Manufacturers are finding that a revolutionary technology has its limits, writes The Wall Street Journal(June 2, 2014). According to enthusiasts, 3-D printing was supposed to rewrite the rules of how things get built. Forget building new factories, or outsourcing production to China. The compact devices would launch a manufacturing renaissance centered in people’s living rooms and garages. Some makers of 3-D printers don’t argue with the critiques. Devices like MakerBot’s are meant to help designers and engineers test ideas and speed the development of products, not necessarily replace large-scale manufacturing.

The crossover point at which point traditional manufacturing is more effective usually comes at 5,000 pieces. So if a company is making a mass-appeal product with a huge production run, such as a Barbie doll, it would probably stick with injection molding. With injection molding, companies must create a different mold for every different part they want to produce. And if the specifications for a part change, they must come up with a new mold for it. But with 3-D printing, there’s no mold—just a computer model of the part that can be updated at any time. What’s more, 3-D printing can easily handle complex designs and print an item with multiple parts all at once. With injection molding, parts often need to be manufactured separately and then assembled.

3-D printing is also becoming invaluable for military applications. Military hardware can have a working life of 30 years, so it’s far less expensive to 3-D print parts as needed than to keep the necessary tooling around for the entire life cycle of the item. For instance, workers assembling the $116 million Lockheed F-35 jet fighter use hundreds of 3-D printed tools to assemble the plane, with numerous 3-D parts in development.

This post provided courtesy of Jay and Barry’s OM Blog at www.heizerrenderom.wordpress.com. Professors Jay Heizer and Barry Render are authors of Operations Management , the world’s top selling textbook in its field, published by Pearson.