Apple Inc. picked plastic instead of metal for the iPhone 3G's casing, but the trend seems to be reversing. The company is switching from plastic to a "very thin aluminum casing" for its new MacBook laptop, according to CNET.

Apple is not alone. Lenovo makes magnesium aluminum alloy casings for its IdeaPad notebooks, and the new luxury line called "Lamborghini VX3" from Taiwan's Asus primarily uses magnesium as well as some leather [not sure if it's genuine or synthetic]. Click here for the report with nice art.

The metal construction certainly appeals to consumers with an anti-plastic attitude and/or retro tastes. Manufacturers also claim that aluminum casings improve the recycling and environmental credentials.

Production is also a factor. Some laptop brands are switching to metal casings out of fear of short supplies of in-mold roller (IMR) treated plastic casing, a recent Chinese article cited International Data Corp. as saying. But I didn't find such a statement on IDG's English-language Web site.

If you are interested in learning about the top suppliers of electronic product cases, here is a report from VerticalEdge Ltd. Just the executive summary contains a good amount of information, such as:

As for the [laptop] case, the plastic cases are mainly supplied by Ju Teng International Holdings Ltd. and Foxconn Technology Group as well as some relatively small companies, including Everskill Technology Co., Ltd., Huan Hsin Holdings Co., Ltd. and Shengmei Precision Industrial (Kunshan) Co. Ltd. The metal cases are mainly supplied by Foxconn Technology Co. Ltd., Catcher Technology Co., Ltd. and Chongqing Huafu Industry Co.,Ltd.

Background link: my blog item iPhone's plastic casing.