Sunday, 24 February 2013

Wait a minute, what the hell is a 3D printer?

Good question!
Many people have already heard of these machines on youtube or the news etc, but just in case I'll make it clear. I'm going to mention these devices often, so I'll do my best to refer to this post when it comes up. I'll also go over some of the terminology I use here.

  A 3D printer is a catch-all term for any type of machine that builds real physical objects from a computer design. It's sort of like a "replicator" from Star Trek -- but very primitive! There are many different kinds and they all work in slightly different ways. The technology has been around for a while, but these machines are only just beginning to reach a build-quality and sale price that is useful for the average designer. Their popularity is starting to bloom.

My company, Monolith Architectural Models, has a 3D printer. It's a V-Flash from 3D Systems. Here's a dorky video. Most of the time I use it for business purposes, but I do sneak in some hobby projects every once in a while. Shhhh!

What do they do? 

They build stuff. Any stuff. If you can model an object in 3D on the computer, you can have a 3D printer make the object for you. No sculpting, no milling, no gluing. Most of them use some kind of plastic material, but there are other options like wax, paper, metal, ceramics, and even chocolate.

How do they work?

Like I said, they are all different, but the general idea is the same. They deposit material in layers, stacking the layers as they go and adding "thickness" to the object. Make sense?
Well think of it like this: Take a ball, and slice it into very thin layers one at a time. The first layer is a very small circle, the next slightly bigger, and so is the next. This carries on until you make it to the middle -- the biggest circle -- then the circles get smaller and smaller until you get to the last slice.
A 3D printer works the same way, depositing material in the shape of the first slice, then building the second slice on top, followed by the next, and the next, and the next, until it's all done.

How the material is placed is the part that is usually different. Some squirt hot plastic droplets close together, some use a UV laser to cure resin liquids into solids, some use a hot laser to fuse powdered particles together, etc... There is more than one way to skin a cat.

How my V-Flash works

I'll explain the process step by step:
Check the Glossary if you don't recognize the terms.
  1. Design an object in CAD.
  2. Save it as an STL file, and send it to the 3D printer.
  3. In the V-Flash software create the build file (place it on the virtual build-pad, rotate it, duplicate it, etc) and then prepare the machine itself by inserting the build pad and cleaning the screens.
  4. Start the build, and come back in a few hours when it's done.
  5. Take the completed build out, clean it, then cure it. 
  6. Remove the build from the build pad and trim off the supports, file/sand the part to the desired finish. 
Sounds easy. Well there are plenty of ways to screw it up. If your CAD file has problems like "multiple shells" or isn't "watertight" it may not turn out very well. Rotating and placing the build properly on the build pad is an art, not a science. If you don't wash it well you'll cure goo all over your nicely printed details. And sometimes the machine throws you for a loop by failing mechanically in some surprising way.
It's a lot of trial and error. Always be prepared for "do-overs" and never leave a build until the 11th hour.

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