At Apple's special event back in October, the company revealed an updated design for the iMac. Besides the removal of the optical drive, better specifications and the Fusion drive, the 5 mm thickness was the most noteworthy change to Apple's desktop computer. However, it seems that the latter causes some production difficulties, according to some rumours.
The French blog MacBidouille reports that the release date will be pushed into 2013, blaming the iMac's new friction-stir welding process as the culprit. The new design features seamless joints, which are not easy to manufacture. Citing Apple, the process involves a "combination of intense friction-generated heat and pressure to intermix the molecules of the two aluminum surfaces". The design also gets rid of the air between the glass front and the display, which leads to additional manufacturing difficulties, especially for the 27 inch model.
Apple's CEO Tim Cook already expressed concerns over the availability during the company's quarterly earnings conference call, stating: "We will have a significant shortage there." Apple hasn't changed the launch windows for the 21,5 and the 27 inch models of the iMac on the Apple Store, which are November and December respectively.