What in the World Is 3D Printing?

3D printing. To some people these two words might sound as foreign as Algebra to a three year old, while others might have seen, used, or even built a 3D printer. Regardless, 3D printing remains an amazing technology. This tutorial will begin by explaining what 3D printing is, and then continue to describe how a 3D printer works and the various components that a typical 3D printer includes.

Note: Please be sure to enlarge all of the images, as many of them are animated GIF's to enhance your understanding.

Disclaimer: Your mind will be blown after you learn about the true awesomeness of 3D printing.

In the modern dictionary, 3D printing is defined as:

“3D print·ing, noun- a process for making a physical object from a three-dimensional digital model, typically by laying down many successive thin layers of a material.”

This definition is exactly right (duh, it's from a dictionary), and it does a very good job of explaining 3D printing. Let's break down the dictionary's rather dense analysis on 3D printing. First, it says that you can make a "physical object" from a "three-dimensional digital model." Personally, I think that this is a bit of an understatement. With the power of 3D printing, you can make just about anything- from toys to other 3D printers to the limits of your imagination. Before you 3D print something, you must first obtain a 3D model. These models are available in online model libraries such as Thingiverse, or you can design your own model in a CAD program such as Sketchup or Tinkercad. You can even scan existing objects (such as your head) and create a 3D model of them using free software such as 123D Catch.

After you download a 3D model, you use a 3D printing host program such as Repetier-Host or Cura to communicate with your 3D printer through a language known as GCODE. The last part of the definition states that a 3D printer builds the 3D model by "...laying down many successive thin layers of a material." To grasp this essential aspect of 3D printing, set a slice of bread on a table. This slice represents the first layer that your 3D printer extrudes. Now add another slice of bread on top of the first slice. This is similar to layer two on a 3D printer. Now continue adding slices of bread one on top of another, layer by layer. Eventually, you will end up with a whole loaf of bread. The loaf is the equivalent of the completed 3D print, the final product. So, in sum, the process of 3D printing begins with a user choosing or designing a 3D model. They then proceed to download the model into 3D printer software which slices the model into a format known as GCODE. This GCODE is then sent to a 3D printer which constructs the model layer by layer, ending with the final masterpiece.

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What are the parts of a 3D printer?

In other words, what parts on a 3D printer allow the machine to make anything imaginable? It is important to become accustomed to the various components present on a 3D printer so that you will be able to understand help forums and support, build and/or maintain your own 3D printer, teach others, and exhibit your 3D printing geekery. Despite the fact that I will focus on the specific parts of Printrbot 3D printers, all of the following components are present on most 3D printers as well. I like to call the main parts on a 3D printer "The Big Four." These will be highlighted in the upcoming steps.

Almost all 3D printers, laser cutters, and CNC routers rely on the same basic concept of motion- the ability to move on 3 different axes. Remember plotting points on graph paper or a coordinate plane in middle school? 3D printing relies on this same concept for 2D movement. The X axis on a 3D printer is usually the lateral movement left to right (or vice versa), while the Y axis on a printer represents movement forward and back. It is important to recognize that the X and Y axes on a 3D printer only represent the 2D movement. This may sound confusing, but just imagine a piece of graph paper. Paper is flat, rectangular, 2D. Unless you are referring to origami, you can’t add a 3rd dimension to the paper- it is only composed of X and Y axes. The Z axis however adds a 3rd dimension to 3D printers. Instead of just being limited to 2D movement like a normal printer or pen, a 3D printer is able to move up and down.

Unmodified, original image from: www.printrbot.com

The print bed or print surface on a 3D printer is where the first layer of melted plastic is applied by the extruder. A solid, flat, and smooth print bed is essential to 3D printing success. When troubleshooting your 3D printer, checking the print bed and first layer is always a primary step in solving your problem. Print beds can be made of a variety of things based on the type of printing material. On the Printrbot Simple, aluminum and wood beds are used. Heated beds are employed when ABS plastic is printed because they prevent the finicky material from warping, and help it bond better to the bed. Print beds are often covered in blue painter's tape or Kapton tape to help the first layer bond even better.

Before you start 3D printing, your going to need a material to print with. 3D printing material is referred to as filament, and looks similar to weed eater line. For most 3D printers, including Printrbots, thermoplastics such as PLA, ABS, and Nylon are used. After you become a more experienced user, you can experiment with materials such as conductive, wood, and even brick filament.

The extruder and hot end are perhaps the most important parts of 3D printers. Many people refer to these components collectively as "the extruder" but each piece plays a very important role. Filament is fed into the extruder between a drive gear and a bearing. When a motor spins, the drive gear turns, forcing the filament into the hot end. The hot end is a heated chamber that melts the filament as it is forced by the extruder. The melted plastic is then pushed through a small nozzle at the bottom of the hot end. The stringy plastic that comes from the nozzle is combined string by string, layer by layer, to form the complete model.

...and that’s it! Well sort of- there is always more to learn about 3D printing. I hope that you thoroughly enjoyed this tutorial, and have learned the aforementioned “Outcomes and Objectives.”

In sum: 3D printed objects began as a 3D model designed in CAD or downloaded from the Internet. From there, they are sliced into GCODE in a 3D printer host program. After that, the tens of thousands of lines of GCODE are transferred to a 3D printer. Using its three axes, X, Y, and Z, the printer moves in a path according to the GCODE’s instructions. Meanwhile, filament is extruded onto the print bed through the hot end strand by strand, layer by layer. Gradually, the 3D object is created. Finally, when the last GCODE command has been finished, a happy person can pull their object off the print board and feel the fruits of success.

Extra Curriculum and Worksheets:

I have created and attached some worksheets and answer keys if this Instructable will be used in a classroom setting. Print them off and distribute to your eager learners.