Apple Computer has filed a patent application (not yet granted!) covering two-shot injection molding. While initial press concerning this patent application refers to it as a patent that covers a two layer molding process common to the iPod and Microsoft’s Zune (see link in Design News), my own reading of the patent application is somewhat different. While it may indeed be broad enough to cover that type of product design, I think it’s geared more towards describing a way to mold very small parts that simply cannot be molded in a single shot. For example, a small part with undercuts may not have room in the tool for the lifters required. This patent application describes a process where the part would be molded in more than one step – some of the features, like walls, would not be molded initially so that the smaller, more challenging features may be molded more easily. A second, or even third, shot would then be used to finish the overall part. I think it’s worth noting that this is just a patent application; an actual patent has not yet been issued as far as I can tell. Still, it’s important to keep this patent in mind when designing plastic parts, to avoid future patent related problems for your employer stemming from what you thought was a very creative way of solving a molding problem. It’s patent application #20070048470.

You might be an engineer if…
(read the rest of this post for the laughs…)
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There’s a good article on managing ordinate dimensions in Pro/E WildFire 2.0 over at Profiles Magazine. More specifically, it details techniques for dealing with lost references, which as you know is not all that uncommon. Rather than recreate all ordinate dimensions on an axes from scratch, this article shows two techniques for replacing the lost references. Click here to read it.

There’s a nice overview of resolving mate errors, over at the SolidWorks website (link). It shows some of the tools available, and reminds me of why I prefer SolidWorks over Pro/E!