I'd love to read a post on your mold making and injection molding adventures.

gonzo · on Dec 31, 2012

Well, the product is a LEGO-compatible case for iPhone 4/4S and iPhone 5, available at smallworks.com. It was my then 12 year-old son's idea.

The first mold, for the iPhone 4/4S) were made in China. The second was for the iPod Touch (4th gen). We've modified the second here in Austin for the iPhone 5.

We use Solidworks to design the part, and then outsource the actual mold design. If it was a two plate mold (just cavity & core), then we would probably do it ourselves, but all three (actually, 2.5, I guess) molds have 3 sliders as well. These require a semi-complex mechanism, and need to be hand fit (with bluing, very old-school/traditional) in order to hold the pressure of the injection molding process.

The pieces for the third mold were all done with EDM, rather than traditional CNC machining.

We do the injection-molding just outside Austin, though I'm considering moving it to Houston.

Duplicating LEGO is about as difficult as it gets in the injection molding world.

Though my degree was in ME, I'm really more of a software guy.

(We're about the same age, btw.)

jacquesm · on Dec 31, 2012

Super stuff man, really. And that's a great idea, your son really got that one right. Amazing story.

I took the liberty of sending out a tweet about this, hope it will get you some sales.

I've worked with a professional moldmaker where we had molds made for the casting of the base/table for a CNC rig (very hard to make a stable rig, lots of interesting postprocessing for hardening).

Molds are fascinating, especially molds for high pressure/high speed injection, the precision and the amount of trickery to deal with warp and cooling are a lifetime of study.

I never quite realized just how much work goes into making molds until I saw it up close, those are very complex devices, far more complex than I ever imagined. Part of the reasons for using EDM rather than regular machining is probably the finish, the precision and the hardness scale of the materials used.