You know the term. Maybe you’ve seen some click bait or a dumb listicle (“Ten 3D Printed Things That Will Give You LIFE”). Perhaps you’ve even seen a printer or two in action.
But, prior to making my own 3D printed pieces, I don’t think I would have been able to really tell you exactly how the technology worked- and if I had a dollar for every time a friend or acquaintance sheepishly said, “This is a dumb question… but how does 3D printing really work?”…*
Because here’s the thing: that’s not a dumb question at all, because “3D printing” is sort of a dumb term. It’s a very simplified catch-all for a huge number of very different processes that yield very different results. Take, for example, these orchids:
Two are plastic, two are metal. All four are made in completely different ways. But they all can be marketed as “3D printed.”
Today we’ll cover two of the four ways I used: extrusion and sintering.
TYPE 1: EXTRUSION
Imagine you’re using a glue gun. Now imagine that glue gun is filled with a long-ass plastic string (aka filament), and you’ve been #blessed with the precision and dexterity of a wizard. Visualize the way you would work, methodically, building your creation layer by tiny layer, not unlike those puzzles in the glass cases at Target that your mom would never let you buy.
That’s basically how extrusion (also known as fused deposition modeling (FDM) or fused filament fabrication (FFF)) 3D printing works. The heated nozzle of an FDM or FFF printer lays down tiny beads of melted material that harden immediately. As material is added, it fuses to the existing material, and slowly, step-by-step, the model is built.
Models printed with extrusion printers will require support material to be added to model. Unfortunately, you can’t really 3D print into thin air (yet), so a scaffold has to be built around anything that overhangs- it’s usually printed in a grid or design that, theoretically, makes it easy to separate from your model. At first, I really thought I would enjoy removing support material- I pick at my nail polish constantly and was one of those kids who spread glue on their hands just for the pleasure of peeling it off ten minutes later, so it should be in my wheelhouse- but it’s not as enjoyable as I imagined. I’ve broken a lot of models trying to pry support material off of delicate little branches. But I digress.
In the wild, you’ll encounter at-home machines like MakerBot or Ultimakers that use this tech. They’ll mostly use varying types of plastics. Most common are PLA, which is a biodegradable material made from corn, and ABS, which is less brittle and can handle higher temperatures, but, like, gives off some mildly poisonous gases when extruded??? So… tread with caution?
Less poisonous and more exciting (for me, at least) is the potential FFF holds for edible applications, like….
3D printed pizza anyone? I mean, it looks, like, very terrible, but Rome wasn’t built in a day, right?
“It’s not delivery, it’s 3D printing!”
There’s a printer called the Foodini (Italians, am I right?) that can “print a bean patty, roll, spread cheese sauce onto a fabricated burger, craft pumpkin gnocchi, and [fashion] a pizza.” Also cookies and pancakes. (Note: A bean patty is a weird thing to give top billing. I would lead with the pizza part.) But you get it. The future is now.
And if your two favorite spots at the mall are the Sharper Image and the food court, you’re going to love this next guy. The upstarts at this chocolate 3D printing establishment want to bring their custom confections to a finer shopping center near you -the website is both deeply disturbing and perhaps a bit arousing, so, you know, use your discretion. NSFW, if you work in a classy joint.
So, in a nutshell:
Extrusion/FDM/FFF= glue gun x plastic (lots of kind)/foods (some kinds)
TYPE 2: SINTERING
Sintering is another catch-all term that encompasses a few processes in a lot of materials- plastics, metals, ceramics, sugar- but here it is, in a nutshell:
Imagine you’re that same wizard with the incredible hand-eye coordination from above, but now, instead of a glue gun, you have a laser, and instead of filament, you have a bed of powder- maybe it’s plastic, maybe it’s ceramic, maybe it’s metal. Again, you work layer by layer, shooting your laser at the bed of powder in JUST the right spots, fusing the grains of material, to build your incredibly complex design. Once you’re finished, you sift through the powder for your piece, blow off the extra powder, and hoist it into the air like the triumphant hero you are. There’s a pretty epic video of this moment from the 3D printing platform Shapeways that I would highly recommend that you can view here.
3D printing services, like the aforementioned Shapeways or iMaterialise, use sintering to print their nylon plastic options (at Shapeways, it’s called Strong and Flexible, at iMaterialise, it’s marketed simply as polyamide). It’s got an incredible level of detail, a matte finish, and a surprising level of strength, and well, flexibility. It looks sort of like matte porcelain in its raw state, but it also can be dyed a rainbow of materials and post-processed in a lot of interesting ways. We’ll get to that in another post. Sintering isn’t just for plastic- this same concept can be applied to numerous materials- it’s just more likely that, in the short term, you’ll experience it in plastic before you do anything else.
Sintering= (Lasers shooting around + bed of powder) x plastic/metal/ceramic/more
Jump to Part II, the riveting sequel, in which we’ll discuss how the two metal orchids were made!
*I wouldn’t know because I already would have spent them.