LESSON 4

Preparing your Model for 3D Printing

In this unit you will learn how to set up a 3D print job by creating a G-code file, the different parameters of a 3D print, and tips and tricks for successful prints.

Now that we have a 3D model, we need to set up the print job. The 3D model file exists on your computer simply as digital information. In order to print it, we need to slice the model into directions that the 3D Printer can follow. These directions are known as G-code and are generated by slicing software.

When slicing a 3D model, there are several factors you can control that will influence the performance of your 3D printed object. These include object orientation, object resolution, infill percentage, object shells, and support material.

Step 1: Position the Digital Object

First, open your 3D model (STL file) in the slicing software. When the object appears in the software, orient it on the build platform.

The position of an object on the build platform can have a dramatic impact on the print's end result. The orientation of your print affects print time, success, accuracy, and strength. Orient your model so a flat surface is facing down on the build platform.

The Buildini™ prints in horizontal layers, building the object from the bottom up. As a rule of thumb, fewer vertical layers make for a stronger object that will also print faster.

Step 2: Object Resolution and Layer Height

Just like a digital photograph, a 3D printed object has a resolution. High-resolution photos are made up of densely packed pixels, creating a smooth picture. In contrast, low-resolution photos use fewer pixels, creating a pixelated image.

In 3D printing, object resolution corresponds to layer height, which is measured in millimeters or microns. Smaller layer heights result in higher resolution objects with smooth surfaces but will increase print time.

Below is a chart of different resolutions and the typical layer heights for each classification:

Step 3: Object Shells

Object shells, or perimeters, are the outer layers of the print that make up the walls of your object. The more shells, the stronger your object will be. Use fewer shells for display items, such as sculptures, and more shells for objects that need to withstand pressure or stress, like mechanical parts. Adding shells will also increase print time and material usage.

Step 4: Infill

The object infill refers to the inside structure and density of a 3D printed object. It is measured in percentages, where 100% infill creates a solid object, and lower percentages create lighter, hollow interiors.

Light-use and decorative objects can have lower infill densities (5%-20%), while objects that need to stand up under heavy use should have a higher infill density (20% or higher).

Step 5: Support Material and Raft

Objects with overhangs or bridges that exceed 45° may require support material. Support material acts as a scaffold, and after printing, it can be easily removed. You can also use a raft for better adhesion on objects with small features or challenging material types.

Step 6: Slice and Save

After adjusting your settings, slice your object to generate a G-code file. Save the G-code file to your computer or SD card, and you’re ready to print with your 3D printer!