Question: I’m into D&D and want to create some special character models for my game. Can’t find what I want online so I decided to buy a 3D printer and make my own. But before I spend the money, I thought it would be good to know just how this amazing technology works. Could you explain it at a basic level? I’m not a scientist and can’t follow the online explanations. Thanks. — GG, Lake Geneva, WI
Answer: Sure thing. Thinking about buying one myself so I’ll share what I’ve learned. First thing you should know is that you can 3D-print a wide variety of materials: plastic, metal, ceramic, and even glass. There are also larger industrial-scale 3D printers that can print an entire house! 3D printers that use metals as their material are being used by NASA to build rockets. But the most common (and inexpensive) printers use mono-color plastic to build their output. That should be sufficient for your D&D models. You can always paint them later. More expensive printers can use the CMYK color palette employing four print nozzles. The video above shows a mono-color 3D print of a toy robot, courtesy of: Wiki Commons, RepRapPro Fisher 3D printer.
The first 3D printer originated in 1981, when Dr. Hideo Kodama built one of the first “rapid prototyping machines” that created parts layer by layer. The process is also know as additive manufacturing, as opposed to subtractive manufacturing, like when you use a lathe to carve a screw out of a cylinder of metal. Additive manufacturing is obviously less wasteful.
3D printing is a multi-step process:
- You need to start with a digital 3D model from a CAD (computer aided design) program. Models can be downloaded for many common objects, or purchased online for more complex or custom models, but if want something unique you’ll need to build your own model using CAD. Be forewarned that CAD software has a steep learning curve. Here’s an example model of an aircraft:
- Next you need to use a slicer. That’s a program that can extract slices of the 3D model to create a series of 2D files collectively referred to as G-code. This is a set of instructions that will control the movement of your 3D printer, layer by layer, to create the 3D product. In practice, the slices are usually less than a millimeter thick to provide better resolution. But here’s a low-resolution exaple showing how a slicer works:
- Finally, you’ll need to do the actual print. Depending on printer model, the UI and instructions may vary. But they all follow this basic protocol. You’ll need to:
1. load the G-code into the printer,
2. load the printing material,
3. navigate the UI to confirm G-code and medium are loaded,
4. select speed vs. resolution preferences.
Some complex designs may not be sufficiently self-supporting and require you to toggle a “scaffolding” structure that can later be trimmed off. The time for the print will depend on complexity, of course, as well as the medium chosen. Print time can range from minutes to days.
The printing process involves a layer-by-layer trace of each slice of the 3D model, with the printing material being applied one layer at a time:
3D Printer Academy, Article by Rod Mackay July 11, 2019, Fair Use.
If you’re printing with plastic, only passive cooling is needed before printing the next layer. For heat-intensive processes like sintering or laser heating for ceramics and metals, active cooling may be needed. You must have a solid base before adding the next layer.
Material extrusion works like a glue gun. The printing material is heated until it liquefies and is extruded through the print nozzle. After the printing is finished, every object requires a bit of post-processing. This can range from unsticking the object from the build platform to removing scaffolding to outside finishing.
Is this getting close to Star Trek replicator technology? Not even close! The replicator could create things at the atomic level by assembling individual atoms. All a 3D printer can do is create things by rearranging the molecules of the print material.
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