When uncle Phil said that Apple was using technologies that were new to them to make the Mac Pro, the brunt of his statement was focused on how the cylindrical case of the machine is formed. Here, Apple is using a process known as hydraulic deep draw stamping.
Most metal stampings go through one or two die tools to produce the final shape. With the Mac Pro though, the challenge is to produce a massive amount of plastic deformation without tearing, rippling or deforming the perfect cylindrical surface. To do this, the enclosure is drawn through a series of dies that progressively stretch the aluminum into something approaching the final shape of a Mac Pro.
Deep drawing is a process that very efficiently produces a “net shape” part. Apple could have just chucked a giant hunk of aluminum in a lathe and created the same part, but that amount of metal removal is extremely inefficient. Deep drawing efficiently creates a hunk of metal that is very close to the final shape of a Mac Pro in just a couple of operations. After that, the Mac Pro enclosure is lathe turned to clean up the surface and achieve desired tolerance, polished, placed back in a machining center to produce the I/O, power button and chamfer features and finally anodized.