3D Printing is just like 2D printing on regular paper.
Why is that, you may ask; isn’t 3D printing by definition totally different, introducing a whole other (excuse me) dimension of technology and complexity? How are they comparable?
On a “normal” paper printer, a user first sends the file they want to have printed from the computer to the printer. This file is a two-dimensional image or document; on a 3D printer, the file is a three-dimensional model. However, the process is the same.
The printer (2D or 3D) does not know how to interpret an image, document, or 3D model because it is simply a connected collection of motors, nozzles, and buttons. It is the computer that interprets these files and translates them into specific instructions for the printer to follow. For example, the first commands given a paper printer would be to bring a sheet of paper down to the print area and to move the nozzle to the top left corner of the sheet.
When a paper printer receives these commands, it proceeds to move its ink nozzle around the surface of the paper, depositing ink in the predetermined pattern to form the image provided by the computer. In the same way, a 3D printer simply interprets the commands by moving its nozzle across the bed of the printer and depositing plastic in the predetermined pattern. (3D printers have to melt their plastic as they are placing it though.) However, unlike a paper printer, the 3D printer does not spit out the page after drawing the image on the bed of the printer. Instead, the plastic laid on the bed of the printer becomes the new “paper” or printing surface, and the printer continues to deposit another layer of plastic.
The many layers of plastic needed in a 3D model
The image formed by each layer of plastic can be thought of as a “slice” of the 3D model. All of these slices joined on top of each other forms the product, a functional plastic object.
Just like with 2D printers, 3D printers can print in different colors. However, not only can they print in different colors, they can print in different materials as well. Different plastics have different properties that are desirable for different applications. For example, if I wanted to print a tire for an RC car, I would use flexible filament for its rubbery texture that can grip many surfaces.
The way I see it, 3D printing can do everything that paper printers do and more. This comparison applies to the end use of the products as well. Printed paper is used to store, share, and display information and images. 3D objects do the same thing; there are 3D printed art pieces and educational models all over the internet. However, plastic isn’t just used to make art and information; it can be used for functional purposes as well. This is the magic of 3D printing: you can think of an object, search for it online to try and print it, not find it, make it yourself, and have it, all within an hour.
Edit: Due to unforeseen (see: predictable) circumstances, this explanation has surpassed 500 words. I apologize for any inconveniences caused.