DigiTimes reports laptop makers are adopting fiberglass chassis for ultrabooks as capacity for magnesium-aluminium is fully loaded:
Since ultrabooks are required to only have a thickness of less than 0.8-inch, the chassis will need to be tough in order to sustain pressure and protect internal components and the panel. But as the production of unibody-based magnesium-aluminum chassis requires CNC lathes, capacity is significantly limited.
As the cost of purchasing a CNC lathe is rather expensive, it has created a high threshold for competitors to join. Currently, Taiwan-based Catcher Technology and Foxconn Technology both have more than 10,000 CNC lathes for metal chassis production.