the updated construction process for the new MacBooks, it is high time you got a brief edumication on the history of unibody construction. It may seem revolutionary, but the method Apple is using derives from the early 20th century monocoque ("single shell") technique of using an object's external skin to support structural loads. It has its roots in the airline industry where a price drop in aluminum in the 1920's made it affordable to meet the demand for stiff, strong, smooth skins that could handle the stress of high altitudes and increasingly powerful aircraft. By the end of WWII, almost all high-performance aircraft were built using monocoque or semi-monocoque technique.


The use of monocoque extended into the realm of automobiles as unibody construction (body is integrated into a single unit with the chassis) starting in 1923 with the Lancia Lambda, but it didn't really take off until Nash Motors released their 600 in 1941. Because the body was constructed as a single unit, Nash produced a vehicle that was not only stronger, but about 500 pounds lighter than a traditional body-on-frame automobile. Today, monocoque or unibody construction is so sophisticated in automobile manufacturing that the windshields often make a significant contribution to the structural strength of the vehicle.

Naturally, the benefits of a stronger, lighter single shell construction have far more applications than just aircraft and automobiles. The technique has also made a significant impact on architecture by allowing designers to eliminate load bearing walls and open up floor plans. Only time will tell if the adoption of the process by Apple will inspire other companies in the computer industry to follow their lead. [Wikipedia]



I think alot of people are missing the big deal about these announcements. It's got to take several minutes to carve one of these chassis from a billet of aluminum. Working backwards from the number of finished notebooks they're making they must have a huge number of CNC milling centers banging these out. I don't know of any mass produced product using this kind of precision machining on this scale. Actually seems pretty impressive.