[starbox] I have been hearing a lot about 3-D printing and how it will revolutionize manufacturing in the United States. Millions are slated to be spent on an advanced manufacturing center here in Chicago just west of the Loop, and bold predictions are made for the number of jobs it will create. The technology is certainly intriguing and the entry price point dropping below $5,000 makes it affordable even for (serious) hobbyists. A local company recently built a scale 1920s Miller race car to showcase the capabilities of the various different 3-D printing methods. A good friend builds large-scale models of famous race cars the old fashioned way — from steel, aluminum and fiberglass — so this Miller model really caught my eye. My model builder thought it was very neat too, but commented that it was “a lot of computer time to make a toy. Probably as many hours as I have in one of my models.” Having observed his projects over the years, I think he has a point. 3-D printing seems to be a new tool that can be used in product development but it doesn’t “do” anything that can’t already be done by conventional means. The biggest limitations that I see are strength and accuracy. Plastic gears and housings have their applications and 3-D printing may be a way to reduce tooling costs for molds. I can’t see the piece cost being low enough to supplant injection molding. My other concern is accuracy. Unconventional means have been used to make gears; we have seen wire EDM (electro discharge milling) produce useable gears at one size (say, 3 inch pitch diameter and 6 diametral pitch) and junk at another size (1 inch diameter and 72 diametral pitch). Where will 3-D printing fall in the accuracy range? Remember when the Segway was touted as the future of personal transportation? Other than a nice way to sightsee tourist areas, it hasn’t lived up to the hype. Before we spend millions of tax dollars and get the public’s hopes up on job creation, perhaps we need a reliable process capability study.