How I was wrong about additive manufacturing

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OK, I admit it. I’ve been wrong a few times. I was once thoroughly convinced that Betamax would beat out VHS, which was an expensive lesson. There was my belief that Thomas Crapper invented the flush toilet (the Englishman advocated for improved and installed toilets, but that’s all). And then there was the time I said the Chicago Cubs would never win another World Series.

These were, admittedly, extreme errors in judgment. Sorry about that.

There’s another long-held belief that I’d like to come clean about. I’ve written dozens of times over the past decade or so that 3D printing won’t replace machining, certainly not in my lifetime, if ever. I was wrong. Bigly. That’s because 3D printing already has replaced machining.

Think about all the rapid prototypes printed over the past three decades—parts that would have been machined if not for additive manufacturing. Think about all the low-volume plastic components that emerge complete from SLS and binder-jet 3D printers, eliminating the need for machined plastic-injection molds. For that matter, think about all the molds and mold inserts produced with 3D printing—many of which boast conformal cooling channels, a feature impossible to replicate through traditional manufacturing.

Then think about the tens of thousands (dare I say millions?) of printed metal parts used each year by industries such as aerospace, medical, and, increasingly, oil and gas. Granted, some amount of machining is needed to complete most of these parts—supports must be removed, flat surfaces milled clean, and holes reamed and tapped. Yet this is nowhere near the amount and complexity of machining that would otherwise have been required.

The situation is similar to that of cylindrical and surface grinding. At one time, it was inconceivable that lathes and mills could achieve comparable levels of accuracy and surface finishes, especially on hardened steel parts. Then came CNC lathes and machining centers, which soon became rigid and accurate enough that hard turning and hard milling eliminated much of the grinding machine market.

That same scenario is playing out today. At least one brand of metal 3D printer is promising to eliminate support structures entirely. Several are advertising speeds “up to 100X faster” than traditional 3D printers. All are working to make their wares more accurate, easier to operate, and festooned with ever more capable technologies. How long will it be until parts—even metal parts—begin popping out of 3D printers like snacks from a vending machine, no postprocessing required?

So, it looks as though I was wrong again. It’s not quite as embarrassing as my Cubs prediction, but still I should have seen it coming. Again, sorry about that.