Book Image

Blender 3D Printing Essentials

Book Image

Blender 3D Printing Essentials

Overview of this book

Like computing, 3D printing has been around for decades but it was expensive and was only used for making complex prototypes. Now, prices have dropped and third-party printing services such as Shapeways have become available, making the technology available to everyone.Blender is an open source modeling and animation program popular in the 3D printing community. 3D printing demands more of a modeler than animation or virtual reality. The model maker must engineer their model to work in the real world. They must keep in mind the particular needs of the materials and printers that they are planning to use to print their model. This practical guide gives Blender users all the information they need to design high-quality 3D printed objects. With a solid exploration of the 3D modeling process, design considerations for 3D printing, plus step-by-step exercises, you will soon be comfortable making 3D objects for real-world enjoyment. Starting with an overview of 3D printing, this guide moves onto to precision measurement, fixing problems in a 3D model, and how to make it light and strong enough for real-world use.You will learn how to scale, build, and detail a model for a 3D printer. You will learn to color and decorate it, as well as making parts precisely in the size you want them, so that multi-part objects fit together smoothly. You will also learn tips on saving money when you have printed your model.With the help of this guide, you will be able to complete your project and learn how to export the file so it is ready for a variety of 3D printers.
Table of Contents (12 chapters)

How is a 3D printer controlled?

Generally, the answer is stepper motors. Stepper motors are motors that move in small discrete angles of rotation instead of spinning like most regular motors. This allows you to make definite, easily repeatable motions. It is also one reason why there are minimum sizes on the detail that you can make. A 3D printer can't make detail smaller than one step of the stepper motor.

Then, through wires, drums, gears, and threaded rods, the motion of the stepper motor is scaled to fit the medium that the printer uses. A hobbyist printer that uses a filament of the ABS or PLA plastic that feeds off of a reel will provide the kind of detail that those plastics can support. A high-end stereolithography printer may get much finer detail.

The next graphic is a diagram of the insides of a stepper motor. The rotor is in the center. It rotates and is attached to a shaft that pokes out of the motor. The stators are attached to the outer shell of the motor. They are wrapped with copper wire and an electrical current is run through the wire to give each stator a negative charge, a positive charge, or no charge as indicated in the next graphic. In the graphic, red represents a positive charge, the blue is a negative charge, and the grey has no charge.

The rotor in the center has 50 teeth. The stators around the outside have a total of 48 teeth. It's this imbalance in the number of teeth that allow the stepper motor's rotor to walk around step-by-step.

The positive charge of the rotor is attracted to the stator teeth that are negatively charged. In the following screenshot, you can see that the rotor teeth aren't well aligned with the uncharged stator that is counter-clockwise from the blue stator. To do a single step, the stepper motor controller changes the negative charge from the blue stator in the following screenshot to the stator just counter-clockwise to it. Then, the teeth in the rotor try to align with that stator. So, the rotor moves just a little, a step. To continue moving more steps, the stator with the negative charge keeps moving to the next stator, as follows:


To see how this works, open the interactive 4597_01_StepperDemo.blend file and follow the instructions.

The stepper motor is then attached to a control belt or a shaft with a screw thread to give the printer precise control of the print head and the printing bed. There may be one or more stepper motors controlling a single axis.