3D Printing Explained

You’ve heard of 3D printing from newscasters and journalists, astonished at what they’ve witnessed. A machine reminiscent of the Star Trek Replicator, something magical that can create objects out of thin air. It can “print” in plastic, metal, nylon, and over a hundred other materials.

Fantastical? Yes. True? Yes. Here now? Yes.

We live in an age that is witness to what many are calling the Third Industrial Revolution. 3D printing, more professionally called additive manufacturing, moves us away from the Henry Ford era mass production line, and will bring us to a new reality of customizable, one-off production.

Need a part for your washing machine? As it is now, you’d order from your repairman who gets it from a distributor, who got it shipped from China, where they mass-produced thousands of them at once, probably injection-molded from a very expensive mold. In the future, the beginning of which is already here now, you will simply 3D print the part right in your home, from a CAD file you downloaded.  If you don’t have the right printer, just print it at your local fab (think Kinkos).

3D printers use a variety of very different types of additive manufacturing technologies, but they all share one core thing in common: they create a three dimensional object by building it layer by successive layer, until the entire object is complete. It’s much like printing in two dimensions on a sheet of paper, but with an added third dimension: UP. The Z-axis.

Each of these printed layers is a thinly-sliced, horizontal cross-section of the eventual object. Imagine a multi-layer cake, with the baker laying down each layer one at a time until the entire cake is formed. 3D printing is somewhat similar, but just a bit more precise than 3D baking.

It Begins with a Digital File

In the 2D world, a sheet of printed paper output from a printer was “designed” on the computer in a program such as Microsoft Word. The file — the Word document — contains the instructions that tell the printer what to do.

In the 3D world, a 3D printer also needs to have instructions for what to print. It needs a file as well. The file — a Computer Aided Design (CAD) file — is created with the use of a 3D modeling program, either from scratch or beginning with a 3D model created by a 3D scanner. Either way, the program creates a file that is sent to the 3D printer. Along the way, software slices the design into hundreds, or more likely thousands, of horizontal layers. These layers will be printed one atop the other until the 3D object is done.

Is it 3D Printing or Additive Manufacturing?

The term 3D printing is the common term for the correct manufacturing term of “additive manufacturing.” But 3D printing will remain the term of choice as who really is going to run around saying things like, “I’m going to go additively manufacture a new iPhone case.” No, they are going to “3D print” it. It just sounds so much cooler too, doesn’t it?

There’s no way subtractive manufacturing is going to make something like this in one clean run.

So what the heck is additive manufacturing? Someday soon enough in the future, people will look back and view our current manufacturing processes as we today view something such as blacksmithing. What’s interesting about that last sentence is that much of today’s manufacturing processes are actually very similar to blacksmithing. Both are what’s called “subtractive manufacturing.”

Subtractive manufacturing relies upon the removal of material to create something. The blacksmith hammered away at heated metal to create a product. Today, a CNC machine cuts and drills and otherwise removes material from a larger initial block of material to create a product. It’s inefficient and wasteful. Other manufacturing techniques abound but they all essentially whittle down raw material into a product.

As you’ve already surmised, additive manufacturing creates something by adding material to the object. Some here, some there, and no where it’s not needed. No waste. Very efficient. You’ll read about many types of 3D printers, but no matter the technology involved, it’s additive.

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