March 23, 2015 by crew
Why Is It Something You Should Care About?
To be perfectly honest, 3D printing is an overrated technology for home use. Do you need a handle for your plastic shopping bags? Not really. Should you print some new knobs for your kitchen cabinets? They won’t be as good as you think. You’d have to have a really convincing reason to print an iPhone cradle when you can buy them from the pound store in a lot less time and with a lot less effort. Don’t get me wrong, it can be cute to make your own Super-Mario-style cookie cutters.
But scale models? Oh-ho-ho, now you’re talking. And what industry is more in need of tabletops full of models than miniature wargaming? OK, maybe model railways, but that’s not my hobby.
The process starts on a computer in a piece of modeling software. Simply put, a 3D model is a collection of triangles that fit together to make a shape. Often these triangles come in twos to make rectangles. With enough of them, you can sculpt any complex object you like.
It’s up to the modeller to decide how much detail they want to put in to it. A building could be represented by a simple cube, or it could be made up 50,000 triangles so that details like cracks in walls and rust on gutters are represented. It’s all about how much time you want to take in it’s construction.
Most 3D models are available to download so, if you don’t have an inclination toward modeling, never fear; there are extensive libraries to draw from.
The transformation from 3D model to real-world starts when you load a model into a piece of software called a slicer. The slicing program decides what’s supposed to be the inside and what is the outside of your model and then shaves layers from the bottom to the top.
Picture the model lying in a deli slicer and wafer-thin cross-sections fall away on the other side. From this, it makes a list of commands to send to the machine for each slice of your model. You can control things like how much structure will be drawn inside of the model or how thick the outside walls of the piece will be.
In this way, “Printing” is a bit of a misnomer. This is actually more like plotting. The commands tell the machine to trace a shape in X and Y, give a slight nudge to the Z, then start tracing the next slice.
Methods of 3D Printing
There are multiple ways to make these slices appear in the real world. Here are three of the most popular methods that apply to us in the hobby at the moment:
FDM or Fused Deposition Modeling – A hot nozzle with a very fine tip is mounted on the end of a system of motor-driven arms or rails that trace the paths from the slicer. A continuous feed of plastic is fed into the nozzle and melted onto the print bed from above where it cools and “fuses” with the rest of the model. This method is good for architectural pieces and larger organic shapes, but not for small organic shapes like figurines.
Stereolithography – The low end (consumer) devices in this range have an inverted print bed that sits in a bath of liquid resin. The resin is hardened by UV light, and the container is clear, so that a blue-ray laser can trace the slices on the underside. After every slice, the print bed moves up. Because we’re talking about lasers, the detail level is very fine and we can use this system for things like figurines.
3D Inkjet Printing (with a binding powder) – This style hasn’t become popular for consumers use yet, but it may do in the future. It’s the style of printing best known for when you send away for prints to be made at a 3D printing company like Shapeways. A thin layer of a powder is spread over a flat surface and an inkjet printhead moves over it, spraying it with a binding agent, and sometimes even a colouring additive. Once a layer is done, a new layer of the powder is spread over top and the process repeats until the print is done. This is one of the only methods where any colour texture you produce with your model can be applied to the model as it is being built.
Choosing a Printer
My personal goal for 3D printing was the desire to fill a gaming table full of terrain. For that reason, I chose FDM printing, which is the more popular style for home use. The price for an FDM printer was within what I called ‘reasonable’. I studied videos about how to use them and what the output was like.
Why did I not choose Stereolithography? It is the highest quality consumer device, after all. Well, from what I understood, these are the reasons it didn’t suit me:
- It took longer to print objects
- It was more prone to failure (midway through a print)
- The printing material was more expensive
- You have to keep the device spotlessly clean
While these are the reasons that helped me make my choice, it is entirely possible that you may have different goals or you are not as concerned with the things that I considered barriers. In which case, do some more research and follow what you think is right.
Then it’s a choice in manufacturer. As with most things you purchase, it comes down to cost versus quality and so this is where reviews are very important to read. I chose the PrintrBot Simple Metal as (at the time) it was reviewing well as a machine that rivaled the quality of printers that cost three times as much.
Another choice that I had to make when I bought my machine was to pay slightly more for a pre-built machine or to construct it myself. It was a hard choice, but I decided to build it myself as I thought that they would only sell kits if it was relatively easy to do. In terms of skill level, it has been compared to building an RC car. Even so, I studied hard, watching numerous build videos that had been made for my specific printer. It was nerve-wracking! I had one issue that I thought would require a new part, but it turned out I had just wired something incorrectly. The build took two hours in total, with three additional hours of problem solving and depression. Followed by extreme happiness!
My printer, the Printrbot Simple Metal, before and after construction:
The next article in this series will be about the issues and considerations you should think about before diving into the world of 3D Printing.
Mail Order Prints (3D inkjet printing):
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"In this way, "Printing" is a bit of a misnomer. This is actually more like plotting..."
"I chose the PrintrBot Simple Metal as (at the time) it was reviewing well as a machine that rivaled the quality of printers that cost three times as much..."