3d Printing

What is it?

So you might have heard the term 3D printing, and it’s okay if you don’t know what it is yet. We are going to explore it in this course together. In general, 3D printing is like regular printing, when you print a document on paper you use two dimensions.  In 3D printing you take a digital model, and when you send it to a printer it results in a physical object.

Have you ever seen someone carve a block of wood or a bar of soap?  That carving is created by removing soap (subtractive) like in the picture.


In 3D printing, the printer does just the opposite! It’s an additive process whereby an object is printed in very thin layers, or slices.

3D printing is also referred to as Rapid prototyping (RP) which is a group of techniques used to quickly fabricate (build) a scale model of a physical part or assembly using three-dimensional computer aided design (CAD) software. Construction or assembly is most commonly done using 3D printers and is also called additive layer manufacturing technology.


A 3D printer receives a print file, just like a conventional printer, and then a filament (most commonly made of plastic) is heated and extruded on a plate in successive layers- sort of like a hot glue gun.  The filament hardens quickly but typically, these files take a lot longer to print than paper!

3 Types of 3D Printing

While many companies manufacture 3D printers, there are three methods that the printers use.

1. Fused deposition modeling – plastic filament is heated and extruded in successive layers

2. Selective Laser Sintering – fine powder is placed and a laser moves over it and fuses it to the layer beneath

3. Stereolithography – photosensitive liquid resin is exposed to ultraviolet light which hardens it

The cheapest, and most readily available to classrooms is fused deposition modeling, and that will be the type that we will use for the lessons in this unit.

There are three ways of printing in 3D that are pictured here by National Geographic: Original image can be seen at


Ways to Create Files

There are now 3D pens. With these devices you can layer an object up by placing the melted plastic in layers. The short video embedded here shows how a 3D pen can be used to create a model.  3D printers do this same thing, but from a digital file and they create an object in layers, or slices.  As you add layers, your piece begins to emerge.

What Kinds of File Formats

The most common and universal file formats for 3D printing are STL and VRML. STL stands for “stereolithography” – it is a 3D rendering that contains only a single color. This is typically the file format you would use with desktop 3D printers. VRML (“vermal”, .WRL file extension) stands for “Virtual Reality Modeling Language” – it is a newer digital 3D file type that also includes color, so it can be used on desktop 3D printers with more than one extruder (i.e. two more nozzles that each can print with a different color plastic), or with full-color binder jetting technology.

Additive Manufacturing File Format (.AMF) is a new XML-based open standard for 3D printing. Unlike STL, it contains support for color. They can also be compressed to about half the size of a compressed STL file. AMF is not widely used, but is expected to grow in the future.

Another file format input for 3D printers in GCode. This file contains detailed instructions for a 3D printer to follow for each slice, like the starting point for each layer and the “route” that the nozzle or print head will follow in laying down the material. In addition, 3D printer manufacturers may have their own proprietary input file formats that contain instructions specific to the methodology for that make or model, and that are compatible only with that manufacturer’s software. This does not create a barrier to printing with these machines, as the proprietary file format is generated from the user’s own STL or WRL file. Some examples include the .form file, used with the PreForm software for Form1 printers, or the .zpr format, proprietary to the ZPrint and ZEdit software used with ZCorp binder jet printers.

*Source: http://3dprint.nih.gov/faqs/1781

Here’s some great Intro videos